Investigation of per- and poly-fluoroalkyl substances at ......The Site is between Somers and Bittern / Crib Point, approximately 70 km south of Melbourne, Victoria. The Site surrounds

Investigation of per- and poly-fluoroalkyl substances at HMAS Cerberus Detailed Site Investigation Department of Defence Reference: 256337

Revision: 4

9 September 2018

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Aurecon Australasia Pty Ltd ABN 54 005 139 873 Aurecon Centre Level 8, 850 Collins Street Docklands, Melbourne VIC 3008 PO Box 23061 Docklands VIC 8012 Australia T F E W

+61 3 9975 3000 +61 3 9975 3444 [email protected] aurecongroup.com

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Document control

Report title Investigation of per-and poly-fluoroalkyl substances at HMAS Cerberus

Document code VIC_0066_PFAS Project number 256337

Client Defence

Client contact Brian Dunn Client reference

Rev Date Revision details/status Author Reviewer Verifier (if required)

Approver

0 24/04/2014 Draft Issued for Comment MJ ST ST

1 24/05/2018 Updated per Auditor comments MJ ST ST

2 21/06/2018 Updated per Auditor & EPA comments

MJ/SS/APW AA ST


MJ/SS/APW ST ST


MJ/SS/APW ST ST

Current revision 4

Approval

Author signature Approver signature

Name Mike Jorgensen Name Stuart Taylor

Title Project Manager Title Project Director

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Executive Summary – Non-Technical Version Aurecon Australasia Pty Ltd (Aurecon) was engaged by the Department of Defence (Defence) to undertake a Detailed Site Investigation (DSI) of per- and poly-fluoroalkyl substance (PFAS) site conditions on, and near HMAS Cerberus (the Site), which have resulted from the historical use of aqueous film forming foam (AFFF) for fire-fighting and fire-fighting training exercises.

Why were the works commissioned?

The DSI works were commissioned as part of Defence’s review of several of its sites around Australia that used legacy AFFF containing PFAS in its training of Defence personnel. This AFFF was discontinued from use at HMAS Cerberus in 2008.

What were the objectives of the DSI?

The objectives of the DSI were to identify the nature and extent of PFAS in the environment from legacy AFFF use at the Site and any potential risks to people or the environment. The understanding of these potential risks is essential for the development of mitigation strategies to minimise exposure, where necessary.

What was the Site setting?

The Site is between Somers and Bittern / Crib Point, approximately 70 km south of Melbourne, Victoria. The Site surrounds Hanns Inlet, which is situated off the north arm of Westernport Bay. On-Site facilities in the main operating area include temporary accommodation, training (non-fire-fighting) and messing, Base services and support, and recreational areas. The eastern arm of the Site, which is disconnected from the main operating area, contains a permanent residential area, golf course and childcare centre.

Off-Site to the east is fishing, fire tugboat berthing and support facilities, and some residential land. North of Site there is residential land, industrial facilities (BlueScope Steel and Long Island Point petroleum storage and processing facilities), natural bushland, urban reserves, and the closed Crib Point municipal landfill. To the west there is agricultural land for grazing and dairy, residential land and South East Water (SEW) Somers Recycled Water Treatment Plant (RWTP). Further, to the south is residential land, agricultural land and natural bushland leading to Western Port Bay.

What works were completed during the DSI?

The DSI was designed and implemented in accordance with the National Environment Protection (Assessment of Site Contamination) Measure 1999 (as amended in 2013, and hereafter referred to as the ASC NEPM). The ASC NEPM provides a nationally consistent framework for the assessment of site contamination, and has been adopted as the primary guide to the conduct of all similar PFAS investigations of other Defence sites nationally.

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The DSI works were subject to review and audit by an independent Environmental Auditor (credited by EPA Victoria) and were scrutinised by EPA Victoria, who were a key stakeholder and member of the HMAS Cerberus DSI Project Control Group.

The DSI for HMAS Cerberus was undertaken between April 2017 and July 2018 and comprised extensive desktop and field-based investigation works. The desktop works involved the review of existing prior site contamination investigation reports, interviews with relevant Site personnel, conduct of a water use survey within a 1-km radius of the Site, and engagement with on-site and off-site community stakeholders. The manner of this investigation was presented at a Community Walk in Session conducted at Stony Point Community Hall on the 31st August 2017.

The field-based works comprised the sampling and analysis of soil (132 samples), sediment (50 samples), surface waters (81 samples), pore water in sediments (19 samples), groundwater (136 samples), sewage sludge (8 samples), limited terrestrial flora (19 samples) and fish (66 samples).

How did we assess potential risk to people (human health) or the environment?

Screening criteria for the preliminary assessment of potential risk to human health and the environment were primarily adopted from EPA Victoria in its Publication 1669.1, Interim position statement on PFAS, dated November 2017, and the Commonwealth’s PFAS National Environmental Management Plan, dated January 2018, as prepared by the Heads of EPA Australia and New Zealand.

What did the DSI find?

Groundwater flow underlying the Site occurs in a general southerly to easterly direction and discharges into Hanns Inlet. Groundwater from the Site flows away from the adjacent residential and community land areas of Crib point, Bitterns and Sommers, which are predominantly located (up hydraulic gradient) to the west, north and east of the Site

Groundwater quality is generally poor and not suitable for potable use. Groundwater is not extracted for any beneficial use on-Site.

Surface water generally flows along topographical gradients and likewise flows in a general south-easterly direction along two main creek systems (South Creek and East Creek) which in turn discharge to Hanns Inlet

In respect of the nature and extent of PFAS-impacted media

Residual PFAS in soils were identified and generally delineated, with respect to the adopted screening criteria, within and surrounding the key areas where known AFFF use, storage and waste management has occurred; including the Fire Ground (and neighbouring South Creek wetlands) and Fire Station (and nearby Ornamental Lake). These soil (and minor concrete) impacts have in turn caused PFAS impact to surface waters and groundwater within the Site. These surface waters and groundwater provide the transport pathways for ultimate discharge into Hanns Inlet.

Residual PFAS in soils were identified and generally delineated, with respect to the adopted screening criteria, within and surrounding the other potential source areas; including the Former Sewage Treatment Plant (STP), the Sports Fields that were irrigated with PFAS-impacted Class C recycled water, and the Sullage Pit (which contains vegetation and sediment from channel maintenance in Hanns Inlet), some of the former aboveground or underground petroleum storage tanks, and a region of a bushfire along the eastern boundary. Likewise, these soil impacts have in turn caused PFAS impact to surface waters and groundwater within the Site. These surface waters and groundwater provide the transport pathways for ultimate discharge into Hanns Inlet.

While not contributing significantly to the PFAS exposure to receptors, other minor sources (based on elevated surface water or groundwater results) were identified at the closed Rifle Range Road landfill, closed outdoor swimming pool landfill, stormwater drain piping, some of the aboveground

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or underground petroleum storage tanks, the former dry-cleaning facility, coal loading area, and the Fire Ground Water Filter Wash-down Area.

Groundwater impacted by Site derived PFAS sources is generally migrating in a southerly to easterly direction and discharges into Hanns Inlet or interacts with surface water within the tidal creeks within the low lying tidal sections of the Site, which ultimately discharge to Hanns Inlet

The closed Rifle Range Road landfill, the closed outdoor swimming pool landfill, the former dry-cleaning facility, and some fuel storage tank areas were identified as potential minor sources due to PFAS detects in the groundwater above anticipated levels in the groundwater plume. Overall these are minor contributions to the overall quantity of PFAS.

Surface water and sediment within the Site is primarily impacted with Site-derived PFAS however PFAS impacted surface water was reported entering the Site via Council drains from unknown off-Site source(s) at two locations along the northern and western Site boundaries.

Overall the findings of the DSI identify a relatively low but diffuse total mass of PFAS predominantly within the soil, surface water and groundwater within the Site.

A figure demonstrating some of the above site features and observations is presented as follows:

What conclusions are drawn from the DSI

The DSI has been completed in accordance with the NEPM and PFAS NEMP. The current extent of PFAS contamination in terms of sources, pathways and receptors has been defined and therefore the objectives of the DSI have been met

In respect of risk to human health

Residual PFAS concentrations in sampled and tested soil within the operational area did not exceed the adopted screening criteria for the protection of human health (industrial and commercial land uses) and accordingly are not considered a potential risk to human health for Base workers and / or Site visitors

Residual PFAS concentrations in sampled and tested soil, surface water and groundwater within the operational area did exceed the adopted screening criteria for the protection of workers

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undertaking intrusive works, but standard Defence procedures for occupational health and safety reduce the risk to low and acceptable levels

Residual PFAS concentrations in sampled and tested soil within the Sports Fields did not exceed the adopted screening criteria for the protection of human health (public open spaces) and accordingly are not considered a potential risk to human health for Trainees, Base workers and / or Site visitors

There is no evidence of any adverse risk to on-Site Base workers and trainees, Site visitors and/or construction workers in respect of the reported residual PFAS impacts in soils, although caution should be exercised in respect of intrusive works to be conducted within the Fire Ground owing to the uncertainty of residual underlying the current lined ponds

The investigation and sampling of groundwater indicates that there is no evidence of impact to off-site groundwater (considered to be east, north, west and south-west of the Site) from Site-derived PFAS impacts and consequently no potential risk to human health

There is no realistic potential for PFAS impacted groundwater and surface waters to discharge and impact upon on-Site permanent residential areas and Child Care Centre, and off-Site residential and mixed land use areas to the north, west and south-west from the Site-derived PFAS impacts

There is no evidence of adverse risk to consumers of edible fish caught within the confines of Hanns Inlet, although it is identified that access to these waters for fishing purposes is strictly prohibited

In respect of risk to the environment (ecological receptors)

There is evidence of potential risk to the environment (on-Site ecological receptors) by direct exposure and bioaccumulation / secondary poisoning to PFAS-impacted soils and surface waters at the Fire Ground, creek system and neighbouring wetlands, the Fire Station and the Former STP

There is evidence of potential risk to the environment (on-Site ecological receptors) by direct exposure and bioaccumulation / secondary poisoning to PFAS-impacted groundwater discharging to wetlands areas

The primary driver of risk is discharge of PFAS-impacted waters and groundwater to the receiving marine environment within Hanns Inlet, and the potential for adverse impacts to marine biota, although Aurecon notes no adverse risk to consumers of edible fish caught within the confines of Hanns Inlet was identified.

In respect of preclusion of Victorian beneficial uses of land, surface water, and groundwater:

Based on exceedances of respective screening levels the following beneficial uses are precluded:

Land SEPP: Maintenance of ecosystems (MoE) On-Site

Land SEPP: Human health – Intrusive / Maintenance Workers On-Site

Groundwater SEPP: Maintenance of ecosystems (MoE) (99% species protection) On-Site

Groundwater SEPP: Agriculture, parks and gardens On-Site

Groundwater SEPP: Stock watering On-Site

Groundwater SEPP: Industrial water use On-Site

Water SEPP: Aquatic plants and animals (99% species protection) On-Site

Water SEPP: Water suitable for aquaculture and edible seafood On-Site

Water SEPP: Water-based recreation

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Recommendations flowing from the findings of the DSI

Based on the characterisation of the key source areas and the understanding of complete linkages with migration pathways and receptors, it is considered that there is sufficient information to devise risk-based remediation strategies without the need to pursue further and more detailed site-specific assessment of risk to human health and/or ecological receptors.

Consistent with the protocols developed by Defence, the findings of the DSI will be used in the preparation of a PFAS Management Area Plan (PMAP), and as part of the PMAP, an ongoing monitoring plan (OMP) will be proposed.

The primary focus of the PMAP will be on the implementation of appropriate measures to address the ongoing discharge of Site-derived PFAS into Hanns Inlet. In addition, potential management options, such as a combination of engineering and administrative controls, will be set out in the PMAP to mitigate the risks posed by beneficial uses of land, surface water, and groundwater that are precluded because of impact by Site sources of PFAS. The PMAP and OMP will also address the data gaps and material areas of uncertainty from the DSI as identified in Section 12.

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Executive Summary – Technical Version

Identify potential PFAS contamination sources associated with the use, storage and waste managementof legacy AFFF products

Identify, confirm and / or characterise the nature, fate and transport of potential PFAS contamination(vertically and laterally)

Evaluate Site data against Tier 1 screening criteria to determine if PFAS contamination poses a risk suchthat a Site-specific human health and / or ecological risk assessment needs to be undertaken

1 http://www.defence.gov.au/Environment/PFAS/Default.asp 2 http://www.epa.vic.gov.au/PFAS_NMP

Introduction and Background Aurecon Australasia Pty Ltd (Aurecon) was engaged by the Department of Defence (Defence) to undertake a Detailed Site Investigation (DSI) of per- and poly-fluoroalkyl substance (PFAS) site conditions on, and near HMAS Cerberus (the Site), which have resulted from the historical use (practice ceased in 2008) of aqueous film forming foam (AFFF) for fire-fighting and fire-fighting training exercises.

The investigations were commissioned as part of Defence’s review of the historical use of aqueous film forming foam (AFFF) containing PFAS across its portfolio of Defence properties and the implementation of a national plan1 to prioritise Defence properties for preliminary and detailed environmental site investigations. The purpose of the comprehensive investigation program, including this Detailed Site Investigation is to identify and document the nature and extent of PFAS contamination, asses potential risk to human health and ecological receptors, and where necessary develop appropriate risk management actions.

This report presents the findings of the Detailed Site Investigation (DSI) of PFAS at HMAS Cerberus and the immediate surrounding area undertaken by Aurecon between April 2017 and July 2018.

The DSI has been designed and implemented in general accordance with the framework for the assessment of site contamination provided by Schedules A and B of the National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in 2013 (NEPC, 2013), and guidance provided by the PFAS National Environmental Management Plan2 (PFAS NEMP) (HEPA, 2018) and relevant jurisdictional guidance established in in Victoria.

Objectives The objectives of the DSI were to identify the nature and extent of PFAS in the environment from legacy AFFF use at the Site and any potential risks to people or the environment. The understanding of these potential risks is essential for the development of appropriate risk management actions associated with any identified AFFF- sourced PFAS contamination on HMAS Cerberus and surrounding environs, where necessary.

Task specific objectives established by Defence included:

http://www.defence.gov.au/Environment/PFAS/Default.asp

http://www.epa.vic.gov.au/PFAS_NMP

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Undertaking a comprehensive contaminated land investigation and associated risk assessment todetermine whether on and off property community stakeholders have access to safe drinking water thathas not been affected by PFAS sourced from the Site

Identify and assess off-property land and water uses associated with food production for humanconsumption

Identify and provide initial characterisation of non PFAS chemicals of concern both on and off-Site

Ensure that all Site specific-information is captured and retained for use by Defence

Develop a PMAP for the Site to manage PFAS contamination

Develop and implement a detailed Stakeholder and Community Engagement Program to ensurestakeholders are appropriately informed and engaged

Scope of works The scope of works designed and implemented for the DSI is consistent with the ASC NEPM and comprised:

Key action Description

Literature review Review of publicly available and Defence-provided literature and previous investigationreports pertaining to the site and general information on PFAS

Water use survey Undertake a survey of water usage/sources of properties within 1 km of the site boundary Results used to inform whether groundwater is consumed and for what uses to allow

evaluation of potential exposure to Site-derived PFAS

Field work Completion of an intrusive investigation on the Site and surrounding areas to assess thenature and extent of PFAS impact

Collection of field data and sampling and analysis of soil, sediment, sludge, surface water andgroundwater, and limited biota (vegetation and fish) from targeted locations on-site and in thesurrounding areas

The intrusive investigation included:

− Soil sampling comprising analysis of 132 primary soil samples on-site across fourmonitoring rounds to identify and delineate sources

− Groundwater sampling comprising installation of 22 new groundwater monitoring wells and analysis of 136 primary groundwater samples across three monitoring rounds to assess aquifer characteristics and PFAS presence within the groundwater

− Surface water sampling comprising 39 on-site-primary samples, 42 off-site primary samples (collected in Hanns Inlet) primary samples across three monitoring rounds to assess the transport of PFAS in surface water during low and high tide

− Pore water sampling comprising 19 primary samples co-located with sediment samples in Hanns Inlet

− Sediment sampling comprising 30 primary on-site samples and 20 Hanns Inlet samples to assess the accumulation of PFAS in the sediment

− Sludge sampling comprising 8 primary samples from the dried out former sewage treatment plant (STP) lagoons

− Biota (vegetation) sampling comprising 19 primary samples (grass root/sward, algae) collected in conjunction with sampling of soil and surface water

− Biota (fish) sampling comprising 66 primary samples (range of species) collected from Hanns Inlet to assess impact on sensitive ecological receptors

Laboratory analysis

Analysis of recovered samples (including intra- and inter-laboratory duplicates) and rinsateblanks for PFAS

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Assessment of Site investigation results

Comparison of laboratory results with documented Tier 1 investigation levels (the assessmentcriteria)

Discussion of results of sampling and analysis, including an assessment of the potential risksand impacts on human health and the environment

Screening (preliminary) risk assessment based on the identified nature and extent of PFASimpact

Development of a Conceptual Site Model to identify the relevant pollutant linkages Identification of the remaining gaps and uncertainties, and the requirement for further

assessment Establishment of appropriate Site management options, and consideration of remedial

options suitable for breaking the identified relevant pollutant linkages (as part of the PFASArea Management Plan3)

Reporting Prepare a stand-alone document combining both factual and interpretative components of thePFAS investigation that contains data to inform the requirements for future actions, includingmanagement of risk and remedial options

Site Setting HMAS Cerberus is located between Somers and Bittern / Crib Point, on Western Port Bay, approximately 70 km south of Melbourne, Victoria. The Site surrounds Hanns Inlet, which is located off the north arm of Westernport Bay, the latter being an internationally significant wetland listed under the Ramsar Convention on Wetlands.

Land use surrounding the Site includes:

North: residential, industrial facilities (BlueScope Steel and Long Island Point petroleum storage andprocessing facilities), natural bushland, urban reserves, closed Crib Point municipal landfill on Lens St,Bittern.

West: agricultural (grazing and dairy), residential and South East Water (SEW) Somers RWTP.

South: agricultural, residential and natural bushland, Western Port Bay.

East: Hanns Inlet and the North Arm of Western Port Bay, fishing, fire tugboat berthing and supportfacilities, and residential

Topographically, the Site is located within a broad valley that slopes to the south-east towards Hanns Inlet and the North Arm of Westernport Bay. Surface water comes onto Site via several drains along the northern and western Site boundaries which are topographically up-gradient of the Site. Site surface water discharges two tidal creeks (South and East Creek) that drain to Hanns Inlet or directly into Hanns Inlet through the storm-water system and outflows.

Shallow aquifers below the Site fall within a groundwater basin coincident with the local surface-water catchment. These shallow aquifers are predominantly recharged directly by rainfall within the local catchment; and to a lesser degree by irrigation of sports fields or agricultural land. Within the operational area of the Site, standing water levels (SWLs) measured between 2016 and 2017 were typically between 2 and 11 m deep. Shallow groundwater beneath the Site generally groundwater flows to the south or east and discharges directly into Hanns Inlet. Groundwater salinity at and near the Site falls within Segment B (that is, between 1,000 mg/L and 3,500 mg/L of total dissolved salts (TDS), indicating that it is generally not suitable for potable use. Seawater intrusion occurs near the tidal channels south and east of the operational area and along the shoreline of Hanns Inlet.

There is no use of groundwater within the Site.

Groundwater use within the surrounding area (~1km around the Site) was found to be minimal, primarily owing to the presence of reticulated mains potable water supply.

3 The PMAP will be produced as a stand-alone document following finalisation of the DSI.

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The Investigation Area The investigation area (IA) for the intrusive component of the DSI works is identified as including the land within the cadastral boundary of the Site (excluding areas to the south) and the channel and flanking intertidal zone within Hanns Inlet. Note that the southern portion of the Site was excluded from the DSI works owing to the presence of unexploded ordnance (UXO), however it is not considered that this would affect the completeness of the DSI as there are no known or suspected AFFF sources or pathways within this portion of the Site.

AFFF use, storage and waste areas AFFF use and storage historically occurred within the Fire Training Ground and the Fire Station (and

adjacent Ornamental Lake). AFFF residue in fire-fighting equipment and hoses was inferred to havebeen used on one occasion to fight a bushfire along a portion of the eastern Site boundary. The use ofAFFF in the immediate vicinity of four underground fuel storage tanks could not be conclusivelyestablished.

AFFF waste disposal (i.e. the disposal or discharge of AFFF and/or AFFF packaging) is understood topotentially occurred within one of the five historical landfills identified on site, as well as historic dischargeto the historic sewerage treatment plant, and the burial of organic matter (sourced from the clearing of thechannel within Hanns Inlet) within the sullage pit.

Other sources of PFAS include potential historical AFFF sourced PFAS present within recycled waterprovided by South-East Water and used to irrigate sporting fields within the Site.

DSI Findings – nature and extent of AFFF PFAS impacted media The DSI results show that the main primary PFAS soil source areas are:

The Fire Ground

Wetlands nearby to the Fire Ground straddling South Creek (South Creek wetlands), which historicallyreceived PFAS discharges from the Fire Ground.

A lesser primary PFAS source area of impacted soil and sediment is at the Fire Station and nearby Ornamental Lake.

Minor soil source areas were identified at:

Former STP and associated settling lagoons

Sports fields irrigated with Class C recycled water

Sullage Pit

An isolated area of PFAS soil impact near the north-eastern land boundary was identified in a region near to bushfires in the 1990’s where AFFF residue may have been present in firefighting equipment.

While not contributing significantly to the PFAS load to receptors, other minor sources (based on elevated surface water or groundwater results) were identified at the closed Rifle Range Road landfill, closed outdoor swimming pool landfill, stormwater drain piping, some of the aboveground or underground petroleum storage tanks, the former dry-cleaning facility, coal loading area, and the Fire Ground Water Filter Wash-down Area.

Samples from the remainder of the Site reported non-detect to negligible PFAS concentrations in soil that were not indicative of source areas.

The nature and extent of PFAS-impacted media reflects migration of PFAS away from the identified source areas via surface water and groundwater. The lateral and vertical extents of detected PFAS was generally defined around each source area except for the primarily vertical extent of impact below the Fire Ground lagoon where access for intrusive investigations beneath the lagoon was limited due to access restrictions.

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The principal PFAS component of these soil impacts is PFOS, where the total interpolated PFOS mass in soil is an order of magnitude above PFHxS total mass and three orders of magnitude above PFOA total mass. Most of this mass is contained in shallow soils around the Fire Ground and nearby wetlands.

All results for soil samples recovered during the Aurecon DSI and the prior Golder works programs were below the Tier 1 screening level for PFOS for the relevant land use scenarios, except for exposure to intrusive workers and ecosystems. For the objectives and purposes of the DSI, it is considered that adequate delineation of the extent of PFAS impact at each of the main sources of PFAS at the Site has been achieved.

The interpolated volumetric mass of total PFAS in Site soils as defined by the extent of the analytical data set is estimated as:

Total PFOS in soil = approximately 60 kg in 750,000 m3 of soil

Total PFOA in soil = approximately 0.06 kg in 6,000 m3 of soil

Total PFHxS in soil = approximately 3 kg in 160,000 m3 of soil

- Total PFOS in groundwater = approximately 2 kg in 9,800,000 m3 of water

- Total PFOA in groundwater = approximately 0.1 kg in 2,700,000 m3 of water

- Total PFHxS in groundwater = approximately 2 kg in 21,850,000 m3 of water

With regards to the distribution of PFOS between soil and groundwater, of the total PFOS mass in soil, 19% of this is residing in the saturated zone, and of the PFOS mass in the saturated zone 20% of that is the total PFOS mass in dissolved in groundwater. This is consistent with the relatively slow movement of PFOS in groundwater that has been observed and the confinement of the PFOS plume to the western section of the base. Without source area abatement these impacts are likely to continue, however the results indicate migration in groundwater is slow and the extent of physical attenuation could be high.

The majority of the observed PFOS and PFHxS is present within the unsaturated (vadose) zone soils (~80%), whilst the majority of the PFOA is observed in the saturated zone soils (~66%).

The Site is situated at the bottom of the local water catchment. Hence, from the higher portions of the water catchment surrounding the Site, both surface water and groundwater pass through the Site before discharging to either Site drainages or directly into Hanns Inlet.

Groundwater impacted by Site derived PFAS sources is not migrating towards off-Site groundwater wells located east, west and north of the Site. These areas are located hydraulically up- or cross-gradient from the Site sources of PFAS. Therefore, a complete groundwater pathway does not exist between Site sources of PFAS and groundwater users located west and north of the Site.

The lateral and vertical extent of PFAS-impacted groundwater has been defined up to discharge points into surface waters either within the Site creek systems or directly to Hanns Inlet. The PFAS plume originating at the Fire Ground migrates towards and discharges into the creek south of the Fire Ground. At the Fire Station and Ornamental Lake, PFAS-impacted groundwater discharges into Hanns Inlet. In the marina area, a source of PFAS, which may originate from the Sports Fields that historically received Class C recycled water, has impacted groundwater that is migrating through both the fill aquifer and the uppermost saturated interval of the Brighton Group aquifer, which discharges into Hanns Inlet. Visualisation of the plume (refer to Section 11) highlighted potential minor sources including the Sullage Pit, closed Rifle Range Road landfill, closedoutdoor swimming pool landfill, some of the fuel storage areas, and the former dry-cleaning facility. Theseareas were identified as potential minor sources during data visualisation due to PFAS detects in thegroundwater above anticipated levels in the groundwater plume. However, there is no evidence of AFFFstorage or use in these areas from desktop review and interviews. Overall, these are minor contributions tothe PFAS mass loading.

PFHxS groundwater impacts originating from the identified source areas are forming a contiguous plume across the Site, whilst PFOS groundwater impacts are confined to a plume covering the western extent of the base infrastructure with two smaller isolated plumes in the eastern area of the base adjacent to Hanns Inlet. PFOA groundwater impacts are confined to a small contiguous plume between the Fire Ground and the wetlands straddling South Creek near the Fire Ground.

The interpolated volumetric mass of total PFAS in Site groundwater as defined by the extent of the analytical data set is estimated as:

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Surface water within the Site is primarily impacted with Site-derived PFAS, however PFAS impacted surface water was reported entering the Site from unknown off-Site source(s) at two locations along the northern and western Site boundaries. In response to local rain events, the calculated approximate flux of total PFAS entering the Site from these unknown off-Site source(s) is approximately 0.12 gm/day (120 mg/day). Impacted Site surface water discharges to tidal creeks that drain to Hanns Inlet or directly into Hanns Inlet through the storm-water system and outflows. The calculated flux of total PFAS discharging into the tidal creeks or directly to Hanns Inlet is approximately 0.8 g/day (800 mg/day).

Surface water in the western and central portions of Hanns Inlet is impacted by PFOS. Results for samples collected from the water column in these areas exceeded the Tier 1 direct toxicity screening level for PFOS for 99% species protection in marine ecosystems. PFAS was not detected in the eastern portion of Hanns Inlet (at the opening of Hanns Inlet into Western Port Bay).

Overall the findings of the DSI identify a relatively low but diffuse total mass of PFAS predominantly within the soil, surface water and groundwater at the Site.

DSI Findings – risk to human health and the environment Based on the findings of the DSI, the following conclusions are made in respect of risk to human health and the environment:

Human Health

The investigation and sampling of groundwater indicates that there is no evidence of a complete pathwaybetween Site sources of PFAS to off-Site groundwater users (considered to be east, north, west andsouth-west of the Site) from Site-derived PFAS impacts. Consequently, there is no potential risk to humanhealth

There is no realistic potential for PFAS-impacted groundwater and surface waters to discharge andimpact upon on-Site permanent residential areas and the Child Care Centre

There is no evidence of adverse risk to consumers of edible fish caught within the confines of Hanns Inlet,although it is identified that access to these wasters for fishing purposes is strictly prohibited

There is no evidence of any adverse risk to on-Base non-intrusive workers or Site visitors.

Intrusive/maintenance workers:

− Reported residual PFAS impacts in soils at the Fire Ground and South Creek wetlands, surface waterat the Fire Ground lagoon, and groundwater at the Fire Ground/South Creek pose an unacceptable risk to workers undertaking intrusive works.

− Note that the residual risk would be low and acceptable because intrusive/maintenance works would be undertaken under standard Defence OHS and construction environmental management plans.

− These administrative controls would manage the risk posed by intrusive works across the Site including works conducted within the key PFAS source areas (Fire Ground and wetlands, Fire Station / Ornamental Lake and Former STP) and address any uncertainty of PFAS impact in other areas at the Site.

Environment

There is evidence of potential risk to the environment (on-Site receptors) by direct exposure andbioaccumulation / secondary poisoning to PFAS-impacted soils and surface waters at the Fire Ground,creek system and neighbouring wetlands, Fire Station / Ornamental Lake, and the former STP

There is evidence of potential risk to the environment (on-Site receptors) by direct exposure andbioaccumulation / secondary poisoning to PFAS-impacted groundwater discharging to wetlands

The primary driver of risk is discharge of PFAS-impacted waters and groundwater to the receiving marineenvironment within Hanns Inlet, and the potential for adverse impacts to marine biota, although Aureconnotes no adverse risk to consumers of edible fish caught within the confines of Hanns Inlet was identified.

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Victorian beneficial uses of land, surface water, and groundwater











Next steps Based on the characterisation of the key source areas it is considered that there is sufficient information to devise risk-based remediation strategies without the need to pursue further and more detailed site-specific assessment of risk to human health and/or ecological receptors.

Consistent with the protocols developed by Defence, the findings of the DSI will be used in the preparation of a PFAS management area plan (PMAP), and as part of the PMAP an ongoing monitoring plan (OMP) will be developed. The primary focus of the PMAP will be on the implementation of appropriate measures to address the risk posed by ongoing discharge of Site-derived PFAS into Hanns Inlet. In addition, potential management options, such as a combination of engineering and administrative controls, will be set out in the PMAP to mitigate the Site conditions that have precluded beneficial uses of land, surface water, and groundwater.

The PMAP and OMP will also address the data gaps and material areas of uncertainty identified by the DSI. Aurecon is currently developing the PMAP, which will be endorsed by the appointed Environmental Auditor and EPA Victoria prior to implementation.

Contents Executive Summary – Non-Technical Version ....................................................................................... i Executive Summary – Technical Version ............................................................................................. vi

Introduction and Background ................................................................................................... vi Objectives ................................................................................................................................ vi Scope of works ....................................................................................................................... vii Site Setting .............................................................................................................................. viii The Investigation Area ............................................................................................................. ix AFFF use, storage and waste areas ........................................................................................ ix DSI Findings – nature and extent of AFFF PFAS impacted media ......................................... ix DSI Findings – risk to human health and the environment ...................................................... xi Next steps ............................................................................................................................... xii

1 Introduction .......................................................................................................................................... 1 1.1. Context of the investigation program ........................................................................................ 1 1.2. Framework of the investigation program .................................................................................. 1 1.3. Per- and Poly- Fluoroalkyl Substances .................................................................................... 3 1.4 Purpose and objectives ............................................................................................................ 3

1.4.1 Key objectives ........................................................................................................... 3 1.4.2 Task Objectives ......................................................................................................... 4

1.5 Scope of Work .......................................................................................................................... 4

2. Site Identification ................................................................................................................................. 6 2.1. Site details ................................................................................................................................ 6 2.2. Investigation Area ..................................................................................................................... 6 2.3. Site operations and features .................................................................................................... 7

2.3.1. Site features .............................................................................................................. 7 2.4. Site infrastructure ................................................................................................................... 12

2.4.1. Water supply ............................................................................................................ 12 2.4.2 Sewer ...................................................................................................................... 12 2.4.3 Drainage .................................................................................................................. 13 2.4.4 Current and historical storage tanks ........................................................................ 13 2.4.5 Other relevant current and historical infrastructure ................................................. 14

2.5. Surrounding land use ............................................................................................................. 15 2.5.1 Summary of surrounding land use .......................................................................... 15 2.5.2 Potential surrounding sources of PFAS .................................................................. 15

3. Environmental Setting ...................................................................................................................... 16 3.1. Ecological setting .................................................................................................................... 16 3.2. Climate ................................................................................................................................... 16

3.3. Geology .................................................................................................................................. 17 3.4. Surface water ......................................................................................................................... 19

3.4.1. Topography and Bathymetry ................................................................................... 19 3.5. Hydrogeology ......................................................................................................................... 21

3.5.1. Regional Hydrogeology ........................................................................................... 21 3.5.2. Local Hydrogeology ................................................................................................. 21 3.5.3. Aquifer water quality ................................................................................................ 22 3.5.4. Surrounding groundwater uses (bores) ................................................................... 22 3.5.5. Water Use Survey ................................................................................................... 23

4 AFFF use, storage and waste management ................................................................................... 25 4.1. Information sources ................................................................................................................ 25

4.1.1. Interviews with key Base personnel ........................................................................ 25 4.1.2. Prior reports ............................................................................................................. 26 4.1.3. Base CSR ................................................................................................................ 26

4.2. AFFF use and storage areas .................................................................................................. 29 4.2.1 Fire Ground (VT0067) ............................................................................................. 29 4.2.2 Fire Station / Ornamental Lake ............................................................................... 33 4.2.3 Underground and Aboveground Storage Tank areas ............................................. 33 4.2.4 Emergency response use ........................................................................................ 34 4.2.5 Other areas of potential use and storage ................................................................ 34

4.3. AFFF waste management ...................................................................................................... 35 4.3.1. On-Site Landfilling ................................................................................................... 35 4.3.2. Other AFFF waste disposal ..................................................................................... 36 4.3.3 Site history summary ............................................................................................... 38

4.4 Non-AFFF PFAS sources ....................................................................................................... 40 4.5 Summary of previous Site investigations ............................................................................... 40

4.5.1 Background information and previous investigations .............................................. 40 4.5.2 Previously identified PFAS contamination .............................................................. 41 4.5.3 Previously identified PFAS receptors ...................................................................... 43 4.5.4 Previously identified non-PFAS contamination ....................................................... 45 4.5.5 Use of historic data in current investigation ............................................................ 45

5 Conceptual Site Model ...................................................................................................................... 46 5.1 Known and potential sources ................................................................................................. 46 5.2 Known and potentially affected media .................................................................................... 48 5.3 Known and potential human and ecological receptors ........................................................... 50 5.4 Potential and complete exposure pathways ........................................................................... 52

5.4.1 Human health .......................................................................................................... 52 5.4.2 Ecological ................................................................................................................ 54

5.5 Conceptual Site Model Visualisation ...................................................................................... 57 5.6 Data gaps and uncertainty ..................................................................................................... 67

6 Beneficial uses and assessment criteria ........................................................................................ 68 6.1 Assessment Framework ......................................................................................................... 68

6.1.1 Commonwealth Legislation, Regulation and Guidance .......................................... 68 6.1.2 Victorian Legislation, Regulation and Guidance ..................................................... 68

6.2 State Environment Protection Policies ................................................................................... 68 6.2.1 Land State Environment Protection Policy .............................................................. 69 6.2.2 Groundwater State Environment Protection Policy ................................................. 69 6.2.3 Waters of Victoria State Environment Protection Policy ......................................... 72

6.3 Site-specific beneficial uses ................................................................................................... 76

6.4 Relevant standards and guidelines ........................................................................................ 76 6.5 Environmental Protection Agency and International Guidelines ............................................ 76

6.5.1 Soil ........................................................................................................................... 77 6.5.2 Groundwater and surface water .............................................................................. 78 6.5.3 Sediment ................................................................................................................. 79 6.5.4 Sewage sludge / biosolids ....................................................................................... 79 6.5.5 Biota (seafood) ........................................................................................................ 79 6.5.6 Grass ....................................................................................................................... 79

6.6 Adopted screening criteria ...................................................................................................... 79

7 Fieldwork, laboratory and analysis methodology .......................................................................... 82 7.1 Data Quality Objectives .......................................................................................................... 82

7.1.1 Data quality objectives............................................................................................. 82 7.1.2 Data quality indicators for field data ........................................................................ 85 7.1.3 Data quality indicators for laboratory data ............................................................... 86

7.2 Sampling, Analysis and Quality Plan ...................................................................................... 87 7.3 Quality Assurance and Quality Control .................................................................................. 87 7.4 Sampling methods .................................................................................................................. 87

7.4.1 Monitoring well installation and soil sampling ......................................................... 88 7.4.2 Groundwater sampling ............................................................................................ 88 7.4.3 Surface water sampling ........................................................................................... 88 7.4.4 Sediment and sludge sampling ............................................................................... 89 7.4.5 Porewater sampling ................................................................................................. 89 7.4.6 Biota (vegetation) sampling ..................................................................................... 89 7.4.7 Biota (fish) sampling ................................................................................................ 89

7.5 Data management and analysis methods .............................................................................. 89 7.5.1 Data Management ................................................................................................... 89 7.5.2 Data interpolation and visualisation ......................................................................... 90

8 Sample design ................................................................................................................................... 91 8.1 Site investigation rationale ..................................................................................................... 91

8.1.1 Introduction .............................................................................................................. 91 8.1.2 Sampling program ................................................................................................... 91

8.2 Program .................................................................................................................................. 92 8.3 Sample locations .................................................................................................................... 93 8.4 Soil .......................................................................................................................................... 93 8.5 Groundwater ........................................................................................................................... 94 8.6 Surface water, sediments and sludge .................................................................................... 94 8.7 Biota (vegetation) ................................................................................................................... 95 8.8 Biota (fish) .............................................................................................................................. 95

9 Data quality assessment................................................................................................................... 97 9.1 Quality assurance and quality control procedures ................................................................. 97 9.2 Assessment of data quality indicators .................................................................................... 97

10 Investigation results .......................................................................................................................... 98 10.1 General ................................................................................................................................... 98 10.2 Soil investigation ..................................................................................................................... 99

10.2.1 Soil types ................................................................................................................. 99 10.2.2 Geology ................................................................................................................... 99 10.2.3 Field observations ................................................................................................... 99 10.2.4 Background concentrations ................................................................................... 100 10.2.5 Soil laboratory results ............................................................................................ 100 10.2.6 Impacts to Beneficial Uses .................................................................................... 104

10.3 Groundwater investigation .................................................................................................... 105 10.3.1 Monitoring well installation .................................................................................... 105 10.3.2 Field observations ................................................................................................. 105 10.3.3 Groundwater elevation and flow direction ............................................................. 105 10.3.4 Horizontal hydraulic conductivity ........................................................................... 109 10.3.5 Field measured groundwater chemistry parameters ............................................. 110 10.3.6 Major ion composition and groundwater types ...................................................... 110 10.3.7 Background PFAS concentrations ........................................................................ 113 10.3.8 Groundwater analytical results .............................................................................. 114 10.3.9 Impacts on Beneficial Uses ................................................................................... 118

10.4 Surface water, sediment, sludge and pore water investigation ............................................ 119 10.4.1 Field observations ................................................................................................. 119 10.4.2 Field measured surface water chemistry parameters ........................................... 120 10.4.3 Background concentrations ................................................................................... 121 10.4.4 Surface water laboratory results ............................................................................ 121 10.4.5 Sediment and sludge laboratory results ................................................................ 127 10.4.6 Pore water laboratory results ................................................................................ 129 10.4.7 Tap water laboratory results .................................................................................. 129 10.4.8 Impacts to Beneficial Uses .................................................................................... 130

10.5 Biota (grass) investigation .................................................................................................... 130 10.6 Biota (algae) investigation .................................................................................................... 131 10.7 Biota (fish) investigation ....................................................................................................... 131

11 Tier 1 Risk Assessment .................................................................................................................. 132 11.1 Delineation of key sources ................................................................................................... 132 11.2 Soil impacts .......................................................................................................................... 132

11.2.1 Fire Ground ........................................................................................................... 136 11.2.2 Fire Station ............................................................................................................ 138 11.2.3 Fire Ground South Creek Wetlands ...................................................................... 138 11.2.4 Former STP ........................................................................................................... 139

11.3 Groundwater impacts ........................................................................................................... 140 11.3.1 Fire Ground ........................................................................................................... 144 11.3.2 Fire Ground – South Creek wetlands .................................................................... 146 11.3.3 Fire Station ............................................................................................................ 146 11.3.4 Former STP ........................................................................................................... 146 11.3.5 Sports Fields .......................................................................................................... 146 11.3.6 Sullage Pit ............................................................................................................. 147 11.3.7 Potential minor sources indicated by groundwater impacts .................................. 147

11.4 Surface water and sediment (sludge) impacts ..................................................................... 147 11.4.1 Fire Ground ........................................................................................................... 147 11.4.2 Former STP ........................................................................................................... 148 11.4.3 Fire Station ............................................................................................................ 148 11.4.4 Hanns Inlet ............................................................................................................ 148 11.4.5 Storm-water drainage ............................................................................................ 149 11.4.6 Tap water (effluent and potable supplies) ............................................................. 149

11.5 Summary of key sources ...................................................................................................... 150 11.6 Transport pathways .............................................................................................................. 151

11.6.1 Groundwater/Soil Impact Interfaces ...................................................................... 151 11.6.2 Groundwater/Surface Water Interaction ................................................................ 151 11.6.3 Volumetrics Cases and Source Area Persistence ................................................ 151 11.6.4 Evaluation of PFAS fluxes via surface-water drain flows ...................................... 152

11.7 Receptors of concern ........................................................................................................... 154 11.8 Refined Conceptual Site Model ............................................................................................ 156

12 PFAS Management .......................................................................................................................... 165 12.1 Identified risk management measures ................................................................................. 165 12.2 Data gaps and additional monitoring .................................................................................... 167

12.2.1 Data gaps .............................................................................................................. 167 12.2.2 Additional monitoring ............................................................................................. 167

13 Conclusions and next steps ........................................................................................................... 168 13.1 Conclusions .......................................................................................................................... 168

13.1.1 Determine the nature and extent of AFFF PFAS impacted media ........................ 168 13.1.2 Evaluate the risk posed by such impact to human health and the environment ... 170 13.1.3 Evaluate the requirement to undertake further, more detailed site-specific risk

assessment studies and / or implement strategic site management strategies. ... 171 13.2 Next steps ............................................................................................................................. 172

14 Statement of limitations .................................................................................................................. 173 15 References ....................................................................................................................................... 174

Appendices Appendix A

Figures

Appendix B Sampling Methods

Appendix C Borehole Logs

Appendix D Photographic Record

Appendix E Field Data

Appendix F Summary of Laboratory Results

Appendix G Laboratory Certificates

Appendix H QA/QC Results

Appendix I Pre-DSI Laboratory Certificates

Appendix J Cross Sectional Diagrams

Appendix K Survey Data and Reports

Figures Figure 1-1 General area for the Detailed Site Investigation indicating the location of the Site Figure 1-2 ASC NEPM general process flowchart Figure 2-1 Investigation area for the intrusive component of the DSI works Figure 2-2 HMAS Cerberus Zone Plan showing the operational area Figure 2-3 Aerial photograph indicating Site details Figure 3-1 HMAS Cerberus Mean Monthly Rainfall 1986 – 2018 (Cerberus BOM Station 086361) Figure 3-2 Surface geology map of HMAS Cerberus Figure 3-3 Surface water catchment (purple line) and topographical (black contours) map of HMAS Cerberus

where Site boundary is indicated by yellow line. Figure 3-4 Regional groundwater flow – Tertiary Brighton Group aquifer (Lakey 1980) Figure 4-1 Contaminated Site Register details and key Site features Figure 4-2 Current layout of the Fire Ground operational area Figure 4-3 Fire Ground Historical Aerial Imagery – 1968 & 1985 Figure 4-4 Fire Ground Historical Aerial Imagery – 1992, 1993 & 2015 Figure 4-5 Sullage Pit fill area for spoils received from reinstatement of channel in Hanns Inlet Figure 4-6 Area of sediment removed from Hanns Inlet and transferred to the Sullage Pit Figure 4-7 Timeline summary of Site history (PFAS related) Figure 4-8 Locations of Preliminary Samples of Surface Water (GHD, 2016) Figure 5-1 Visualisation of the Conceptual Site Model at the Fire Ground (Exposure pathways and receptors) Figure 5-2 Visualisation of the Conceptual Site Model at the Fire Station (Exposure pathways and receptors) Figure 5-3 Visualisation of the Conceptual Site Model at the Former Sewage Treatment Plant (Exposure

pathways and receptors) Figure 5-4 Visualisation of the Conceptual Site Model at the Sullage Pit (Exposure pathways and receptors) Figure 5-5 Visualisation of the Conceptual Site Model at the Sports Fields (Exposure pathways and

receptors) Figure 5-6 Visualisation of the Conceptual Site Model at the potential minor sources (Exposure pathways

and receptors) Figure 5-7 Visualisation of the Conceptual Site Model at the Bushfire Area (Exposure pathways and

receptors) Figure 5-8 Visualisation of the Conceptual Site Model at the Hanns Inlet Sediment and Pore Water

(Exposure pathways and receptors) Figure 5-9 Visualisation of the Conceptual Site Model at the storm-water drains (Exposure pathways and

receptors) Figure 10-1Brighton Group aquifer inferred groundwater flow contours – March-May 2018 Figure 10-2Stony Point tide heights – 29 June 2018 to 3 July 2018 Figure 10-3Data-logged Groundwater Elevations – Wetlands South of the Fire Ground Figure 10-4Data-logged Groundwater Elevations –South Creek at the closed Rifle Range Road landfill Figure 10-5 Piper Plot Figure 11-1 PFOS + PFHxS in Soil above 2 µg/kg Figure 11-2 PFOS + PFHxS in Soil above human health low density residential screening criteria (HHSV 1;

9) Figure 11-3 Fire Ground PFOS in Soil above 50 µg/kg Figure 11-4 PFOS in groundwater above Drinking Water Guidelines (0.07 µg/L) Figure 11-5 PFOS in groundwater above Human Health Recreational Guidelines (0.7 µg/L) Figure 11-6 Fire Ground Interpolated Soil PFOS Impacts with Groundwater Level Figure 11-7 Fire Ground Interpolated Soil PFHxS Impacts with Groundwater Level Figure 11-8 Visualisation of the Refined CSM – Fire Ground & Tidal Flats Figure 12-1 ASC NEPM general process flowchart (Green highlight indicates path followed for the DSI) Figure 13-1 Summary of key PFAS sources, transport pathways and receptors

Tables Table 1-1 Scope of works Table 2-1 Summary of Site identifying details Table 3-1 Regional Geology Table 3-2 Summary of surrounding groundwater uses Table 4-1 Department of Defence Contaminated Site Register Table 4-2 Maximum measured PFAS concentrations within various media recovered from within and

surrounding the Fire Ground Table 4-3 Maximum measured PFAS concentrations within various media recovered from within and

surrounding the Fire Station Table 4-4 Maximum measured PFAS concentrations in storm-water system outlets Table 4-5 Maximum measured PFAS concentrations within various media recovered from the potential Fire

Ground water filter wash-down area Table 5-1 Known and potential PFAS source areas Table 5-2 Known and potential human and ecological receptors Table 6-1 Land SEPP Beneficial Uses Table 6-2 Protected Beneficial Uses of Groundwater Segments Table 6-3 Groundwater SEPP Beneficial Uses Table 6-4 Water SEPP Beneficial Uses Table 6-5 Summary of adopted Tier 1 screening criteria for PFAS contamination Table 7-1 Data quality objectives Table 7-2 Data quality indicators for field data Table 7-3 Data quality indicators for laboratory data Table 8-1 Program of works Table 8-2 Investigation Sample Numbers Summary Table 10-1 Summary of soil analysis and soil screening criteria exceedances Table 10-2 Land SEPP beneficial uses – evaluation of preclusion Table 10-3 Interpreted hydraulic conductivities Table 10-4 Major Cations & Anions (mg/L) Table 10-5 Summary of groundwater analysis and groundwater screening criteria exceedances Table 10-6 Evaluation of Groundwater SEPP Beneficial Uses Table 10-7 Surface Water Field Parameter Readings Table 10-8 Summary of surface water analysis and surface water screening criteria exceedances Table 10-9 Summary of sediment (and sludge in the Former STP) analysis Table 10-10 ...... Evaluation of Water SEPP Beneficial Uses Table 11-1 Summary of known and potential PFAS source areas following field investigation Table 11-2 Evaluation of PFAS flux at drain sampling locations Table 11-3 Refined list of potential human and ecological receptors Table 11-4 Assessment of known and potential human and ecological receptors Table 12-1 Precluded beneficial uses and potential management measures

Acronyms Term Definition

10:2 FTS 10:2 Fluorotelomer sulfonic acid




AFFF Aqueous film forming foam

AHD Australian Height Datum

AJAAC Australian Joint Acoustic Analysis Centre

ANZBP Australian and New Zealand Biosolids Partnership

ANZECC Australian and New Zealand Environment Conservation Council

AS Australian Standard

ASLP Australian Standard Leaching Procedure

bgl Below ground level

BOM Bureau of Meteorology

CoC Chain of Custody

Concawe Conservation of Clean Air and Water in Europe

CRC CARE Cooperative Research Centre for Contamination Assessment and Remediation of the Environment

CSM Conceptual Site Model

DBYD Dial Before You Dig

Defence Department of Defence

DER Western Australia Department of Environment Regulation

DNAPL Dense non-aqueous phase liquid

DNSDC Defence National Storage Distribution Centre

DoEE Department of the Environment and Energy

DQI Data quality indicators

DQO Data quality objectives

DSI Detailed Site Investigation

ECC Environmental Clearance Certificate

EGV Environmental Guideline Value

enHealth Environmental Health Standing Committee

ENM Excavated natural material

EPA Environment Protection Authority

EPBC Act Environment Protection and Biodiversity Conservation Act 1999 (Cwth)

FTS Fluorotelomer sulfonic acid

GDE Groundwater Dependent Ecosystem

HDPE High-density polyethylene

HEPA Heads of EPAs Australia and New Zealand

HHERA Human health and ecological risk assessment

HHSV Human Health Screening Value

LC-MS/MS Liquid chromatography tandem mass spectrometry

LNAPL Light non-aqueous phase liquid

Term Definition

LOR Limit of reporting

MoE Maintenance of Ecosystems

NATA National Association of Testing Authorities

NEMP 2018 PFAS National Environmental Management Plan (January 2018)

NEPM 2013 National Environment Protection (Assessment of Site Contamination) Measure 1999 (Amendment 1, 2013)

N-EtFOSA N-ethylperfluoro-1-octane ulphonamide

N-EtFOSAA N-ethyl-perfluorooctane sulfonamidoacetic acid

N-EtFOSE 2-(N-ethylperfluoro-1-octane sulfonamido)-ethanol

N-MeFOSA N-methylperfluoro-1-octane sulfonamide

N-MeFOSAA N-methyl-perfluorooctanesulfonamidoacetic acid

N-MeFOSE 2-(N-methylperfluoro-1-octane sulfonamido)-ethanol

NZS New Zealand Standard

OEH Office of Environment and Heritage

PFAS Per- and poly-fluoroalkyl substances

PFBA Perfluorobutanoic acid

PFBS Perfluorobutane sulfonic acid

PFCA Perfluorinated carboxylic acid

PFDA Perfluorodecanoic acid

PFDoA Perfluorododecanoic acid

PFDS Perfluorodecane sulfonic acid

PFHpA Perfluoroheptanoic acid

PFHpS Perfluoroheptane sulfonic acid

PFHxA Perfluorohexanoic acid

PFHxS Perfluorohexane sulfonic acid

PFNA Perfluorononanoic acid

PFOA Perfluorooctanoic acid

PFOS Perfluorooctane sulfonic acid

PFOSA Perfluorooctane sulfonamide

PFPeA Perfluoropentanoic acid

PFPeS Perfluoropentane sulfonic acid

PFSA Perfluorinated sulfonic acids

PFTeDA Perfluorotetradecanoic acid

PFTrDA Perfluorotridecanoic acid

PFUnDA Perfluoroundecanoic acid

PMAP PFAS Management Area Plan

POP Persistent organic pollutant

PCA Principal constituent analysis

PSI Preliminary Site Investigation

QA Quality assurance

QC Quality control

RAN Royal Australian Navy

RESO Regional Environment and Sustainability Officer

Term Definition

RPD Relative percent deviation

SAQP Sampling and Analysis Quality Plan

SEPP State Environmental Protection Policy

SPFE Stored Pressure Foam Extinguishers

STP Sewage treatment plant

SWMS Safe Work Method Statements

TDI Tolerable daily intake

TDS Total dissolved solids

TOC Top of casing

UCL Upper confidence level

US EPA United States Environmental Protection Agency

VIC Victoria

WoV Waters of Victoria

WWTP Wastewater Treatment Plant

Reference List of Common PFAS Compounds Functional group Parameter Perfluorocarbon

chain length

Perfluoro carboxylates (PFCAs)

Perfluorobutanoic acid (PFBA) C4

Perfluoropentanoic acid (PFPeA) C5

Perfluorohexanoic acid (PFHxA) C6

Perfluoroheptanoic acid (PFHpA) C7

Perfluorooctanoic acid (PFOA) C8

Perfluorooctane sulfonamide (PFOSA) C8

Perfluorononanoic acid (PFNA) C9

Perfluorodecanoic acid (PFDA) C10

Perfluoroundecanoic acid (PFUnDA) C11

Perfluorododecanoic acid (PFDoA) C12

Perfluorotridecanoic acid (PFTrDA) C13

Perfluorotetradecanoic acid (PFTeDA) C14

Fluorotelomer sulfonates (FTSs)

4:2 Fluorotelomer sulfonic acid (4:2 FTS) C6




Perfluroalkyl sulfonates (PFSAs)

Perfluorobutane sulfonic acid (PFBS) C4

Perfluoropentane sulfonic acid (PFPeS) C5

Perfluorohexane sulfonic acid (PFHxS) C6

Perfluoroheptane sulfonic acid (PFHpS) C7

Perfluorooctane sulfonic acid (PFOS) C8

Perfluorodecane sulfonic acid (PFDS) C10

Perfluorooctane sulfonamidoethonals and perfluorooctane sulfonamidoacetic acids

N-methylperfluoro-1-octane sulfonamide (N-MeFOSA) C9

N-ethylperfluoro-1-octane sulphonamide (N-EtFOSA) C10

2-(N-methylperfluoro-1-octane sulfonamido)-ethanol (N-MeFOSE) C11

N-methyl-perfluorooctanesulfonamidoacetic acid (N-MeFOSAA) C11

2-(N-ethylperfluoro-1-octane sulfonamido)-ethanol (N-EtFOSE) C12

N-ethyl-perfluorooctane sulfonamidoacetic acid (N-EtFOSAA) C12

Project 256337 File 256337-HMAS Cerberus-DSI_Rev4-Final.docx Date 10/09/2018 Revision 4 1

1 Introduction

Aurecon Australasia Pty Ltd (Aurecon) was engaged by the Department of Defence (Defence) to undertake a comprehensive investigation of Per- and Polyfluoroalkylated Substances (PFAS) site conditions at HMAS Cerberus (Defence Site Number 0066) at Crib Point in Victoria, here afterwards referred to as the Site.

HMAS Cerberus is a Royal Australian Navy (RAN) Base operated by Defence that serves as a primary training establishment for RAN personnel. The Site is located between Somers and Bittern / Crib Point, on Western Port Bay, approximately 70 km south of Melbourne, Victoria (refer to Figure 1-1).

Figure 1-1 General area for the Detailed Site Investigation indicating the location of the Site

1.1. Context of the investigation program The investigations were commissioned as part of Defence’s review of the historical use of aqueous film forming foam (AFFF) containing PFAS across its portfolio of Defence properties and the implementation of a national plan4 to prioritise Defence properties for preliminary and detailed environmental site investigations. The purpose of the comprehensive investigation program, including this Detailed Site Investigation is to identify and document the nature and extent of PFAS contamination, asses potential risk to human health and ecological receptors, and where necessary develop appropriate risk management actions.

This report presents the findings of the Detailed Site Investigation (DSI) of PFAS at HMAS Cerberus and the immediate surrounding area undertaken by Aurecon between April 2017 and July 2018.

1.2. Framework of the investigation program The DSI has been designed and implemented in general accordance with the framework for the assessment of site contamination provided by Schedules A and B of the National Environment Protection (Assessment of Site Contamination) Measure 1999, as amended in 2013 (NEPC, 2013), and guidance provided by the PFAS National Environmental Management Plan5 (PFAS NEMP) (HEPA, 2018) and relevant jurisdictional guidance established in in Victoria.

4 http://www.defence.gov.au/Environment/PFAS/Default.asp 5 http://www.epa.vic.gov.au/PFAS_NMP

http://www.defence.gov.au/Environment/PFAS/Default.asp

http://www.epa.vic.gov.au/PFAS_NMP


The ASC NEPM sets out a process for undertaking site assessments. Figure 1-2 shows the general process flowchart, which typically entails completion of a Tier 1 PSI, then a Tier 1 DSI. Based on the findings from the DSI, the flowchart shows that the next step in the process would be either undertaking a Tier 2 / Tier 3 site-specific risk assessment, or progressing to developing risk-based remediation strategies. Hence, following the ASC NEPM flowchart, when there is sufficient information to devise risk-based mitigation strategies, then remediation and/or management can be considered without undertaking a Tier 2 / Tier 3 risk assessment.

Figure 1-2 ASC NEPM general process flowchart


The DSI (and accordingly the Site) is also the subject of a voluntary s53V6 environmental audit (contaminated land) commissioned by Defence and being undertaken by Mr Paul Fridell of Environmental Resources Management (ERM), who is a contaminated land auditor appointed by EPA Victoria.

1.3. Per- and Poly- Fluoroalkyl Substances PFAS are manufactured compounds that comprise a carbon background containing many carbon-fluorine bonds that impart oil and water repellent properties. PFAS were first manufactured in the 1940’s and have been widely used in many industrial applications and processes, e.g., fire-fighting foams, electroplating, paper manufacturing, and were commonplace in many domestic household products e.g., non-stick cookware, fabric, furniture and carpet stain protection and food packaging.

PFAS are widely distributed in the global environment due to their high solubility in water, low to moderate sorption to soils and sediments and resistance to biological and chemical degradation. PFAS, including perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), have recently emerged as ‘potential contaminants of concern’ around the world due to their persistence in the environment and ability to bioaccumulate in biota (plants and animals) and humans. As a result, significant numbers of people are reported to have measurable levels of PFAS in their body (National Centre for Environmental Health 2017). Consequently, PFOS, its salts and precursors are now recognised as persistent organic pollutants (POPs), listed under Annex B of the Stockholm Convention. They are classified as ‘emerging contaminants’, which means there is limited information available about them and the understanding of the risks to human health and the environment are being developed.

AFFF containing PFAS was used extensively throughout Australia and the world due to its effectiveness in fighting liquid fuel fires. These products were typically used by Defence, as well as civil aviation authorities, the petroleum industry and emergency services. Since the 1970’s Defence has used AFFF to suppress liquid fuel fires, in either training or emergency response applications. At HMAS Cerberus, Defence historically used 3M Lightwater AFFF, which contained PFOS and PFOA (Colville and McCarron 2003, Senate Estimates Brief SB15-000647). Since 2004, Defence has been progressively replacing 3M Lightwater with Ansulite (3% and 6% AFFF concentration), which does not contain PFOS and PFOA as active ingredients. Ansulite contains other PFAS compounds such as 6:2 Fluorotelomer sulfonic acid (6:2 FTS) and 8:2 Fluorotelomer sulfonic acid (8:2 FTS) and has the issue of impurities and precursor transformation. Around 2008, usage of Ansulite at the Site ceased and was replaced with a Solberg foam that does not contain PFAS.

1.4 Purpose and objectives Defence’s primary objective is to understand potential Site contamination risks both on HMAS Cerberus and to the surrounding environment resulting from the historical PFAS-based AFFF.

1.4.1 Key objectives The four key objectives of the project were to:

Conduct of environmental investigations and human health and / or ecological risk assessment (if required) compliant with the requirements of the ASC NEPM

Conduct of ASC NEPM compliant human health and / or ecological risk assessments (if assessed as being required)

Development, maintenance, and management of Site specific stakeholder information and engagement

Development of a PFAS Area Management Plan (PMAP) to address identified risks

6 Section 53V of the Environment Protection Act


1.4.2 Task Objectives The RFQTS identifies that the DSI needs to be focused on characterising sources of contamination because of the use, storage and waste management of legacy AFFF products on HMAS Cerberus, and possible connections between potential contamination to humans, the human food chain and ecology. This characterisation is to be focused on the development and implementation of appropriate risk management actions associated with any identified AFFF- sourced PFAS contamination on HMAS Cerberus and surrounding environs. For the sake of clarity any further reference to PFAS in this report is made in the context and reference to PFAS sourced from legacy AFFF products, unless otherwise stated.

The specific task objectives established by the RFQTS include:

Identify potential PFAS contamination sources associated with the use, storage and waste management of legacy AFFF products

Identify, confirm and / or characterise the nature, fate and transport of potential PFAS contamination (vertically and laterally)

Evaluate Site data against Tier 1 screening criteria to determine if PFAS contamination poses a risk such that a Site-specific human health and / or ecological risk assessment needs to be undertaken

Undertaking a comprehensive contaminated land investigation and associated risk assessment to determine whether on and off property community stakeholders have access to safe drinking water that has not been affected by PFAS sourced from the Site

Identify and assess off-property land and water uses associated with food production for human consumption

Identify and provide initial characterisation of non PFAS chemicals of concern both on and off-Site

Ensure that all Site specific-information is captured and retained for use by Defence

Develop a PMAP for the Site to manage PFAS contamination

Develop and implement a detailed Stakeholder and Community Engagement Program to ensure stakeholders are appropriately informed and engaged

1.5 Scope of Work The scope of works for the DSI is generally consistent7 with the ASC NEPM and comprises the key actions presented in Table 1-1.

Table 1-1 Scope of works


Literature review Review of publicly available and Defence-provided literature and previous investigation reports pertaining to the site and general information on PFAS

Water use survey Undertake a survey of water usage/sources of properties within 1 km of the site boundary Results used to inform whether groundwater is consumed and for what uses to allow

evaluation of potential exposure to Site-derived PFAS

7 The commissioning of the DSI works in part represents a departure from the systematic investigation process advocated in Schedule B2 of the ASC NEPM in that no prior preliminary site investigations (PSI), specific to the investigation of potential PFAS impacts, have been conducted and / or formally reported, and Defence has not contracted Aurecon to undertake any such PSI works or the production of a PSI report.



Field work Completion of an intrusive investigation on the Site and surrounding areas to assess the nature and extent of PFAS impact

Collection of field data and sampling and analysis of soil, sediment, sludge, surface water and groundwater, and limited biota (vegetation and fish) from targeted locations on-site and in the surrounding areas

The intrusive investigation included:

− Soil sampling comprising analysis of 132 primary soil samples on-site across four monitoring rounds to identify and delineate sources

− Groundwater sampling comprising installation of 22 new groundwater monitoring wells and analysis of 136 primary groundwater samples across three monitoring rounds to assess aquifer characteristics and PFAS presence within the groundwater

− Surface water sampling comprising 39 on-site-primary samples, 42 off-site primary samples (collected in Hanns Inlet) primary samples across three monitoring rounds to assess the transport of PFAS in surface water during low and high tide

− Pore water sampling comprising 19 primary samples co-located with sediment samples in Hanns Inlet

− Sediment sampling comprising 30 primary on-site samples and 20 Hanns Inlet samples to assess the accumulation of PFAS in the sediment

− Sludge sampling comprising 8 primary samples from the dried out former sewage treatment plant (STP) lagoons

− Biota (vegetation) sampling comprising 19 primary samples (grass root/sward, algae) collected in conjunction with sampling of soil and surface water

− Biota (fish) sampling comprising 66 primary samples (range of species) collected from Hanns Inlet to assess impact on sensitive ecological receptors

Laboratory analysis

Analysis of recovered samples (including intra- and inter-laboratory duplicates) and rinsate blanks for PFAS

Assessment of Site investigation results

Comparison of laboratory results with documented Tier 1 investigation levels (the assessment criteria)

Discussion of results of sampling and analysis, including an assessment of the potential risks and impacts on human health and the environment

Screening (preliminary) risk assessment based on the identified nature and extent of PFAS impact

Development of a Conceptual Site Model to identify the relevant pollutant linkages Identification of the remaining gaps and uncertainties, and the requirement for further

assessment Establishment of appropriate Site management options, and consideration of remedial

options suitable for breaking the identified relevant pollutant linkages (as part of the PFAS Area Management Plan8)

Reporting Prepare a stand-alone document combining both factual and interpretative components of the PFAS investigation that contains data to inform the requirements for future actions, including management of risk and remedial options

8 The PMAP will be produced as a stand-alone document following finalisation of the DSI.


2. Site Identification This section defines the Site and the investigation area for the purposes of the DSI, and provides details relating to Site (and surrounding land) features, use and environmental setting.

2.1. Site details HMAS Cerberus is located between Somers and Bittern / Crib Point, on Western Port Bay, approximately 70 km south of Melbourne, Victoria (refer to Table 2-1). The Site surrounds Hanns Inlet, which is located off the north arm of Westernport Bay, the latter being an internationally significant wetland listed under the Ramsar Convention on Wetlands. Site identifying details are summarised in Table 2-1.

Table 2-1 Summary of Site identifying details

Item Relevant Site Information Site address HMAS Cerberus, VIC, 3920

Site area 1,517 ha (15.17 km2) Current Site owner Department of Defence

Municipality Mornington Peninsula Shire Council Property Number 80160 Current Land Use Zoning Commonwealth Land (CA)

Current Site Occupier Department of Defence (RAN) Lot and Plan Number 45 parcels of land (refer to Appendix K for full list)

2.2. Investigation Area The investigation area (IA) for the intrusive component of the DSI works is identified in Figure 2-1 and includes the channel and flanking intertidal zone within Hanns Inlet. Note that the southern portion of the Site was excluded from the DSI works owing to the presence of unexploded ordnance (UXO), however it is not considered that this would affect the completeness of the DSI as there are no known or suspected AFFF sources or pathways within this portion of the Site. Refer to Section 9 for more detail.

The assignment of the IA within the boundary of the Site has been informed by the results and findings of preliminary investigations conducted by Aurecon including the review of background information and the results and findings of prior environmental and / or Site contamination investigations undertaken on-site by others (refer to Sections 3 and 4 for further details). The body of knowledge to date identifies that:

Topographically, the Site is located within a broad valley that slopes to the south-east towards Hanns Inlet and the North Arm of Westernport Bay

Surface water comes onto Site via several drains along the northern and western Site boundaries which are topographically up-gradient of the Site

Groundwater flow direction underlying the Site is in a general south to south easterly direction and groundwater is anticipated to discharge to Hanns Inlet and the North Arm of Westernport Bay

Known and suspected source areas of existing AFFF impact and operational areas where AFFF is known to have been used, stored and generated wastes are all located topographically and hydraulically downgradient of the northern and western Site boundaries (noting these are the boundaries to the adjacent residential and commercial properties)

Existing groundwater monitoring data indicates significantly decreasing concentration of AFFF sourced PFAS in groundwater along transects extending in up- or cross-hydraulic gradient locations


Figure 2-1 Investigation area for the intrusive component of the DSI works

2.3. Site operations and features The Site was historically acquired by the Commonwealth Government in 1911 with development undertaken between 1912 and 1920 (including reclamation of land in the marina area). In 1912, the Site opened as Royal Australian Navy (RAN) Flinders Naval Depot. In 1921, the Site was commissioned as HMAS Cerberus and became the main training facility for the RAN. The present owner of the Site remains the Department of Defence.

The Site is currently the main training facility for the Royal Australian Navy. Additionally, four tri-service schools have been established over the last 13 years, hence Site users include Army, Navy and Air Force personnel, as well as contractors and visitors. Training activities at the Site include exercises at the RAN School of Survivability and Ship Safety (SSSS) facility. These exercises comprise training in fighting simulated ship fires and repairing a flooding mocked-up ship structure (referred to as the Fire Ground). The Site provides training for 6,000 Defence (primarily Naval) personnel annually with an average of 800 personnel training on-site at any one point in time.

2.3.1. Site features The Site comprises a significant number of buildings, structures and facilities which can be broadly classified based on the following functional zones and uses:

Temporary accommodation, training (non-fire-fighting) and messing

Permanent accommodation

Recreational

Base services and support


The general location of these functional zones is shown in Figure 2-2 (from HMAS Cerberus Redevelopment Report, Department of Defence, June 2017)9.

Figure 2-2 HMAS Cerberus Zone Plan showing the operational area

Temporary accommodation, training (non-firefighting) and messing These buildings typically provide temporary accommodation, training (non-firefighting) and messing facilities for Defence personnel who are undertaking training at the Site, as well as Site services including medical centre, cinema and concert hall. The buildings typically comprise single and multi-story brick buildings with surrounding landscaping and sealed roadways. The accommodation is provided as dormitory style rooms, with shared and common facilities. Whilst within the main training and operational areas of the Site, the accommodation and messing areas are remote from the known primary AFFF source and use areas.

Permanent accommodation The permanent accommodation is located in two areas on the north-eastern finger of the Site and is set aside from the main training and operational areas of the Site (refer Figure 2-3). The accommodation is typically single storey detached brick buildings with individual front and read landscaped areas and sealed driveways. Of relevance to the DSI is that these dwellings are remote and set well aside from the known primary AFFF source and use areas (with the exception of the Sullage pit – refer further commentary below).

A child care centre is present within the western-most permanent accommodation area, adjacent to the north-eastern boundary of the Site and the adjacent off-Site residential area of Crib Point. It is understood that the child-care centre is for use by children of Base personnel only. Again, of relevance to the DSI is that these dwellings are remote and set well aside from the known primary AFFF source and use areas.

9 The HMAS Cerberus redevelopment project has identified upgrades to Site facilities and infrastructure. The upgrades relevant to this investigation include improvements to the water supply, sewerage services and storm-water network, gas and electrical infrastructure. The project will also involve constructing a new RAN School of Survivability and Ship Safety (Fire Ground) and the decommissioning and remediation of the current Fire Ground


Outdoor recreational areas Sports Fields

There are two sporting fields within the main training and operational areas of the Site. Both of these comprise grassed surfaces and were irrigated using Class C recycled water provided by the South-East Water Somers Recycled Water Treatment Plant (RWTP) until January 2018 (refer further commentary below). The obstacle course north of the northern-most sporting field is not irrigated.

Golf Course

A nine-hole golf course is located on the north-eastern finger of the Site between the two permanent residential accommodation areas. The golf course is irrigated by mains water and is for use by both Base personnel and the general public. Of relevance to the DSI is that the golf course and these dwellings are remote and set well aside from the known primary AFFF source and use areas (with the exception of the Sullage pit – refer further commentary below).

Base Services and Support General Base services and support include;

Administrative buildings

Teaching facilities (e.g., Communications School)

Medical services

Gymnasium

Cinema

Security at east and west entrances

General store (Millies General Store) and canteen services

Wharf and marina area

The following areas are considered of relevance to the investigation of PFAS within the Base:

Fire Training Area (Fire Ground)

The fire training area is located adjacent to the RAN SSSS facility and comprises a mocked-up listing ship superstructure for Leak-Repair-Live training, fire-fighting training area, drum storage area, above ground storage tanks (AST), a wastewater treatment system and a wastewater storage pond. The fire training area is a known area of historical AFFF use and PFAS presence. Further details regarding the historical development and use of the fire training area is provided in Section 4.4.

Fire Station and Ornamental Lake

The fire station (operated under contract by Broadspectrum) is located in the eastern portion of the Site adjacent to Hanns Inlet. The fire station is a known area of historical AFFF use and PFAS impact. Further details regarding the historical development and use of the fire training area is provided in Section 4.4.

Former Sewage Treatment Plant and associated lagoons

The decommissioned on-Site Sewage Treatment Plant (referred to as the Former STP) and its three associated lagoons is located to the south-east of the Site near the eastern border with Somers RWTP (located off-Site). This plant was in operation during the period of historical AFFF use. Although the trickling filter plant was decommissioned in 2001 and the area was infilled, there are three associated wastewater treatment lagoons that contain sludge from the period of operation. Further details regarding the historical development and operation of the on-Site sewage treatment plant is provided in Section 4.4.

Closed Landfills

Several landfills have been used to contain Site waste or construction material, including;

Closed Stony Point landfill - on Stony Point to the east of the Site.

Closed Rifle Range Road landfill (on-Site) immediately south of the operational area


Closed outdoor swimming pool landfill (on-Site) to the south of operational area adjacent to Hanns Inlet

Closed indoor swimming pool landfill (on-Site) in the operational area to the west of the Sports Fields

Closed Fire Ground landfill (on-Site) adjacent to the Fire Ground

The Sullage Pit (on-Site) is to the east of the operational area on the northern side of Hanns Inlet. It is also down a steep slope to the south of the golf course and childcare centre. This area was used as a landfill, and received vegetation and sediment from Hanns Inlet channel maintenance in 1988 and 2006

Further details regarding the use and closure of these landfills is provided in Section 4.4.

The Site details are shown in Figure 2-3 (Appendix A: Figure 3).


Figure 2-3 Aerial photograph indicating Site details


2.4. Site infrastructure The historical maps and aerial photographs are presented in Appendix D. These historical maps and aerial photographs show the development of the Site over the last century. Major earthworks were performed during the construction of the Site that moved soil from the north-east of the Site to construct the marina area.

A Dial Before You Dig (DBYD) application on February 26, 2018 indicates that current underground services include Telstra communications lines, United Energy underground cables, APA Group Networks gas services and National Broadband Network (NBN) fibre optical cables.

2.4.1. Water supply

Potable water The current potable water service to the Site consists of mains water supplied by South East Water (SEW). The potable water mains servicing the Site were upgraded in 2004. A significant percentage of the current pipe network has been assessed to be in poor condition. The network provides water for both domestic and fire-fighting requirements. However, the water pressure is inadequate for fire-fighting purposes. It is understood that the proposed HMAS Cerberus redevelopment includes plans to upgrade the potable water supply by providing a new potable water storage tank. Further, the potable water mains downstream of the existing meter are to be replaced in redevelopment upgrades. A new fire-fighting water network will also be constructed during these construction works.

Discussion with Base staff (John Goodchap) indicated that Site groundwater has not been used. On-Site wells listed in the Victorian groundwater database (refer Appendix A - Figure 2 for bore locations) indicates four wells used for groundwater investigation, one well for industrial use (Bore ID WRK061409) and one well (Bore ID 50163 installed in 1983) in the northwest corner used for domestic use. However, this domestic-use well was not observed during site visits and is likely to be mis-located in the Victorian well database.

Irrigation water The two sports fields within the main training and operational areas of the Site are currently irrigated with sprinklers connected to the mains potable water supply. Historically, these areas were flood irrigated using Class C recycled water provided by the SEW Somers RWTP. The recycled water external audit in 2008-2009 indicates that irrigation of recycled water commenced in October 2006 by tanker from SEW Somers RWTP and a piped supply commenced in 2008. Flood irrigation involved two PVC distribution pipes (12 m in length) at the top of the irrigated area, with gravity flow across the Sports Fields. A quantity of 25 ML/year was applied to an area of 11.4 hectares. The use of this recycled water stopped in January 2018.

Most of the general grass areas situated between buildings are irrigated with potable water, and the HMAS Cerberus golf course is irrigated with potable water (SEW supply).

The Sports Fields that were irrigated with recycled water were noted as potential secondary sources and are discussed further in Section 4.1 and are identified in Appendix A - Figure 3A.

2.4.2 Sewer The Site is connected via sewer to SEW Somers RWTP (formerly known as Hastings STP to the west of the Site. Most of the flow from the Site occurs in the morning before training and in the afternoon following training (personal communication BSOM), which indicates that the source is the temporary residences.

The capacity of the current trade waste system is reported to be at its limit. The sewerage network condition has been assessed as poor for the proposed redevelopment plans. There are significant sections of inadequate or unserviceable sewerage mains, and two of the major pump stations are in poor condition. It is understood that the proposed redevelopment includes plans to replace the existing sewerage pumping stations and replace the primary trunk sewer mains.


The Fire Ground wastewater treatment system is nominally closed-loop. However, a connection existed between the Fire Ground’ wastewater treatment system’s flocculation tank pipeline and the sewerage system. This connection was closed in 2017. The connection meant that small quantities of PFAS impacted wastewater may have been discharged to the sewer.

2.4.3 Drainage The storm-water network for the operational areas of the Site consists of a combination of open drains and an engineered concrete pit-and-pipe network as shown in Appendix A – Figure 3C.

Surface water is conveyed onto and out of Site by a storm-water drainage system constructed during early development of the Site. The general topography of the Site indicates that the surface water at the boundary of the Site flows in a general south-east direction away from off-Site residents.

The pipe sizes in the network do not meet current Australian standards for capacity, size and configuration, such that there are areas where a one-in-ten-year storm event cannot be discharged by the network, thus resulting in localised flooding. It is understood that the proposed redevelopment includes plans to replace collapsed areas of the storm-water trunk infrastructure and install four bio-retention basins on key storm-water mains prior to the outfalls into the wetlands of Hanns Inlet.

Refer to Appendix A - Figure 3C for details of the storm-water system, which indicates the discharge points into Hanns Inlet, as well as other storm-water inflow and outflow drains.

Further discussion of non-engineered surface water flow is included in Section 3.

2.4.4 Current and historical storage tanks Several underground storage tanks (UST) and aboveground storage tank areas (AST) were located across the operational area of Site (ERM 2007). A desktop review indicated that there were no active USTs in use on-Site (GHD 2012). Historically, there were five locations for USTs, with at least three USTs decommissioned in-situ and a further four former USTs that were removed (ERM 2007, GHD 2012). Further details on ASTs can be found in GHD 2012. The details of the key storage tanks are summarised as follows;

The UST west of Building 192 (referred to as CER02) was located in front of Millies General Store at the centre of the main operating area. This UST was installed in 1959/1960 and used to store diesel/heating oil (GHD 2012). It was decommissioned in-situ by infilling with concrete in 2006 (ERM 2006)

The UST (CER01) and two other ASTs (A0618, A0619) were located in the north-west corner of the main operating area, north of Building 501, also referred to as the Transfield Services Yard (ERM 2007) or Grounds Maintenance Yard (GHD 2012). The UST contained petrol and had a capacity of 10 kL and it was removed in 2006 (ERM 2006). The ASTs were located on a hardstand area and contained fuel and oil. Two ASTs (1.5 kL and 4 kL) were still in use in 2012 (GHD 2012). It was observed that these ASTs have been removed from the area

The two USTs (CER03) were located to the east of the main operating area. More specifically, one was installed to the west and the other to the south east of Building 25. The USTs were reported to be used for fuel storage, specifically super and standard petrol (GHD 2012). It was estimated that the tanks were installed pre-1950’s (ERM 2007). The western tank was filled in-site with sand and covered in concrete and the southeast tank was concreted over with decommissioning details unknown (ERM 2007)

The petrol station USTs (66_UST 5 and 66_UST 6) were located in the main operating area on the corner of Cook and Phillip Roads. It was reported that the petrol station, historically operated by Shell, used two USTs for fuel storage. These tanks were removed in the early 1990’s (ERM 2007, GHD 2012)

The filling station USTs (one referred to as 66_UST 1) were located in the southeast of the main operating area near the Marina to the south of Building 55. These USTs were used for fuel storage prior to the decommissioning of the filling station around 1975. It was reported that a single UST remained in 2007 (ERM 2007), which was decommissioned by removal (GHD 2012)

The AST associated with the Demonstration Building (Building 49) is also located in the southeast of the main operating area near the Marina. The building was constructed in 1977 and incorporate diesel


powered marine engines used for training purposes. There is a large external UST (still in use) surrounded by concrete bunding

The AST (66_AST2) to the south of Building 151 (Ward Room) was located in the south of the main operating area. The unbunded tank was used to store over 100 kL of diesel for transfer to the power house. It was installed before 1940 to service the power house, which was modified for diesel combustion from previous coal combustion set up. The tank was removed in 1988 (ERM 2007)

The Fire Ground AST (66_AST1) was located in the western side of the concreted section of the fire training area. The tank was unbunded with drip trays below the outlet (Aurecon 2009). This tank was used to store training foam (personal communications WO Ian Waller). Inspection of aerial imagery indicated that the tank was on the western edge of the handstand area in 2005 and moved 10 m to the north to be under the cover of an awning in 2011-2012

2.4.5 Other relevant current and historical infrastructure Dry-cleaning facility

The Cerberus Dry Cleaning building (former dry-cleaning facility) was located off Phillip Road to the west and south of Millies General Store (VT0368). It was reported that the building operated until the 1960’s (ERM 2007). The area of the former dry-cleaning facility is now used as an unsealed carpark.

Catering school

The former catering school was adjacent to the former dry-cleaning facility (VT0386). There is minimal historic information available about the former catering school (ERM 2007). It was reported that the school was demolished in 2000 and the building debris disposed as fill material next to the Former STP (ERM 2007). The area of the former catering school is now a grassed recreational area next to an unsealed carpark.

Coal loading area

A historic railway line running north to south along the waterfront to the east of the main operating area was used to transport materials and fuels to the Site (VT0367). This railway line finished at the coal loading area in the southwest of the operating area near the Marina. The Base Support Manager indicated that the area (and the southwest corner) was constructed from reclaimed materials transported from the north west of the Site. The nearby Powerhouse used the coal that was unloaded and stored at the coal loading area. This area was also used to store significant amounts of fuels, chemicals and other products in drums, where the historical storage practices were not recorded (ERM 2007). This area is currently well grassed open space.

Power house

The power house is located to the south east of the operating area near the coal loading area (VT0374). Historically, the power house used coal and later diesel until its closure in 1985/1986 (ERM 2007). The coal was transferred from stockpiles next to the coal loading area and diesel was provided by the AST to the south of Building 151 (Ward Room). The location of waste ash disposal was not known (ERM 2007).

Gun Club

The Gun Club was located to the north west of the main operating area (VT0387). It was reported to have been used on average nine days per month over 40 years for clay target practice (ERM 2007). The area is currently used for archery.

Rifle range and ordnance areas

The Rifle Range (VT0002) and Sandy Point ordnance area (VT0066) is located to the south of the Site. The land encompassed by the Sandy Point ordnance area is separated topographically from the main operating area and Former STP by an intervening drainage and Hanns Inlet. This area was used for target practice and disposal of UXOs since before 1913 (ERM 2007). The presence of UXOs meant that access to this area was restricted and investigation was not performed in this region.


2.5. Surrounding land use

2.5.1 Summary of surrounding land use Land use surrounding the Site includes:

North: residential, industrial facilities (BlueScope Steel and Long Island Point petroleum storage and processing facilities), natural bushland, urban reserves, closed Crib Point municipal landfill on Lens St, Bittern.

West: agricultural (grazing and dairy), residential and South East Water (SEW) Somers RWTP.

South: agricultural, residential and natural bushland, Western Port Bay.

East: Hanns Inlet and the North Arm of Western Port Bay, fishing, fire tugboat berthing and support facilities, and residential

2.5.2 Potential surrounding sources of PFAS Potential sources of PFAS in the surrounding areas are summarised below.

Residential

Consumer/personal products with (non AFFF) PFAS are likely to be present in the residences

BlueScope Steel and Long Island Point facilities

AFFF is understood to be used at the BlueScope Steel and Long Island Point facilities, which are located approximately 6 km north of the Site on the shore of Western Port Bay

Closed Crib Point municipal landfill

PFAS may be present in leachate at the closed Crib Point municipal landfill located approximately 200 m north of the northern Site boundary. This landfill is suspected to be unlined. Landfilling occurred at the municipal landfill from late 1970’s to the early 1990’s.

Somers RWTP

PFAS is understood to be present in influent and effluent at the Somers RWTP

Fire tugboat berthing and support facilities

AFFF is understood to be present at the fire tugboats and support facilities, which is located approximately 3 km north of Site


3. Environmental Setting

3.1. Ecological setting HMAS Cerberus borders the Western Port Bay Ramsar wetlands, which encompasses Hanns Inlet. Refer to Appendix A - Figure 2 for the wetlands boundary location relative to the Site boundary. Using the on-line search tool for matters of national environmental significance, SMEC (2009) identified 37 threatened species of birds, frogs, mammals, sharks and plants in Western Port Bay. Ecological communities comprise mangrove and saltmarsh wetlands (ecological community), adjacent bushland (ecological community), and seagrass beds (ecological community). An updated search conducted by Aurecon indicated that there were now 63 threatened species of birds, frogs, mammals, sharks and plants. Two ecological communities (Subtropical / Temperate Coastal Saltmarsh and Natural Damp Grassland of the Victorian Coastal Plains) were listed as threatened.

The sensitive ecological receptors identified in the investigation area, include but are not limited to;

Mammals, such as rabbits, kangaroos and possums

Birds, migratory and local

Reptiles and insects

Semi-aquatic biota, including crabs and worms

Fish, including flathead, whiting, mullet, Australian salmon, toad fish and trevally

Fiddler rays (banjo sharks) and gummy sharks

Pipis, oysters and crustaceans

Benthic detritivores

Grass, trees and other vegetation

Cattle are maintained off-Site to the west and south of the Site for agricultural business (grazing and dairy). Horses are also maintained in this agricultural area off-Site to the west and south.

Aurecon undertook a self-assessment for the proposed conduct of the DSI fieldwork, which determined that no referral to the Commonwealth was required for the purposes of implementing the proposed DSI works.

3.2. Climate As shown on Figure 3-1, long-term climatic data collected at the Site weather station (Bureau of Meteorology station number 086361) between 1986 and 2017 indicates the following:

Annual rainfall is approximately 723 mm, which occurs over approximately 178 days of rain.

Highest average monthly rainfall is approximately 75 mm, which occurs in August

Lowest average monthly rainfall is approximately 38 mm, which occurs in January and February

Average maximum temperatures range between 14ºC in the winter and 25ºC in the summer. Average minimum temperatures range between 6ºC and 14ºC. Average annual wind speed is approximately 15 km/hr in the morning and 20 km/hr in the afternoon.


Figure 3-1 HMAS Cerberus Mean Monthly Rainfall 1986 – 2018 (Cerberus BOM Station 086361)

3.3. Geology Interrogation of the GeoVic10 and Visualising Victoria Groundwater (VVG)11 websites indicated that geology at and near the Site comprised the following strata (refer Table 3-1). Surface geology is summarised on Figure 3-2, and presented with more detail on Appendix A - Figure 5.

Table 3-1 Regional Geology

Strata Characteristics Thickness (m)

Recent dune, river, swamp and alluvial deposits Dune sands (Sandy Point), predominantly silts and clays with some interbedded sands 0 - 15

Tertiary Brighton Group (river and near-shore marine deposits) (lateral equivalent to Baxter Sands)

Sandy clays to clayey sands with localised iron staining and cement 1 - 20

Tertiary Yallock Formation and Sherwood Marl (marine) (lateral equivalent to the Fyansford Formation)

Sand and clays with some limestone layers 50 - 60

Tertiary Childers Formation (coastal/near-shore marine) (lateral equivalent to the Werribee Formation)

Lignite and clay with some sand 10 - 15

Interbedded with the Werribee Tertiary Older Volcanics (terrestrial deposits)

Variably weathered and fractured basalt lava flows 10 - 20

Silurian Bedrock (marine deposits) Siltstones and sandstones >100

10 http://earthresources.vic.gov.au/earth-resources/maps-reports-and-data/geovic 11 http://www.vvg.org.au/

http://earthresources.vic.gov.au/earth-resources/maps-reports-and-data/geovic


Figure 3-2 Surface geology map of HMAS Cerberus


Structurally, the bedrock is deformed into a series of tight folds with mainly northeast-southwest fold axes. During the Tertiary period, movement along mainly active faults have broken the Tertiary and older strata into numerous blocks that have tilted and shifted during and after deposition. This has created a complex geology where the thicknesses and depths to these strata varies significantly over short distances (on the scale of kilometres to tens of kilometres) across the Mornington Peninsula. Along the faults at or near the Site, preferential erosion of the fractured Tertiary strata created the current topography with northwest-southeast trending valleys where alluvial and estuarine soils were deposited.

At the Site, up to 3 m of Recent alluvium has been deposited in shallow drainages located between ridges of faulted Tertiary Brighton Group sediments, where the main operational and residential portions of the Site are situated. Alluvial / estuarine delta deposits of silts and clays occur within the tidal zone, including the mangrove swamps and salt marshes south and east of the operational portion of the Site.

3.4. Surface water

3.4.1. Topography and Bathymetry Topographically, the Site is located within a broad valley that slopes to the southeast towards Hanns Inlet and the North Arm of Westernport Bay. The highest portion of the broad valley ranges in elevation between 50 mAHD and 90 mAHD (refer to Figure 3-3 and Appendix A – Figure 4). The main operational area of the Site is between sea level and approximately 10 mAHD on a low ridge flanked by two drainages that flow to the southeast towards Hanns Inlet. On-site, higher ridges with remnant vegetation (up to approximately 20 mAHD) are located north and south of the two main drainages.

Hanns Inlet, which is a tidally influenced estuary, connects to the North Arm of Western Port Bay. Findings from a study of tidal flushing in Hanns Inlet by Pollock and Wallis (1974) indicated that during tidal cycles minimal flushing occurred in the western and central portion of the inlet. The eastern third of the inlet (at the connection with Western Port Bay) did flush and turnover with each tidal cycle. Water depths in Hanns Inlet varies with tide level. The tidal flats are often exposed during low tides; while at high tides water depths can be up to 2 m. Within the access channel to the Site marina water depths range between 2 m and 4 m over tide cycles.

With a tidal range of approximately 2 m, most of Hanns Inlet consists of a broad tidal flat with a main tidal channel extending out from the two main natural drainages (South Creek and East Creek) located south and east of the main operational area of the Site. Typically, the tidal flat is inundated twice a day with high tides rising to approximately 1 mAHD and low tides falling to approximately -1 mAHD. To provide ship access to the Site, a man-made channel between 2 m and 3 m deep is maintained. This access channel was last dredged (to remove mainly weed and marine vegetation) in 2006 with the spoil placed in the Sullage Pit located on the north shore of Hanns Inlet.


Figure 3-3 Surface water catchment (purple line) and topographical (black contours) map of HMAS Cerberus where Site boundary is indicated by yellow line.


3.5. Hydrogeology

3.5.1. Regional Hydrogeology Regionally, groundwater generally flows towards the southeast from the head of the local groundwater basin located northwest of the Site. As shown by the purple arrows on Figure 3-4, groundwater flows generally to the southeast where discharge occurs through the seafloor of Western Port Bay (including Hanns Inlet).

Figure 3-4 Regional groundwater flow – Tertiary Brighton Group aquifer (Lakey 1980)

3.5.2. Local Hydrogeology Shallow aquifers below the Site fall within a groundwater basin coincident with the local surface-water catchment shown on Figure 3-3. Shallow groundwater (less than 20 m in depth) occurs in the Recent alluvial sediments (Quaternary Aquifer under the Victorian Aquifer Framework, SKM, 2009) and the Tertiary Brighton Group sands and clays (Upper Tertiary Aquifer (fluvial)). A water-table aquifer is developed in the Recent alluvial soils (mainly silts and clays) deposited in the drainages south and east of the operational portion of the Site (south of the Fire Ground and east of the Fire Station) and in fill soils in the marina area. A semi-confined aquifer is developed in the Tertiary Brighton Group sediments (Lakey, 1980).

These shallow aquifers are predominantly recharged directly by rainfall within the local catchment; and to a lesser degree by irrigation of sports fields or agricultural land. Groundwater discharges via either evapotranspiration, surface-water features, such as the local drainages and Hanns Inlet, or extraction wells.


Within the operational area of the Site, standing water levels (SWLs) measured between 2013 and 2017 (EES, 2014, Agon, 2016 and Golder, 2017) were typically between 2 and 11 m deep with reduced water levels (RWLs) ranging between approximately 1 mAHD and 4 mAHD. RWLs at the Fire Ground are approximately 3 mAHD, while RWLs for wells located between the Fire Ground and the drainage channel south of the Fire Ground are less than 1 mAHD, which suggests that shallow groundwater beneath the Fire Ground flows to the southwest. Across the central and eastern part of the operational area the RWLs suggest that groundwater flows to the south or east and discharges directly into Hanns Inlet. Note that the inferred directions of are from private extraction bores onto the operational area of Site. This means that the private extraction bores are inferred to be located hydraulically up- or cross-gradient (east, north and west) of the Site.

3.5.3. Aquifer water quality Interrogation of the VVG12 website indicates groundwater salinity at and near the Site falls within Segment B (that is, between 1,000 mg/L and 3,500 mg/L of total dissolved salts (TDS). Salinities of groundwater (as electrical conductivity (EC)) reported for the Site monitoring wells (Golder, 2017) ranged between approximately 1,000 µS/cm and 30,000 µS/cm, which indicate that fresh (potable) to saline groundwater is present beneath the Site. Golder indicate that potable groundwater (Segment A) is locally present in the western portion of the Fire Ground, which may reflect local recharge and / or leakage from the storage pond at the Fire Ground.

In addition, seawater intrusion occurs near the tidal channels south and east of the operational area and along the shoreline of Hanns Inlet. In these area, a wedge of saline groundwater extends landward (to the west) from Hanns Inlet. In addition, the wide tidal range of approximately 2 m results in typically a twice-daily inundation of the tidal flats of Hanns Inlet. This seawater recharges the surface soils of the tidal flats and mixes with shallow groundwater in a mixing (hyporheic) zone. Hence, along the shoreline shallow groundwater is generally brackish and not used for potable supply.

3.5.4. Surrounding groundwater uses (bores) Interrogation of the VVG portal indicates that there are 66 wells located within 1 km of the Site boundary (refer Appendix A - Figure 2). A breakdown of these wells by usage is presented in Table 3-2.

Table 3-2 Summary of surrounding groundwater uses

Use Number of Wells

Domestic and Stock 48

Industrial 1

Irrigation 2

Groundwater Investigation 7

Not indicated 8

Total 66

The majority of the wells are categorised as being for the purpose of domestic and stock usage. The well listed under industrial use is located on Site to the northeast of the permanent residences. Base staff indicated that this well has not been used for decades. Of the two wells used for irrigation, one well is located east of the Site near the Crib Point pool; while the other well is located to the northwest of the Site. These irrigation wells are approximately 20 m deep; hence, likely to be completed in the Brighton Group aquifer (Tertiary sands and clays).

12 http://www.vvg.org.au/ accessed 1 August 2017.

http://www.vvg.org.au/


3.5.5. Water Use Survey A water use survey was issued to properties within 1 km of the Site boundary between 28 July and 7 August 2017 to determine water use and land use activities on properties adjacent to HMAS Cerberus. The format of the water use survey was provided by Defence to ensure consistency with other Defence Sites where DSI works were being conducted.

A total of 280 surveys were completed using hard copy or online (Survey Monkey) format, between 1 August 2017 and 27 November 2017.

To summarise the results of those returned surveys:

243 identified as private residential properties

28 identified as rental properties

12 identified as hobby farms

1 identified as industrial

1 identified as horticultural

2 identified as food production

1 identified as aquaculture

1 identified as other

Water supply and use on those properties comprised:

239 used mains water

145 used rain water

33 used bore water (exact locations cannot be indicated on Appendix A - Figure 2 due to privacy laws)

2 used recycled water

195 had rain water tanks

6 users currently mixed bore water with rain water in tanks for mixed use (see below) and 9 users have previously mixed bore water with rain water

Water use surveys identified bore water was used directly or via tank top up for:

1 for domestic use

5 for household purposes

2 for drinking

1 for washing

2 for watering animals

3 for livestock

1 for vines

5 for gardens

1 for vegetables

3 for swimming pools

1 for toilets

1 for firefighting

1 for wetlands

1 for contingency livestock watering

It was determined that sampling of these bores was not required as previous sampling of such off-site bores reported PFAS concentrations below drinking water guidelines (GHD 2016). This was further supported by


sampling and analysis of groundwater undertaken for this investigation at locations along the Site boundary which likewise reported PFAS concentrations in groundwater below NEMP (2018) drinking water screening criteria (refer Section 9 for further discussion).


4 AFFF use, storage and waste management One of the specific task objectives established by the RFQTS was to identify potential PFAS contamination sources associated with the use, storage and waste management of legacy AFFF products. The following section presents the results and findings of the enquiries made Aurecon to determine these potential PFAS contamination sources.

4.1. Information sources Information was sourced from a range of both direct and indirect inquiries including:

Interviews with key Base personnel

Review and consideration of prior environmental investigation and other reports

Review and consideration of the Base’s Contaminated Sites Register (CSR)

4.1.1. Interviews with key Base personnel Interviews were conducted with the following key personnel on the indicated topics:

Base Services Operations Manager (BSOM) John Goodchap

− Potential for Site flooding and flood-related incidents

− Modifications to the configuration of Fire Ground pond overflow pipes

− Wastewater treatment process and trade waste agreement with SEW

− Use of recycled water on the Sporting Grounds

− Bushfire in the 1990’s at Site eastern boundary

Base Support Manager (BSM) Les Moseley

− Sewerage outfall locations

− Historic configuration of the Ornamental Lake and Fire Station

− Major earthworks to develop the Marina

− Bushfire in 1990’s at Site eastern boundary

Warrant Officer (WO) Ian Waller

− Typical training and operation at the Fire Ground

− Closure of the Fire Ground in 2016

− Indicative quantities of training foam used at the Fire Ground

− Closed circuit wastewater treatment system at the Fire Ground

− Modifications to the configuration of Fire Ground pond overflow pipes

Broadspectrum staff (Fire Station)

− Fire related incidents on-Site

− Storage and handling of AFFF

− Spraying of AFFF at Fire Station

− Disposal of AFFF at Former STP

Brian Dunn, Channel reinstatement Project Manager

− Management of spoils from channel maintenance in Hanns Inlet


− Construction of the storage area at Sullage Pit

4.1.2. Prior reports The following sources of information were used to develop the understanding of the use, storage and waste management of AFFF products on the Base, and the nature and extent of previously identified PFAS contamination:

HMAS Cerberus historical aerial photograph book, Defence (date unknown)

Dispersion and Tidal Flushing in Hanns Inlet, Pollock, T. J. and Wallis, I. G. (August 1974)

Environment Audit Report – HMAS Cerberus, Kinhill (June 1994)

Stage 1 Environmental Investigation, ERM (November 2007)

Stage 2 Environmental Assessment, SMEC (2008)

Environmental Review of Fire Fighting Training and Facilities, Aurecon (2009)

Targeted soil investigation – fire training facility, EES (September 2010)

Groundwater monitoring report for HMAS Cerberus, Environmental Earth Sciences (December 2013)

Groundwater Monitoring Report for HMAS Cerberus, Environmental Earth Sciences (May 2014)

Defence per- and poly-fluoroalkyl substances (PFAS) Environmental Management Preliminary Sampling Program Final Report, GHD (September 2016)

AFFF Summary Report, Agon Environmental (July 2016)

In-Ground Contamination-site Assessment, Golder Associated (June 2016)


Delineation Assessment at Existing RAN SSSS, Golder Associates (January 2017)

Further Groundwater Assessment RAN SSSS, Golder Associates (May 2017)

HMAS Cerberus Integrated Surface Water Quality Management Plan, MWH Stantec (June 2017)

4.1.3. Base CSR Areas of identified contamination (both PFAS and non-PFAS) have been placed on the Defence contaminated sites register (CSR) and are identified by a “VT” prefix followed by four digits. For the Site, Appendix A - Figure 3B shows the locations of the areas listed on the CSR. The previously designated CSR areas are summarised in Table 4-1.


Table 4-1 Department of Defence Contaminated Site Register

Legacy CSR Number EFR ID EFR Title Location

VT0001 CSR_VIC_000136 Stoney Point Burrow Pit - Buried Waste Clinical

Stony Point

VT0002 CSR_VIC_000132 South of Site - Rifle Range Ammunition Small Arms Training Area VT0066 CSR_VIC_000141 Sandy Point- Ordnance Sandy Point VT0067 CSR_VIC_000276 South of Wilson Ave - Stockpile AFFF Fire Ground VT0191 CSR_VIC_000155 West of Building 192 - UST CER2 West of Building 192 VT0192 North of Building 501 - UST CER01 and

ASTs North of Building 501

VT0363 CSR_VIC_000148 North Side Hanns Inlet - Sullage Pit Adjacent to Hanns Inlet VT0364 CSR_VIC_000150 Landfill East of SSSS Training Ground East of Fire Ground

VT0365 CSR_VIC_000137 Landfill Road to Rifle Range Rifle Range Road VT0366 CSR_VIC_000143 South of Building 475 - Former

Swimming Pool Landfill South of Building 475

VT0367 CSR_VIC_000138 East of Building 28 - Reclaimed Land, Former Coal/Fuel Storage

East of Building 28

VT0368 CSR_VIC_000149 Car park West of Building 189 - Former Dry Cleaning

Carpark West of Building 189

VT0369 CSR_VIC_000280 Between Nelson Rd & Building 25 - UST CER03

Between Nelson Road and Building 25

VT0370 CSR_VIC_000279 Corner Cook & Bass Rd - Former Petrol Station USTs

Corner of Cook and Phillip Roads

VT0371 South of Building 55 - Filling Station USTs

South of Building 55

VT0372 CSR_VIC_000277 Building 49 - Demonstration Building - AST

Building 49 Demonstration Building

VT0373 CSR_VIC_000278 Ward Room Store 102 - AST Ward Room Store 102 VT0374 CSR_VIC_000147 Building 55 - Powerhouse Building 55 VT0375 CSR_VIC_000140 Road to Small Arms Training Area -

Former STP Road to Small Arms Training Area

VT0376 CSR_VIC_000146 Sandy point road - Oil sludge Sandy Point Road VT0377 CSR_VIC_000145 Building 154 - Pesticide storage Building 154 VT0378 CSR_VIC_000142 Slipway group - Vessel cleaning Near Marina VT0380 CSR_VIC_000139 Former indoor swimming pool - buried

landfill South of Gunroom

VT0381 CSR_VIC_000144 Former Railway line bend NE of site - Train use

East edge of the Site near Fire Station

VT0382 CSR_VIC_000158 Tank feed line from ward room - Oil feed line

Near Ward Room

VT0384 CSR_VIC_000135 Building 106/108 floor - Odour Building 106/108 VT0386 CSR_VIC_000134 Car park east of building 251 - former

catering school East of building 251

VT0387 CSR_VIC_000133 Gun club Gun Club, North of Building 501

VIC1057 CSR_VIC_000067 Buried redundant steam pipes - petroleum contamination

North of Building 261

VIC1066 CSR_VIC_000084 Asbestos conduit

These CSR areas in relation to receptors are shown in Figure 4-1.


Figure 4-1 Contaminated Site Register details and key Site features


4.2. AFFF use and storage areas The following areas have been identified from the cited information sources to either be areas in which AFFF was used and/or stored on Site.

4.2.1 Fire Ground (VT0067) Background

The Fire Ground was constructed in the 1960’s based on historical aerial images. The Fire Ground was identified as a known contaminated area on the Defence CSR with the relevant assigned reference being VT0067 due to the use of AFFF and burning of hydrocarbons. The Stage 1 Environmental Investigation of ERM (2007) assigned the area a medium risk rating.

Normal operations at the Fire Ground were temporarily halted for approximately 6 months in 2016 once Defence was made aware of potential PFAS impact in this area. During this period, testing of the wastewater system was performed (refer to subsequent sections for further details of Fire Ground wastewater system) and modifications to the Fire Ground pond overflow pipework were made to prevent overflow discharge (further details in subsequent sections). To maintain freeboard in the Fire Ground lagoon, water in the lagoon was pumped out and treated off-Site by Veolia. The investigations by Golder Associates (2016-2017) aimed to delineate PFAS impact around the Fire Ground.

AFFF Use

As part of fire-fighting and training operations, PFAS is understood to have been used at the Site since the 1970’s. Based off inventory record from the 1990’s and 2000’s, it is a known source area of AFFF PFAS use.

During the Basic Combat Survivability course trainees become familiar with the charging and use of Stored Pressure Foam Extinguishers (SPFE) and first response firefighting. Trainees are shown the charging and refilling procedures, historically involving the use of firefighting foam, then later training foams and simple pressurised water-filled extinguishers. Historically, trainees would fill their own extinguishers then use these in the training of fire first response scenarios at the Fire Ground. Trainees enter the simulator two at a time and use SPFE to extinguish a gas fire, then rotate through to refill the extinguishers and the training activity is run again. During filling extinguishers can overflow resulting in spills of firefighting foam, extinguishers with excess foam were also either discharged onto the fires or onto grassed areas and washed out, draining onto the concrete before being used by the next class. AFFF was stored in the SPFE filling area in a stainless-steel header tank and a small cup was used to fill the extinguisher with foam, before being taken to a row of taps to be filled with water. Note that it was indicated during interviews that the stainless-steel header tank was likely sourced from a decommissioned ship prior to 2004 (pers. comms WO Ian Waller).

AFFF was used in training activities until at least 2006 at HMAS Cerberus, both in the SPFE and in-line inductor hoses to demonstrate the foam forming characteristics and provide realistic training environments. Since 2004, Defence has progressively replaced 3M Lightwater with Ansulite (3% and 6% AFFF concentration). Around 2008, usage of Ansulite at the Site ceased and was replaced with a Solberg training foam that does not contain PFAS.

The general usage of AFFF for training purposes has been approximately 800 L per year (personal communication with WO Ian Waller). The empty containers are transported off-site twice a year as part of a hazardous waste collection program. There is no evidence that these empty containers have been disposed of on-site. It is noted that an audit was conducted in 2017 and no containers of AFFF were located on Site (pers. comms WO Ian Waller).

Current Layout

The current layout of the Fire Ground comprises a mocked-up listing ship superstructure for Leak-Repair-Live training, fire-fighting training area, drum storage area, above ground water storage tanks, a wastewater treatment system and a wastewater storage pond.

Two separate closed-loop water systems are used at Fire Ground. One system is at the Leak-Repair-Live facility and the other system is at the fire-training area. Water used to simulate flooding at the Leak-Repair-Live facility drains to a storage tank pending chlorination prior to re-use. Wastewater generated during fire-


fighting training is retained in the bunded concrete area, which drains to the oil-water separator then to the Fire Ground lagoon for storage until pumped to the Fire Ground treatment plant. This creates two closed loops with mains water used to make up any losses due to evaporation from land or the storage lagoon.

The current training area is covered in concrete with a perimeter bund. Drain points convey wastewater to an oil-water separator, which drains into the plastic-lined lagoon until being transferred to the on-Site wastewater treatment plant. Treated water is stored in ASTs for re-use at the next training exercise.

These features are indicated in the overhead photograph shown in Figure 4-2.

Figure 4-2 Current layout of the Fire Ground operational area

Historical modifications to the Fire Ground

From the 1970’s through mid-1980’s fire training occurred at the Damage Control Centre (DCC). Figure 4-3, shows aerial imagery taken between 1968 and 1985 that shows changes in features at the DCC.


Figure 4-3 Fire Ground Historical Aerial Imagery – 1968 & 1985

The DCC used liquid hydrocarbons, such as diesel and spent cooking oil, to fuel fires for training purposes. Inspection of historical Site maps indicate that the DCC comprised above-ground storage tanks for fuels. Fires were set on bare earth with runoff collected in three unlined settlement ponds, which are evident in the 1985 image shown on Figure 4-3.

Key changes noted by comparing the 1968 and 1985 aerial photographs was construction of three unlined pits and a likely drainage line from the pits that flowed into the wetlands south of the Fire Ground. EPA Victoria had expressed concern regarding bypass of the triple interceptor trap (TIT) by oily wastewater, which flowed across land to Hanns Inlet. Kinhill (1994) indicate that the original TIT was decommissioned in 1985 and a new TIT with the three clay-lined settling ponds constructed, which are visible in the 1992 imagery presented on Figure 4-4. The floors of these three settling ponds ranged between 9.2 mAHD and 8.3 mAHD. Design maximum water depth in the three ponds was 1.3 m. These settling ponds discharged to Hanns Inlet. Kinhill (op. cit.) note that because of poor tidal flushing in the western portion of Hanns Inlet, discharge of oily wastewater with AFFF would be hazardous to the environment because of the slow degradability of AFFF.

Inspection of 1985 and 1988 imagery indicated that the DCC was upgraded as the RAN School of Survivability and Ship's Safety (SSSS). In the mid-1990’s the fuel source used at the SSSS was changed from liquid fuel to gas.

Comparison between imagery captured in 1992 and 1993 indicate that the northmost unlined pit had been filled in. As shown on Figure 4-4, comparison between the 1993 and 2015 imagery indicates that the unlined pits had been replaced with a single plastic-lined lagoon located where the unlined pits had been constructed. Discussion with Base staff indicates that the plastic-lined lagoon was installed around 1995. The Defence maintenance contractor interviewed after the upgrade indicated that some contaminated soil was excavated and removed, but the quantity, extent and contamination levels were not recorded. During high rainfall events, it was noted that pond overflows occurred and potentially contaminated water went to ground south of the ponds and flowed towards the inlet (creek south of Fire Ground). The lagoon berm was raised in 2016 to reduce the risk of overtopping.


Figure 4-4 Fire Ground Historical Aerial Imagery – 1992, 1993 & 2015

The storage area for 205 L drums was unbunded. An unbunded AST (3,000 L) was used to store AFFF. The AFFF concentrate (typically 6%) was diluted in the AST and then transferred either to fire extinguishers where it was further diluted, or into 20 L containers that were educted into the hoses during fire-fighting exercises. The tank had only a drip tray below the outlets and it was reported that spills of AFFF have potentially occurred (ERM 2007).

The Fire Ground treatment plant does not remove PFAS from the wastewater and that until 2017 the treatment plant had a connection via a flocculation tank to the sanitary sewer that conveys Site sewage to the SEW Somers recycled water plant. This connection was un-metered, but it is not likely that significant volumes of effluent were discharged via this connection.

Discharge to land and water

Historically, the overflow from the ponds discharged from drainage lines connected to the unlined ponds or overtopped the pond walls. The overflow setup from the pond in the Fire Ground changed when the pond system was upgraded on multiple occasions and the outlet location may have changed (personal correspondence with BSOM John Goodchap.

The overflow system was also changed after initial testing confirmed PFAS detection in the area (personal communication with WO Ian Waller). The pond overflow configuration was modified such that the inlet was capped and extended above the lagoon walls to prevent further overflow via the drain pipe.

Other events

Prior to around 2003 the Fire Ground water system was isolated from the Site mains water system by a flap valve. Site staff indicated that on one occasion as water in the fire-training loop was being pumped excessive water pressure drove some of the water out into the mains water line that supplied the laundry used to wash the protective clothing worn by trainees at the Fire Ground. Foam was noticed coming out of some of the washing machines, which was assumed to reflect AFFF in the wash water. This event prompted replacement of the flap valve with a non-return valve to prevent this type of event occurring again.

The BSOM described an event in which there was a combination of king tide and strong south-south-easterly winds, which resulted in flooding of the closed Rifle Range Road landfill and the creek area south of the Fire Ground. This caused overflow of the bridge on Rifle Range Road near the closed Rifle Range Road landfill. This has occurred once in eleven years between 2007 and 2018 (personal communication with the BSOM).


4.2.2 Fire Station / Ornamental Lake The Fire Station building was constructed in the 1940s-1950s based on historical aerial images. It is currently used as an operations base for fire-fighting activities. This is a known source area of AFFF PFAS use. The Fire Station has been operated by a contractor (currently Broadspectrum Ltd) since the mid-1990’s. Prior to that time the Fire Station was manned by Navy fire fighters. Fire appliances able to apply AFFF continue to be garaged at the Fire Station. Broadspectrum staff stated that AFFF has not been used at the Fire Station since 2008. In 2009, Aurecon staff noted that only non-PFAS training foams were used for training at the Fire Ground, but 6% 3M Lightwater (four containers of 20 L each) was stored on spill pallets at the Fire Station. The Fire Station staff indicated that these containers were subsequently transferred in 2008 to RAAF Site East Sale.

Discussions with Base staff (Les Moseley) indicated that in the past 40 years there had not been any building or vehicle fires at the Site except for a fire in the former medical centre (now used for accommodation of officers), which was extinguished by the building mains-water-charged fire-fighting system (that is, the Fire Station staff did not respond to this fire). As further discussed in the Site boundary events section, two bush fires occurred in 2008 with one bush fire on the eastern boundary and one on the southern shoreline of Hanns Inlet.

Current practise does not use PFAS-based AFFF, but concentrate is stored at the Fire Station to charge the foam appliance. PFAS had been stored and intermittently used in foam appliances through 2008. Site staff indicated that PFAS had been sprayed in the grassed area between the south edge of the Fire Station and the Ornamental Lake.

The historical aerial images indicate that the Ornamental Lake was constructed around 1960. It used to be squarer and larger but did not advance north of its current position. These configuration changes to the current setup were made around the early 1970s.

4.2.3 Underground and Aboveground Storage Tank areas The storage tanks are situated across the operational area of Site and have been given CSR designations of VT0191, VT0192, VT0369, VT0370, VT0371, VT0372 and VT0373.

The UST, CER02, in VT0191 was a decommissioned UST in front of Millies General Store. There is potential for the leakage of heating oil. This UST was in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

The UST, CER01, and other ASTs in VT0192 were used for fuel storage. These tanks were in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

The two USTs, CER03, in VT0369 were decommissioned USTs located west and south east of Building 25. There is potential for leaks and spills of hydrocarbons in the area. These USTs were in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

The petrol station USTs in VT0370 were used for fuel storage. It was reported that one of the USTs had a leak. There is also potential for leaks and spills of solvents from the old mechanics building in the area. These USTs were in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

The filling station USTs in VT0371 were used for fuel storage. There is the potential for leaks and spills of hydrocarbons in the area. This UST was in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

The AST near Building 49 in VT0372 is used for fuel storage. There is the potential for leaks and spills of hydrocarbons in the area. This AST was in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

The AST to the south of Building 151 (Ward Room) in VT0373 was used for diesel storage. This AST was in operation during period of AFFF usage, hence use of AFFF in the area cannot be discounted

There is no evidence of a fire suppression system associated with these fuel storage areas. However, the use of handheld Stored Pressure Foam Extinguishers (SPFE) in these areas cannot be discounted. These


areas are not considered to be potential major sources of PFAS impact and will be assessed as part of groundwater monitoring across the entire operational area.

4.2.4 Emergency response use A historical incident was identified during which AFFF residue was potentially present in the hose and tank of firefighting equipment.

Bush Fire ~ 2008

During discussions with Base staff (Les Moseley and John Goodchap) a bush fire was noted to have occurred approximately 10 years ago (circa 2008) along a portion of the eastern Site boundary (north of the permanent residential area) and in the bush along the south shore of Hanns Inlet (north of the rifle range). The Base Fire Station responded to the fire on the eastern boundary, which entailed pulling hoses into the area to fight the fire with water. AFFF was not used, however there is the potential for AFFF residue to have been present in the hose and tanks. The fire on the shore of Hanns Inlet was not fought as unexploded ordnance was heard to be detonating so it was unsafe to enter the area. It is possible that the fire zone was impacted by PFAS and is considered a potential secondary source.

4.2.5 Other areas of potential use and storage There are several other areas where foam-based fire extinguishers were potentially located. A discussion of the possible use and storage of AFFF in other key areas is provided in this section.

Communication school

PFAS may have been used to charge foam-based fire extinguishers, which were noted by Kinhill (1994) at the Communication School (four extinguishers). However, no evidence of AFFF use in this area was indicated from Site interviews and desktop review. This area is hydraulically down gradient from the Fire Ground.

Former dry-cleaning facility and former catering school

The former dry-cleaning facility was reportedly operated until the 1960’s pre-dating the use of AFFF (ERM 2007). The nearby former catering school was demolished in 2000, so there is potential for use of handheld SPFE. However, no evidence of AFFF use or storage in this area was indicated from Site interviews and desktop review. The area is now and unsealed car park, which introduces the potential for non-AFFF derived PFAS associated with cars. This area is also hydraulically down gradient from the Fire Ground.

Coal loading area

Foam-based fire extinguishers may have also been stored at the Marina near the coal loading area. However, there is no evidence of AFFF use or storage in this area from Site interviews and desktop review. This area is hydraulically down gradient from the Fire Ground.

Power house

The power house was operated until1985/1986, so there is potential for storage and / use of AFFF. However, no evidence of AFFF use or storage in this area was indicated from Site interviews and desktop review. This area is hydraulically down gradient from the Fire Ground.

Gun Club

There is no evidence of AFFF use or storage in this area from Site interviews and desktop review.

Rifle range and ordnance areas

Water for fire control at the rifle range is reportedly delivered from a fixed sprinkler type system (pers. comms BSOM). There is no evidence of AFFF use or storage in this area from Site interviews and desktop review. This area is separated topographically from the former STP by an intervening drainage.


4.3. AFFF waste management The current waste management practice is for training foam containers to be collected twice annually by HAZMAT disposal contractors (pers. comms Ian Waller). It is believed that this system was in place during the period of AFFF storage and use at the Fire Ground. The following areas have been identified from the cited information sources to either be areas that are potentially affected by AFFF related waste.

4.3.1. On-Site Landfilling Anecdotal and prior reported evidence identifies historic disposal of AFFF source, waste packaging materials and potentially secondary impacted materials as follows.

Closed Landfill next to the Fire Ground (VT0364)

The Closed Landfill next to the Fire Ground is an unlined landfill that operated since around 1915 (ERM 2007). This landfill does not appear in historical images from the 1960’s in which earthworks appear to have levelled out the area. As this landfill was closed and did not receive PFAS impacted material, it has been discounted as a potential PFAS source. However, this area requires further investigation due to the proximity to the Fire Ground.

Closed Rifle Range Road Landfill (VT0365)

The Rifle Range Road Landfill was an unlined landfill that was operated through the late 1960’s to early 1970’s. Construction debris (including asbestos) placed was also placed here in the 1990’s (ERM 2007). The period of operation of this landfill means that there is the potential for disposal of used AFFF containers in this area. This area is prone to flooding caused by a combination of a king tide and strong south-south-easterly winds.

Closed outdoor swimming pool landfill (VT0366)

The closed outdoor swimming pool landfill (also referred to as the former swimming pool landfill) is a concrete-lined former swimming pool that is located to the south of the main operating area, more specifically to the south of the Communications School. It was filled with construction debris between 1991 and 1992 (ERM 2007). It has a direct pipe connection to Hanns Inlet. This landfill potentially contains asbestos. Although there is no evidence that this landfill received PFAS impacted waste, it was filled during a period of PFAS use, hence it is carried forward as a potential minor source.

Closed indoor swimming pool landfill (VT0380)

The closed outdoor swimming pool landfill (formerly Building 193) is a concrete-lined pool that received construction debris and soil, including potentially asbestos containing materials from the roof. Demolition works were completed around 1997 (ERM 2007). Although there is no evidence that this landfill received PFAS impacted waste, it was filled during a period of PFAS use, hence it is carried forward as a potential minor source.

Closed Stony Point landfill (VT0001)

The Stony Point landfill is an unlined landfill that was previously a quarry. The former quarry was operated from 1958 until the 1980’s. It was required during the construction of the Stony Point ‘Ports and Harbours’ facility. This area was excavated to remove the clay soils required for the construction of the Cerberus Golf Course (ERM 2007).

The borrow pits at the Stony Point landfill were filled with vegetation and mulch from around the facility. This landfill was reportedly burned weekly. The predominant waste was organic and gardening wastes, such as tree butts from the surrounding area (Kinhill 1994). It was also reported that some medical wastes were buried in the pits, as well as other solid waste including asphalt, bitumen, concrete, timber and packaging wastes (Kinhill 1994), which is presumed to come from nearby as this area is difficult to access from Site. The landfill closed in the 1990’s because of excessive weed growth in the area dominating native vegetation. Site inspections by ERM (2007) revealed significant amounts of landfilled materials visible above surface soils.


As this landfill received mainly green waste from the surrounding area, it is unlikely to have received large quantities of PFAS impacted material. It has been discounted as a potential PFAS source and not investigated further.

4.3.2. Other AFFF waste disposal Anecdotal and prior reported evidence identifies historic transport of potentially PFAS containing material to the following areas of Site.

Former STP (VT0375)

The on-site former STP is a likely location of former AFFF PFAS residue discharge; also received construction debris during its decommissioning. It is understood to have operated between the 1950’s and early 2000’s (HLA, 2001). The Former STP received wastewater from the operational area of the Site, mainly from the on-Site residences, with smaller contributions from administration and operations buildings (including the Fire Ground).

Initially, three lagoons were used to treat sewage prior to discharge via a drain into the western arm of Hanns Inlet. A treatment plant comprising concrete tanks and trickling filters was constructed north of the lagoons at some point in time, which could not be established. Upon decommissioning in the early 2000’s, Site sewage was conveyed to the SEW Hastings STP (now the Somers Recycled Water Plant) for treatment. A Broadspectrum staff member described the disposal of a small quantity of AFFF near the fire hydrant near the former STP.

The Former STP discharged via drains from the final southernmost lagoon to the nearby woodlands across Rifle Range Road. The drainage channels eventually discharge to Hanns Inlet.

Sullage Pit (VT0363)

The Sullage Pit is a known location of the disposal of asbestos, medical waste and drums, then received spoil and vegetation removed during re-instatement of the channel in Hanns Inlet in 1988 and 2006 (ERM 2007). As this spoil may have been impacted by PFAS, this area cannot be discounted as a secondary source.

A bund wall was extended in 2006 to create a storage area to contain the received spoil from Hanns Inlet. This spoil was mainly organic matter with small amount of sediment. The dredge used for the works was a suction and not a bucket dredge, hence there was a significant amount of surface water in the mixture (see Figure 4-5). The bund wall captured the surface water, which was slowly released back into Hanns Inlet to prevent increases in turbidity. Note that the works were to reinstate the original founding depth, and the inlet was not deepened (pers. comms. Brian Dunn).


Figure 4-5 Sullage Pit fill area for spoils received from reinstatement of channel in Hanns Inlet

The low solids concentration of this mixture is likely to result in an even distribution of PFAS impact across the Sullage Pit. As the spoil was removed from the northern arm of Hanns Inlet, it is unlikely that there are high PFAS concentrations as it is not on the pathway from the Fire Ground (refer to Figure 4-6).

Figure 4-6 Area of sediment removed from Hanns Inlet and transferred to the Sullage Pit


This fill zone of the sullage pit is marked with warning signs to avoid the quicksand. Although this region has consolidated and dried since filling in 2006, sampling was conducted from the solid berm.

Fire Ground filter wash-down area (in or around VT0192)

Base staff indicated that filters from the water treatment plant at the Fire Ground may have been cleaned in the area near Building 136, which is located north of the Fire Ground and encompassed by CSR area VT0192. This area was also used for fuel storage (see below).

4.3.3 Site history summary

The Site history including the AFFF storage and transfer areas, AFFF usage, spoils, losses, incidents and accidents (including fires), discharges to land and water, waste produced, waste disposal locations and imported fill and earthmoving activities carried out on the site is summarised in Figure 4-7.


Figure 4-7 Timeline summary of Site history (PFAS related)


4.4 Non-AFFF PFAS sources Somers Recycled Water Treatment Plant (Class C Recycled Water)

Information provided by South East Water indicates that PFAS was detected in Class C recycled water produced at the SEW Somers RWTP, which is located west of the site. The SEW Somers RWTP provides Class C recycled water to the Site, which had been used to irrigate sports fields at the Site until January 2018.

Audits of effluent reuse indicate that recycled water has been applied to Site sports fields and ovals by tanker since October 2006 and via a piped system since 2008. The summer-time irrigation of the Site sports fields with typically 25 ML/year of recycled water from Somers RWTP presents a potential PFAS pathway. Communication with SEW indicates that PFAS was detected in Class C recycled water at concentrations in the units to tens of ng/L. At the time of issuing this DSI report approval from South East Water to include this data in the report had not been formally provided; therefore, this data has not been included. Refer to Section 7 for discussion of on-Site sampling of the recycled water for this investigation.

Base staff (BSOM) advised that the handover date of the HMAS Cerberus Recycled Water Project was 11th of August 2008, which included some water disbursement as part of handover testing. The system began full operation in early October 2008. The use of recycled water on-site was discontinued on 29th of January 2018.

The PFAS in the Class C recycled water produced at the SEW Somers RWTP is believed to originate predominantly from non-Site sources of PFAS. The Site sends approximately 0.5 ML/day of wastewater to Somers RWTP, which mixed with the typical 6-8 ML/day flowrate from the community (data from SEW).

As the use of recycled water has been discontinued, this is not considered as an ongoing source. However, it is likely that the Sports Fields were impacted and are a potential secondary source.

Off-Site residential sources

The storm-water drainage system conveys storm-water from off-Site onto the Site at seven inflows on the north-eastern, northern and western land boundaries (MWH/Stantech 2017). This introduces possible off-Site residential sources of PFAS entering the Site via the storm-water drains.

On-Site residential sources

There is the potential for non-AFFF PFAS impact associated with on-Site residential sources. Examples of these potential non-AFFF sources include PFAS in car wax, stain-resistant coatings for carpets and textiles, car cleaning products and personal care products (USEPA, 2018). These sources were not investigated further but contribution from these sources was considered during assessment of impacted areas.

4.5 Summary of previous Site investigations

4.5.1 Background information and previous investigations Defence provided Aurecon with 41 environmental and / or site contamination investigations reports for the Site for review and consideration in the design and undertaking of the DSI works.

Our initial review identified the following reports as being of relevant probative value to assist in the understanding of the historical storage and use of AFFF on-site and potential contaminant sources, potential transport or migration pathways and potential receptors at risk:

Dispersion and Tidal Flushing in Hanns Inlet, Pollock, T. J. and Wallis, I. G. (August 1974)

Environment Audit Report – HMAS Cerberus, Kinhill (June 1994)

Stage 1 Environmental Investigation, ERM (November 2007)

Stage 2 Environmental Assessment, SMEC (2008)

Targeted soil investigation – fire training facility, EES (September 2010)


Groundwater monitoring report for HMAS Cerberus, Environmental Earth Sciences (December 2013)

Groundwater Monitoring Report for HMAS Cerberus, Environmental Earth Sciences (May 2014)


Briefing Paper – Potential Onsite Containment of PFAS Contaminated Soil, Golder Associates (August 2016)

AFFF Summary Report, Agon Environmental (July 2016)

In-Ground Contamination-site Assessment, Golder Associated (June 2016)


Delineation Assessment at Existing RAN SSSS, Golder Associates (January 2017)

Briefing Paper – PFAS Soil Contamination in Former Fire Training Area, Golder Associates (February 2017)

Further Groundwater Assessment RAN SSSS, Golder Associates (May 2017)

HMAS Cerberus Integrated Surface Water Quality Management Plan, MWH Stantec (June 2017)

Aurecon undertook a review of these reports for the purposes of informing the development of a CSM, presented in Section 3, and the initial works program.

4.5.2 Previously identified PFAS contamination A review of reports prepared by Kinhill (1994), ERM (2007), SMEC-WSP (2008), Aurecon (2009) and Golder (2016a, 2016b, 2017a through 2017c) noted the following information pertaining to site history and the historical use of PFAS at the Site.

The Site has been operating as a naval training facility since 1921. Since commencing operations, numerous chemicals have been stored and used at the Site. Fuels, oils, dry-cleaning fluids, lead-based paints, ship anti-foulants and PFAS are noted as potential chemicals of concern (PCOCs). PFAS was used at the Fire Station and the Fire Ground. PFAS may have been used to charge foam-based fire extinguishers, which were noted by Kinhill (1994) at the Communication School (four extinguishers) and likely to have been located at the former petrol station and marina.

4.4.4.2.1 Fire Ground and nearby wetlands

The Fire Ground is identified as a known contaminated area on the Defence CSR with the relevant assigned reference being VT0067. This area has undergone investigation to delineate PFAS contamination in the groundwater and soil (Golder 2016a through 2017c). The reports produced by Golder Associates for redevelopment of HMAS Cerberus include PFOS, PFOA and 6:2FTS as PCOCs. This investigation involved the installation of three groundwater monitoring wells on or surrounding the Fire Ground (MWSSS, MW103, MW117), and a further three on the groundwater flow path to the nearby wetlands (MW121, MW122S, MW122D). Further soil and concrete samples were collected and analysed from test pits and bore holes on and around the Fire Ground. This investigation highlighted the Fire Ground as the main source of PFAS, which identified a narrow plume of PFAS impacted groundwater to the south of the Fire Ground.

Key findings from the previous investigations (Golder 2016a through 2017c) identify PFAS within soils, concrete pavements and groundwater within the Fire Ground as shown in Table 4-2.

Table 4-2 Maximum measured PFAS concentrations within various media recovered from within and surrounding the Fire Ground

Area PFOS PFOA 6:2 FTS PFHxS

Soil 2.5 mg/kg 0.695 mg/kg 0.1 mg/kg 0.0844 mg/kg

Concrete 0.508 mg/kg 0.0134 mg/kg 0.124 mg/kg



Groundwater 86.6 µg/L 39.0 µg/L <0.01 µg/L 31.9 µg/L

Other relevant findings indicate:

PFOS concentrations up to 25 µg/L in groundwater have been reported in a monitoring well (MW121) which is located half way (presumed to be down-hydraulic gradient) to the creek south of the Fire Ground

PFOS concentrations up to 0.31 µg/L have been reported for surface water samples collected from the creek immediately south of the Fire Ground (MWH/Stantec 2017)

Of the 17 groundwater monitoring wells at the Fire Ground, 10 were dry, which reflects a drop-in groundwater levels since these wells were installed by SMEC in 2008. The status of these groundwater wells is an important consideration for future sampling of existing monitoring wells

Our review of the previously collected data indicates that the soil, concrete and groundwater conditions at the Fire Ground are sufficiently characterised to confirm that the Fire Ground (and the three historical settling ponds that received spent training water and AFFF from the Fire Ground) is a primary source of PFAS and is likely to be the most significant source of PFAS at the Site.

4.4.2.2 Fire Station and Ornamental Lake

The Fire Station is not identified as a known contaminated area on the Defence CSR. However, the Fire Station was identified as a contamination area of concern due to potential PFAS storage and use. Further details on the Fire Station are not provided in previous studies. The area contains a Building for the firefighters, parking area for fire trucks and an Ornamental Lake.

PFAS is known to have been stored and used within at or near the Fire Station based on discussion with Fire Station staff. The investigations by Golder Associates for redevelopment of HMAS Cerberus included installation of two groundwater monitoring wells and collection of soil samples. These previous investigations reported residual PFAS within soils and groundwater within and immediately surrounding the Fire Station as shown in Table 4-3.

Table 4-3 Maximum measured PFAS concentrations within various media recovered from within and surrounding the Fire Station


Soil 0.0026 mg/kg <0.0005 mg/kg <0.005 mg/kg 0.0016 mg/kg

Groundwater 0.004 µg/L <0.002 µg/L <0.01 µg/L 0.257 µg/L

Our review of the previously collected data indicates that the soil and groundwater conditions at the Fire Station are sufficiently characterised to confirm that the Fire Station is a primary source of PFAS. However, the lateral and vertical extent of PFAS-impacted soils had not been delineated.

4.4.2.3 Storm-water drains

Surface water investigations indicated that there was a PFAS source entering the Site directly above the Former STP, where the maximum inflow surface water concentration was 0.008 µg/L PFOS at Inflow 6. Inflow 6 is located on the western boundary, where surface water runoff is originating from adjacent farms and residential properties (MWH/Stantec 2017).

This previous investigation reported PFAS within surface water at storm-water outlets as shown in Table 4-4.

Table 4-4 Maximum measured PFAS concentrations in storm-water system outlets


Storm-water inflow 0.008 µg/L <0.002 µg/L <0.005 µg/L <0.002 µg/L

Our review of the previously collected data indicates that the surface water and sediment conditions in the storm-water system are sufficiently characterised to confirm that the storm-water system is a primary source of PFAS.

4.4.2.4 Fire Ground Water Filter Washdown Area


The Filter Washdown area was indicated by Base staff during interviews to be in or around the contaminated area VT0192 on the Defence CSR. The investigations by Golder Associates for redevelopment of HMAS Cerberus included sampling of soils from bore holes and groundwater sampling from existing wells. These previous investigations reported residual PFAS within soils and groundwater in the area as shown in Table 4-5.

Table 4-5 Maximum measured PFAS concentrations within various media recovered from the potential Fire Ground water filter wash-down area


Soil 0.0081 mg/kg <0.0002 mg/kg <0.0005 mg/kg 0.0007 mg/kg

Groundwater 0.026 µg/L <0.002 µg/L <0.01 µg/L 0.367 µg/L

Our review of the previously collected data indicates that the soil and groundwater conditions at the Fire Ground Water Filter Washdown Area are sufficiently characterised to confirm that there is PFAS impact at the Fire Ground Water Filter Washdown Area. This area is to be incorporated in the Fire Ground investigation area.

Other potential PFAS sources

No previous PFAS specific investigations were undertaken in respect of the following Site areas:

The Former STP

Sullage Pit

Closed landfills

Sports Fields

Fuel storage areas

Bushfire Zone

Hanns Inlet sediment and pore water

Closed landfills

Fuel storage tanks

Other potential minor sources

4.5.3 Previously identified PFAS receptors 4.4.3.1 Hanns Inlet

The inferred groundwater flow paths and surface water flows indicate that Hanns Inlet is a potential receptor of PFAS from primary sources. Further, there is the potential for the sediments and pore water within Hanns Inlet to become secondary sources.

Three samples of surface water collected by GHD (2016) during preliminary PFAS testing (see Figure 4-8).


Figure 4-8 Locations of Preliminary Samples of Surface Water (GHD, 2016)

Results for three samples of surface water collected along the shoreline of Hanns Inlet indicate that PFAS (as 1.58 µg/L of PFOS) was only detected in CER_SW03. Our review of the previously collected data indicates that the surface water, sediment and pore water conditions in Hanns Inlet have not been sufficiently characterised to confirm whether there is a complete pathway from primary sources to ecological receptors in Hanns Inlet. Additionally, it is not confirmed that the sediment and pore water in Hanns Inlet is a secondary source of PFAS impact.

Fishing is not permitted in Hanns Inlet or Naval waters. These waters are patrolled by water police. Some species, such as flathead and whiting, are likely to remain inside of Hanns Inlet. Other species, such as snapper, are migratory and may leave Hanns Inlet and be either eaten by other fauna or caught for human consumption.

4.4.3.2 Off-site residents

GHD (2016) also collected one sample of groundwater as part of the formal preliminary sampling program and three additional samples from private wells located to the west and north of the Site. PFAS concentrations were below laboratory detection limits in all of these samples. On-Site soil samples were collected by Golder (2016) across the region north of the operational area of Site. This area is potentially on the pathway to off-Site residents. This area had detectable PFAS levels in 16 of the 61 samples analysed, where the maximum detected concentration was 0.008 mg/kg PFOS (note that this data has been included in Appendix A - Figure 25).

Our review of the previously collected data indicates that the groundwater and soil conditions at the boundary of the Site have not been sufficiently characterised to confirm whether there is a complete pathway from primary sources to off-Site residents.


4.5.4 Previously identified non-PFAS contamination Sources of on-site non-PFAS contamination are VOCs associated with the former Dry Cleaners (VT0368), hydrocarbons from fuel storages (VT0067, VT0192, VT0363, VT0365, VT0369, VT0370 and VT37113), BTEX (VT0192 and VT0369), heavy metals (VT0363 and VT0378) and asbestos containing material from landfills (VT0001, VT0365).

Petroleum hydrocarbon impacts in the C16-C34 fraction range have previously been reported in both soils and groundwater within and near the Fire Ground. Staining associated with the light paraffin oil (Ordina Oil) was observed on the ground near the storage tanks in the Fire Ground, where 500 L were reportedly discharged to an unsealed surface.

Soil samples recovered from the Rifle Range Road Landfill recorded heavy metal concentrations above ASC NEPM (1999) HIL ‘F’ guidelines with lead concentrations of 1,950 mg/kg at 1.2 mbgl and mercury concentrations of 319 mg/kg at 0.5 mg/kg. This landfill was also TPH impacted with a recorded TPH C10-C36 concentration of 4,920 mg/kg at 1.5 mbgl. Asbestos containing materials were also detected in the soil in this area

The extent of a PCE plume from the former Dry Cleaners is also uncertain. SMEC (2008) state that the PCE in groundwater has the potential to move beyond the CSR. A maximum PCE of 978 µg/L (guideline value of 10 µg/L) in groundwater was reported. The monitoring of solvents in groundwater suggests a 50% reduction from 2014 to 2016.

In accordance with Defence instructions no further investigation or enquiry into other potential non-PFAS sources or the delineation of the extent of non-PFAS sourced contamination was undertaken as part of the DSI.

4.5.5 Use of historic data in current investigation Aurecon has conducted a review of the quality and completeness of the data from previous investigations (Golder 2016a through 2017c). The soil laboratory data has been relied upon and presented in the figures shown for the current investigation. The assessment of the data quality is presented in Appendix H.

13 The naming of monitoring wells in and around VT0371 during ongoing groundwater monitoring has shown a deviation from original installation descriptions. This issue is due to Agon (2016) describing GHD installed wells, which were originally named GW01-VT082, GW02-VT0374 and GW03-VT0371, as GW01-VT0371, GW02-VT0371 and GW03-VT0371, respectively. However, there are already SMEC installed wells, GW01-VT0371 and GW02-VT0371, hence it is impossible to develop a consistent naming convention that agrees with all previous reports. The naming convention from the most recent reports has been adopted to avoid ongoing confusion. The original GW01-VT0371 and GW02-VT0371 wells have been renamed GW04-VT0371 and GW05-VT0371 so that there is no double up of well names. The adopted well names are summarised below.

Original name Reference Ongoing use Reference Adopted name GW01-VT0382 GHD (2016) GW01-VT0371 Agon (2016) GW01-VT0371 GW02-VT0374 GHD (2016) GW02-VT0371 Agon (2016) GW02-VT0371 GW03-VT0371 GHD (2016) GW03-VT0371 Agon (2016) GW03-VT0371 GW01-VT0371 SMEC (2008) None GW04-VT0371 GW02-VT0371 SMEC (2008) None GW05-VT0371


5 Conceptual Site Model The findings from site investigations, interviews and previous site investigations by others were used to develop a preliminary CSM. The CSM represents on-site sources of PFAS contamination, on- and off-Site receptors that could be affected through exposure to these chemicals, and pathways by which receptors could be exposed to the Site-derived PFAS. An iterative process was used to develop the Site-specific CSM. The conduct of these works has been in accordance with Defence Guidance Document A (Defence 2016).

Cross-sectional visualisations of key source areas and pathways are presented in Appendix J.

5.1 Known and potential sources A review of potential sources of PFAS contamination associated with the former use, storage and handling of historical AFFF products and the disposal of their waste products was undertaken. These works have included review of prior reports (provided post works commission) and additional information collected through inspections at the Site and interviews with Site personnel and contractors familiar with the former use and management of AFFF products.

These potential sources have been assessed and the summarised in Table 5-1.

Table 5-1 Known and potential PFAS source areas

CSR Area Comment Source

status Carried

forward as a source?

VT0067 Fire Ground and nearby wetlands Confirmed PFAS use and source

Known Yes

Fire Station/Ornamental Lake Confirmed PFAS use and source

Known Yes

VT0192 Fire Ground Water Filter Wash-down Area and UST (CER01) and ASTs

Likely minor PFAS impact indicated by Golder (2016)

Known Yes

Storm-water drains Confirmed PFAS source Known Yes VT0365 Former STP Unconfirmed, but likely PFAS

source Likely Yes

Somers RWTP (Recycled Water) Investigation to focus on Sports Fields as secondary source as SW has been discontinued

Likely, but no longer in use

No

Sports Fields Unconfirmed potential PFAS source

Potential Yes

Bushfire zone Unconfirmed potential PFAS source

Potential Yes


Unconfirmed potential PFAS source

Potential Yes

VT0363 Sullage Pit Unconfirmed potential PFAS source

Potential Yes

VT0365 Closed Rifle Range Road landfill Unconfirmed potential minor PFAS source

Potential Yes

VT0366 Closed outdoor swimming pool landfill

Unconfirmed potential minor PFAS source

Potential Yes

Communications school Unconfirmed potential minor PFAS source

Potential Yes

VT0380 Closed indoor swimming pool landfill

Unconfirmed potential minor PFAS source

Potential Yes

VT0191 UST (CER2) Unconfirmed potential minor PFAS source

Potential Yes

VT0369 USTs (CER03) Unconfirmed potential minor PFAS source

Potential Yes


VT0370 Former Petrol Station USTs Unconfirmed potential minor PFAS source

Potential Yes

VT0371 Filling Station USTs Unconfirmed potential minor PFAS source

Potential Yes

VT0372 Demonstration Building AST Unconfirmed potential minor PFAS source

Potential Yes

VT0373 Ward Room AST Unconfirmed potential minor PFAS source

Potential Yes

VT0374 Powerhouse Unconfirmed potential minor PFAS source

Potential Yes

VT0367 Coal loading area Unconfirmed potential minor PFAS source

Potential Yes

VT0368 Former dry-cleaning facility Unconfirmed potential minor PFAS source

Potential Yes

VT0364 Fire Ground landfill Appears to have been closed before AFFF use on-Site, this is incorporated into Fire Ground area

Unlikely No

VT0001 Stony Point landfill No evidence of PFAS impact Unlikely No VT0002 Williams Rifle Range No evidence of PFAS impact Unlikely No VT0066 Sandy Point Ordnance area No evidence of PFAS impact Unlikely No VT0376 Sandy point road - Oil sludge No evidence of PFAS impact Unlikely No VT0377 Building 154 - Pesticide storage No evidence of PFAS impact Unlikely No VT0378 Slipway group - Vessel cleaning No evidence of PFAS impact Unlikely No VT0381 Former Railway line bend No evidence of PFAS impact Unlikely No VT0382 Tank oil feed line from Ward Room No evidence of PFAS impact Unlikely No VT0384 Building 106/108 floor No evidence of PFAS impact Unlikely No VT0386 Car park east of building 251 -

former catering school No evidence of PFAS impact Unlikely No

VT0387 Gun club No evidence of PFAS impact Unlikely No VIC1057 Buried redundant steam pipes No evidence of PFAS impact Unlikely No VIC1066 Asbestos conduit No evidence of PFAS impact Unlikely No

Many of the sources are located in areas of similar land use and exposure scenarios. The major known sources were grouped with the surrounding area for investigation and discussion purposes, and potential minor sources in the operating area were also grouped due to similar exposure scenarios.

The known and potential sources summarised in Table 5-1 were grouped as follows;

Fire Ground:

− Training area and wetlands to the south straddling south creek

− Fire Ground landfill

− Fire Ground Water Filter Wash-down Area and UST (CER01) and ASTs

Fire Station and Ornamental Lake

− Fire Station building and operational area

− Grassland surrounding Fire Station

− Ornamental Lake

Former STP

− Decommissioned trickling filter wastewater treatment plant

− Three current settling lagoons

Sullage Pit

Sports Fields


− Sports Field to north of Cook Road

− Main Sports Fields to south of Cook Road

Potential minor sources in the main operating area

− Closed Rifle Range Road landfill

− Closed outdoor swimming pool landfill and Communications school

− Closed indoor swimming pool landfill

− UST West of Building 192 (CER2)

− USTs between Nelson Rd and Building 25 (CER03)

− Former Petrol Station USTs

− Filling Station USTs

− Demonstration Building AST

− Ward Room AST

− Powerhouse

− Coal loading area

− Former dry-cleaning facility

Bushfire Zone

Hanns Inlet Sediment and Pore Water

Storm-water drains

− Storm-water inflows

− Storm-water outflows

It should be noted that the Somers RWTP no longer provides recycled water for irrigation of the Sports Fields, but the Sports Fields are potential secondary sources. Further assessment of Somers RWTP was not continued as it is not possible to distinguish Site-derived PFAS in wastewater from other PFAS sources beyond the Site borders. The relative wastewater flow from the Site to Somers RWTO is small (approximately 5-10%) compared to other sources.

The potential PFAS sources carried forward were further investigated in the field program, together with known and potential pathways and receptors summarised in the following sections.

5.2 Known and potentially affected media This section summarises the known and potentially affected media based on the Site history and interviews.

The known primary sources and their affected media are summarised as follows:

Fire Ground (including Fire Ground landfill and nearby wetlands along South Creek)

− Collected water in the historical storage ponds or current storage dam

− Collected water in the storage tanks

− Concrete pavement

− Grass and soils on the Fire Ground and surrounding area

− Groundwater flowing towards wetlands

− Surface water in the wetlands and the South Creek flowing towards Hanns Inlet

Fire Station/Ornamental Lake

− Grass and soil located between the Fire Station and the Ornamental Lake


− Sediment and surface water in the adjacent Ornamental Lake

− Concrete pavement and storm-water pipes at the Fire Station

− Concrete pipe draining the Ornamental Lake to Hanns Inlet

Storm-water drains

− Concrete drainpipes and culverts

− Surface water and sediment in storm-water / interceptor pits and pipes

The potential sources and their affected media include:

Former STP

− Collected water in the lagoon system

− Sludge/sediment in the lagoon system

− Grass and soils on the Former STP and surrounding area

− Groundwater flowing towards West Creek

− Surface water in the West Creek flowing towards Hanns Inlet

Sports Fields irrigated with recycled water

− Grass and soil on the Sporting Grounds

Sullage Pit that received spoil from channel maintenance

− Sediment and surface water in area filled with Hanns Inlet sediment and vegetation

− Grass and soil in surrounding area

− Groundwater flowing towards Hanns Inlet

Bushfire zone

− Grass and soil at the area of bushfire (note that it was stated that no AFFF was used in this area, which was responded to by the CFA, Base staff and aerial water bombers)


Potential minor sources

− Grass and soil located at the closed Rifle Range Road landfill, closed indoor swimming pool landfill, closed outdoor swimming pool landfill/Communications school and former petrol station, and Ward Room AST

− Grass and soil located at the former coal loading area

− Gravel and soil at the former dry-cleaning facility

− Communications school soil and nearby surface water

− Concrete and bitumen at some former fuel storage areas and powerhouse

− Surface water in drains within the fuel storage areas


Hanns Inlet (including south and East Creeks)

− Surface water, sediment and porewater in Hanns Inlet

− Aquatic biota


5.3 Known and potential human and ecological receptors Aurecon have identified potential receptors that could be exposed to PFAS originating from the Site, based on Site history, interviews and Project Control Group meetings.

These potential human and ecological receptors have been grouped according to likely exposure scenarios (noting that there is some cross-over between groups).

On-Site human receptors (Commercial/Industrial)

Base Workers and Trainees, which comprise (but are not limited to):

− Base operations workers

− Defence personnel

− Trainees, which includes members of sports teams that use the Sports Fields

− General administrative staff

− Base facilities staff

− Other staff performing activities of commercial/industrial nature

Intrusive construction workers, which comprise (but are not limited to):

− Construction or maintenance workers involved in Site redevelopment works

− Workers performing channel maintenance in Hanns Inlet

− Other construction or maintenance workers performing activities of commercial/industrial nature

On-Site human receptors (Public open space)

Site visitors, which comprise (but are not limited to):

− Visiting personnel

− Visiting sports teams using the Sports Fields

− Contractors and other non-recreational Site visitors 14

− Trainee and Base workers’ family and friends (visiting for graduation ceremonies and other events)

On-Site human receptors (Residential)

Childcare attendees, which comprise (but are not limited to):

− Children attending childcare

− Parents / carers

− Childcare centre staff

Permanent on-Site residents, which comprise (but are not limited to):

− Base workers living with family in permanent accommodation

Temporary on-Site residents, which comprise (but are not limited to):

− Trainees staying in temporary accommodation

Off-Site human receptors (Residential)

Commercial producers of agricultural products, which comprise (but are not limited to):

− Off-Site producers of cattle

Commercial producers of aquaculture products, which comprise (but are not limited to):

14 Contractors/non-recreational visitors are Site visitors but their exposure scenarios will be considered commercial/industrial


− Mussel aquaculture reserve off Shoreham (Flinders Aquaculture Fisheries Reserve)

Western Port Bay fish consumers, which comprise (but are not limited to):

− Recreational fishers consuming fish caught in Western Port Bay

− Others consuming fish caught in Western Port Bay

Wildlife or game consumers, which comprise (but are not limited to):

− None identified

On-Site ecological (Commercial/Industrial)

On-Site terrestrial biota, which comprise (but are not limited to):

− Mammals, including rabbits, kangaroos and possums

− Birds, migratory and local

− Reptiles and insects

− Grass, trees and other vegetation

− Semi-aquatic biota, including crabs and worms

On-Site (including Hanns Inlet) aquatic biota, which comprise (but are not limited to):

− Fish, including flathead, whiting, mullet, Australian salmon, toad fish and trevally

− Fiddler rays and gummy sharks

− Pipis, oysters and crustaceans

− Benthic detritivores

Off-Site ecological (Commercial/Industrial)

Off-Site terrestrial biota, which comprise (but are not limited to):

− Mammals, including horses, cows, rabbits and possums

− Birds, migratory and local

− Grass, trees and other vegetation

Off-Site aquatic biota

− Refer to on-Site aquatic biota


5.4 Potential and complete exposure pathways

5.4.1 Human health Potential pathways that could connect Site sources of PFAS and human receptors comprise the following:

Inhalation of dust and airborne particulates (minor pathway)

Ingestion

− Incidental soil ingestion

− Incidental ingestion of groundwater or surface water during non-potable use, such as during swimming associated with survival training in Hanns Inlet, or during the conduct of site maintenance and/ir intrusive construction works

− Deliberate ingestion during potable uses15

Dermal contact (minor pathway)

Details of these pathways are discussed below.

Inhalation Inhalation of fugitive dust and / or concrete (during demolition) is considered a potential exposure

pathway for construction workers during intrusive works in PFAS impacted areas

Inhalation of fugitive dust is not considered a likely significant exposure pathway to all other potential receptors16. Winds blowing across the Site may mobilise PFAS-impacted dust and aerosols. However, a study in similar setting has assessed the risk from inhalation exposure to mobilised dust to be extremely low (OEH 2017)

Inhalation of volatile PFAS is not considered a potential exposure pathway to all other potential receptors. PFAS compounds associated with AFFF (PFOS, PFOA, PFHxA, PFHxS) are not volatile and do not occur in the vapour phase, hence the exposure pathway is not complete. AFFF is not known to contain the volatile PFAS compounds that can be transported by air, consequently there is no on-Site source above background concentrations (OEH 2017)

Air quality monitoring for particulates (airborne dust) or volatile PFAS is not considered necessary to further inform understanding of potential airborne exposure pathways.

Ingestion Soil, concrete and vegetation

Ingestion of soil, concrete17 dust (during demolition) and vegetation by on-Site human receptors is considered a potential exposure pathway. PFAS may be ingested by on-Site human receptors after contacting impacted material, such as soil or vegetation that adheres to clothing or skin. This is especially relevant to Site visitors and Base workers/trainees (users of the Sports Fields), Base workers/trainees at the Fire Ground and Fire Station, and construction workers/non-recreational Site visitors during Site redevelopment activities. This exposure scenario is further discussed in Section 11.8.

Ingestion of soil and vegetation at the Sullage Pit is considered an unlikely exposure pathway to on-Site and off-Site human receptors as access to this area is limited and the risk of soil impact is considered low

15 For example, bore water users. Note that this is not a relevant pathway for the current investigation as groundwater and surface waters are not used on-Site for potable water supply. Further, there is no transport pathway between source areas and potential off-Site receptors (which are located hydraulically up- and cross-gradient from sources). 16 It is noted that the location of the temporary on-site residences is in closer proximity to sources via the air pathway compared to other receptors in the permanent residential area and off-Site residences 17 Concrete ingestion is considered an unlikely pathway, except during demolition activities where construction workers may be exposed to dust


Ingestion of soil, concrete and vegetation is considered an unlikely exposure pathway to off-Site human receptors as they are unlikely to encounter impacted soil, concrete and vegetation

Groundwater

Ingestion of groundwater is not considered a potential exposure pathway to on-Site human receptors. Interviews with key Site personnel indicate that there are no on-Site groundwater bores used as a potable supply. On-Site permanent residents and the Childcare centre attendees are also located hydraulically up- and cross-gradient to known sources

Ingestion of groundwater is a not considered a potential exposure pathway to off-Site human receptors. The off-Site receptors are located hydraulically up- and cross-gradient to known sources. The groundwater flow direction is to be confirmed with field program

Incidental ingestion of groundwater by construction workers is considered a potential exposure pathway during intrusive works requiring excavation below groundwater level, however this exposure scenario is brief with consideration to the human health recreational screening criteria18, and is further discussed in Section 6.5.2.

Surface water and sediment (or sludge)

Ingestion of on-Site surface water and sediment is not considered a likely exposure pathway to on-Site human receptors. However, it is possible that a trainee, Base worker or Site visitor may fall into the Fire Ground pond, Former STP lagoons or Ornamental Lake and ingest the surface water. This scenario is not a regular occurrence (particularly for individuals) and the resultant risk is low. No anecdotal evidence suggests that such exposure has occurred.

Some trainees may be exposed to surface water in the Leak-Repair-Live facility at the Fire Ground, this exposure scenario is also brief with consideration to the human health recreational screening criteria 19

Incidental ingestion of on-Site surface water and sediment is considered a potential exposure pathway to intrusive construction workers however this exposure scenario is brief with consideration to the human health recreational screening criteria20, and is further discussed in Section 6.5.2.

Ingestion of off-Site surface water (in Hanns Inlet) is considered a potential exposure pathway to Trainees. It is possible that Trainees may enter Hanns Inlet and ingest water whilst swimming21 during training activities

Ingestion of on-Site surface water and sediment is not considered a potential exposure pathway to off-Site human receptors. The storm-water drain outlets are not accessible from off-Site and the receptors are hydraulically upgradient from any outlets

Dermal contact Dermal contact is reported as being a minor exposure pathway because dermal absorption is slow and does not result in significant absorption (National Center for Environmental Health 2017).

Soil, concrete and vegetation

Dermal contact with soil, concrete and vegetation by on-Site human receptors is considered a potential exposure pathway. This is especially relevant to users of the Sports Fields, Base Workers at the Fire Ground and Fire Station, and intrusive construction workers during Site redevelopment activities

Dermal contact with soil, concrete and vegetation at the Sullage Pit is considered an unlikely exposure pathway to on-Site and off-Site human receptors as access to this area is limited and the risk of soil impact is considered low

18 It is noted that this exposure period is brief in comparison to human health recreational water screening criteria, which is based on daily ingestion of 0.2 L over a period of decades 19 As above 20 It is noted that this exposure period is brief in comparison to human health recreational water screening criteria, which is based on daily ingestion of 0.2 L over a period of decades 21 As above


Dermal contact with soil, concrete and vegetation is considered an unlikely exposure pathway to off-Site human receptors as they are unlikely to encounter impacted soil, concrete and vegetation

Groundwater

Dermal contact with groundwater is not considered a potential exposure pathway to on-Site human receptors. Interviews with key Site personnel indicate that there are no on-Site groundwater bores being used

Dermal contact with groundwater is a potential exposure pathway to off-Site human receptors using bore water for showering and washing. Although this pathway is incomplete due to the groundwater flow direction causing PFAS migration away from these receptors

Dermal contact with groundwater by intrusive construction workers is not considered a significant potential exposure pathway during intrusive works requiring excavation below groundwater level due to existing administrative controls and PPE, and the brief nature of exposure with respect to human health guideline values 22


Dermal contact with on-Site surface water and sediment is not considered a likely exposure pathway to Base workers, trainees and Site visitors. It is possible that on-Site human receptors may fall into the Fire Ground pond, Former STP lagoons or Ornamental Lake and ingest the surface water. This scenario is considered possible, but it is not a regular occurrence (particularly for individuals) and the resultant risk is low. No anecdotal evidence suggests that such exposure has occurred.

Trainees may be exposed to surface water in the Leak-Repair-Live facility at the Fire Ground, this exposure scenario is brief with consideration to the human health recreational screening criteria 23

Dermal contact with on-Site surface water and sediment is not considered a significant potential exposure pathway to intrusive construction workers due to existing administrative controls and personal protective equipment. This exposure scenario is brief with consideration to the human health recreational screening criteria 24

Dermal contact with off-Site surface water (Hanns Inlet) is considered a potential exposure pathway to Trainees. It is possible that Trainees may enter Hanns Inlet during training activities and come in contact with the surface water25

Dermal contact with on-Site surface water and sediment is not considered a potential exposure pathway to off-Site human receptors. The storm-water drain outlets are not accessible from off-Site and the receptors are hydraulically upgradient from any outlets

5.4.2 Ecological Potential pathways that could connect Site sources of PFAS and ecological receptors comprise the following:

Direct contact and uptake/ingestion

Bioaccumulation or secondary poisoning

Details of these pathways are discussed below.

Direct contact or uptake Direct contact (exposure) or uptake applies specifically to protection of organisms that live within, or are closely associated with, the soil, such as earthworms and plants.

Soil and vegetation

22 It is noted that this exposure period is brief in comparison to human health recreational water screening criteria, which is based on daily ingestion of 0.2 L over a period of decades 23 As above 24 As above 25 As above


The direct contact with surface soil/vegetation and uptake of PFAS is considered a potential pathway to on-Site terrestrial flora and fauna

The direct contact with surface soil/concrete/vegetation and uptake of PFAS is not considered a potential pathway to off-Site terrestrial flora and fauna. There is no access to on-Site source areas to these off-Site receptors. The quantitative assessment of risk to mobile wildlife, such as birds and mammals, that can move on and off Site are not within the remit of this study

Direct contact with and uptake of PFAS from soils and vegetation in the wetland areas is a potential exposure pathway to on-Site aquatic biota (including crabs and worms living in the soils and sediments in the wetlands or Hanns Inlet)

Groundwater

Direct contact with groundwater and uptake of PFAS is a potential exposure pathway to on-Site terrestrial flora and fauna. This exposure pathway is only relevant to deep rooted trees and plants capable of reaching the groundwater

Direct contact with groundwater and uptake of PFAS is a potential exposure pathway to on-Site aquatic flora and fauna, especially in the wetlands areas (including crabs and worms living in the soils and sediments in Site wetlands or Hanns Inlet, and fish exposed to groundwater discharging to Hanns Inlet)

Direct contact with groundwater and uptake of PFAS is an unlikely exposure pathway to off-Site terrestrial flora and fauna (deep rooted trees and plants). This pathway is unlikely to be complete due to the groundwater flow direction causing PFAS migration away from these receptors


Direct contact with and uptake of PFAS from surface water and sediment in drainage lines and surface water bodies (such as Fire Ground pond and Ornamental Lake) is a potential exposure pathway to on-Site aquatic flora and fauna.

Direct contact with and uptake of PFAS from surface water and sediment in Hanns Inlet and connected creeks is a potential exposure pathway to on-Site aquatic biota (including crabs and worms living in the soils and sediments in Site wetlands or Hanns Inlet, and fish in Hanns Inlet)

Direct contact with and uptake of PFAS from surface water in Western Port Bay due to Site activities is a potential exposure pathway to off-Site aquatic flora and fauna. However, this exposure pathway is unlikely to be complete due to flushing properties of Hanns Inlet

Bioaccumulation / Secondary poisoning These indirect exposure scenarios account for the various pathways other organisms can be exposed due to bioaccumulation and/or off-site transport.

Ingestion of PFAS that have bioaccumulated within the food chain is considered a potential exposure pathway to on-Site terrestrial biota. This exposure pathway is only relevant to higher order mammals and birds. It is noted that no stock is maintained on-Site.

The off-Site exposure scenario (i.e. the biota is located off-Site when in contact with media) is not considered a potentially complete pathway.

The quantitative assessment of mobile wildlife, such as birds, mammals and reptiles, was not within the remit of this study, but a qualitative assessment of movement on-site and off-site was considered. Off-Site biota that come onto the Site could potentially be exposed to on-Site sources of PFAS, such as in the wetlands straddling South Creek

Ingestion of PFAS that have bioaccumulated within the food chain is considered a potential exposure pathway to on-Site (including Hanns Inlet) aquatic biota. Hanns Inlet is incorporated in this category as delineation between the creeks and Inlet is arbitrary when considering fish movement.

Ingestion of PFAS that have bioaccumulated within the food chain is considered a potential exposure pathway to off-Site aquatic biota in Western Port Bay. This exposure pathway is considered in field works


This discussion of potentially complete, unlikely to be complete and incomplete pathways is summarised in the following section.

These human and ecological receptors and potential pathways to these receptors have been assessed and the summarised in Table 5-2.

Table 5-2 Known and potential human and ecological receptors

Potential Receptor Comment Receptor Status

Considered a potential receptor for investigation?

Intrusive construction workers

Confirmed, known PFAS impacts in Fire Ground and Fire Station

Known Yes

Base Workers or Trainees

Confirmed, known PFAS impacts in Fire Ground and Fire Station

Known Yes

Site visitors Unconfirmed. Pathway from sources likely Likely Yes On-Site terrestrial biota Unconfirmed. Pathway from sources likely Likely Yes On-Site aquatic biota (including Hanns Inlet)

Unconfirmed. Pathway from sources likely Likely Yes

Off-Site residents Off-Site bore water users identified in Water Use Survey, pathway from sources unlikely

Unlikely Yes

Temporary on-Site residents

Unconfirmed. Pathway from sources unlikely Unlikely Yes

Off-Site terrestrial biota Unconfirmed. Pathway from sources likely Unlikely Yes Off-Site aquatic biota Unconfirmed. Pathway from sources unlikely Unlikely Yes Western Port Bay fish consumers

Unconfirmed. Pathway from sources unlikely Unlikely Yes

Childcare attendees Due to sensitive nature, this receptor has been carried forward. However, there is no bore water use, and risk via air considered negligible (refer to potential and complete exposure pathways)

No Yes

Permanent on-Site residents

Due to sensitive nature, this receptor has been carried forward. However, there is no bore water use, and risk via air considered negligible (refer to potential and complete exposure pathways)

No Yes

Commercial producers of agricultural products

Pathway from sources incomplete due to flow direction of surface water and groundwater. This receptor to be protected by Off-Site terrestrial biota assessment

No No

Wildlife or game consumers

No indications of wildlife or game consumption in the area

No No

Commercial producers of aquaculture products

No fishing or aquaculture is permitted in Hanns Inlet and Naval Waters. Flushing properties of Hanns Inlet indicate limited potential for PFAS to reach this receptor outside Hanns Inlet

No No

The ‘Base Workers or Trainees’ and ‘Site visitors’ categories also incorporate the users of the Sports Fields previously irrigated with recycled water. Physical activities are a mandatory component of a Trainee’s education at HMAS Cerberus including sporting activities on the Sports Fields. Site visitors, such as visiting sports teams, also use the Sports Fields for competitions including AFL football matches.

Western Port Bay fish consumers have been included as a receptor because even though fishing is not permitted in Hanns Inlet, some fish may leave Hanns Inlet and be either eaten by other fauna or caught for human consumption.

The potential human receptors that were further assessed include Base Workers or Trainees, Site visitors, Temporary on-Site residents, Permanent on-Site residents, Childcare attendees, off-Site residents and Western Port Bay fish consumers. The potential ecological receptors that were further assessed include on-Site terrestrial biota, on-Site aquatic biota (including Hanns Inlet), off-Site terrestrial biota, off-Site aquatic biota


5.5 Conceptual Site Model Visualisation The known and potential sources, receptors and pathways that are discussed above form a CSM. A visualisation of the CSM is presented the following set of figures, which show the known and potential exposure media and pathways for the nine potential PFAS sources26 on the Site:

Fire Ground and associated wetlands (Figure 5-1)

Fire Station and Ornamental Lake (Figure 5-2)

Former STP (Figure 5-3)

Sullage Pit (Figure 5-4)

Sports Fields (Figure 5-5)

Potential minor sources in the main operational area, including Closed Rifle Range Road landfill, closed outdoor swimming pool landfill, closed indoor swimming pool landfill, Communications school, former dry cleaning facility, powerhouse, coal loading area and former fuel storage areas (Figure 5-6)

Bushfire Zone (Figure 5-7)

Hanns Inlet Sediment and Pore Water (Figure 5-8)

Storm-water drains (Figure 5-9)

It is important to note that anecdotal information has been relied upon, and the data gaps are to be assessed in the field work program.

26 The potential minor sources have been grouped for clarity


Figure 5-1 Visualisation of the Conceptual Site Model at the Fire Ground (Exposure pathways and receptors)


Figure 5-2 Visualisation of the Conceptual Site Model at the Fire Station (Exposure pathways and receptors)


Figure 5-3 Visualisation of the Conceptual Site Model at the Former Sewage Treatment Plant (Exposure pathways and receptors)


Figure 5-4 Visualisation of the Conceptual Site Model at the Sullage Pit (Exposure pathways and receptors)


Figure 5-5 Visualisation of the Conceptual Site Model at the Sports Fields (Exposure pathways and receptors)


Figure 5-6 Visualisation of the Conceptual Site Model at the potential minor sources (Exposure pathways and receptors)


Figure 5-7 Visualisation of the Conceptual Site Model at the Bushfire Area (Exposure pathways and receptors)


Figure 5-8 Visualisation of the Conceptual Site Model at the Hanns Inlet Sediment and Pore Water (Exposure pathways and receptors)


Figure 5-9 Visualisation of the Conceptual Site Model at the storm-water drains (Exposure pathways and receptors)


5.6 Data gaps and uncertainty The desktop review and visualisation of the CSM identified the following key data gaps to be further investigated in the field program:

Assessment of the ingestion pathway of impacted groundwater by off-Site residential bore water users

− Groundwater monitoring wells required at Site boundary (note that these monitoring wells will provide confirmation of groundwater flow directions and detects in these wells may indicate background PFAS from off-Site sources)

Delineation of the known and likely sources (focusing on the Fire Ground, Fire Station and Former STP)

− Groundwater monitoring of existing monitoring wells in the Fire Ground, Fire Station and Former STP

− Groundwater monitoring wells required at Fire Ground and wetlands

− Surface soil sampling around Fire Ground and associated closed landfill

− Surface water and sediment sampling at Fire Ground

− Groundwater monitoring of existing wells at Fire Station on groundwater pathway to Hanns Inlet

− Surface soil sampling around Fire Station and Ornamental Lake

− Surface water and sediment sampling at Ornamental Lake

− Groundwater monitoring wells required at Former STP lagoons near West Creek

− Surface soil sampling around in-filled Former STP infrastructure and lagoon outlets

− Surface water, sediment and sludge sampling from Former STP lagoons

Assessment of the dermal contact pathway with surface water and sediment in storm-water drains

− Surface water and sediment sampling after rain event

Assessment of nature and extent of impact at other potential sources

− Groundwater sampling from existing monitoring wells

− Surface water, sediment, soil and vegetation sampling (where applicable) at Sullage Pit, closed Sports Fields, Bushfire Zone and other potential minor sources

Assessment of the flow of impacted groundwater to Hanns Inlet

− Groundwater monitoring wells required at the Marina that targets the groundwater flowing below fill

Assessment of Hanns Inlet as a sensitive ecological receptor and ongoing secondary source

− Sediment and pore water sampling in Hanns Inlet

− Biota sampling in different regions of Hanns Inlet

Assessment of the pathway via surface water from Hanns Inlet to Western Port Bay

− Surface water sampling along Hanns Inlet to the mouth of the Inlet

It is noted that there remain some data gaps and uncertainty that were not in the current scope of works;

Additional sources

− Rifle range and ordnance area

− Areas of use, storage or disposal of AFFF not discovered in desktop review or Site interviews

Additional media and receptors

− Concrete in Fire Ground and Fire Station

− Biota in Western Port Bay and other off-Site areas


6 Beneficial uses and assessment criteria This section details the overarching assessment framework at Commonwealth and State levels. The relevance of the beneficial uses protected under the State Environmental Protection Policies (SEPP) are discussed based on the Conceptual Site Model presented in Section 5. The relevant guidelines used to determine screening criteria are also summarised. Screening criteria is also commonly referred to as investigation levels, assessment criteria or screening levels.

6.1 Assessment Framework The Site falls under Commonwealth jurisdiction, but is surrounded by land and water that falls under Victorian jurisdiction. Therefore, both Commonwealth and State legislation relevant to assessment of site contamination were considered while the DSI was undertaken.

6.1.1 Commonwealth Legislation, Regulation and Guidance Commonwealth legislation regulates the site, which is located on Commonwealth land. Hence, PFAS impact at the Site was assessed with regards to the following legislation, regulation and guidance.

Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)

ASC NEPM

Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC, 2000)

Ramsar Convention on Wetlands – note that Western Port Bay, including Hanns Inlet is a listed as a Ramsar wetland

PFAS National Environmental Management Plan (NEMP, January 2018) - Heads of EPAs Australia and New Zealand (HEPA)

6.1.2 Victorian Legislation, Regulation and Guidance Victorian legislation regulates the area surrounding HMAS Cerberus, including Hanns Inlet. The relevant subordinate legislation that implements the Victorian legislation, regulation and guidance includes:

State Environmental Protection Policies (SEPP)

− SEPP (Prevention and Management of Contamination of Land) (PMCL SEPP)

− SEPP (Waters of Victoria) (WoV SEPP)

− SEPP (Groundwaters of Victoria) (Groundwater SEPP)

These SEPPs set out beneficial uses of land, water and groundwater that are to be protected. Note that the Groundwater SEPP and WoV are being merged, but have not been promulgated yet.

The beneficial uses have been applied to on-Site and off-Site locations, including Hanns Inlet and Western Port Bay.

6.2 State Environment Protection Policies Uses and values of land, surface water and groundwater comprise the beneficial uses of these elements of the environment. Protection of these beneficial uses is achieved by maintaining the level of environmental quality or improving the quality via realistically achievable improvements, which are set out under attainment programs. Each SEPP sets out objectives and criteria for evaluating whether a beneficial use is being protected.


6.2.1 Land State Environment Protection Policy The beneficial uses of land protected under the Prevention and Management of Contamination of Land (PMCL) SEPP are:

Maintenance of ecosystems (MoE) for natural ecosystems, modified ecosystems and highly modified ecosystems

Human health

Buildings and structures

Aesthetics

Production of food, flora and fibre

Table 6-1 summarises whether these beneficial uses are existing, likely or potential, or unlikely for On-Site and Off-Site. Note that on-Site refers to the area within the IA. Land SEPP beneficial uses that are existing or likely / potential are carried forward for evaluation in Section 10.2.6.

Table 6-1 Land SEPP Beneficial Uses

Beneficial Use Existing Likely /

Potential Unlikely

Maintenance of ecosystems (MoE)

On-Site X

Off-Site X

Human healtha

On-Site X

Off-Site X


On-Site X

Off-Site X

Aesthetics

On-Site X

Off-Site X


On-Site X

Off-Site X a Human health – residential, open spaces / playing fields, commercial / industrial use, and intrusive / maintenance workers. Refer to areas of the Site as shown on Figure 2 3.

6.2.2 Groundwater State Environment Protection Policy Beneficial uses set out in the Groundwater SEPP are based on the segment to which the groundwater is assigned. In the first instance the segment is assigned based on the total dissolved solids (TDS) of the groundwater. Protected beneficial uses for each segment are presented in Table 6-2.


Table 6-2 Protected Beneficial Uses of Groundwater Segments

Beneficial Uses

Segments (mg/L TDS)

A1( 0

-500

)

A2 (5

01-1

,000

)

B (1

,001

-3,5

00)

C (3

,501

-13,

000)

D (>

13,0

00)

1. Maintenance of ecosystems

2. Potable water supply:

desirable

acceptable

3. Potable mineral water supply

4. Agriculture, parks and gardens

5. Stock watering

6. Industrial water use

7. Primary contact recreation (e.g., bathing, swimming)

8. Buildings and structures

The groundwater salinity at and near the Site falls within Segment B (that is, between 1,000 mg/L and 3,500 mg/L of TDS. Salinities of groundwater (as electrical conductivity (EC)) reported for the Site monitoring wells (Golder, 2017) ranged between approximately 1,000 µS/cm and 30,000 µS/cm, and the relevant beneficial uses potentially include;

Maintenance of ecosystems

Potable water supply

Potable mineral water supply

Agriculture, parks and gardens

Stock watering

Industrial water use

Primary contact recreation



Outside the Ramsar-listed areas, criteria for protection of maintenance of ecosystems for slightly to moderately disturbed ecosystems (95% species protection) would apply (refer Table 6-5). For areas within the Ramsar-listed areas the criteria for protection of largely unmodified ecosystems (99% species protection) are considered relevant beneficial uses (refer Table 6-5).


Potable water supply is not considered a protected beneficial use on-Site due to the predominantly brackish nature of the groundwater. Potential off-Site groundwater users for drinking and primary contact recreational that were indicated by the Water Use Survey and VVG are located hydraulically up- and cross-gradient to known sources. Therefore, this beneficial use is existing off-Site (refer Section 10.3.9).



The Site groundwater is not within a declared mineral water supply area. This beneficial use is not existing or likely / potential.


The availability of mains water would make it unlikely that the mainly brackish Site groundwater would be used for irrigation. This is supported by information collected during this DSI, indicating irrigation is not undertaken with groundwater. However, this is a potential beneficial use.

Potential off-Site groundwater users for irrigation that were indicated by the Water Use Survey and VVG are located hydraulically up- and cross-gradient to known sources.

Therefore, this beneficial use is to be considered in further investigations. The human health drinking water screening level for PFAS is considered protective of this beneficial use.

Stock watering

No stock is currently kept on-Site. In addition, the availability of mains water would make it unlikely that Site groundwater would be used for on-Site stock watering. Therefore, this beneficial use is not considered likely to be realised on-Site. However, it is a potential beneficial use. The human health drinking water screening level for PFAS is considered protective of this beneficial use.

Off-Site areas are likely to use groundwater for stock watering. Note that these off-Site areas are located hydraulically up gradient from the Site.

Therefore, this beneficial use is to be considered existing off-Site. The human health drinking water screening level is considered protective of this beneficial use.


The availability of mains water would make it unlikely that the mainly brackish Site groundwater would be used for industrial uses. While the one industrial-use well listed on the State groundwater database is located on-Site, this well could not be located and had not been used for decades according to Base staff. However, this is a potential beneficial use and is carried forward in the investigation for assessment in Section 10.3.9. The human health drinking water screening level is considered protective of this beneficial use.

Primary contact recreation

Exposure as part of primary contact recreation was considered to include swimming, bathing, and exposure to workers during intrusive works, such as part of construction dewatering. With regards to swimming, Site swimming pools are filled using mains water. Groundwater is not used to top up any of the Site swimming pools. Swimming (as part of training) and boating activities occur on Hanns Inlet.

This beneficial use is considered existing both on- and off-Site and is carried forward for assessment in Section 10.3.9.


While PFAS-impacted groundwater is not anticipated to adversely affect buildings or structures, this is an existing beneficial use both on- and off-Site.

Summary

An evaluation of groundwater beneficial uses is presented in Table 6-3, which summarises whether these beneficial uses are existing, likely or potential, or unlikely for On-Site and Off-Site. Note that on-Site refers to the area within the IA. Groundwater SEPP beneficial uses that are existing or likely / potential are carried forward for evaluation in Section 10.3.9.


Table 6-3 Groundwater SEPP Beneficial Uses

6.2.3 Waters of Victoria State Environment Protection Policy As set out in the Waters of Victoria (WoV) SEPP, protected beneficial uses of Victorian surface waters include:

Aquatic plants and animals

Water suitable for aquaculture and edible seafood

Water-based recreation

Water suitable for human consumption

Water suitable for aesthetic enjoyment


Potential Unlikely

Maintenance of ecosystems (MoE) (99% species protection)

On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X

Stock watering

On-Site X

Off-Site X


On-Site X

Off-Site X

Primary contact recreation (including intrusive workers)

On-Site X

Off-Site X


On-Site X

Off-Site X


Cultural and spiritual values

Water suitable for industry and shipping

Water suitable for agriculture.

The waters of Hanns Inlet fall in the marine and estuarine segments of the WoV SEPP. Specifically, Hanns Inlet falls within the Western Port Segment. The Western Port Segment consists of the marine and estuarine segments identified in the State environment protection policy (Waters of Victoria) - Schedule F8. Waters of Western Port and Catchment. In addition, Western Port Bay is an area of high conservation value due to the wetlands within Western Port Bay being listed as a Ramsar wetland.


The WoV SEPP states that aquatic ecosystems and their surface waters must be free of any substance at levels that pose a risk to beneficial uses. The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC and ARMCANZ, 2000) specifies the environmental quality objectives for protection of beneficial uses. For aquatic plants and animals, the levels of protection used to determine the objective are:

99% for natural, substantially natural, and largely unmodified ecosystems

95% for slightly to moderately disturbed ecosystems

90% for highly or largely disturbed ecosystems

80% for highly disturbed ecosystems27

These four protection levels are pertinent to the assessment of direct toxicity to aquatic plants and animals. The Site has been assessed as a slightly to moderately disturbed ecosystem with areas (such as the wetlands) that are largely unmodified and of high ecological value (Ramsar listed wetlands). Following ANZECC and ARMCANZ (2000) recommendations, the next higher protection level was adopted for assessment of potential bio-accumulative / secondary poisoning effects where site-specific data on bioaccumulation is not available. For example, to assess potential bio-accumulation and secondary poisoning in a slightly to moderately disturbed ecosystem, the 99% species protection level would be applied.

Maintenance of ecosystems for slightly to moderately disturbed ecosystems (95% species protection) and largely unmodified ecosystems (99% species protection) are considered relevant beneficial uses. For screening purposes criteria protective of 99% of species was used.


There is no fishing or aquaculture is permitted on-Site, in Hanns Inlet or in the adjacent Naval Waters in Western Port Bay. Flushing properties of Hanns Inlet indicate limited potential for PFAS to reach receptors in Western Port Bay. This beneficial use is potential on-Site but is existing off-Site, such as in Western Port Bay. For screening purposes criteria protective of 99% of species was used.

Water based recreation

Training exercises occur in Hanns Inlet, including swimming, so there is the potential for dermal contact with and incidental ingestion of surface waters (noting that this is a short exposure time). Construction activities, such as excavations for infrastructure, may result in exposure of workers to PFAS-impacted surface water. Hence, water-based recreation and incidental exposure during construction activities are existing beneficial uses.


While there is potable water in the Fire Ground pond, Ornamental Lake and Former STP lagoons, these are not typically accessed by human receptors. Any potable water dams are located hydraulically upgradient

27 As portions of the investigation area are highly disturbed, such as the channel in Hanns Inlet and the drains that were constructed to replace the natural tidal creeks, the guideline would still be relevant as a starting point for establishing SEPP objectives. The SEPP states that the 80th percentile of background established for reference sites with low levels of human impact may be used as a default guideline values where the trigger value is less than the reliable background figure.It is noted that the 80th percentile of background established for reference sites with low levels of human impact may be used as a default guideline values where the trigger value is less than the reliable background figure


from Site, hence it is unlikely that PFAS-impacted surface water would reach these dams. Base workers and trainees do not consume or swim in these potentially impacted potable surface-water bodies.


The aesthetic enjoyment of the surface water is to be assessed based on observations of odour and/or visual amenity impact, such as foaming. No aesthetic impacts were noted for PFAS impacted water during Site inspections. This beneficial use is existing both on- and off-Site.


PFAS screening criteria for protection of the beneficial use of cultural and spiritual values (Indigenous and / or non-Indigenous) are not available. This beneficial use is existing both on- and off-Site.


The water in Hanns Inlet is used for training purposes and the water in Western Port Bay is frequently used for ferry operation. It is not anticipated that PFAS-impacted surface water would adversely affect use of the water for shipping in Hanns Inlet or Western Port Bay. There is no industrial use of surface water within Hanns Inlet. This beneficial use is existing on- and off-Site.

Water suitable for agriculture

The surface water in Site tidal creeks and Hanns Inlet is generally too saline for irrigation or watering stock. Hence, this is an unlikely beneficial use on-Site, but is existing off-Site.

Summary

An evaluation of water beneficial uses is presented in Table 6-4, which summarises whether these beneficial uses are existing, likely or potential, or unlikely for On-Site and Off-Site. Note that on-Site refers to the area within the IA. Water SEPP beneficial uses that are existing or likely / potential are carried forward for evaluation in Section 10.4.8.


Table 6-4 Water SEPP Beneficial Uses


Potential Unlikely


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


On-Site X

Off-Site X


6.3 Site-specific beneficial uses The land use has been classified with regard to beneficial uses, which is presented in Appendix A -Figure 3B.

Temporary residences – high density residential

Permanent residences – low density residential

Off-site residences – low density residential

Child care centre (for Base children only) – low density residential

Golf course – public open space

Gymnasium, Sports Fields– public open space

General administration, Medical services, Education and training areas, Marina, Fire Ground (RAN SSSS), Fire Station and Ornamental Lake – industrial and commercial

Former Sewage Treatment Plant (STP) and associated lagoons28 – industrial and commercial

Williams Rifle Range– industrial and commercial

Sullage Pit– industrial and commercial

Landfills– industrial and commercial

Other spaces on-site – public open space

There are areas on-site that do not fit directly into the public open space classification. The wetlands south of the Fire Ground contain sensitive ecological receptors and has been classified as Environmentally Constrained Land (HMAS Cerberus redevelopment, Western Port Bay, Victoria, Submission 1, Department of Defence, June 2017). Similarly, the urban bushlands at the land boundaries of the Site are also classified as Environmentally Constrained Land (Defence, 2017). The Former STP is currently classified as industrial / commercial, but it has been zoned for Future Development (Defence, 2017).

6.4 Relevant standards and guidelines In January 2018, the Heads of EPAs issued the PFAS National Environmental Management Plan, which provided interim soil screening levels for protection of ecosystems. These criteria were used for evaluating results from the DSI.

The guidance documents and standards used to inform the sampling program are listed in the DSI SAQP.

6.5 Environmental Protection Agency and International Guidelines

There are considerable knowledge gaps in the current understanding of the risks posed to human and ecological receptors by PFAS. The guideline values have been revised during the investigations and expected to undergo further revisions as understanding of human health and ecological impacts are improved. Currently, guideline values are only available for PFOS, PFOA, PFHxS (often grouped with PFOS) and 6:2 FTS. Guideline values are not currently available for the other 24 PFAS compounds that were analysed, and it is to be highlighted where non PFOS/PFOA/PFHxS PFAS compounds make a substantial contribution to the PFAS identified. This section briefly summarises the current state of PFAS guidelines.

28 The future development in this area includes a potential containment cell for excavated soils and is considered to be industrial / commercial


6.5.1 Soil Soil quality assessment criteria for the protected beneficial uses of land are specified in SEPP PMCL (Table 2). This table specifies that objectives for human health and MoE beneficial uses must be sourced from the NEPM (NEPC, 2013). The objectives for food, flora and fibre beneficial use must consider guidelines in the FSANZ Code. As criteria or guidelines for PFAS in soils have not been specified in the NEPM or the FSANZ Code, the assessment criteria have been adopted from other risk-based sources. This is the same approach used in the NEPM and/or FSANZ Code.

Human Health The PFAS National Environmental Management Plan (NEMP, January 2018) - Heads of EPAs Australia and New Zealand (HEPA) contains human health screening values (HHSV) for PFOS/PFHxS and PFOA in sensitive (residential), public open space, and industrial / commercial land use categories. These values are summarised in Table 6-5.

These guidance values were based on 20% of the FSANZ (2017) Total Dietary Intake, which assumes 80% of exposure is assumed to come from other pathways. The details of the assumptions behind the derived values are provided in the NEMP.

It should be noted that the public open space land use scenario makes assumptions for playing fields and footpaths, which is relevant to areas on-Site. However, it does not include urban bushlands and reserves (such as those found at Site land boundaries), which require site-specific assessment.

With regards to intrusive construction / maintenance workers, the NEPM industrial / commercial exposure scenario assumes a soil and dust ingestion rate of 25 mg/day and exposure frequency to the contaminant in soil and dust via ingestion, dermal contact and inhalation, every work day (240 days per year) for 30 years. HHSVs for intrusive construction and/or maintenance workers during intrusive works at the Base are the NEMP HHSVs for industrial / commercial land use that have been adjusted to reflect a higher soil and dust ingestion rate of 330 mg/day (as set out in USEPA 1991 Risk Assessment Guidance for Superfund) and retaining the 240 days per year. Note that the exposure frequency during excavation or similar intrusive works would be likely to be considerably shorter. However, the longer exposure frequency is retained to provide a level of conservatism. Therefore, using an adjustment factor of (25 mg/day)/(330 mg/day), which corresponds to 7.6%, the industrial / commercial HHSVs are adjusted to the following values as the HHSVs for intrusive (and maintenance) workers:

Analyte Industrial / Commercial

HHSV (mg/kg) Intrusive Worker HHSV

(mg/kg)

PFOS + PFHxS

20 1

PFOA 50 4

Ecological The NEMP (HEPA, 2018) contains interim soil environmental guideline values (EGV) for public open spaces (direct exposure) and residential/parkland and industrial/commercial (indirect exposure) land uses. These values are summarised in Table 6-5.

The direct exposure guidance values for PFOS and PFOA are interim values based on the human health public open space screening value. This value is under review based on exposure criteria proposed by CRC Care (2017).

The indirect exposure guidance values were sourced from the risk based approach outlined in Environment and Climate Change Canada (2017), Draft Federal Environmental Quality Guidelines Perfluorooctane Sulfonate (PFOS), Government of Canada, April 2017. These indirect exposure pathways are for PFOS only. The residential and parkland value relates to soil ingested by a secondary consumer. The commercial and industrial value relates to the concentration in coarse soil that is expected to protect against potential impacts


on freshwater life from PFOS that may enter the groundwater and then discharge to a surface water body. This value has been applied in lieu of values relating to marine life.

6.5.2 Groundwater and surface water

Human Health Health-based guidance values are used to investigate and assess potential human health risks and were used for setting human-health-based screening criteria.

The NEMP (HEPA, 2018) contains human health guidelines (PFOS/PFHxS and PFOA) for drinking water and recreational water. The Defence Contamination Directive (DCD) #8 (Version 2) released in March 2018 also aligns with these screening guidelines. These values are summarised in Table 6-5.

These guidance values were based on recommendations by the Australian Government Department of Health (2017). There is a significant degree of conservatism in the drinking water and recreational water guidance values (which assume a lifetime of consumption), in which 90% attributed to other exposure pathways. This means that exceeding these values does not constitute a risk if other pathways are controlled.

With regards to exposure to impacted waters by Base workers, trainees, and intrusive / maintenance workers, the exposure scenario for drinking water screening levels is lifetime consumption of 2 L of water each day, and recreational water assumes lifetime consumption of 0.2 L each day. The transient nature of exposure to impacted waters by Base workers, trainees, and intrusive / maintenance workers means that application of screening levels for primary contact recreation is conservative and protective of these beneficial uses. Note that as a level of conservatism, the use of administrative controls, including appropriate health and safety plans and safe work practices that include personal protective equipment, have not been considered in the application of these screening levels for primary contact recreation.

Ecological

Freshwater The NEMP (HEPA, 2018) contains ecological guidelines (PFOS/PFHxS and PFOA) for the freshwater exposure scenario. These values are summarised in Table 6-5.

These guidance values were based on the ANZECC technical draft guidelines for fresh and marine water quality. It should be noted that EPA Victoria acknowledge current Australian laboratory analytical procedures are only able to reliably detect PFOS at a concentration of 0.001 μg/L, which is well above that required to assess the 99% standard for species protection. A provision is made for this in the NEMP (HEPA, 2018), and the EPA Victoria have recommended the current limit of detection (0.001 μg/L) as the practical standard for ‘slightly to moderately disturbed’ and ‘high conservation value systems’ until laboratory procedures are able to report on lower concentrations. Therefore, while our primary lab used a limit of reporting below the interim guideline for PFOS (0.00023 µg/L), our secondary lab typically used a limit of reporting of 0.001 µg/L, which is consistent with EPA Victoria’s observations.

Marine The NEMP (HEPA, 2018) advises that freshwater values are to be used on an interim basis as final marine guideline values have not been set using the nationally-agreed process under the Australian and New Zealand Guidelines for Fresh and Marine Water Quality. The Water Quality Guidelines further advise that in the case of estuaries, the most stringent of freshwater and marine criteria apply, taking account of any available salinity correction.


6.5.3 Sediment There is a gap in the current knowledge relating to human health and ecological impacts caused by contaminated sediment. The only published guideline values relate to the predicted no effect concentration for sediments in freshwater and marine environments, which were developed by the Environment Agency UK. The reported PFOS values were 67 µg/kg for freshwater and 6.7 µg/kg for marine environments (EA UK 2004). These values have been provided for indicative purposes and no reliance has been placed on them as sediment screening levels.

The main concerns associated with sediment contamination include the potential for;

Human health risk of direct contact with sediment during construction works

Sediment to become a secondary source of PFAS

Sediment and/or pore water concentrations to be a direct toxicity risk to ecological receptors

The data gap relating to the human health risk, direct ecotoxicological risk and remobilisation from sediments mean that no screening criteria have been adopted for these pathways. Any detects of PFAS in sediments were assessed in conjunction with surface water results in that area.

6.5.4 Sewage sludge / biosolids The approach set out by the ASC NEPM for assessing emerging contaminants was used by the Australian and New Zealand Biosolids Partnership (ANZBP) as the basis for determining safe levels of PFOS and PFOA in biosolids (Hopewell and Darvodelsky, 2017).

The ANZBP Assessment of Emergent Contaminants in Biosolids, December 2017, reports that the limiting Health Investigation Level value for PFOS is 0.3 mg/kg and PFOA is 2.4 mg/kg for child exposure29. The assumptions outlined in ANZBP (2017) and the NEPM analysis were used to calculate recommended values for PFOS and PFOA in biosolids that are suitable and safe for restricted use, such as application to agricultural land. These guidelines are provided for indicative purposes as further clarification is likely to be provided in future revisions of the NEMP (HEPA, 2018).

6.5.5 Biota (seafood)

Human Health Human health based guidelines for PFOS + PFHxS combined and PFOA were derived by FSANZ based on total dietary intake (TDI). These values are specified as trigger points for investigation, and are the maximum concentration level of these chemicals that could be present in individual foods or food groups so even high consumers of these foods would not have dietary exposures exceeding the relevant TDI. These values for finfish flesh and liver are summarised in Table 6-5.

6.5.6 Grass There are currently no screening criteria published for samples of grass. Any detects of PFAS are indicative of impact in that area and were assessed qualitatively. The detected levels of PFAS in grass were considered assessed in conjunction with soil results in that area.

6.6 Adopted screening criteria The adopted screening criteria for different exposure scenarios are summarised in Table 6-5. It should be noted that these screening criteria are for risk assessment purposes only, and should not be interpreted as action levels for remediation.

29 At this level, a child eating 100 mg of biosolids per day would ingest 10% of the maximum daily amount of PFOS/PFOA recommended by the NSW Department of Health and FSANZ.


Table 6-5 Summary of adopted Tier 1 screening criteria for PFAS contamination

Exposure Scenario PFOS PFOA 6:2FTS Guidance Original references SOILa (mg/kg)

Residential with garden / accessible soil (HHSV 1) 0.009b 0.1 - HEPA (2018)a Based on FSANZ TDI

(2017) Residential with minimal opportunities

for soil access (HHSV 2) 2b 20 - HEPA (2018) Based on FSANZ TDI (2017)

Public Open Space / Playing Fields (HHSV 3)

1b 10 - HEPA (2018) Based on FSANZ TDI (2017)

Industrial / commercial (HHSV 4) 20b 50 - HEPA (2018) Based on FSANZ TDI

(2017)

Intrusive / maintenance worker (HHSV 5) 1b, c 4c -

Adjusted Industrial / commercial

Based on FSANZ TDI (2017)

Interim ecological direct exposure for Public open space (EGV 1) 1 10 - HEPA (2018) Based on FSANZ TDI

(2017) Interim ecological indirect exposure for

Residential Land Use (EGV 2) 0.01 - - HEPA (2018) ECC Canada (2017)

Interim ecological indirect exposure for Industrial / Commercial Land Use (EGV 3) 0.140 - - HEPA (2018) ECC Canada (2017)

GROUNDWATER (µg/L) Human Health - Drinking Water Quality

Guideline d 30 0.07b 0.56 - HEPA (2018) Department of Health (2017)

Ecological Refer to surface water ecological guidelines SURFACE WATER (µg/L)

Human Health - Surface Water Recreational/Intrusive works 0.7b 5.6 50 HEPA (2018)

Dept. of Health (2017)

Jarman et al (2014) Human Health - Drinking Water Quality

Guideline 0.07b 0.56 - HEPA (2018) Department of Health (2017)

Fresh Water / Marine (95% species protection) 0.13 220 - HEPA (2018)

ANZECC technical draft guidelines for fresh and marine

water quality

Fresh Water/ Marine (99% species protection) 0.00023d 19 - HEPA (2018)

ANZECC technical draft guidelines for fresh and marine

water quality SEWAGE SLUDGE (BIOSOLIDS) (µg/kg dry weight basis)

Human Healthe 300 2,400 - ANZBP (2017)


Agricultural Application 4,200 33,600 - ANZBP (2017)


SEAFOOD (µg/kg wet weight basis)

Finfish Flesh 5.2f 41 - FSANZ (2017) FSANZ (2017) Finfish Liver 280b 2,240 FSANZ (2017) FSANZ (2017

DIET µg/kg bw/day

Total Dietary Intake 0.02b 0.16 - HEPA (2018) FSANZ (2017)

DoH (2017) a Defence Contamination Directive #8 Version 2 aligns with NEMP (HEPA, 2018), b Combined PFOS/PFHxS, c Industrial / commercial screening levels adjusted by a factor of 330/25 to reflect a higher ingestion rate of 330 mg/day compared to the NEPM default value of 25 mg/day. d practical screening guideline of 0.001 µg/L based on typical current laboratory limit of reporting, e Guidelines for the use of biosolids are relevant from a future Site management perspective in the circumstances where sludge/sediments within the former STP lagoons are removed. f Child exposure scenario based on children 2-6 years old. Note that waste soil containing more than 50 mg/kg of PFOS or PFOA must be managed in accordance with the Stockholm Convention requirements.

The criteria were selected to reflect the exposure scenarios at the Site, which comprise industrial / commercial in the operational areas of the Site, residential (for the temporary and permanent residents), and open space for the users of the Sports Fields and undeveloped portions of the Site (refer to Appendix A – Figure 3B).


The boundary areas do not fit exactly into the any of the categories ecological screening criteria for soil. In the event of a detect above LOR in this area, the qualitative impact is to be considered. The soil results are considered as an additional line of evidence for PFAS impact to be assessed in conjunction with groundwater and surface water results. These results from this area were compared against residential guidelines for indicative purposes.

The wetlands results are not directly comparable to guidelines for direct exposure in Public open spaces. Similarly, the qualitative impact is to be considered in conjunction with groundwater results in the area. These results from this area were compared against public open spaces guidelines for indicative purposes.

It is anticipated that guidance values will become available for other PFAS compounds, but these are not currently available, and no screening criteria have been applied to these compounds. The high level detects (especially above current PFOA guidelines) are to be highlighted.


7 Fieldwork, laboratory and analysis methodology

7.1 Data Quality Objectives

7.1.1 Data quality objectives The Data Quality Objectives (DQO) process was used to define the type, quantity and quality of the data needed to support decisions relating to the environmental condition of a Site.

A summary of the Site-specific DQO process for this DSI is provided in the following sections, in the context of the seven-step iterative planning approach provided in Appendix B of Schedule B2 of the ASC NEPM and the US EPA (2000, 2006) documents Guidance for the Data Quality Objectives Process and Data Quality Objectives for Hazardous Waste Site Investigations and Guidance on Systematic Planning Using the Data Quality Objectives Process, EPA QA/G-4.

The DQOs for the DSI have been prepared in line with the DQO process outlined in the ASC NEPM (Schedule B2) and are presented in the seven-step DQO approach in Table 7-1.

Table 7-1 Data quality objectives

Process Response

Step 1: State the Problem

Previous investigations report that PFAS associated with the use of AFFF at the Site has impacted soil, surface water and groundwater at the Site. However, the nature and extent of AFFF impacted media and the risk posed by the PFAS impact on human health and the environment (particularly off-Site) has not been fully evaluated. Accordingly, a comprehensive investigation has been commissioned to delineate the nature and extent of the PFAS contamination both on- and off-site and to evaluate whether the PFAS impact poses an unacceptable risk to human health and / or the environment.

Our approach to the comprehensive investigation is to undertake these works in a staged approach (which generally aligns with guidance provided by the ASC NEPM) whereby each stage of works seeks to build upon the results, findings and understanding of Site contamination conditions developed from the previous stage until there is sufficient information to evaluate whether the PFAS impact poses an unacceptable risk to human health and / or the environment.


Process Response

Step 2: Identify the Decision / Goal of the Study

The fundamental goal of the study is to determine the nature and extent of AFFF PFAS impacted media and the risk posed by such impact to human health and / or the environment, and the requirement to undertake further, more detailed Site-specific risk assessment studies and / or implement strategic Site management strategies.

The specific goals of the DSI works program include:

Confirmation of groundwater quality and levels to evaluate the direction of groundwater flow underlying the Site

Determination of background and terrestrial Site boundary conditions, including the presence or absence of off-site sourced PFAS in surface water and groundwater flowing onto the Site, soils and groundwater at anticipated up-hydraulic gradient terrestrial Site boundaries

Determining the presence or absence of PFAS contamination at on-site points of use

Determination of the presence or absence of AFFF sourced PFAS impacts in surface water and sediment anticipated in surface transport pathways and anticipated deposition zones, including on-site creek and drainage lines and sediments within Hanns inlet

Establishing whether off-site migration of AFFF-sourced PFAS has occurred and / or is occurring, and evaluate the mechanisms by which such migration has occurred or is occurring.

Determine through the application of Tier 1 risk screening guidelines whether further, more detailed Site-specific risk assessment is required and / or the implementation of strategic Site management measures.

Step 3: Identify the Inputs to the Decision

The primary inputs required include:

Relevant background data on-site history and any relevant data obtained from previous investigations

Preliminary CSM that describes sources, pathways and receptors

New data collected and observations made during fieldworks

Findings from field investigations, including field methods, such as sampling, sample storage and preservation, laboratory methods, quality control (QC) and quality assurance (QA)

Results of chemical analysis of samples collected

Statistical interpretation of new and existing datasets

Adopted assessment criteria for sampled media

Step 4: Define the Boundaries of the Study

The investigation area for the DSI works is identified as the area within the cadastral terrestrial boundary of the Site and the off-site area within Hanns Inlet. (refer to Figure 2-1) and the intertidal zone within Hanns Inlet. For the purposes of initiating the Water Use Survey, only those properties within a general 1km radius of the Site (and the residential quarters within the Site have been targeted).

The investigation area for intrusive works (including the recovery of off-site surface and / or groundwater samples, or other relevant media) may increase beyond the cadastral terrestrial boundary of the Site depending on the results and findings of the Water Use Survey and the on-site intrusive sampling and analysis works.

Vertically, the study boundary is from ground surface to a depth of 15 m.

There are no temporal boundaries for this investigation.

Sampled media include soil, sediment, surface water, groundwater, pore water, sludge and selected flora receptors.


Process Response

Step 5: Develop a Decision Rule

From a holistic perspective Aurecon needs to be satisfied (and in turn needs to satisfy relevant project stakeholders including, Defence and the environmental auditor) that the data (field and laboratory) is of sufficient quality and completeness to be able to draw meaningful and robust conclusions in respect of the stated key project objectives.

Matters to be considered include:

Is data of acceptable quality for interpretive purposes?

Is there an appropriate level of understanding of background concentrations to inform the investigation outcomes?

Has sufficient environmental data been collected to address the study objectives?

Are there potentially unacceptable risks to human health and / or ecological receptors on-site or off-site because of exposure to PFAS impacted media?

Has the nature and extent of Site-derived PFAS impacts been determined to the extent necessary to inform the undertaking of a HRA or ERA?

These matters were critically examined through application of the data quality indicators (DQI) articulated by the ASC NEPM.

Step 6: Specify Tolerable Limits on Decision Errors

Assessment of the reliability of field procedures and analytical results were performed consistent with the guidance provided by the ASC NEPM and the Western Australia Department of Environment Regulation Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) dated January 2017 (version 2.1).

Data quality indicators (DQI) of precision, accuracy, representativeness, comparability and completeness were used to assess the reliability of both field procedures and analytical results.

Acceptance limits for field data and field work activities were primarily of a qualitative nature and are detailed in Table 7-2.

Acceptance limits for laboratory data were both of a qualitative and quantitative nature. The quantitative and qualitative measures employed to satisfy these parameters are detailed in Table 7-3.

Step 7: Optimise the Design for Obtaining Data

This SAQP and these Data Quality Objectives are specifically constructed to provide a framework for all phases of intrusive works contracted by defence for the conduct of the proposed DSI works.

From the perspective of developing decision-making rules around the treatment of analytical data, and consistent with the approach advocated by the ASC NEPM, PFAS concentrations reported in any media in excess of the Tier 1 screening criteria (refer Section 6) were considered in the context of the CSM and the objectives of the DSI program. In circumstances where the exceedances are minor or trivial this may result in the subsequent undertaking of a qualitative risk assessment. Where the exceedances are other than minor or trivial, this may result in the undertaking of a quantitative risk assessment.

The absence of PFAS in the targeted media was determined by relevant concentrations of target PFAS being reported below the respective laboratory limits of reporting (and accordingly below the adopted Tier 1 screening criteria).


7.1.2 Data quality indicators for field data The DQIs for the assessment are presented in Table 7-2.

Table 7-2 Data quality indicators for field data

DQI Performance Standards Acceptable Criteria

Precision Were the SOP appropriate and complied with?

If not, the impact of any departures on the DQO(s) were considered and reported.

Accuracy Were the SOP appropriate and complied with?


Representativeness Were appropriate media sampled in accordance with the SAQP?


Completeness

Were all critical locations sampled? If not, the impact of any departures on the DQO(s) were considered and reported.

Were all samples collected from required locations and depth?

Were standard operating practices adopted?

Was sampling completed by an experienced sampler?

Is the sampling documentation complete and correct?

Were all critical locations sampled?

Comparability

Were standard operating practices adopted?


Was sampling completed by an experienced sampler?

Were climatic conditions similar?

Were the same types of samples collected?


7.1.3 Data quality indicators for laboratory data The DQIs for the assessment of laboratory data are presented in Table 7-3.

Table 7-3 Data quality indicators for laboratory data

DQI Performance Standards Acceptable Criteria

Precision

Collection and analysis of intra-laboratory duplicate samples and calculation of Relative Percent Differences (RPD) between the duplicate and primary samples

Collection and analysis of inter-laboratory duplicate samples and calculation of RPD values between the primary and duplicate samples

RPD values were considered acceptable if they are below 30% relative difference. RPD’s which exceed this range may be considered acceptable where:

Results are less than 10 times the LOR

Results are less than 20 times the LOR and the RPD is less than 50%

Heterogeneous materials are encountered

Accuracy

The closeness of the reported data to the “true” value is assessed through review of the performance of:

Method blank samples

Matrix spike and matrix spike duplicate samples

Laboratory control samples

All method blank samples below the LOR for all analytes

MS and MSD sample RPD’s within 30%

LCS results ranging from 70% to 130% recovery

Representativeness

To ensure the data produced by the laboratory is representative of conditions encountered in the field, the following measures were implemented:

Blank samples were run in parallel with field samples to detect laboratory analytical artefacts

Review of lab and field RPD’s to reveal discrepancies in analytical methods (if any)

The appropriateness of sample collection methodologies, handling, storage and preservation techniques were assessed to ensure interference is minimised

All blank sample results below the LOR

All RPD’ within acceptable control limits

All sampling conducted in accordance with ASC NEPM and Australian Standards as appropriate

Completeness

Groundwater identified to be potentially impacted by contamination pose a potential risk to health, safety and the environment and may require risk management to limit exposure to onsite users

Appropriate sampling procedures to be used

Experienced field team to undertake preliminary investigation

Correct documentation to be completed

All required samples analysed

Appropriate methods

Appropriate laboratory Level of Reporting (LORs)

Sample documentation correct

Sample holding times in compliance

Comparability

Correct sample procedures used at each location

Experienced field team

Same type (medium, volume and sampling technique) of samples collected

Same analytical methods used

Appropriate LORs

Samples submitted to the same NATA accredited laboratory

Analytical data is presented in the same units


7.2 Sampling, Analysis and Quality Plan A sampling, analysis and quality plan (SAQP) was prepared to support the field works for this DSI. The SAQP was intended as a ‘living’ document and was amended and revised when new information relevant to the undertaking of the DSI was identified. Hence, to address high-priority data gaps identified during implementation of the initial works, an addendum to the initial works SAQP was prepared.

The purpose of the SAQP was to guide field investigations at HMAS Cerberus with regard to obtaining results that are defensible, reliable and representative of the nature and extent (both laterally and vertically) of impact by PFAS. These results were used to evaluate whether a human-health risk assessment (HHRA) and / or an ecological risk assessment (ERA) needed to be undertaken.

The SAQP was prepared in general accordance with the requirements of the ASC NEPM and relevant Defence Guidance documents. The DSI works were likewise undertaken in general accordance with the requirements of the ASC NEPM and relevant Defence Guidance documents.

The SAQP and the subsequent conduct of the intrusive DSI was designed to achieve prioritisation of those works described by Defence as the ‘outward-in’ sampling approach, which seeks to identify potential off-site risks and / or impacts as a matter of priority over the delineation of known or suspected on-site risks and / or impacts. This approach is not inconsistent with the operation of the ASC NEPM and once all contracted works were complete the overall approach meets the desired intent and end points of the ASC NEPM. Further detail on the sequencing of DSI works relevant to the requisite matters to satisfy the general ASC NEPM are presented in Section 6.

7.3 Quality Assurance and Quality Control Quality control procedures are designed to both increase sample data quality and help interpret discrepancies in results. Work was conducted in accordance with industry-accepted standards and quality assured procedures. Field quality control included rigorous sample collection, decontamination procedures (where appropriate), and sample documentation.

As each sample was collected, it was labelled with a unique sample identifier, the initials of the sampler, the date and the project number. All sample jars were filled leaving no headspace and placed immediately into ice-filled cooler boxes. All samples were transported in ice-filled coolers to prevent degradation of organic compounds. Chain of Custody (CoC) documentation was completed, with data including sample identification, date sampled, matrix type, preservation method, analyses required

Data quality assessment for the DSI (field and laboratory protocols) is presented in Section 9 of this report.

7.4 Sampling methods The methods for the following sampling activities are detailed in Appendix B;

Monitoring well installation and soil sampling

Groundwater sampling

Surface water sampling

Sediment and sludge sampling

Porewater sampling

Biota (vegetation) sampling

Biota (fish) sampling

A brief summary of each of these sampling methods is presented in this section.


7.4.1 Monitoring well installation and soil sampling

Monitoring well installation Installation of groundwater wells and subsequent soil sampling was conducted by Star Drilling under the supervision of Aurecon environmental scientists who are trained and experienced in the supervision of a drilling activities and soil sampling. Soil samples were collected where new groundwater wells were installed, which targeted and delineated potential sources, pathways and receptors of PFAS.

In the deeper boreholes the uppermost water bearing layer in the Brighton Group aquifer was thin (less than 0.2 m of clayey sand) and surrounded by stiff to hard clays, hence the boreholes were skinned up during drilling to seal off the upper water-bearing zone and allow construction in the deeper water-bearing zone.

The locations of groundwater monitoring wells installed during this DSI (MW200 series wells) are shown in Appendix A - Figure 8.

Soil sampling All soil samples were collected by suitably qualified Aurecon environmental scientists. Shallow soil locations were manually excavated up to 0.2 mbgl. Samples were collected by hand using either a gloved hand, stainless-steel hand trowel. Trowels were decontaminated between sampling locations. Monitoring bore samples were collected from each monitoring well core at the surface, at changes in lithology, where observations (such as odour) were noted and where sufficient soil was encountered to sample. The samples were collected throughout the profile of the borehole. Shallow monitoring bore samples were collected using a hand auger and a hand protected by a nitrile glove. Hand augers were decontaminated between sampling locations. Samples deeper than approximately 1 m were collected using single-use plastic liners, which were cut open for logging purposes and to collect soil samples. Some locations deeper than 8 m required a solid flight auger. In this case, samples were collected directly off the side of the auger at the appropriate depth using a hand protected by a nitrile glove.

New nitrile gloves were used for the collection of each sample. All soil samples were collected directly into 250 mL containers, which were labelled and immediately stored on ice. Sampling containers were laboratory supplied and made from high-density polyethylene (HDPE) with polypropylene lids.

The locations of surface soil, test pits are shown Figure 9 of Appendix A.

7.4.2 Groundwater sampling The subsequent groundwater sampling was conducted by Aurecon environmental scientists who are trained and experienced in groundwater investigations. Groundwater sampling was undertaken in accordance with Aurecon’s Standard Operating Procedures for Low-Flow and Hydra-sleeve sampling operations, which are based on accepted industry practice for groundwater sampling projects. A comparison between the sampling results for the two groundwater sampling methods is provided in Appendix H.

New nitrile gloves were used for the collection of each sample. All groundwater samples were collected directly into 500 mL PFAS specific bottles, which were labelled and immediately stored on ice. Sampling bottles were laboratory supplied and made HDPE bottle fitted with a polypropylene screw-cap.

The locations of groundwater samples are shown on Figure 9 and Figure 10 of Appendix A.

7.4.3 Surface water sampling Surface water and sediment/sludge sampling was conducted by Aurecon environmental scientists who are trained and experienced in surface water and sediment investigations. The surface water samples were collected using 500 mL PFAS specific bottles, either hand held or using a dipper with a pole that could be extended, to collect a sample from at least 0.1 m below the water surface and at least 0.1 m above the sediment bed.


New nitrile gloves were used for the collection of each sample. All surface water samples were collected directly into sample bottles, which were labelled and immediately stored on ice. Sampling bottles were laboratory supplied and made HDPE bottle fitted with a polypropylene screw-cap.

The locations of surface water samples are shown on Figure 9 and Figure 10 of Appendix A.

7.4.4 Sediment and sludge sampling Sediment and surface sludge locations were manually excavated to depths of 0.1 and 0.2 m bgl. Samples were collected by hand using a stainless-steel hand trowel. Samples were collected by hand using either a gloved hand, stainless-steel hand trowel. Trowels were decontaminated between sampling locations.

Following the same methodology as surface soil sampling, new nitrile gloves were used for the collection of each sample and samples were collected directly into 250 mL containers, which were labelled and immediately stored on ice.

The locations of sediment and sludge samples are shown on Figure 9 and Figure 10 of Appendix A.

7.4.5 Porewater sampling Porewater sampling was conducted by suitably qualified Aurecon environmental scientists. Pore water samples were extracted from marine sediments in the laboratory. A large zip-lock plastic bag was filled with sediment collected from Hanns Inlet using a weighted ponar grab sampler. The sample was transferred to containers using a nitrile gloved hand, collecting the sample from the centre of the grabbed sediment. New nitrile gloves were used for the collection of each sample, which were collected directly into large zip-lock plastic bags, labelled and immediately stored on ice.

The locations of sediment samples are shown on Figure 10 of Appendix A.

7.4.6 Biota (vegetation) sampling Vegetation sampling was conducted by suitably qualified Aurecon environmental scientists. Biota sampling involved the removal of grass root and sward during bore hole drilling. Samples were transferred to sample bag using a nitrile gloved hand. New nitrile gloves were used for the collection of each sample, which were collected directly into small zip-lock plastic bags, labelled and immediately stored on ice.

The locations of biota (flora) samples are shown on Figure 9 of Appendix A.

7.4.7 Biota (fish) sampling Biota sampling was conducted by specialist marine and freshwater environmental consultants at Elgin Associates, supported by Aurecon environmental scientists. Fish sampling involved catching of fish using fishing lines or nets. Samples were transferred to sample bag using a nitrile gloved hand. New nitrile gloves were used for the collection of each sample, which were collected directly into large zip-lock plastic bags, labelled and immediately stored on ice.

The locations of biota (fish) samples are shown on Figure 10 of Appendix A.

7.5 Data management and analysis methods

7.5.1 Data Management Field and analytical data was collected, processed and managed in the EQuIS Environmental Data Management System. The EQuIS data management system enforces a series of data integrity requirements designed around protecting the integrity, quality and reliability of data processed into it and that which is reported for interpretive purposes.


Field data was collected using the EQuIS Data Gathering Engine (EDGE), a companion program to the EQuIS data management system designed to collect, record and organise all data and information generated during fieldworks. The following data types were recorded in EDGE:

Easting and northing coordinates, elevations and location data of all boreholes, groundwater monitoring wells and surface water locations from which samples were collected. Survey data from survey activities was also included in the EDGE data collection

Lithology and geology data and hole observations collected during borehole drilling

Water level data for monitoring wells during groundwater monitoring

Aquifer testing results

Water quality parameters for groundwater and surface water samples

Depth range of sample collection in each borehole and monitoring well

Sample names, locations, types and chain of custody information for all samples

This information was consolidated into Electronic Data Deliverables (EDD) and uploaded to the EQuIS database on completion of each fieldworks event.

Laboratory analytical results were received from the testing labs as EQuIS EDD’s and processed into the database on receipt. This information was then married with the field data to form the complete dataset. Assessments of completeness were conducted after uploading each EDD to ensure that data had been processed correctly in its entirety and that reports and data outputs were functioning correctly. Where errors were found in data files these were corrected to conform to the EQuIS data integrity requirements prior to upload. Once processed into the database and checked for completeness, that data formed the true and accurate record and all subsequent reports, analyses and interpretations were drawn from data contained in the EQuIS database only. Data presented on GIS figures and 3D models was sourced from the EQuIS database to preserve data integrity.

7.5.2 Data interpolation and visualisation The Kriging technique was used to interpolate the laboratory data. Kriging is a statistical interpolation technique which estimates values of parameters of interest (e.g., contaminant concentrations) in areas which have not been sampled. The technique uses weighted averages of all neighbouring data points to calculate probabilistic unknown values at a given location or across a specified domain. In addition, the location of all samples (known values) and the relevant statistical relationships (distance and direction) between each point are both honoured and used in the estimation of unknown values. When applied in a three-dimensional (3D) grid, the technique yields a 3D “surface”, object or plume which accurately represents the configuration of the interpolated values of interest (i.e. dissolved phase contaminants) and provides an aggregated standard error which is useful in assessing the confidence level of the interpolated object.

Kriging is widely used in the minerals and resources exploration industries for estimating the size and yield of ore bodies, petroleum reserves and coal seams and is the gold standard method for development of geological models to aid in construction of mines and planning extractive operations. Earth Volumetric Studio 2017.6 was used to conduct 3D volumetric modelling.

No alteration of contours has been performed post generation to preserve data integrity and reproducibility. Plotted contours of groundwater, selected COPC and 3D surfaces of COPC concentrations are presented in Appendix A, and raw data used for creating the contours is presented in Appendix F.


8 Sample design

8.1 Site investigation rationale The Site investigation approach and rationale were detailed in the following SAQP documents:

Aurecon (2017), Sampling, Analysis and Quality Plan for Detailed Site Investigations, September 2017

Aurecon (2018), Proposed field work to address DSI data gaps, February 2018

8.1.1 Introduction The intrusive site investigation was designed to assist in identifying the nature and extent of PFAS impacts within the site and surrounding area within soil, sediment, sludge, surface water, groundwater and limited biota. The intrusive site investigation is based on the previous environmental investigations and the preliminary CSM, targeting the nine identified sources on Site, along potential pathways and at sensitive receptors.

8.1.2 Sampling program The sampling locations and number of samples at each location were determined in general accordance with the following:

Preliminary CSM

AS/NSZ 4482.1 – 2005 Guide to the investigation and sampling of sites with potentially contaminated soil Part 1: Non-volatile and semi-volatile compounds

ASC NEPM – Schedule B2: Site Characterisation

Site accessibility constraints

The location of underground and overhead services

Findings from the Water Use Survey

The sampling program aimed to adequately identify sources, pathways and mechanisms for PFAS transport and attenuation, and for identification of the location and likely impacts to ecological and human receptors.


8.2 Program A summary of the program of works for the DSI is provided in Table 8-1.

Table 8-1 Program of works

Activity Date

Site induction 13 July 2017

Underground service location 17 September 2017 7 March 2018

Drilling of boreholes, soil sampling and groundwater monitoring well construction

Groundwater monitoring well installation Round 1: 21 to 28 September 2017 Round 2: 1 and 2 March 2018

8 to 14 March 2018

Surface water sampling Round 1: 17 to 28 August 2017 (Low tide) at 35 of 70 locations Round 2: 14 and 15 December 2017 (Marine) at 21 of 70 locations Round 3: 16 March 2018 (High tide) at 3 of 70 locations 4 April 2018 (Fire Ground) Round 4: 7 May 2018 (Marine) at 12 of 70 locations 28 to 30 May 2018 (Marine)

Sediment sampling Round 1: 17 to 28 August 2017 Round 2: 14 and 15 December 2016 (Marine)

Groundwater well development Following construction

Groundwater sampling Round 1: 5 to 7 September 2017 (3 of 69 wells sampled) Round 2 17 to 20 October 2017 (14 of 81 wells sampled) Round 3: 4 to 7 December 2017 (60 of 81 wells sampled) Round 4: 16 March 2018 (46 of 91 wells sampled)

28 and 29 March 2018 4 to 5 April 2018

Round 5: 30 May 2018 (3 of 91 wells sampled)

Soil sampling Round 1: 21 to 28 September 2017 Round 2: 1 to 2 March 2018 Round 3: 8 to 14 March 2018 Round 4: 16 March 2018

21 to 23 March 2018 4 to 5 April 2018

Round 5: 11 May 2018 (including grass) 28 May 2018 (including grass)

Surface water, sediment and pore water sampling

Round 1: 4 to 7 December 2017 Round 2: 16 March 2018

Sludge sampling 15 and 16 March 2018

Fish and surface water sampling Round 1: 7 to 8 May 2018 Round 2: 28 to 30 May 2018

An Environmental Clearance Certificate (ECC) was issued by the Regional Environment and Sustainability Officer (RESO) for HMAS Cerberus. Safe Work Method Statements (SWMS) and “Take 5” Risk Assessments were completed prior to commencement of site works.


8.3 Sample locations The locations of all Site samples collected during the DSI field investigations are shown in Appendix A - Figure 7. These samples were collected to address the data gaps identified in Section 5 – Conceptual Site Model.

For each sample location the laboratory results classified against either detection / non-detection or the screening level for that matrix are presented on Figure 8 through Figure 25 in Appendix A. Additionally, Table 8-2 lists the number of samples analysed by matrix.

8.4 Soil The soil sampling program was designed to address the following data gaps:


− The soil samples collected from groundwater monitoring bores (9 bores) installed for this investigation at the Site boundary aim to confirm groundwater flow paths and provide an indication for background PFAS levels

Delineation of the nature and extent of impact around the Fire Ground

− Previous investigations have sufficiently characterised the operational area of the Fire Ground, the surface soil samples collected around Fire Ground and associated closed landfill provide indication of the lateral extent of soil impact

− Additional monitoring bores were drilled at two locations south of the Fire Ground providing indication of the vertical and lateral extent of soil impact

− Further monitoring bores were drilled at two locations in the wetlands to the south of the Fire Ground provide indication of the vertical and lateral extent of soil impact

− The surface soil samples collected from the wetlands south of the Fire Ground and associated closed landfill provide indication of the lateral extent of soil impact near the creek that leads to Hanns Inlet

Delineation of the nature and extent of impact around the Fire Station

− The surface soil samples collected around Fire Station and Ornamental Lake provide indication of the lateral extent of soil impact

− These surface soil samples focus on the area where AFFF may have been sprayed from the Fire Station towards the Ornamental Lake

Assessment of the nature and extent of impact around the Former STP

− The soil samples collected from groundwater monitoring bores (3 bores) installed between the Former STP provide an indication of the pathway between the lagoons and the West Creek

− The surface soil samples collected around the in-filled Former STP infrastructure and lagoon outlets provide an indication of soil impact


− The surface soil samples collected from the Bushfire Area indicate the lateral extent of soil impact

− The surface soil samples collected from the Sports Fields indicate the lateral extent of soil impact

− A surface soil sample was collected from the Sullage Pit indicate soil impact

In total, 22 boreholes and 37 surface soils/test pits were excavated (refer Appendix C for logs). Surface soil locations were excavated to a maximum depth of 0.1 m and test pits to 0.2 m, while boreholes were excavated to between 2.5 m and 12.5 m bgl, depending on the depth to groundwater and the geology encountered.


8.5 Groundwater The groundwater sampling program was designed to address the following data gaps:

Confirmation of groundwater flow direction

− Multiple rounds of gauging of groundwater monitoring wells to assess groundwater flow direction


− The groundwater samples collected from groundwater monitoring wells installed for this investigation at the Site boundary allow assessment of background PFAS levels and assess PFAS near off-Site residents


− Multiple rounds of sampling (including both HydraSleeve and Low Flow techniques) from the existing wells to better characterise groundwater flows around the operational area of the Fire Ground

− Installation of two shallow and deep groundwater monitoring well pairs south of the operational zone to indicate vertical and lateral groundwater impact

− Groundwater sampling from the three existing wells in the wetlands south of the Fire Ground to better characterise groundwater flows near the South Creek

− Installation of two groundwater monitoring wells in the wetlands south of the Fire Ground indicate lateral groundwater impact


− Groundwater sampling from the two existing wells between the Fire Station and Hanns Inlet

Delineation of the nature and extent of impact around the Former STP

− Groundwater sampling from the existing wells to better characterise groundwater flows around the Former STP

− Installation of a shallow and deep groundwater monitoring well pair and a standalone groundwater monitoring well to indicate impact to groundwaters discharging to the West Creek


− Groundwater samples collected from existing groundwater monitoring wells at the Sullage Pit, Closed Rifle Range Road landfill, Closed indoor and outdoor swimming pools, former fuel storage areas

− Installation of a groundwater monitoring well near the Bushfire Zone

Assessment of the flow of impacted groundwater to Hanns Inlet

− Installation of a groundwater monitoring well at the Marina targeting the groundwater flowing below the fill material

− Groundwater sampling from existing monitoring wells across the operational area of the Site

It is noted that temporal impacts to groundwater concentrations are anticipated, especially over the course of a 12-month investigation. The concentration of PFAS in the groundwater is expected to fluctuate slightly with seasonal and climatic conditions, which influence the reported values. This is especially important for wells that were only sampled once (i.e. monitoring wells outside of main source areas). The potential variability is a data gap to be addressed during ongoing monitoring.

8.6 Surface water, sediments and sludge The surface water, sediment and sludge sampling program was designed to address the following data gaps:

Assessment of the dermal contact pathway with surface water and sediment in storm-water drainage network

− Sampling of surface water and sediment following a rain event



− Sampling of surface water and sediment from the Fire Ground Pond

− Sampling of water from Fire Ground infrastructure including the laundry, leak repair unit and oil/water interceptor


− Sampling of surface water and sediment from the Ornamental Lake

Delineation of the nature and extent of impact around the Former STP

− Sampling of surface water and sediment (sludge) from the Former STP lagoons

− Sampling of dried sludge from the Former STP lagoons


− Sampling of surface water and sediment from the Sullage Pit

− Sampling of surface water and sediment from South Creek near the Closed Rifle Range Road landfill


− Sampling of surface water and sediment from different regions of Hanns Inlet

Assessment of the pathway via surface water from Hanns Inlet to Western Port Bay

− Sampling of surface water along Hanns Inlet to the mouth of the Inlet

8.7 Biota (vegetation) Assessment of nature and extent of impact at other potential sources

− Sampling of vegetation at the Sports Fields

Assessment of pathway to off-Site terrestrial biota

− Sampling of vegetation at new monitoring wells installed at Site land boundaries

8.8 Biota (fish) The fish sampling program was designed to address the following data gaps:


− Two rounds of biota sampling in different regions of Hanns Inlet targeting a range of species, including; whiting (edible), mullet (edible), Australian Salmon (edible), Fiddler Ray (edible) and Toadfish (inedible)

Note that the second round of fish samples from marine sampling were placed on hold after it was established that the first round produced a complete and reliable dataset.


Table 8-2 Investigation Sample Numbers Summary

Facility2 Soil Samples

Groundwater Samples

Surface Water Samples

Sediment Samples

Pore Water Samples

Sludge Sample

Flora Samples

Biota Samples

Fire Ground 27 34 51 1 - - - -

Fire Station 18 4 2 2 - - - -

Former STP 13 10 4 3 - 8 1 -

Hanns Inlet - - 43 20 19 - - 66

Closed Rifle Range Road Landfill 1 8 3 2 - - - -

Marina 4 32 - - - - - -

Sullage Pit 1 2 2 2 - - - -

Site boundary region 49 23 14 13 - - 11 -

Sports Field 7 - - - - - 5 -

Wider site area 12 23 81 7 - - 2 -

Total Primary Samples 132 136 81 50 19 8 19 66

Duplicate/Triplicate Samples 19 20 21 13 2 0 3 8

Totals 151 156 102 63 21 8 22 74 1 Surface water sample locations in these areas include a tap water sample, which was named in the SW series prior to advice that the Defence naming convention (DCD#7) has expanded to include effluent (EFF series) and potable (POT series) 2 Facilities are grouped geographically based on key sources, pathways and receptors


9 Data quality assessment

9.1 Quality assurance and quality control procedures Aurecon implemented a comprehensive quality assurance / quality control (QA/QC) program as part of the DSI based guidance provided by section 13 and Appendix C of Schedule B2 of the ASC NEPM.

The implemented QA/QC program included the following: The use of an appropriately qualified and trained environmental scientists and engineers to conduct the

assessment

The use of standardised operating procedures to conduct all field works

The use of standardised field records to document the findings of the assessment

Appropriate preservation of samples during transport from the field to the laboratory in accordance with standard chain of custody protocols which are consistent with the requirements of Schedule B2 of the ASC NEPM

The use of chain of custody (CoC) documentations to ensure the traceability of sample transport and handling

The use of laboratories accredited by the National Associated of Testing Authorities Australia (NATA) for the analysis of soil samples

The collection and analysis of field quality control samples

Review of internal analysis of laboratory quality control samples

The use of appropriate laboratory reporting limits

Compliance with sample holding times

Comparison of field and analytical data to check for the occurrence of apparently unusual or anomalous results.

Laboratory QA/QC procedures and results are detailed in the certified laboratory results contained in Appendix G.

9.2 Assessment of data quality indicators The assessment of Data Quality Indicators (DQIs) has been undertaken in accordance with Schedule B2 of the ASC NEPM. These DQIs include both field and laboratory considerations for the following: Completeness

Comparability

Representativeness

Precision

Accuracy

The findings of the data quality assessment are presented in detail in Appendix H however, in summary Aurecon is satisfied that the data is of sufficient quality upon which to draw meaningful and robust conclusions in respect to the key objectives of the DSI.


10 Investigation results

10.1 General This investigation results section details the physical observations and field results, and the laboratory analysis of the sampling of soil, groundwater, surface water, pore water, sediment, sludge, grass and vegetation, fish flesh and fish liver. A photographic record of fieldwork activities is presented in Appendix D. Photography on site was approved by the Site Support Manager. The field results are provided in Appendix E, the summary of laboratory results and details of sample locations in Appendix F and laboratory certificates in Appendix G. Attached figures are in Appendix A. Figures pertaining to results are listed below.

Figure 7 in Appendix A shows all sample locations over the IA

Figure 8 in Appendix A shows the locations of the monitoring wells (existing and installed during this investigation)

Figure 9A-D in Appendix A shows the locations of surface soil, surface water, test pits and sludge samples collected on-site

Figure 10 in Appendix A shows the locations of surface soil, surface water, and pore water samples collected off-site in Hanns Inlet

Figure 12 in Appendix A provides an overview of key areas for laboratory results

Figure 13 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the soil from the Fire Ground at a range of depths

Figure 14 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, surface soil, groundwater and sediment at the Fire Ground

Figure 14a in Appendix A shows historical results for groundwater monitoring wells near Fire Ground

Figure 15 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the soil from the wetlands south of the Fire Ground at a range of depths

Figure 16 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, surface soil, groundwater and sediment at the wetlands south of the Fire Ground

Figure 17 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the soil from the wetlands south of the Fire Station at a range of depths

Figure 18 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, surface soil, groundwater and sediment at the wetlands south of the Fire Station

Figure 19 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the soil from the wetlands south of the Former STP at a range of depths

Figure 20 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, surface soil, groundwater and sludge at the wetlands south of the Former STP

Figure 21 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the soil from the Marina area at a range of depths

Figure 22 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, surface soil, groundwater and sediment from the Marina area

Figure 23 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, sediment, fish flesh, and fish liver in Hanns Inlet

Figure 24 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the soil from the other Site areas at a range of depths


Figure 25 in Appendix A shows detects and screening criteria exceedances for PFOS + PFHxS in the surface water, surface soil, groundwater and sediment from other Site areas

Figure series 26 through 31 show PFAS-impacted soil on a Site-wide basis and at source areas

Figure series 32 through 34 show PFAS-impacted groundwater on a Site-wide basis and at source areas

Figure series 35 shows cross sectional view of PFAS-impacted soil at the Fire Ground

The figures show values for PFOS + PFHxS because many guidelines are based on the sum of these two compounds31. They are also indicative of the presence of a wider range of PFAS compounds. A detailed summary laboratory results table is provided in Appendix F with each PFAS concentration above screening criteria highlighted in orange.

10.2 Soil investigation

10.2.1 Soil types Regionally, the State soils database indicates that the Site comprises the Bittern soil complex comprising brown and yellow Chromosols with some Sodosols. Surface soils comprise dark brown, slightly acidic loamy sands to fine sandy clay loams. Subsoils comprise moderately acidic, yellow-brown heavy clay.

The regional soil characteristics were evident in the surface soils sampled at the Site, which typically comprised silty sands to clayey sands, coloured grey to brown with moist to wet moisture conditions. Acid sulphate soils are likely to be present in the wetlands soils (hydrosols) deposited along the tidally influenced portions of the Site creeks. In the tidal flats swamp deposits occur, which are wet for most of the year and are dark grey clays or silty clays, which become bluish grey with depth. These soils can be described as Extratidal Hydrosols.

Fill soils comprising Brighton Group sediments excavated from the northern portion of the Site were used to reclaim tideland along the marina area. Logs for boreholes in this area indicate approximately 4 m of clayey fill material was placed in this area.

10.2.2 Geology Geological materials observed during intrusive works reflected the regional surficial geology consisting of Brighton Group sediments with alluvial sediments occurring along the creeks. As presented on borehole logs in Appendix C, the subsoils consisted predominantly of clays, which were typically frim to stiff, orange to brown to a depth of approximately 6 to 7 m below ground level (mbgl).

At greater depths (up to 12 mbgl) grey, soft, saturated soils that were usually sandy clays to clayey sands were typically encountered. However, some boreholes, such as for MW201 and MW203, encountered sandy to gravelly intervals.

This distribution of soils reflects the fluvial depositional environment of the Brighton Group sediments with localised channel sands occurring within the dominant clay soils.

Along the Site creeks and tidal wetlands up to 2 m of grey to dark brown to black, soft silts and clays were observed. These soils were deposited as a thin veneer over the eroded surface developed on the top of the Brighton Group sediments.

10.2.3 Field observations The following observations were noted during the soil sampling program. The borehole details from Aurecon investigations, as well as previous environmental investigations by SMEC (2008), GHD (2011) and Golder 31 Note that soil data collected by others during investigations in 2016-2017 have also been presented in the figures for completeness as they contribute to the assessment of risks. These results are discussed in Section 4. The results presented in the tables in this section pertain only to the current investigation.

http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/gloss_HR#hydrosols


(2017), are provided in Appendix C – Borehole Logs. Soil investigation locations are shown in Appendix A – Figures 9A-D.

Visual and olfactory indications of potential contamination were not observed in surface soil or monitoring well borehole soil samples.

10.2.4 Background concentrations Nine out of ten soil samples from the groundwater monitoring wells at the Site land boundaries recorded non-detects for all PFAS compounds. The exception was MW207, which was located near a zone potentially affected by bushfire. Therefore, the background concentration is assumed to be below the respective LORs (0.001-0.005 µg/L).

10.2.5 Soil laboratory results Soil analytical results were compared to adopted screening criteria (where land use relevant), which are summarised in Section 6 and presented in Table 6-5. Soil investigation locations and analytical results for combined PFOS and PFHxS screened against adopted ecological and human health screening criteria are presented on Figures 13, 15, 17, 19, 21, 23 and 25. The laboratory certificates of analysis are provided in Appendix G.

A summary of laboratory results and screening criteria exceedances is included in Table 10-1. These results are grouped based on known and potential sources, pathways and receptors identified in Section 3 - Conceptual Site Model. The soil samples at the boundary assess the pathway to sensitive off-Site receptors as well as investigating the bushfire area. The soil samples at the Fire Ground, Fire Station and Former STP help to delineate known and likely PFAS sources. The soil samples at the other potential PFAS sources are grouped due to similar land uses and detection levels Note that the only screening criteria exceedances in the grouped minor sources occurred in the Sports Fields (indirect ecological exposure – residential), where the screening level is not directly applicable to the land use. Further details on source delineation are provided in Section 11.2.


Table 10-1 Summary of soil analysis and soil screening criteria exceedances

Analyte No.

samples tested

No. of detects

Measured concentrations (mg/kg)

Screening criteria (mg/kg) Number of samples exceeding screening

criteria Human Health Ecological

Min Mean Max HH1 HH2 HH3 HH4 HH5 EGV1 EGV2 EGV3

SITE LAND BOUNDARIES (INCLUDING BUSHFIRE AREA AT MW207)

PFOS 49 6 <0.005 0.0045 0.039 - N/A - N/A N/A 1 0.01 N/A EGV1 direct exposure (public open space): 0 EGV2 indirect exposure (residential):52

PFOA 49 0 <0.005 <0.005 ND 0.1 N/A 10 N/A 4 10 - N/A All screening criteria: 0

6:2 FTS 49 0 <0.010 <0.005 ND - N/A - N/A - - - N/A -

PFHxS 49 0 <0.001 <0.005 ND - N/A - N/A - - - N/A -

Other PFAS 49 0 <0.005 N/A ND - N/A - N/A - - - N/A -

PFOS+PFHxS 49 6 <0.005 0.0045 0.039 0.009 N/A 1 N/A 1 - - N/A HH1 Low Density Residential: 52 HH3 Public open space: 0 HH4 Commercial/Industrial: 0 HH5 Intrusive / maintenance workers: 0

Sum of PFAS 49 51 <0.005 0.024 0.22 - N/A - N/A N/A - - N/A -

FIRE GROUND AND SOUTH CREEK WETLANDS

PFOS 27 20 <0.001 0.705 12.0 N/A N/A - - N/A 1 N/A 0.14 EGV1 direct exposure (public open space): 4 EGV3 indirect exposure (industrial/commercial): 7

PFOA 27 7 <0.001 0.005 0.030 N/A N/A 10 50 4 10 N/A - All screening criteria: 0

6:2 FTS 27 0 <0.005 <0.005 ND N/A N/A - - - - N/A - -

PFHxS 27 20 <0.001 0.047 0.280 N/A N/A - - - - N/A - -

Other PFAS 25 12 <0.001 N/A 0.090 N/A N/A - - - - N/A - -

PFOS+PFHxS 27 22 <0.002 0.752 12.1 N/A N/A 1 20 1 - N/A - HH3 Public open space: 4 HH4 Industrial/commercial: 0 HH5 Intrusive / maintenance workers: 4

Sum of PFAS 27 211 <0.001 0.788 12.3 N/A N/A - N/A N/A - N/A - - Table note: HH1: FSANZ HBGV A SOIL 2017 – Low Density Residential, HH2: FSANZ HBGV B SOIL 2017 - Residential with minimal opportunities for soil access HH3: FSANZ HBGV C SOIL 2017 - Public open space, HH4: FSANZ HBGV D SOIL 2017 - Industrial/commercial, HH5: adjusted HH4 for intrusive / maintenance workers EGV1: Interim soil - ecological direct exposure (public open space), EGV2: Interim soil - ecological indirect exposure (residential), EGV3: Interim soil - ecological indirect exposure (industrial/commercial)

Concentrations detected above the screening criteria are highlighted in orange with the corresponding screening criteria that have been exceeded are highlighted in bold and underlined 1The recorded LOR for sum of PFAS is higher than PFOS and PFHxS, hence a non-detect may be recorded for sum of PFAS when low-level PFOS/PFHxS/PFOA are recorded

2All ecological and human health screening criteria exceedances occurred near the Bushfire Zone (around MW207). These residential screening levels are not directly applicable to the land use in this area


Summary of soil analysis and soil screening criteria exceedances (continued)

Analyte No.

samples tested

No. of detects





FIRE STATION AND ORNAMENTAL LAKE

PFOS 18 18 0.006 0.301 1.10 N/A N/A - - - 1 N/A 0.14 EGV1 direct exposure (public open space): 1 EGV3 indirect exposure (ind./comm.): 7


6:2 FTS 18 0 <0.005 <0.005 ND N/A N/A - - - - N/A - -

PFHxS 18 16 <0.001 0.009 0.026 N/A N/A - - - - N/A - -


PFOS+PFHxS 18 18 0.006 0.310 1.12 N/A N/A 1 20 1 - N/A - HH3 Public open space: 1 HH4 Industrial/commercial: 0 HH5: Intrusive workers: 1

Sum of PFAS 18 18 0.006 0.345 1.15 N/A N/A - - - - N/A - -

FORMER SEWAGE TREATMENT PLANT

PFOS 13 5 <0.001 0.039 0.16 N/A N/A - - - 1 N/A 0.14 EGV1 direct exposure (public open space): 0 EGV3 indirect exposure (ind./comm.): 1


6:2 FTS 13 0 <0.005 <0.005 ND N/A N/A - - - - N/A - -

PFHxS 13 4 <0.001 0.006 0.038 N/A N/A - - - - N/A - -


PFOS+PFHxS 13 8 <0.001 0.039 0.171 N/A N/A 1 20 1 - N/A - HH3 Public open space: 0 HH4 Industrial/commercial: 0 HH5: Intrusive workers: 0

Sum of PFAS 13 41 <0.001 0.050 0.195 N/A N/A - - - - N/A - - Table note: HH1: FSANZ HBGV A SOIL 2017 – Low Density Residential, HH2: FSANZ HBGV B SOIL 2017 - Residential with minimal opportunities for soil access HH3: FSANZ HBGV C SOIL 2017 - Public open space, HH4: FSANZ HBGV D SOIL 2017 - Industrial/commercial, HH5: adjusted HH4 for intrusive / maintenance workers EGV1: Interim soil - ecological direct exposure (public open space), EGV2: Interim soil - ecological indirect exposure (residential), EGV3: Interim soil - ecological indirect exposure (industrial/commercial)



Summary of soil analysis and soil screening criteria exceedances (continued)

Analyte No.

samples tested

No. of detects





SULLAGE PIT, SPORTS FIELD AND POTENTIAL MINOR SOURCES

PFOS 25 3 <0.001 0.002 0.013 N/A N/A - - - 1 0.01 0.14 EGV1 direct exposure (public open space): 0 EGV2 indirect exposure (residential): 23 EGV3 indirect exposure (ind./comm.): 0

PFOA 25 0 <0.001 <0.001 ND N/A N/A 10 50 4 10 All screening criteria: 0

6:2 FTS 25 0 <0.005 <0.005 ND N/A N/A - - - -

PFHxS 25 0 <0.001 <0.001 ND N/A N/A - - - -

Other PFAS 25 0 <0.001 <0.001 ND N/A N/A - - - -

PFOS+PFHxS 25 3 <0.001 0.002 0.013 N/A N/A 1 20 1 - All screening criteria: 0

Sum of PFAS 25 11 <0.005 <0.005 0.013 N/A N/A - - - - Table note: HH1: FSANZ HBGV A SOIL 2017 – Low Density Residential, HH2: FSANZ HBGV B SOIL 2017 - Residential with minimal opportunities for soil access HH3: FSANZ HBGV C SOIL 2017 - Public open space, HH4: FSANZ HBGV D SOIL 2017 - Industrial/commercial, HH5: adjusted HH4 for intrusive / maintenance workers EGV1: Interim soil - ecological direct exposure (public open space), EGV2: Interim soil - ecological indirect exposure (residential), EGV3: Interim soil - ecological indirect exposure (industrial/commercial)


3Both ecological screening criteria exceedances occurred in the Sports Fields, which is not directly applicable to this land use


10.2.6 Impacts to Beneficial Uses Table 10-2 presents an evaluation of preclusion of land beneficial uses based on the screening levels presented in Table 6-5.

Table 10-2 Land SEPP beneficial uses – evaluation of preclusion

Beneficial Use Precluded? Comment


On-Site Yes Numerous detections of PFOS across the Site

Off-Site No PFAS not reported above screening levels along the Site boundary (including the bushfire area near MW207)

Human health - Residential

On-Site No Bushfire area near MW207 reported PFOS above the low-density residential, but

fire did not reach the permanent residential area. Hence, unlikely PFAS residue is in the permanent residential area

Off-Site No Only PFAS detected along the Site boundary was at the bushfire area near MW207.

The bushfire did not burn east of the rail line, hence did not reach the off-Site residences east of the Site

Human health – Open spaces / playing fields

On-Site No PFAS screening levels not exceeded


Human health – Commercial / Industrial

On-Site No PFAS screening levels not exceeded


Human health – Intrusive / Maintenance Workers

On-Site Yes PFAS screening levels exceeded (Fire Ground and South Creek wetlands)



On-Site No PFAS not reported to impact buildings and structures

Off-Site No As above

Aesthetics

On-Site No No evidence of visual impact by PFAS (such as foams) including the area of highest reported PFAS (South Creek wetlands)



On-Site No No evidence of AFFF use in the permanent residential area.

Off-Site No Up-gradient from Base AFFF PFAS sources


10.3 Groundwater investigation

10.3.1 Monitoring well installation The monitoring well locations are presented in Appendix A – Figure 8

22 new monitoring wells were installed

− All new wells (except MW212, MW213 and MW217S) were screened in the Brighton Group aquifer

− MW212, MW213, and MW217S were screened in the alluvial / estuarine aquifer

− Refer to Appendix C – Borehole Logs for further details of screened intervals

Two monitoring wells were installed midway between the known sources and the land boundary of Site (MW200 and MW201)

10 wells were installed at the Site land boundaries (MW202-MW211)

Two wells were installed in the wetland south of the Fire Ground (MW212 and MW213)

Four wells (two shallow and deep pairs targeting different water bearing zones within the Brighton Group aquifer) were installed south of the operational area of the Fire Ground (MW214S/D, MW215S/D)

One well was installed in the uppermost Brighton Group aquifer (below fill material) at the Marina on the potential groundwater flow path between the known sources and Hanns Inlet (MW216)

Three wells (one pair: shallow, MW217S, in alluvial / estuarine aquifer; and deep, MW217D, in the Brighton Group aquifer, and one deep, MW218, in the Brighton Group aquifer) were installed at the Former STP (MW217S/D and MW218)

10.3.2 Field observations The following observations were noted during the groundwater sampling program. The monitoring well borehole details from Aurecon investigations, as well as previous environmental investigations by SMEC (2008), GHD (2011) and Golder (2017), are provided in Appendix C – Borehole Logs. The details from installation of groundwater monitoring wells, gauging and sampling are provided in Appendix E – Field Data.

The clayey soils assigned to the Brighton Group sediments dominate between ground surface and the limit of drilling (up to 12 mbgl). Localised intervals of sandy clays to clayey sands were noted. Coarser intervals (typically clayey sands but with sands to gravels in MW201 and MW203) that occurred at depths greater than approximately 6 mbgl were the main saturated intervals, which are semi-confined (artesian to flowing artesian). A water table occurs in the estuarine / alluvial sediments deposited in the wetlands and tidal flats of Hanns Inlet, and in the Fill material in the marina area.

With regards to visual and olfactory indications of potential contamination, extracted groundwater was generally clear to slightly turbid except for turbid groundwater extracted from MW216 (at the marina), GW01-VT0365 (closed Rifle Range Road landfill), and MW217D (at the former STP). No odours were detected during gauging or sampling except at the following wells:

GW02-VT0372 (Building 49 - Demonstration Building – AST): petrol odours

GW03-VT0365 (closed Rifle Range Road landfill): rotten egg (hydrogen sulphide) odour

10.3.3 Groundwater elevation and flow direction

Inferred groundwater flow direction Figure 10-1 (refer to Figure 6 in Appendix A for more detail) shows inferred groundwater elevation contours for the uppermost Brighton Group aquifer based on water levels measured between March and May 2018. Note that groundwater levels across the Site were measured between 22 March and 4 April 2018, except for the four wells at the Sullage Pit, which were measured on 28 May 2018 due to access issues. The inferred


groundwater contours were based on gauging of wells screened in the uppermost Brighton Group aquifer (typically between 8 and 10 mbgl). Site groundwater in the shallow Brighton Group aquifer generally flows with a horizontal gradient of approximately 0.004 to the southeast with localised flow to the Site tidal creek east of the former STP, south of the Fire Ground, or the creek northeast of the Fire Station. In response to generally below-average rainfall (particularly during February 2018), the March/April 2018 groundwater levels generally dropped between 0.5 m and 1 m since gauging in the August-September monitoring event. The lower groundwater levels reported for the March/April 2018 gauging event was accompanied by a slight reduction in the flow gradient. The inferred flow direction in the shallow Brighton Group aquifer was generally consistent between the gauging events.

Groundwater contours shown on Figure 10-1 and on Figure 6 in Appendix A suggest the presence of localised mounds of groundwater at and north of the Fire Ground (VT0067), former petrol station (VT0370), closed Rifle Range Road landfill (VT0365), and the Sports Fields. These inferred mounds, along with groundwater fresher than ambient groundwater, suggest local recharge, such as leakage from mains water, lagoon leakage at the Fire Ground, and irrigation at the Sports Fields. Note that based on the groundwater levels in wells located next to the Fire Ground lagoon (such as GW07-VT0067), unsaturated soils are likely to be present beneath the lagoon.

In contrast, a groundwater sink is inferred at MW121. Groundwater levels measured in this well have been dropping since measurements were taken in August 2017. The latest groundwater elevations are below 0 mAHD, which corresponds to the elevations of low tides reported for the Stony Point tide gauge located at the mouth of Hanns Inlet. The groundwater levels for MW121 suggest that this well exhibits a greater degree of hydraulic connection compared to other wells closer to Hanns Inlet, such as MW122D or MW216. This greater connection is presumed to reflect northwest-southeast trending faulting of the Brighton Group strata, which has created more permeable aquifer material that results in a higher degree of hydraulic connection with surface waters in Hanns Inlet.

Figure 10-1 Brighton Group aquifer inferred groundwater flow contours – March-May 2018

Several paired wells (MW214S/D and MW215S/D at the Fire Ground and MW217S/D at the former STP) were installed with completions in the uppermost (between 6 and 8 mbgl) and deeper saturated intervals


(between 10 and 12 mbgl) of the Brighton Group aquifer. Comparison of reduced water levels (RWLs) for each pair indicate upward gradients at the locations of these well pairs.

Tidal influence In the wetlands south of the Fire Ground, paired wells MW122S (2 m deep) and MW122D (5 m deep) are completed in the alluvial aquifer and uppermost Brighton Group aquifer, respectively. RWLs in this pair also indicate an upward gradient with the Brighton Group bore (MW122D) exhibiting flowing artesian conditions occurring during some tide cycles. The net effect of this oscillating groundwater level is a variable flux of PFAS-impacted groundwater discharging into the Site tidal creeks and Hanns Inlet.

Tide fluctuations in Hanns Inlet affects groundwater levels in wells (particularly wells completed in fill or alluvial/estuarine material) located near the tidal creeks or shoreline of Hanns Inlet. Figure 10-2 shows representative tide levels measured at Stony Point tide station, which is located just north of the mouth of Hanns Inlet. Note that the 0-m tide level corresponds to -1.69 mAHD.

Figure 10-2 Stony Point tide heights – 29 June 2018 to 3 July 2018

Figure 10-3 shows the elevation of water in South Creek near the closed Rifle Range Road landfill and barometrically corrected RWLs based on data logging during February through March 2018 of groundwater levels in MW122S and MW122D, along with nearby MW121.

Water levels in South Creek ranged between a minimum of approximately -0.5 mAHD (when the creek was effectively dry) and 1 mAHD at high tide. The tide exhibited a range of approximately 1.7 m during the data logging; while the tides measured at Stony Point tide station ranged between approximately -1 mAHD and 1.3 mAHD.

Time-series plots of these RWLs indicate that the shallow well (MW122S) completed in the alluvial aquifer is coupled with the tidal fluctuations in the nearby tidal creek with groundwater fluctuating approximately 0.1 m in response to water-level fluctuations of approximately 1.7 m in the stilling well established in the tidal creek. However, the groundwater levels recorded in MW122S fluctuate daily while the levels in the tidal creek reflect the generally twice-daily cyclic fluctuation in surface-water levels (as measured at the stilling well located approximate 300 m southeast along the creek south of the Fire Ground).

Nearby wells completed in the uppermost Brighton Group aquifer (MW121 and MW122D) do not seem to be coupled with tidal fluctuations in the water level in South Creek. However, over the monitoring period groundwater levels in MW121 became negative, which reflects the local sea elevation in Western Port Bay and Hanns Inlet, which measured as low as -1 mAHD during the logged interval and has been recorded to fall as low as -1.99 mAHD at lowest astronomical tide.


Figure 10-3 Data-logged Groundwater Elevations – Wetlands South of the Fire Ground

RWLs from multiple gauging events and data logging in select wells along the creek south of the Fire Ground indicate tidal influence in wells located near the shoreline of the marina area and near the creek south of the Fire Ground. A stilling well was established at the bridge crossing South Creek (next to the closed Rifle Range Road landfill). Tidal range measured using a data logger in the stilling well and in Hanns Inlet (based on the Stony Point tide gauge; refer Figure 10-3 was approximately 1.7 m during the timeframe of these gauging events. RWLs for MW216, which is a deeper well screened in the Brighton Group sediments located about 50 m west of the marina shoreline, ranged between -0.14 mAHD and 0.73 mAHD. This suggests hydraulic influence of tides in the marina area extends at least 50 m landward. Shallower wells located near MW216, such as MW114 (screened mainly in the Fill aquifer), also exhibited fluctuating RWLs, but do not drop below sea level and exhibited a narrower range of fluctuation compared to contemporaneous RWLs in MW216.

As shown on Figure 10-4, tidal fluctuations in the creek south of the Fire Ground (next to the closed Rifle Range Road landfill) also affected groundwater levels in wells located near the creek, such as GW02-VT0365. Groundwater levels in GW02-VT0365 mimic the tidal fluctuations recorded in the stilling well.


Figure 10-4 Data-logged Groundwater Elevations –South Creek at the closed Rifle Range Road landfill

10.3.4 Horizontal hydraulic conductivity Aquifer behaviour during well development and sample purging suggests that the hydraulic conductivity of the shallow Brighton Group aquifer is generally low (that is, less than 0.1 m/d). However, interpretation of short-term aquifer tests for wells in some areas, such as VT0192 (north of the Fire Ground) suggest higher conductivities (0.1 m/d to 1 m/d), which correlates with coarser-grained aquifer material in these wells (such as MW201 located on the west edge of the eastern Site creek). Interpretation of the aquifer testing is presented in Appendix E.

A compilation of interpreted values of hydraulic conductivity based on drawdown during purging is presented in Table 10-3.

Table 10-3 Interpreted hydraulic conductivities

Area Well ID Interpreted hydraulic

conductivity (m/d)

Geology of screened interval

VT0192 (north of Fire Ground) GW01-VT0192 0.3 Brighton Group sandy clay Fire Ground GW06-VT0067 0.3 Brighton Group clayey sand / silty sand Fire Ground GW07-VT0067 0.4 Brighton Group clayey sand / silty sand South Creek wetland MW212 10 Recent Alluvial clay South Creek wetland MW213 0.1 Recent Alluvial clay South of Fire Ground MW214S 0.2 Brighton Group clay South of Fire Ground MW214D 0.06 Brighton Group clay with thin gravel layer South of Fire Ground MW215S 0.2 Brighton Group sandy clay South of Fire Ground MW215D 0.04 Brighton Group clay with sand Marina MW216 0.2 Brighton Group sandy clay with thin gravel

layer Former STP MW217S 0.09 Brighton Group clay Former STP MW217D 5 Brighton Group clay with gravel layer Former STP MW218 0.6 Brighton Group clay with coffee rock


Interpretations of short-term aquifer tests for wells in some areas, such as at the former STP with value ranging between 0.9 and 5 m/d, suggest higher conductivities that reflects thin, coarser-grained aquifer material in some wells (such as MW217D) located at the former STP. Interpretation of the aquifer testing is presented in Appendix E.

10.3.5 Field measured groundwater chemistry parameters As part of monitoring groundwater conditions, field parameters (temperature, dissolved oxygen, reduction/oxidation potential, and electrical conductivity (EC)) were measured.

Measured groundwater temperatures ranged between approximately 15⁰C and 22⁰C, which reflects seasonal variation in air temperatures in the region.

Measured concentrations of groundwater dissolved oxygen ranged between approximately 0.4 mg/L and 8 mg/L. The lower concentrations (reported for wells located at the closed Rifle Range Road landfill) are inferred to reflect reducing conditions associated with degradation of wastes or groundwater contaminants, such as petroleum compounds. The higher concentrations, such in some wells at the Fire Ground, are inferred to reflect local recharge.

Measured EC, which can be used to evaluate salinity, ranged between approximately 200 µS/cm and 42,200 µS/cm, which correlates to approximately 120 mg/L total dissolved solids (TDS) and 25,300 mg/L TDS using a conversion factor of 0.6. Saline groundwater was detected in the shallow wells completed in the alluvial / estuarine sediments in the South Creek wetlands and the wells completed in the fill material in the marina area (refer Figure 6). The field measured groundwater chemistry parameters are provided in Appendix E.

Based on measurements of EC (as a proxy for salinity), the groundwater EC measured in MW216 (near the marina shoreline) indicated brackish groundwater (rather than sea water), which suggests that while there are hydraulic effects from tidal fluctuations in Hanns Inlet, seawater is not intruding inland to the location and depth of MW216 (approximately 50 m landward). In contrast, EC values measured in wells along the east shoreline of the operational area completed in fill material (refer Appendix A -Figure 6) indicate seawater is intruding into the fill material. This indicates that saline groundwater (in the Fill aquifer) overlies fresher groundwater (within the uppermost Brighton Group aquifer).

In contrast, the inferred mound at the Fire Ground coincides with a zone of fresher groundwater in wells GW07-VT0067, GW08-VT0067, MW215S and MW121, which are all located hydraulically down-gradient (south) of the Fire Ground lagoon. Groundwater salinities measured in wells located cross-gradient to the Fire Ground lagoon, such as MW103, are saltier than the down-gradient wells and reflect the background salinity of groundwater in the Brighton Group aquifer. The inferred mound and fresher groundwater suggests that leakage from the Fire Ground lagoon is locally recharging the Brighton Group aquifer.

A similar relationship is evident for the inferred mound at VT0370 (former petrol station) where readings of electrical conductivity for groundwater collected from two of the wells (GW02-VT0370 and GW03-VT0370) are much lower, which indicates fresher groundwater, than the reading for the remaining well (GW01-VT0370).

Taking this inferred limited local recharge into account, the natural background groundwater salinity at the Site (based on background wells MW203 to MW206) is brackish with an average TDS of 1,500, which falls within Segment B of the Groundwater SEPP.

10.3.6 Major ion composition and groundwater types Samples collected from select wells were analysed for major cations and anions to evaluate the types of groundwater across the Site. These results provide context about the interaction between locally recharged groundwater and regional groundwater results from analysis of major cations and anions A compilation of laboratory results and calculated total dissolved solids (TDS) is presented in Table 10-4.


Table 10-4 Major Cations & Anions (mg/L)

Area (see notes)

Sample Location Ca Mg Na K

CO3-2

as CO3-2

HCO3- as

HCO3- Cl

SO42-

as SO42- TDS

UG-NW MW200 53 85 840 5 10 45.6 1400 120 2559

CG-NE MW201 54 65 640 5.5 10 50.4 1100 24 1949

UG-NW MW202 41 88 900 5 10 20 1500 94 2658

UG-NW MW203 12 23 320 5 10 20 510 8.9 909

UG-N MW204 24 81 920 5 10 20 1500 100 2660

UG-N MW205 23 43 330 1.6 10 20 720 5 1153

UG-N MW206 20 26 290 1.1 10 39.6 450 9.5 846

UG-NE MW207 2.3 9.6 98 5 10 96 80 55 356

UG-NE MW208 23 32 360 1 10 36 570 29 1061

UG-N MW209 39 64 640 5 10 20 1200 34 2012

UG-W MW210 53 100 590 5 10 51.6 1100 13 1923

UG-W MW211 140 230 2100 5 10 20 4800 100 7405

FG Wetlands MW212 390 1100 9400 310 10 156 9400 2000 22766

FG Wetlands MW213 590 1800 17000 580 10 144 21000 3000 44124

FG-DG MW214D 34 56 570 5 10 20 960 54 1709

FG-DG MW214S 41 85 860 5 10 20 1400 78 2499

FG-DG MW215D 8.9 17 330 0.7 10 20 300 120 807

FG-DG MW215S 4.5 5.5 200 0.6 10 20 180 140 561

Marina MW216 40 65 850 20 10 33.6 1200 230 2449

FSTP MW217D 300 260 1800 58 10 264 2800 190 5682

FSTP MW217S 340 740 4700 120 10 456 5700 580 12646

FSTP MW218 290 170 1600 33 10 300 2100 180 4683

VT0192 GW01-VT0192 16 31 580 0.5 10 20 900 140 1698

VT0192 GW02-VT0192 26 49 690 0.5 39 20 1100 120 2045

VT0192 GW03-VT0192 31 67 1100 0.5 10 20 1800 110 3139

VT0370 GW01-VT0370 11 28 710 0.5 10 20 1200 66 2046

VT0370 GW02-VT0370 1.1 2.2 130 0.5 10 20 58 190 412

VT0370 GW03-VT0370 1.5 4.2 150 0.5 10 20 120 100 406 Notes: Ca calcium, Mg magnesium, Na sodium, K potassium, CO3

-2 carbonate, HCO3- bicarbonate, Cl chloride, SO4

2- sulphate UG up-gradient, CG cross-gradient, DG down-gradient, N north, W west, NE north-east, NW north-west FG Fire Ground, FSTP Former Sewage Treatment Plant

Inspection of Table 10-4 indicates the following:

TDS ranges between 356 mg/L (Brighton Group aquifer well MW207 on the northeast boundary) and 44,124 mg/L (alluvial aquifer well MW213 at the wetlands south of the Fire Ground).

− The lower values of TDS (less than 1,000 mg/L) reported for MW203 (northwest boundary well), MW206 (north boundary wells), and MW207 (northeast boundary) are considered to reflect the dilution of brackish regional groundwater by local recharge from leaking water mains or stormwater which for the MW207 data point is manifested as a shift towards the bicarbonate+carbonate vertex.

− Higher values of TDS (similar or greater than seawater) reported for the alluvial aquifer wells in the wetlands south of the Fire Ground, which is considered to reflect concentration of surface waters by evaporation in the wetlands.


Wetlands wells with the higher TDS also reported higher concentrations of potassium (around two orders of magnitude higher than the results reported for the background wells), which may reflect the breakdown of organic material in the wetlands soils or the use at the Fire Ground of AFFF that was derived from a potassium- based salt, which had periodically discharged directly to the wetlands during the 1970’s and 1980’s before the upgrade of the Fire Ground occurred.

Wells at the former STP also exhibited concentrations of potassium one to two orders of magnitude higher than background concentrations. This is considered to reflect elevated potassium concentrations of influent to the STP when the plant was operating

A Piper trilinear plot, which is presented in Figure 10-5, was used to visualise the groundwater types. The Piper plot presents the relative abundance of the major cations (lower left triangle showing sodium + potassium, magnesium, and calcium) and major anions (lower right triangle showing carbonate+bicarbonate, sulphate, and chloride). The diamond shows the intersection for each sample of the relative cations and relative anions. Key findings shown on the Piper plot are:

Site groundwater is typically of a sodium-chloride type

Sulphate was relatively more abundant in one result reported from the former petrol station (VT0370) where the low TDS also suggests local recharge from leaking mains

The data point for MW207 shown on the anion triangle is offset from the chloride vertex, where most of the data plots, towards the bicarbonate + carbonate vertex, which is considered to reflect a mixture of background groundwater with local, bicarbonate-rich recharge, such as from leaking pipelines carrying mains water near the northeast Site boundary


Figure 10-5 Piper Plot

10.3.7 Background PFAS concentrations The Victorian EPA provided two previous audits of groundwater quality from 2007-2008 and 2009-2010 for the Crib Point (Closed) Landfill located approximately 200 m north of the Site. PFAS results from this Site would assist with determining background PFAS concentrations, however these results did not include PFAS testing.

Nine out of ten groundwater monitoring wells at the Site land boundaries recorded non-detects for all PFAS compounds. The exception was MW207, which was located near a zone potentially affected by bushfire. Therefore, the background concentration is assumed to be below the respective LORs (0.001-0.005 µg/L).


10.3.8 Groundwater analytical results Groundwater analytical results were compared to adopted screening criteria (where land use relevant), which are summarised in Section 6 and presented in Table 6-5. Groundwater monitoring well locations and analytical results for combined PFOS and PFHxS screened against adopted ecological and human health screening criteria are presented on Appendix A - Figures 12, 14, 14a, 16, 18, 20, 22 and 24. A compilation of laboratory results by medium is presented in Table F-1 in Appendix F. The laboratory certificates of analysis are provided in Appendix G.

Key observations regarding the laboratory results include:

Fire Ground:

− Highest PFAS concentrations reported for the well (GW07-VT0067) next to the Fire Ground lagoon

− GW07-VT0067 was the only well to report 6:2 FTS (as was reported for a water sample collected from the Fire Ground lagoon)

− PFAS concentrations in wells located hydraulically down-gradient from the Fire Ground lagoon typically one to two orders of magnitude lower than corresponding results for GW07-VT0067

South Creek wetlands:

− PFAS concentrations (as PFOS) in the order of tens of micrograms per litre were reported in alluvial / estuarine well MW212 located in the South Creek wetlands.

− PFAS concentrations (as PFOS) reported for the shallow well (MW122S) was two orders of magnitude higher than for the deeper well (MW122D). This is inferred to reflect the generally upward gradient in this area.

Fire Ground area in the Brighton Group aquifer located hydraulically:

− Down-gradient from the Fire Ground in the uppermost (MW215S) and deeper (MW215D) saturated intervals the PFOS concentrations were similar (micrograms per litre). This is inferred to reflect the similar groundwater levels in the uppermost and deeper saturated intervals of the Brighton Group aquifer in this area where both intervals have been impacted by PFAS sources at the Fire Ground.

− Cross-gradient to the Fire Ground the PFOS concentration reported for the uppermost saturated interval (MW214S) was three orders of magnitude lower than the deeper saturated interval (MW214D). This is inferred to reflect the upward gradient between the deeper saturated interval and the uppermost saturated interval.

A summary of laboratory results and screening criteria exceedances is included in Table 10-5. These results are grouped based on known and potential sources, pathways and receptors identified in Section 3 - Conceptual Site Model. The groundwater samples at the land boundary assess the potential pathway via groundwater to sensitive off-Site receptors, as well as investigating the bushfire area around MW207. The groundwater samples at the Fire Ground, Fire Station, Former STP and Sullage Pit help to delineate the known and likely PFAS sources. The groundwater samples at the other potential PFAS sources are grouped as they are all located in the main operational area with similar exposure scenarios. This grouping provides an indication of exceedances in the operational area and further details on source delineation are provided in Section 11.3.


Table 10-5 Summary of groundwater analysis and groundwater screening criteria exceedances

Analyte No.

samples tested

No. of detects

Measured concentrations (μg/L)

Screening criteria (μg/L)

Number of samples exceeding screening

criteria Min Mean Max Human health 1

(Drinking Water)

Human health 2

(Recreational)

Human health 3

(Incidental Contact - Workers)

Ecological (95%

protection)

Ecological (99%

protection)

SITE LAND BOUNDARIES (INCLUDING BUSHFIRE AREA) PFOS 23 6 <0.001 0.002 0.006 - - 0.13 0.00023 Eco (95%): 0

Eco (99%): 6 PFOA 23 3 <0.001 0.004 0.025 0.56 5.6 8,000 220 19 All: 0

6:2 FTS 23 0 <0.005 <0.05 ND - - - - -

PFHxS 23 3 <0.001 0.003 0.012 - - - - -

Other PFAS 23 3 <0.001 N/A 0.007 - - - - -

PFHxS+PFOS 23 6 <0.002 0.004 0.016 0.07 0.7 1,000 - - HH1: 0 HH2: 0 HH3: 0

Sum of PFAS 23 32 <0.005 0.024 0.064 - - - - -

FIRE GROUND AND NEARBY WETLANDS PFOS 34 34 0.001 24.2 240

(382)1 N/A - 0.13 0.00023 Eco (95%): 27

Eco: (99%): 34 PFOA 34 27 <0.001 2.93 63.0 N/A 5.6 8,000 220 19 Eco (95%): 0

Eco: (99%): 1 HH2: 4 HH3: 0

6:2 FTS 34 7 <0.005 0.60 6.9 (8.38)1

N/A - - - -

PFHxS 34 33 <0.001 26.5 560 N/A - - - -

Other PFAS 34 30 <0.001 N/A 24.06 N/A - - - -

PFHxS+PFOS 34 34 0.007 50.7 598 N/A 0.7 1,000 - - HH2: 273 HH3: 0


Analyte No.

samples tested

No. of detects





(Drinking Water)

Human health 2

(Recreational)

Human health 3


Ecological (95%

protection)

Ecological (99%

protection)

Sum of PFAS 34 34 0.007 65.8 780 N/A - - - -

FIRE STATION AND ORNAMENTAL LAKE PFOS 4 4 0.0015 0.013 0.025 N/A - 0.13 0.00023 Eco (95%): 0

Eco: (99%): 4 PFOA 4 2 <0.001 0.018 0.038 N/A 5.6 8,000 220 19 All criteria: 0

6:2 FTS 4 0 <0.005 <0.005 ND N/A - - - -

PFHxS 4 4 0.007 0.260 0.660 N/A - - - -

Other PFAS 4 4 <0.001 N/A 0.25 N/A - - - -

PFHxS+PFOS 4 4 0.01 0.273 0.682 N/A 0.7 8,000 - - HH2: 04

HH3: 0 Sum of PFAS 4 4 0.0265 0.602 1.37 N/A - - - -

FORMER SEWAGE TREATMENT PLANT PFOS 10 8 <0.001 0.019 0.067 N/A - 0.13 0.00023 Eco (95%): 0


6:2 FTS 10 0 <0.001 <0.001 ND N/A - - - -

PFHxS 10 7 <0.001 0.056 0.200 N/A - - - -

Other PFAS 10 8 <0.001 N/A 0.520 N/A - - - -

PFHxS+PFOS 10 8 <0.002 0.074 0.267 N/A 0.7 1,000 - - HH2: 0

Sum of PFAS 10 52 <0.005 0.366 1.683 N/A - - - -

SULLAGE PIT PFOS 2 1 <0.01 1.65 3.30 N/A - 0.13 0.00023 Eco (95%): 1


6:2 FTS 2 0 <0.05 ND ND N/A - - - -


Analyte No.

samples tested

No. of detects





(Drinking Water)

Human health 2

(Recreational)

Human health 3


Ecological (95%

protection)

Ecological (99%

protection)

PFHxS 2 1 <0.01 0.42 0.84 N/A - - - -

Other PFAS 2 1 <0.01 N/A 0.14 N/A - - - -

PFHxS+PFOS 2 1 <0.02 2.07 4.14 N/A 0.7 1,000 - - HH2: 65

HH3: 0 Sum of PFAS 2 1 <0.05 2.33 4.61 N/A - - - -

POTENTIAL MINOR SOURCES+ IN OPERATIONAL AREA PFOS 63 58 <0.0001 0.072 0.7 N/A - 0.13 0.00023 Eco (95%): 10


6:2 FTS 63 2 <0.005 0.003 0.012 N/A - - - -

PFHxS 63 56 <0.001 0.258 3.700 N/A - - - -

Other PFAS 63 52 <0.001 N/A 0.089 N/A - - - -

PFHxS+PFOS 63 56 <0.002 0.33 3.72 N/A 0.7 8,000 - - HH2: 55

HH3: 0 Sum of PFAS 63 532 <0.005 0.438 4.42 N/A - - - -

Table note: 1Values in brackets represent PFAS concentrations within intra- or inter-laboratory duplicates 2The recorded LOR for sum of PFAS is higher than PFOS and PFHxS, hence a non-detect may be recorded for sum of PFAS when low-level PFOS/PFHxS/PFOA are recorded 3Note that there were 2 exceedances of drinking water guidelines, the pathway is not considered complete as there are no on-Site groundwater users 4Note that there were 27 exceedances of drinking water guidelines, the pathway is not considered complete as there are no on-Site groundwater users 5Note that there were 39 exceedances of drinking water guidelines, the pathway is not considered complete as there are no on-Site groundwater users 6Detects of other PFAS compounds in excess of PFOA human health recreational and ecological screening criteria – this risk assessed in conjunction with exceedances for PFOS/PFOA/PFHxS + Potential minor sources include closed landfills, storage tank areas, former dry-cleaning facility, former coal loading area. Refer to Table 5-1. Concentrations detected above the screening criteria are highlighted in orange with the corresponding screening criteria that have been exceeded are highlighted in bold and underlined


10.3.9 Impacts on Beneficial Uses The impacts of the identified contamination on the protected beneficial uses of groundwater on-Site and off-Site are summarised in Table 10-6.

Table 10-6 Evaluation of Groundwater SEPP Beneficial Uses


Maintenance of ecosystems (MoE) (99% species protection)

On-Site Yes PFAS reported above guideline in numerous wells across the Site

Off-Site No PFAS not detected in boundary or off-Site wells, which are located hydraulically up-gradient from the Site


Off-Site No PFAS not detected in off-Site wells, which are located hydraulically up-gradient from the Site


On-Site Yes PFAS above drinking water guideline in numerous wells across the Site


Stock watering






Primary contact recreation (including intrusive workers)

On-Site Yes PFAS above PCR guideline in several wells across the Site



On-Site No PFAS not reported to adversely impact buildings or structures



10.4 Surface water, sediment, sludge and pore water investigation

10.4.1 Field observations Three main creeks drain the Site (refer Figure 4 in Appendix A). One creek (South Creek on Figure 3 in Appendix A) enters the Site from the west of South Beach Road and continues to the south of the Fire Ground then to the southeast where this creek discharges to the tidal flats of Hanns Inlet. The second creek (West Creek on Figure 3 in Appendix A) also enters the Site from the west just south of the former STP, then continues to the east to discharge into the tidal flats of Hanns Inlet. The third creek (East Creek on Figure 3) comprises two tributaries that enter the Site on the northern boundary, then continue to the southeast to discharge into the tidal flats of Hanns Inlet. Note that the upper reaches of these three Site creeks (above the tidal zone) are ephemeral.

Stormwater drains service the Site with an extensive network across the main operational area of the Site. Site plans indicate that this network discharges at numerous locations along the shoreline of Hanns Inlet and into the creek south of the Fire Ground and the creek northeast of the Fire Station.

Sampling of surface water at drain outlets occurred between 17 August and 28 August 2018. During this interval nine days of rain were recorded with the highest recorded (13.4 mm) for August 2017 recorded on 16 August 2018, which was the day before the sampling event began and the second highest value recorded (12.0 mm) recorded on 24 August 2018. The total rainfall recorded during the sampling event totalled 48.6 mm, which was 63% of the total rainfall of 77.6 mm recorded for August 2017. Note that based on 1986 to 2018 data recorded at BOM station 086361 Cerberus, the median Decile 10, 50, and 90 monthly rainfall for August are 40.5, 71.8, and 119.2 mm, respectively. Hence, the August 2017 total of 77.6 mm is comparable to the median rainfall recorded.

During sampling of surface water at drain discharge points and along the Site creeks water quality parameters were measured to characterise the physio-chemical properties of this potential PFAS pathway. Results of these measurements indicate the following characteristics. A compilation of readings is presented in Table 10-7. Locations of readings are shown on Appendix A - Figure 9.

Key observations for the field conditions follow:

Northern Site storm-water drains:

− Storm water entering the Site from the north via ephemeral drains is slightly acidic, oxidising and fresh

− Surface water discharging from on-Site drains in the northern portion of the Site are also slightly acidic to slightly alkaline, slightly oxidising and generally fresh except in the active tidal channel of the East Creek, which is brackish to saline.

In the Fire Ground area:

− Surface water flowing onto the Site from the western boundary is slightly acidic, slightly oxidising and fresh

− Surface water in the Fire Ground lagoon interceptor is slightly acidic, slightly oxidising and fresh

− Surface water in the Fire Ground lagoon is near neutral to slightly acidic, oxidising and fresh

Closed Rifle Road Landfill

− Surface water in the drains on the northwest corner of the landfill are neutral, slightly oxidising and fresh

− Surface water in the creek running along the southwest margin of the landfill is acidic, oxidising and brackish at low tide and saline at high tide

Fire Station

− Surface water in the Ornamental Lake is slightly alkaline, slightly oxidising and brackish


− Surface water in the discharge point from the Ornamental Lake is near neutral, slightly oxidising and brackish

Former STP

− Surface water in the STP lagoons is acidic to slightly alkaline, slightly oxidising to oxidising and brackish

− Surface water in the drain immediately south of the northeast STP lagoon, which is tidally influenced, is slightly alkaline, slightly oxidising and saline

Hanns Inlet

− Surface water in the drains discharging to Hanns Inlet is slightly alkaline, slightly oxidising to oxidising and fresh to brackish.

Sullage Pit

− Surface water in the sullage pit is slightly alkaline to neutral, oxidising and brackish.

In summary, based on the measured field parameters (particularly electrical conductivity) surface water flowing onto the Site is predominantly slightly acidic, slightly oxidising and fresh. Surface water in the south and East Creeks, which are tidally influenced, are slightly alkaline.

Sediment samples were collected at the locations where a surface water sample was collected from the discharge point of storm water drains or along Site creeks. In the marina area sediments generally comprised mottled orange-brown to red-brown clayey soils derived from fill of Brighton Group sediments. In contrast, sediments collected along Site creeks generally consisted of dark grey to black, silty to clayey material with dead vegetation incorporated into the sediments.

10.4.2 Field measured surface water chemistry parameters The field measured surface water chemistry parameters for Site surface waters during Round 1 of surface water and sediment sampling are summarised in Table 10-7.

Table 10-7 Surface Water Field Parameter Readings

Site Area Description Alternative

Name (MWH/Stantec)

Location ID pH

Redox Potential

(mV) TDS

(ppm) Temp.

(°C)

Storm-water inflow: Site land boundary

Drain onto Site from north Inflow 3 SW021 6.46 225 225 11.1


Drain onto Site from north Inflow 4 SW022 6.22 120 120 10

Storm-water outflow: North-eastern operational area

Discharge to East Creek HC679 SW009 5.6 104 430 11.4


Discharge to East Creek HC1003 SW010 4.94 120 1260 10.9


Discharge to East Creek HC980 SW011 6.3 84 40.8 10.7

Storm-water outflow: Northern operational area

Discharge to East Creek HC1014 SW012 7.16 143 74.9 10

Storm-water outflow: Northern operational area

Discharge to East Creek HC628 SW013 7.94 115 53.4 11.3

Fire Station East creek near Fire Station

SW020 7.92 126 11110 9.1


Drain onto Site from west near Fire Ground wetlands

Inflow 5 SW024 6.33 130 225 9.4

Fire Ground Fire Ground Lagoon Interceptor

SW031 5.78 65 174 12.7

Fire Ground Fire Ground Lagoon SW033 6.64 302 151 13.1


Site Area Description Alternative

Name (MWH/Stantec)

Location ID pH

Redox Potential

(mV) TDS

(ppm) Temp.

(°C)

Fire Ground Leak-Repair-Live unit SW032 7.2 712 122 17.3

Closed RRR Landfill (Storm-water outflow)

Outflow drain from operational area

HC420 SW029 7.07 64 257 9.9

Closed RRR Landfill (Storm-water outflow)

Outflow drain from operational area

HC544 SW030 6.63 63 195 10.8

Closed RRR Landfill South Creek upstream of landfill

SW028 4.7 139 2230 9.2

Closed RRR Landfill South Creek downstream of landfill

SW027 5.73 153 2630 8.4

Fire Station: Ornamental Lake

Ornamental Lake SW019 7.97 73 1076 9.6

Fire Station: Ornamental Lake

Ornamental Lake drain outlet

HC772 SW018 6.77 85 3810 11.9

Former STP South-west lagoon SW014 4.55 353 4090 8.7

Former STP North-west lagoon SW015 4.32 47 3120 8.5

Former STP North-east lagoon SW016 6.44 129 1140 8.9

Former STP: Former STP: drain to south Outflow 3 SW017 7.6 162 28000 8.4

Storm-water inflow: Former STP

Drain onto Site from west Inflow 6 SW023 6.49 132 338 11.7

Storm-water outflow: Hanns Inlet

Southern operational area drain discharge point

Outflow 8 (HC945)

SW001 7.17 53 309 12.3



HC886 SW002 7.54 38 38 11.8


Marina drain discharge point

Outflow 6 (HC665)

SW003 7.55 57 4050 12.5



Outflow 9 (HC164)

SW004 8.46 168 3000 10.4


South-eastern operational area drain discharge point

Outflow 7 (HC911)

SW006 7.57 128 2137 10.8


South-eastern operational area drain discharge point

Outflow 5 (HC787)

SW007 7.1 75 108 11.3


Powerhouse and filling station drain discharge point

Outflow 4 (HC787)

SW008 7.23 109 96.2 8.6

Sullage Pit Sullage pit ponded area SW025 5.59 174 1590 15.1

Sullage Pit Sullage pit ponded area SW026 7.1 160 4690 12.3

10.4.3 Background concentrations The surface water and sediment samples collected from Hanns Inlet near Western Port Bay recorded non-detects for all PFAS compounds, therefore the background concentration is assumed to be below the respective LORs.

10.4.4 Surface water laboratory results Surface water analytical results were compared to adopted screening criteria (where relevant), which are summarised in Section 6 and presented in Table 6-5. Surface water and sediment sample locations and analytical results for combined PFOS and PFHxS screened against adopted ecological and human health screening criteria are presented on Appendix A - Figures 12, 14, 16, 18, 20, 22 and 24. The laboratory certificates of analysis are provided in Appendix G.

A summary of laboratory results and screening criteria exceedances is included in Table 10-8. These results are grouped based on known and potential sources, pathways and receptors identified in Section 3 - Conceptual Site Model. The surface water and sediment samples in Hanns Inlet were assessed this area as


a sensitive ecological receptor with some human dermal contact with the water. The surface water and sediment samples at the Fire Ground, Fire Station and Former STP (including sludge samples at Former STP) help to delineate the known and likely PFAS sources. The surface water and sediment samples at the minor sources, including the Sullage Pit and Closed Rifle Range Road landfill, were grouped due to similar land uses and detection levels. The surface water and sediment samples collected from storm-water drain inlets and outlets provide an indication of PFAS flows onto and out of Site.


Table 10-8 Summary of surface water analysis and surface water screening criteria exceedances

Analyte No.

samples tested

No. of detects

Measured concentrations (μg/L) Screening criteria (μg/L) Number of samples

exceeding screening

criteria Min Mean Max

Human health 1 (Drinking

Water)

Human health 2

(Recreational)

Human health 3 (Incidental

Contact - Workers)

Ecological (95%

protection)

Ecological (99%

protection)

HANNS INLET PFOS 43 21 <0.0001 0.002 0.0089 N/A - 0.13 0.00023 Eco (95%): 0

Eco (99%): 21 PFOA 43 0 <0.001 <0.001 ND N/A 5.6 8,000 220 19 All criteria: 0

6:2 FTS 43 0 <0.005 <0.005 ND N/A - - - -

PFHxS 43 4 <0.001 0.001 0.002 N/A - - - -

Other PFAS 43 0 <0.001 <0.001 ND N/A - - - -

PFHxS+PFOS 43 21 <0.002 0.002 0.011 N/A 0.7 1,000 - - All criteria: 0

Sum of PFAS 43 42 <0.005 0.008 0.011 N/A - - - -

FIRE GROUND PFOS 4# 4 0.33 20.8 33.0 N/A - 0.13 0.00023 Eco (95%): 4

Eco (99%): 4 PFOA 4 4 0.02 0.43 0.780 N/A3 5.6 8,000 220 19 Eco (95%): 0

Eco (99%): 0 HH2: 03

HH3: 0 6:2 FTS 4 3 <0.05 3.48 6.00 N/A - - - -

PFHxS 4 4 0.07 2.44 3.90 N/A - - - -

Other PFAS 4 4 <0.01 N/A 6.808 N/A - - - -

PFHxS+PFOS 4 4 0.4 23.2 36.9 N/A 0.7 1,000 - - HH2: 34

HH3: 0 Sum of PFAS 4 4 <0.05 33.9 55.2 N/A - - - -

FIRE STATION AND ORNAMENTAL LAKE PFOS 2 2 0.01 0.23 0.45 N/A - 0.13 0.00023 Eco (95%): 1

Eco (99%): 2 PFOA 2 2 0.01 0.05 0.10 N/A 5.6 8,000 220 19 All criteria: 0


Analyte No.

samples tested

No. of detects


exceeding screening



Water)

Human health 2

(Recreational)


Contact - Workers)

Ecological (95%

protection)

Ecological (99%

protection)

6:2 FTS 2 0 <0.05 <0.005 ND N/A - - - -

PFHxS 2 1 <0.01 0.70 1.40 N/A - - - -

Other PFAS 2 2 <0.01 N/A 0.62 N/A - - - -

PFHxS+PFOS 2 2 0.01 0.93 1.85 N/A4 0.7 1,000 - - HH2: 13

HH3: 0 Sum of PFAS 2 12 <0.1 1.94 3.82 N/A - - - -

FORMER SEWAGE TREATMENT PLANT PFOS 4 4 0.96 3.09 5.4 N/A - 0.13 0.00023 Eco (95%): 4

Eco (99%): 4 PFOA 4 4 0.45 0.805 1.30 N/A 5.6 8,000 220 19 All criteria: 0

6:2 FTS 4 0 <0.005 <0.005 ND N/A - - - -

PFHxS 4 4 1.60 2.7 5.1 N/A - - - -

Other PFAS 4 4 <0.01 N/A 6.208 N/A - - - -

PFHxS+PFOS 4 4 2.96 5.79 10.5 N/A 0.7 1,000 - - HH2: 44

HH3: 0 Sum of PFAS 4 4 8.97 13.6 23.6 N/A - - - -

STORM-WATER INFLOW PFOS 4 2 <0.01 0.018 0.050 N/A - 0.13 0.00023 Eco (95%): 0

Eco (99%): 2 PFOA 4 0 <0.01 <0.01 ND N/A 5.6 8,000 220 19 All criteria: 0

6:2 FTS 4 0 <0.05 <0.05 ND N/A - - - -

PFHxS 4 1 <0.01 0.024 0.080 N/A - - - -

Other PFAS 4 1 <0.05 N/A 0.010 N/A - - - -

PFHxS+PFOS 4 2 <0.02 0.038 0.130 N/A 0.7 1,000 - - All criteria: 0

Sum of PFAS 4 12 <0.05 0.075 0.150 N/A - - - -


Analyte No.

samples tested

No. of detects


exceeding screening



Water)

Human health 2

(Recreational)


Contact - Workers)

Ecological (95%

protection)

Ecological (99%

protection)

STORM-WATER OUTFLOW PFOS 17 17 0.007 0.102 0.57 N/A - 0.13 0.00023 Eco (95%): 11

Eco (99%): 17 PFOA 17 15 <0.001 0.008 0.034 N/A 5.6 8,000 220 19 All criteria: 0

6:2 FTS 17 0 <0.005 <0.005 ND N/A - - - -

PFHxS 17 17 0.003 0.068 0.25 N/A - - - -

Other PFAS 17 16 <0.001 N/A 0.082 N/A - - - -

PFHxS+PFOS 17 17 0.011 0.170 0.79 N/A 0.7 1,000 - - HH2: 15

HH3: 0 Sum of PFAS 17 162 <0.005 0.237 0.97 N/A - - - -

SULLAGE PIT AND OTHER MINOR SOURCES

PFOS 5## 4 <0.0001 0.13 0.32 N/A - 0.13 0.00023 Eco (95%): 26 Eco (99%): 4

PFOA 5 1 <0.001 0.004 0.24 N/A 5.6 8,000 220 19 All criteria: 0

6:2 FTS 5 0 <0.005 ND ND N/A - - - -

PFHxS 5 3 <0.001 0.027 0.06 N/A - - - -

Other PFAS 5 1 <0.001 N/A 0.001 N/A - - - -

PFHxS+PFOS 5 4 <0.002 0.155 0.34 N/A5 0.7 1,000 - - HH2: 07

HH3: 0 Sum of PFAS 5 32 <0.005 0.17 0.38 N/A - - - -

Table note: 1Values in brackets represent PFAS concentrations within intra- or inter-laboratory duplicates 2The recorded LOR for sum of PFAS is higher than PFOS and PFHxS, hence a non-detect may be recorded for sum of PFAS when low-level PFOS/PFHxS/PFOA are recorded 3Note that there was 1 exceedance of drinking water guidelines, the pathway is not considered complete as there are no surface water consumers 4Note that there were 4 exceedances of drinking water guidelines, the pathway is not considered complete as there are no surface water consumers 5Note that there were 8 exceedances of drinking water guidelines, the pathway is not considered complete as there are no surface water consumers 6Note that there were no exceedances at the Sullage Pit 7Note that there were 2 exceedances of drinking water guidelines (including recycled water sample), the pathway is not considered complete as there are no surface water / recycled water consumers 8Detects of other PFAS compounds in excess of PFOA human health recreational and ecological screening criteria – this risk assessed in conjunction with exceedances for PFOS/PFOA/PFHxS #This number does not include a tap water sample collected from Fire Ground laundry that was given a SW series sample name


##This number does not include a tap water sample collected a recycled water tap that was given a SW series sample name Concentrations detected above the screening criteria are highlighted in orange with the corresponding screening criteria that have been exceeded are highlighted in bold and underlined


10.4.5 Sediment and sludge laboratory results Sediment analytical results and sludge analytical results from the Former STP are presented in Table 10-9. Surface water and sediment sample locations and analytical results for combined PFOS and PFHxS screened against adopted ecological and human health screening criteria are presented on Appendix A - Figures 12, 14, 16, 18, 20, 22 and 24. The laboratory certificates of analysis are provided in Appendix G.

Table 10-9 Summary of sediment (and sludge in the Former STP) analysis

Analyte No. samples tested No. of detects Measured concentrations (mg/kg)

Min Mean Max

HANNS INLET

PFOS 20 0 <0.0001 <0.0001 ND

PFOA 20 0 <0.001 <0.001 ND

6:2 FTS 20 0 <0.005 <0.005 ND

PFHxS 20 0 <0.001 <0.001 ND

Other PFAS 20 0 <0.001 N/A ND

PFHxS + PFOS 20 0 <0.002 <0.002 ND

Sum of PFAS 20 0 <0.05 <0.005 ND

FIRE GROUND

PFOS 1 1 2 2 2

PFOA 1 0 <0.005 <0.005 ND

6:2 FTS 1 1 0.023 0.023 0.023

PFHxS 1 1 0.017 0.017 0.017

Other PFAS 1 1 <0.005 N/A 0.036

PFOS + PFHxS 1 1 2.02 2.02 2.02

Sum of PFAS 1 1 2.18 2.18 2.18

FIRE STATION AND ORNAMENTAL LAKE

PFOS 2 1 <0.005 0.0038 0.0051

PFOA 2 0 <0.005 <0.005 ND

6:2 FTS 2 0 <0.010 <0.005 ND

PFHxS 2 0 <0.001 <0.005 ND

Other PFAS 2 0 <0.005 N/A ND

PFOS + PFHxS 2 1 <0.005 0.0038 0.051

Sum of PFAS 2 1 <0.05 0.025 0.051

FORMER SEWAGE TREATMENT PLANT (SLUDGE AND SEDIMENT RESULTS)

PFOS 11 11 0.0067 0.82 2.30

PFOA 11 10 <0.005 0.031 0.120

6:2 FTS 11 0 <0.005 <0.010 ND

PFHxS 11 10 <0.001 0.088 0.350

Other PFAS 11 10 <0.005 N/A 0.260

PFOS + PFHxS 11 11 <0.005 0.907 2.53

Sum of PFAS 11 11 <0.05 1.09 3.03

STORM-WATER INFLOW

PFOS 4 1 <0.001 0.0035 0.0063

PFOA 4 0 <0.005 <0.005 ND


Analyte No. samples tested No. of detects Measured concentrations (mg/kg)

Min Mean Max

6:2 FTS 4 0 <0.005 <0.005 ND

PFHxS 4 0 <0.001 <0.001 ND

Other PFAS 4 0 <0.005 <0.005 ND

PFOS + PFHxS 4 1 <0.005 0.0035 0.0063

Sum of PFAS 4 02 <0.05 <0.05 ND

STORM-WATER OUTFLOW

PFOS 16 8 <0.001 0.009 0.053

PFOA 16 0 <0.005 <0.005 ND

6:2 FTS 16 1 <0.005 0.006 0.022

PFHxS 16 0 <0.001 <0.001 ND

Other PFAS 16 1 <0.005 N/A 0.012

PFOS + PFHxS 16 8 <0.005 0.009 0.053

Sum of PFAS 16 22 <0.05 0.029 0.061

SULLAGE PIT AND OTHER MINOR SOURCES

PFOS 4 23 <0.001 0.011 0.018

PFOA 4 0 <0.005 <0.005 ND

6:2 FTS 4 0 <0.005 <0.005 ND

PFHxS 4 0 <0.001 <0.001 ND

Other PFAS 4 0 <0.005 <0.005 ND

PFOS + PFHxS 4 0 <0.005 <0.005 ND

Sum of PFAS 4 0 <0.05 <0.005 ND Table note: 1Values in brackets represent PFAS concentrations within intra- or inter-laboratory duplicates

2The recorded LOR for sum of PFAS is higher than PFOS and PFHxS, hence a non-detect may be recorded for sum of PFAS when low-level PFOS/PFHxS/PFOA are recorded 3Note that both detects were in the South Creek near the Closed Rifle Range Road landfill Concentrations detected above the screening criteria are highlighted in orange with the corresponding screening criteria that have been exceeded are highlighted in bold and underlined


10.4.6 Pore water laboratory results Pore water samples were collected at 19 locations that were co-located with surface water and sediment samples (see Appendix A - Figure 10). There were no PFAS detects for these pore water samples. However, due to limitations in collection volumes, the LOR had to be increased from the adopted surface water screening criteria of 0.001 µg/L to 0.01 µg/L. This introduces the potential for false negatives relative to the adopted screening levels.

10.4.7 Tap water laboratory results Tap water samples were collected from the Fire Ground laundry and recycled water pump station. These samples were named in the SW series before update to Defence naming convention (DCD#7) to include potable (POT) and effluent (EFF). These samples both reported detects of PFAS above LOR. The Fire Ground laundry sample result was below screening levels for drinking and primary contact recreation. The result for the sample of Class C recycled water was below primary contact recreation, but above drinking water screen levels.


10.4.8 Impacts to Beneficial Uses The impacts of the identified contamination on the protected beneficial uses of surface water on-Site and off-Site are summarised in Table 10-10.

Table 10-10 Evaluation of Water SEPP Beneficial Uses

10.5 Biota (grass) investigation Samples of grass (including roots and swards) were collected at the location for wells MW200 through MW211 and GW01-VT0192. PFAS were not detected in any of these samples above the LOR. Five samples of grass were collected from the Sports Fields. Two of the five samples recorded detects above the LOR, with a maximum detect of 0.0009 mg/kg PFOS and 0.0004 mg/kg PFHxS. There are currently no screening criteria available for grass, but this is additional evidence of PFAS impact at the Sports Fields.


Aquatic plants and animals (99% species protection)

On-Site Yes PFAS reported above screening levels

Off-Site Yes PFAS reported above screening levels in some drains flowing onto the Site, but not Site PFAS sources


On-Site Yes PFAS reported for Hanns Inlet and Site creeks exceed screening levels

Off-Site No PFAS not detected at the mouth of Hanns Inlet, which is tidally flushed and well connected to Western Port Bay


On-Site Yes PFAS reported above screening level in the Fire Ground lagoon and South Creek, but not above screening levels in Hanns Inlet

Off-Site No PFAS not detected at the mouth of Hanns Inlet, which is tidally flushed and well connected to Western Port Bay


Off-Site No Off-Site surface waters are located hydraulically upgradient


On-Site No No aesthetic impacts were noted for PFAS impacted water during Site inspections



On-Site No No aesthetic impacts were noted for PFAS impacted water during Site inspections.



On-Site No No evidence of PFAS adversely impacting on this beneficial use



Off-Site No Off-Site surface waters are located hydraulically upgradient


10.6 Biota (algae) investigation One sample of algae was collected from a sump at the Former STP. This sample reported concentrations of 2.2 mg/kg of PFOS, 0.13 mg/kg of PFOA, 0.32 mg/kg PFHxS and 10 other PFAS compounds. There are currently no screening criteria for algae, but this is additional evidence of PFAS impact in this area.

10.7 Biota (fish) investigation Fish samples were collected at eight locations that were generally co-located with surface water (see Appendix A – Figure 10). A total of 37 fish samples were collected for multiple species, including snapper, flathead, whiting, estuarine perch, toadfish, fiddler ray (banjo shark), and mullet. A total of 37 flesh samples and 29 liver samples were analysed for PFAS.

Of the species caught, snapper, flathead, whiting, fiddler ray (banjo shark), and mullet are typically migratory. Estuarine perch and toadfish are typically residential and would remain within Hanns Inlet.

PFAS were detected in 35 of 37 flesh samples and all 29 liver samples, where generally PFOS was the predominant compound. PFOA, PFHxS, PFDS, PFUnA, PFPeA, PFNA, PFDA, PFDoA, PFTrDA and NEthFOSA were detected at concentrations significantly below PFOS except for one sample (liver from an inedible toadfish) with PFOS reported at a concentration of 0.7 µg/kg versus a 1.1 µg/kg reported for N-EtFOSE.

All edible flesh samples were below the PFOS / PFHxS and PFOA screening level of 5.2 µg/kg. All liver samples were below the PFOS / PFHxS and PFOA screening level of 280 µg/kg. Refer to Appendix F for details of the results for the fish sampling.


11 Tier 1 Risk Assessment This section discusses the nature and extent of PFAS impacts detected in the various environmental media, and the significance of these detections in relation to the identified sources, pathways and receptors.

11.1 Delineation of key sources PFAS analytical data collected for soil and groundwater was interpolated and visualised across the Site to delineate the PFAS soil source areas and co-located groundwater impacts. Data was interpolated using Kriging and visualised using Earth Volumetric Studio (EVS), the resultant visualisations of soil data presented in Appendix A.

Soil and groundwater analytical results from both datasets were interpolated to derive the following information:

Lateral and vertical distribution of PFAS in soils

Differences in lateral and vertical distribution between PFAS compounds

Relationship between detected soil PFAS concentrations and areas of known PFAS application where spills have been historically/anecdotally reported

Relationship between interpolated soil impacts and geological units present

Relationship between soil bound PFAS and groundwater impacts, including extents of interpolated soil impacts residing in the saturated zone

Relationship between groundwater impacts and surface water bodies

Mass of PFAS contained in soil and groundwater

11.2 Soil impacts Figures 26A-D in Appendix A show the Site-wide soil PFOS, PFOA and PFHxS soil impacts (PFOS + PFHxS results shown in Figure 11-1). PFOS, PFOA and PFHxS have been interpolated individually to a 2 µg/kg isolevel; whilst the limits of reporting of these compounds are an order of magnitude lower, analysis of Horwitz Curves from various PFAS analytical runs has shown varying levels of measurement uncertainty at low levels of detection, therefore to increase the statistical confidence of the interpolation an isolevel one order of magnitude above the LOR has been applied.

PFOS, PFOA and PFHxS were further interpolated to their respective adopted investigation levels to identify areas of exceedance and overlap with sensitive receptors to assess potential exposure pathways.

PFAS soil impacts are concentrated in four main areas:

The Fire Ground

South Creek Wetlands associated with Fire Ground

The Fire Station and Ornamental Lake

The former STP

Minor soil PFAS impacts were also detected on the northeast boundary (in the vicinity of MW207), a small area in the middle of the sports field and an area to the north of the former STP. The main areas of PFAS impact correlate with the known areas of use of PFAS containing products at the Site, namely the Fire Ground and Fire Station and secondary sources which have (or have had) connectivity with these source areas, namely the former STP. The minor soil PFAS impacts at the northeast boundary extend off-Site, however these concentrations are below the human health screening level for low density residential land use. The minor concentrations detected in soils at the sports field reflects irrigation with PFAS-impacted Class C recycled water. On the northeast boundary PFAS impacts may have been due to fire emergency response (with PFAS residue in Base hoses or CFA equipment), as the detected concentrations are not


indicative of a heavy use source area such as the Fire Ground. PFAS concentrations in the South Creek wetlands are likely to be a secondary source area, with the primary source having been the Fire Ground.

No concentrations of PFOS, PFOA, or PFHxS are exceeding the HHSV 4 (industrial/commercial), HHSV 5 (intrusive/maintenance works), or HHSV 2 (high density residential) soil investigation levels except for the South Creek wetlands. Exceedances of HHSV 1, 2 and 3 (high and low density residential, and public open space criteria) are noted at the South Creek wetlands; and exceedances of both HHSV 1 and 3 (low density residential and public open space criteria) are noted at the Fire Ground.

Exceedances of the interim ecological screening levels for PFOS direct contact in public open space settings and indirect contact in residential settings are noted at the Fire Ground wetlands source area. Exceedances of the ecological screening level for indirect contact in residential settings are also noted in the Fire Ground, Fire Station and former STP. Exceedance of the ecological screening level for indirect contact in commercial/industrial settings is noted in the Fire Ground and South Creek wetlands source areas.

Figures 27A-G in Appendix A show the interpolated areas of PFAS impacts that are exceeding the adopted human health soil investigation levels (an example for HHSV 1 shown in Figure 11-2). Figures 28A-C show the interpolated PFAS impacts that are exceeding the adopted ecological health investigation levels. Figure 29 in Appendix A shows the interpolated extent of PFOS+PFHxS in soil below groundwater level.


Figure 11-1 PFOS + PFHxS in Soil above 2 µg/kg


Figure 11-2 PFOS + PFHxS in Soil above human health low density residential screening criteria (HHSV 1; 9)


11.2.1 Fire Ground 253 soil samples were analysed for PFAS in soil by Golder (2016), collected from boreholes, monitoring well installation and several test pits. This was supplemented by 27 samples collected bas part of this DSI consisting of soil samples from monitoring well installation and surface soil samples.

Analytical results indicate the majority of PFAS contained in soils at the Fire Ground consists of PFOS, with a total of 203 detections. Figure 11-3 shows the interpolated extent of PFOS in soils (further detail on Figure 30A-B in Appendix A). The lateral extent covers the entire Fire Ground area and the downhill area to the southwest of the Fire Ground. The interpolated vertical extent shows the plume confined to the top 3 – 4 metres of the soil profile, consistent with the collected analytical results and relative hydrophobicity of PFOS; vertical migration through the soil profile with surface water infiltration appears to be slow.

PFOA was detected in 133 samples with an interpolated total volumetric mass of 0.036 kg. PFOA soil impacts are mainly constrained to an area in the western section of the Fire Ground where SPFE are filled during firefighting training (see Figure 30C-D in Appendix A). Historic spills of concentrate in this area and residual PFAS concentrations in concrete32 and soil are likely responsible for this hotspot. A second isolated area of PFOA impact is at depth on the southern edge of the settling pond, possibly due to sediment bound PFOA from the former settling pond which was buried and filled over with the current settling pond. The remaining PFOA detections are low level within one order of magnitude of the LOR.

PFHxS was detected in 217 samples, however the detections were significantly lower than those of PFOS, with an interpolated total volumetric mass of 1.4 kg of PFHxS in 21,303 m3 of soil. Figure 30E-F in Appendix A shows the interpolated extent of PFHxS impacts in soil; overall the lateral extent of PFHxS is less than that of PFOS and a significant difference between vertical extents is present, PFHxS is interpolated to extend at least 6 metres below ground, likely due to the greater hydrophilicity of PFHxS as compared to PFOS and greater vertical migration with surface water infiltration.

Principal constituent analysis33 (PCA) indicates the AFFF product to be primarily 3M Lightwater, due to the prevalence of perfluoroalkyl sulphonates and the relative absence of perfluoroalkyl carboxylates. PCA also shows an aged PFAS soil mass with shorter chain PFAS being less present than longer chain PFAS, consistent with profiles of hydrophobicity and environmental mobility, and consistent with the Site history that use of 3M Lightwater in training was discontinued circa 2004.

PFAS was introduced to the environment through surface infiltration in this area, and over time it has moved downwards through the soil profile due to surface water infiltration. Concrete is also a likely secondary source of PFAS to surface water and soil given the quantities of AFFF which had been used in this area in the past (Golder, 2016a and b). Without source area abatement, these soil PFAS concentrations are likely to remain largely unchanged.

32 Note that no concrete samples were collected as part of the current investigation 33 PCA refers to a non-statistical approach comparing the relative concentrations of PFAS compounds to the known reference material composition. A sample of 3M Lightwater concentrate was characterised and these results formed the basis of the principal constituent (component) analysis, rather than a statistical approach


Figure 11-3 Fire Ground PFOS in Soil above 50 µg/kg


11.2.2 Fire Station A total of 41 soil samples were recovered from the Fire Station area and analysed for PFAS. Most samples consisted of shallow surface samples and test pits collected during this investigation, and several soil samples collected during the installation of MW110 to the east of the Fire Station and MW111 to the south, part of the 2016 Golder investigation. Soil results indicate a hotspot of soil bound PFAS impact immediately south adjacent to the Fire Station concrete hardstand, the interpolated extent of which extends to cover the ornamental lake and down into the ground near MW110.

PFOS impacts are interpolated to be confined to the shallow geology, and covering the northern half of the ornamental lake (see Figure 31A in Appendix A). As most samples in this area were shallow, there is a degree of uncertainty as to the vertical extent, however the interpolated extent shows PFOS impacts extending to approximately 2.5 m bgl.

PFOA soil impacts are confined to the immediate area south adjacent to the Fire Station concrete hardstand with an interpolated vertical extent of 2.5 mbgl (see Figure 31B in Appendix A).

PFHxS impacts show a similar lateral distribution to that of PFOS, but covering the entire Ornamental Lake and a greater area to the east of the Fire Station (see Figure 31C in Appendix A). The interpolated vertical extent of PFHxS is greater than that of PFOS, extending up to approximately 6 mbgl and was detected in soil samples recovered from the depth of the screened intervals in MW110 and MW111. the interpolated extents do not indicate a contiguous area of soil impact within the saturated zone between MW110 and MW111, as such the soil detection at MW111 may be an outlier, it may be the result of adsorption of dissolved phase PFAS to soils in this area, or it may be localised AFFF use and disposal to ground.

As PFHxS soil impact is present in the saturated zone, this is a likely pathway towards dissolved phase groundwater impacts in this area.

11.2.3 Fire Ground South Creek Wetlands The wetlands near the Fire Ground flanking South Creek (refer Figure 3A in Appendix A) are southwest and topographically down-gradient of the Fire Ground, and were formerly connected via surface water runoff through a drain that ran from the Fire Ground lagoon and discharged into the northern area of the wetlands. Surface soil PFAS concentrations were an order of magnitude above those detected in the Fire Ground; as there is no history of direct AFFF usage in this area the wetlands are likely to be a tier 2 source, which had received PFAS-impacted surface water from the Fire Ground. Two scenarios to explain these high detections are possible:

The surface water discharge from the Fire Ground seeped into the surface soils and evaporated over time, gradually concentrating soil-bound PFAS and resulting in a concentrated source

A spill (or spills) of AFFF concentrate occurred at the Fire Ground, the runoff from which drained to Hanns Inlet and resulted in a concentrated source

The latter scenario was noted by EPA during site inspections where a mixture of fuel oils and AFFF were observed to have discharged from the Fire Ground. This process transported PFAS-impacted surface water into the wetlands, where evapotranspiration (evaporation and plant uptake) caused concentrations of PFAS to increase in the wetlands soils. Hence, the observed concentrations are consistent with periodic releases of PFAS-impacted surface water from the Fire Ground discharging into the wetlands, where evapotranspiration over time resulted in gradually increasing concentrations of PFAS in the wetlands.

PFOS and PFHxS concentrations in shallow soils show high concentrations at surface and subsurface levels, however concentrations reduce on average by one order of magnitude or greater per 1 metre of depth, indicating that most of the impact is contained in surface and shallow subsurface soil

PFOA concentrations in surface soils are up to three orders of magnitude below PFOS concentrations, indicating the soil impacts are primarily 3M Lightwater derived, and indicating the impacts may be aged.


11.2.4 Former STP Soil samples at the Former STP were analysed to assess the PFAS accumulation associated with the operation of the Former STP between the 1970’s and 2001. There were two samples of surface soil collected from within 10 m of one of two discharge points at the end of the wastewater treatment process and soil samples collected near the infilled former treatment plant area is located. Three monitoring wells were installed adjacent to the Former STP lagoons.

Surface soils in the former STP area are showing PFAS impacts consisting of PFOS and PFHxS with minor concentrations of PFOA and shorter chain perfluoroalkyl carboxylates, indicative of an aged source area where PFAS impacts were either incremental in nature or did not occur recently. PFAS concentrations at greater than 1 mbgl are below LOR, typical of PFAS impacts in source areas such as STP where soil impacts are often due to overflow events. Interpolation of soil PFAS concentrations indicates a larger area of PFAS impact surrounding the former STP area, however as soil sampling in this area was opportunistic (i.e. co-located with monitoring well installation and incidental soil samples) the lateral extent of PFAS impacts in soils remains to be defined.

There were no PFAS detects within the soils at the Former STP of the Site above the human health soil criteria. PFOS was reported in the borehole advanced for MW217 and the levels were higher at a depth of 1 m than at the surface. This sample at a depth of 1 m is closest to the water level because the well was installed on a raised bund. This indicated that the PFAS-impacted sewage seeped out of the lagoons laterally and vertically, which impacted deeper soils around each lagoon. In addition, earthworks for the construction of roadways may have resulted in clean fill being placed in the area (HLA ,2001). The highest detect was PFOS in SS018 (160 µg/kg) at one of the outlets from the final treatment lagoon.

As PFAS impacts are contained to shallow soils, it is unlikely that shallow soil PFAS impacts are contributing to the groundwater detections in this area.


11.3 Groundwater impacts Figures 30A-C in Appendix A show the interpolated groundwater PFAS impacts across the Site. PFOS, PFOA and PFHxS have been interpolated individually to a 0.05 µg/L isolevel; whilst the limits of reporting of these compounds are an order of magnitude lower, analysis of Horwitz Curves from various PFAS analytical runs has shown varying levels of measurement uncertainty at low levels of detection, therefore to increase the statistical confidence of the interpolation an isolevel one order of magnitude above the LOR has been applied.

PFOS, PFOA and PFHxS were further interpolated to their respective adopted investigation levels to identify areas of exceedance and overlap with sensitive receptors to assess potential exposure pathways.

Three main areas of groundwater PFAS impact are identified:

The Fire Ground;

Tier 2 groundwater impacts at Fire Ground wetlands; and

The Fire Station

Minor groundwater impacts were also identified at:

Downgradient of the former STP

Around the Sports Fields

The former fuel storage areas, including the Filling Station USTs and the Building 49 AST

The closed Rifle Range Road landfill

The closed outdoor swimming pool landfill

The former dry-cleaning facility

The former coal loading area

Except for VT0192, VT0370 and the former STP, all areas of PFAS groundwater impact are forming a contiguous plume when PFHxS is interpolated at the 0.05 µg/L isolevel. This level was chosen to improve statistical confidence and illustrate distinct groundwater sources and residual downgradient dissolved phase in the absence of a source. The former STP is forming an isolated groundwater plume, as is VT0370 (former service station) and VT0192 (former UST’s). PFHxS is the most widespread PFAS compound, consistent with its greater hydrophilicity than PFOS or PFOA.

PFOS dissolved-phase impacts interpolated at the same isolevel are showing a contiguous plume between the Fire Ground, Hanns Inlet Wetland, the closed Rifle Range Road landfill and the former drycleaners, with isolated plumes around the former service station, the coal loading area and the southeast foreshore.

PFOA dissolved-phase impacts interpolated at the same isolevel show a contiguous plume between the Fire Ground and nearby wetlands, with isolated plumes around the former dry-cleaning facility and the closed Rifle Range Road landfill.

Figure 29 in Appendix A shows the interpolated soil bound PFAS impacts which are residing in the saturated zone, based on this interpolation two soil source areas which are likely to be contributing to the groundwater dissolved phase are the Fire Ground wetlands and the Fire Station. All other PFAS compounds in the soil reside in the vadose zone, as such there is a large discontinuity between the most likely source of groundwater impact and the interpolated nature and extent of groundwater PFAS impacts, even at higher levels of statistical confidence. Infiltration of surface water may partly explain the extent of the groundwater PFAS impacts, however the presence of confining/impermeable layers in the geology across the site indicates that contribution from surface water infiltration is likely to be small. In areas where landfilling has taken place, namely the Fire Ground, the closed Rifle Range Road landfill and the outdoor swimming pool landfill, PFAS impacted solid materials may be contributing leachate to the groundwater.

The minor groundwater impacts observed at the former dry-cleaning facility, closed Rifle Range Road landfill, closed outdoor swimming pool landfill, and some former fuel storage areas (refer to Table 11-1) suggest that these areas are potential minor sources. This is indicated by data visualisation due to PFAS detects above


anticipated levels in the groundwater plume. Note that these areas were not highlighted as likely sources in desktop review and site interviews because there is no evidence of AFFF use or storage in these areas. It would be supposition to infer a cause for what is observed. Notwithstanding this, the data does indicate a localised PFOS and PFHxS impact (elevated concentration relative to surrounding groundwater concentrations) within what is considered a diffuse plume. These are minor contributions to the overall mass loading and are not sources which warrant any future remedial intervention or management but will be subject to ongoing monitoring.

The interpolated extent of PFOS dissolved phase exceeding the human health drinking water investigation level covers the Fire Ground, Fire Ground wetlands, the closed Rifle Range Road Landfill and the western section of the base infrastructure forming a contiguous area of impact (see Figure 11-4 and Figure 33A in Appendix A).

PFOA shows a more limited area of extent covering the Fire Ground and nearby wetlands, with isolated impacts at the former dry-cleaning facility and the closed Rifle Range Road landfill. Two localised areas of impact exceeding the drinking water investigation level exist around the Fire Ground and nearby wetlands (see Figure 33B in Appendix A).

PFHxS shows a larger area of impact, consistent with its greater hydrophilicity and the interpolated extent of the groundwater plume exceeding the drinking water investigation level covers most of the site (see Figure 33C in Appendix A).

Both PFOS and PFHxS show similar areas of extent exceeding the human health recreational investigation level, a contiguous area between the Fire Ground and nearby wetlands, whilst PFOA shows no exceedance of the recreational investigation level (see Figure 11-5 and Figures 34A-B in Appendix A).No groundwater extraction for drinking water purposes takes place at the Site, as such the risk to human health from ingestion is considered low and acceptable.


Figure 11-4 PFOS in groundwater above Drinking Water Guidelines (0.07 µg/L)


Figure 11-5 PFOS in groundwater above Human Health Recreational Guidelines (0.7 µg/L)


11.3.1 Fire Ground The interpolated extents of PFAS in soils at the Fire Ground do not show overlap with the groundwater surface in this area, as illustrated on Figure 11-6 and Figure 11-7 (see Figure 35a and b in Appendix A), however dissolved-phase PFAS concentrations have been detected in groundwater beneath the Fire Ground. As soil samples collected during the Golder 2016 investigation were recovered from the saturated zone in several locations (which showed PFAS concentrations below LOR), the extent of vertical migration of PFAS through the soil profile has not been significant enough to result in migration to the water table. As such, the contribution of PFAS from shallow soils to the groundwater PFAS impacts is likely to be negligible and not capable of causing the magnitude of dissolved-phase PFAS impacts observed. In consideration, two scenarios are possible:

The former settling ponds and excavated sediments now either reside in the saturated zone or have leached over time, and PFAS-impacted sediments beneath the former settling ponds (which were located where the current plastic-lined lagoon is presently located) are the source of the dissolved-phase impact to groundwater

Monitoring well GW07-VT0067, installed on the southern edge of the current settling pond, was drilled through the sediments of the former settling ponds and created a preferential pathway to groundwater (this is unlikely as the current lagoon had been raised)

Groundwater dissolved-phase PFAS at the Fire Ground is on average one order of magnitude below the soil impacts that have been detected. Given the apparent spatial discontinuity between soil and groundwater impacts, and the magnitude of groundwater impacts that have been detected, it is likely that an uncharacterised PFAS source is residing in the unsaturated to saturated zone beneath the Fire Ground lagoon, which is separate to the shallow soil impacts reported for areas outside the footprint of the lagoon. This is likely to be soils that had been impacted by leakage from the former settling ponds, which from were filled in and the new lagoon constructed on top.

The new lagoon is lined, therefore leakage of PFAS-impacted surface water in the lagoon into PFAS-impacted soils beneath the lagoon is likely to be less than the former unlined or clay-lined settling ponds, but leakage would provide a driving head to promote downward movement of groundwater through the unsaturated PFAS-impacted sediments, which would then reach the water-bearing zone beneath the lagoon. Hence, it is likely that PFAS-impacted soils beneath the former settling ponds (and leachate thereof) are the cause of groundwater impacts at the Fire Ground.

Interpolation of PFAS groundwater impacts indicates a contiguous plume between the Fire Ground and the nearby wetlands. Groundwater flow is both to the south and to the east from the Fire Ground, and although a separate groundwater source has been inferred at Hann’s Inlet Wetlands, over time these two plumes are believed to have migrated and become contiguous, resulting in a PFAS “front” migrating southeast with groundwater. Groundwater may also be tidally influenced from Hanns Inlet and this may affect PFAS concentrations in groundwater. Historically, there was also transport of PFAS via the surface water in an overflow drainpipe discharging near the wetlands. This surface water pathway is believed to have contributed significantly to PFAS impact in the wetlands south of the Fire Ground.


Figure 11-6 Fire Ground Interpolated Soil PFOS Impacts with Groundwater Level

Figure 11-7 Fire Ground Interpolated Soil PFHxS Impacts with Groundwater Level


11.3.2 Fire Ground – South Creek wetlands Dissolved-phase PFAS is being detected in monitoring wells in the South Creek wetlands near the Fire Ground. MW212 and MW213 are installed in the centre of the interpolated soil impact in the wetlands, however the groundwater PFAS concentrations are three orders of magnitude below those detected in soils, indicating that vertical migration with surface water infiltration is minimal.

A contiguous plume exists between the Fire Ground and Hanns Inlet. However, in consideration of the concentration gradients, the plume has two distinct points of origin and have merged over time, forming a “front” which appears to be migrating to the southeast. The interpolated depth of the plume is at least to the aquifer base, however the absence of monitoring wells installed deeper than the Brighton Group renders uncertainty around the vertical extent of the dissolved phase impacts. However, based on the low groundwater elevation reported for MW121 (as low as -0.9 mAHD), it is likely that denser seawater is intruding beneath the brackish PFAS plume, which would be anticipated to limit the vertical extent of PFAS-impacted groundwater.

The periodic inundation of the wetlands, in addition to mobilising PFAS in surface waters, would result in some downward movement of PFAS in groundwater due to the effect of driving head from the surface water. At lower concentration isolevels the Hanns Inlet groundwater plume merges with the plume originating at the closed Rifle Range Road Landfill, however they are likely to be co-mingled plumes as the concentrations being detected at the landfill are more indicative of a concentrated source and are higher than those being detected at the leading edge of the Hanns Inlet plume. Note that the contribution of PFAS discharging into South Creek is greater from the Fire Ground and nearby wetlands compared to the contribution from the closed Rifle Range Road landfill.

11.3.3 Fire Station Groundwater dissolved phase PFHxS is being detected in groundwater from MW110, consistent with the interpolated connection with soil bound PFHxS at this area. The interpolated plume extends out into the northern section of the Hanns Inlet wetlands to the east of the Fire Station. Approximately 10% of the interpolated soil impact is below the water table in this area, therefore the contribution of PFAS to the groundwater is minimal and primarily consists of PFHxS.

11.3.4 Former STP Minor dissolved phase PFHxS was detected in groundwater at the Former STP settling ponds and at an area to the north of the former STP footprint. Soil bound PFAS was also detected in surface soils in this area; anecdotal reports indicate that surplus AFFF may have been disposed of at this area, thus explaining the occurrence of PFAS impacts in soil and the concomitant impacts in groundwater. Groundwater impacts in this area are minimal and do not indicate migration towards Hanns Inlet, as evidenced by no detections of PFAS in monitoring wells MW0001 and MW218 to the north and northeast of the interpolated groundwater plume.

11.3.5 Sports Fields As discussed in Section 2.4.1, Class C recycled water was used to irrigate the Sports Fields. The water elevations in Figure 10-1 show the inferred mounding effect created by the irrigation of this area. There is a plume in the tens of nanograms associated with the mound of PFAS-impacted water that has developed at the Sports Fields. The visualisation of the data indicates a complete pathway between this source at the Sports Fields discharging to Hanns Inlet, which is overprinted by isolated point sources associated with the storage tanks in VT0369 and fuel storages near the powerhouse.


11.3.6 Sullage Pit There is evidence of PFAS impact at the Sullage Pit. The groundwater sampling data from GW03-VT0363 indicates a potentially complete pathway to Hanns Inlet. The data indicate it is a small contribution to the overall mass loading to Hanns Inlet.

11.3.7 Potential minor sources indicated by groundwater impacts There is evidence of PFAS impact to the groundwater at the closed Rifle Range Road landfill (VT0365) above the anticipated concentrations down-gradient of the Fire Ground. The groundwater sampling data at the four monitoring wells in VT0365 indicate a localised region of PFOS and PFHxS impact (elevated concentration relative to surrounding groundwater concentrations) within what is considered a diffuse plume. The groundwater sampling is the only evidence that this is a potential minor source. It would be supposition to infer a cause for what is observed. Further, the data indicate it is a small contribution to the overall mass loading to Hanns Inlet compared to the Fire Ground and wetland.

An assessment criterion of 0.1 µg/L sum of PFOS/PFOA/PFHxS was applied to the other potential minor sources that are located in the main operational area. These areas are located hydraulically down-gradient from other sources, including the Sports Fields irrigated with Class C recycled water. The assessment criterion is based on the PFAS concentration in the recycled water (<0.1 µg/L PFOS/PFOA/PFHxS), which is also an order of magnitude greater than prevailing plume (refer Appendix A – Figure 32). This highlights potential minor sources, such as the closed outdoor swimming pool landfill (VT0366) / Communications School, fuel storage area in VT0369, filling station near the powerhouse (VT0371), Demonstration Building (Building 49) AST in VT0372, and the former dry-cleaning facility (VT0368). It is noted that there was no evidence of AFFF use at these potential minor point sources. The data indicate these are small contributions to the overall mass loading. This assessment discounts some areas of PFAS impact as being sources, including the Fire Ground Water Filter Wash-down Area and UST (CER01) and ASTs (VT0192), coal loading area (VT0367) and fuel storage areas (VT0191, VT0370, VT0373), which is more likely due to hydraulically up-gradient sources. The data indicate it is a small contribution to the overall mass loading. There is no evidence of PFAS impact at the closed indoor swimming pool landfill (VT0380).

11.4 Surface water and sediment (sludge) impacts

11.4.1 Fire Ground Surface water samples were collected at five samples from five separate locations on or near the Fire Ground. These samples allowed the assessment of PFAS at or near the source. Three of five surface water samples collected from the Fire Ground contained combined concentrations of PFHxS and PFOS above the recreational screening criteria (ranging from 0.04-36.9 μg/L), with all samples above the 99% marine protection level. The maximum recorded concentrations for PFOS was 33 µg/L, PFOA was 0.78 µg/L, PFHxS was 3.9 µg/L, PFHxA was 6.8 µg/L and 6:2 FTS was 6.0 µg/L, from the sample collected within the Fire Ground lagoon. This elevated 6:2 FTS detection is indicative of use of the replacement AFFF (Ansulite). There were no exceedances of the assessment criteria for PFOA. It is noted that there are currently no guidelines for PFHxA, however these levels are in excess of PFOA human health screening criteria.

The surface water at the Fire Ground is a source of PFAS and further investigation was performed into the pathways to sensitive ecological receptors. Previous monitoring of surface waters indicated the presence of PFAS in the creek south of the Fire Ground (MWH/Stantec 2017). A detection of 0.311 µg/L PFOS was reported for Outflow 11, which is the creek receiving discharges from Fire Ground at a point upstream of the closed Rifle Range Road landfill site. This was supported by results further down the stream towards Hanns Inlet.

A sample of water ponded with the Leak-Repair-Live facility reported the following concentrations: PFOS 0.33 µg/L, PFOA 0.02 µg/L, PFHxS 0.07 µg/L and PFHxA 0.06 µg/L. None of these reported concentrations exceeded respective screening levels for human health recreational waters.


A sediment sample was collected at the Fire Ground from the oil-water separator that discharges into the Fire Ground lagoon. Concentrations of 2 mg/kg PFOS, 0.023 mg/kg 6:2 FTS, 0.017 mg/kg PFHxS were reported for this sample.

11.4.2 Former STP Previous investigations have highlighted a PFAS source entering the Site directly above the Former STP, where the maximum inflow surface water concentration was 0.008 µg/L PFOS in Inflow 6 (SW023). This location is on the western boundary, where surface water runoff is originating from adjacent farms and residential properties.

Surface water samples were collected at four samples from four separate locations at the Former STP. The results indicate PFAS detected above LOR. All surface water samples contained combined concentrations of PFHxS and PFOS above the 99% marine protection and human health recreational screening criteria (ranging from 2.96-10.5 μg/L). The maximum recorded concentrations for PFOS was 5.4 µg/L, PFOA was 1.3 µg/L, PFHxS was 5.1 µg/L and PFHxA was 6.2 µg/L, from the sample collected within the sump at the south-west lagoon. It is noted that there are currently no guidelines for PFHxA, however these levels are in excess of PFOA human health screening criteria. There were no exceedances of the assessment criteria for PFOA.

Three sediment samples were collected from the wet lagoons in August 2017, note that these samples may be more appropriately categorised as sludge samples. These samples allowed the assessment of PFAS accumulation in the sludge at the bottom of the Former STP lagoons. These samples contained predominantly PFOS, but there were also a range of other PFAS compounds detected at lower concentrations. The detectable PFOS + PFHxS ranged from 0.067-1.544 mg/kg, with the highest detect at SD013.

Eight opportunistic sludge samples of biosolids were collected from four separate locations, when the north-west and south-west lagoons dried out. These samples all reported PFAS concentrations below the adopted biosolids screening levels for agricultural application, however there were exceedances of the human health screening levels. The maximum detect was in the northwest lagoon (SL001) at 2.3 mg/kg PFOS. The sample from the south west lagoon (SL004) had detects of 0.12 mg/kg PFOA and 0.35 mg/kg PFHxS. A range of other PFAS compounds were detected in the sludge samples above the laboratory LOR.

11.4.3 Fire Station Surface water samples were collected at two locations near the Fire Station, including the Ornamental Lake and a storm-water drain outfall. The sample from the Ornamental Lake (SW019) contained combined concentrations of PFHxS and PFOS above the environmental and human health recreational screening criteria (total 1.8 μg/L). In addition, both surface water samples also contained combined concentrations of PFHxS and PFOS above the screening criteria for marine protection (0.01 and 1.8 μg/L).

The Ornamental Lake sample recorded a PFOS detection of 0.45 µg/L, as well as 0.10 µg/L PFOA, 1.40 µg/L PFHxS and a range of other PFAS compounds. The drain outlet sample (SW020) had a detect for PFOS and PFPeA at the LOR (0.01 µg/L). Neither sample exceeded the PFOA criteria.

Sediment samples were collected at the two locations, co-located with surface water samples in the Ornamental Lake (SD019) and the unnamed creek to the east (SD020). The sample from the creek was non-detect for all compounds and SD019 recorded a PFOS concentration of 0.005 mg/kg with no other PFAS detected.

11.4.4 Hanns Inlet A total of 33 surface water samples were collected at 22 locations off-Site in Hanns Inlet, which receives surface and groundwater from Site. These samples allowed the assessment of surface PFAS flows onto and out of the Site via the storm-water network. The results from surface water samples collected from Hanns Inlet during both ebb and flood tides are provided in Appendix F. The surface water samples collected from Hanns Inlet closest to the Marina contained combined concentrations of PFHxS and PFOS above the


adopted screening criteria. The maximum detections were 0.0108 and 0.0109 µg/L at SW036 and SW054 on the ebb tide. Most of the detects were close to the LOR. The samples near Westernport Bay were all non-detects. There were no PFOA detects in Hanns Inlet.

While Aurecon is aware of AFFF storage and use in other parts of Western Port Bay, such as the fire-fighting tug boats berthed north of Stony Point, PFAS concentrations in Western Port Bay are not known at this stage. However, considering that the eastern portion of Hanns Inlet is flushed with water from Western Port Bay during tidal cycles, the non-detect of PFAS for water samples collected in the eastern portion suggests the absence of detectable PFAS in the waters of Western Port Bay immediately outside the mouth of Hanns Inlet.

Sediment samples were collected at locations that were co-located with surface water samples. There were no detects for PFAS in the sediment samples above the laboratory LOR.

11.4.5 Storm-water drainage There is evidence of PFAS entering Site from off-Site sources via the storm-water drainage system on the northern boundary and western boundary (adjacent to Former STP). The surface water and sediment samples at the northern boundary reported combined PFOS/PFHxS concentrations of 0.05 µg/L and 6.3 µg/kg, respectively. The surface water sample at the western boundary near the Former STP reported a combined PFOS/PFHxS concentration of 0.01 µg/L. This indicates impact on-Site from off-Site residential sources.

The highest concentration of PFAS in the storm-water outflows was from the Ornamental Lake overflow discharge. This sample reported surface water concentrations of 0.79 µg/L (combined PFOS/PFHxS) and 0.97 µg/L (PFAS), and sediment levels of 53 µg/kg (PFOS only). PFAS impacted surface water was also reported at SW006 (0.64 µg/L PFAS), which is collected from around the powerhouse and associated fuel storages, and discharges to Hanns Inlet. This supports groundwater results that indicate there is a minor source in this area. PFAS impact is also observed near the closed outdoor swimming pool landfill (SW004 and SW001 reporting concentrations of 0.46 µg/L and 0.60 µg/L respectively). It is noted that all 17 surface water samples collected from storm-water outlets contained detectable concentrations of PFAS, including drains with catchments near the carparks associated with temporary residences. This indicates minor impact from non-AFFF, on-Site residential sources.

It is likely that the concrete (unlined) in the pipes are impacted by PFAS, which is providing an minor ongoing low-level secondary source. These storm-water drainage pipes are scheduled to be upgraded during redevelopment works and four bio-retention basins are to be installed on key storm-water mains prior to the outfalls, which are likely to improve storm-water collection and release to Hanns Inlet.

11.4.6 Tap water (effluent and potable supplies) Recycled water

The sample of Class C recycled water (SW035) from the pumphouse tap reported values of 0.09 µg/L PFOS, 0.06 µg/L PFHxS, 0.02 µg/L PFOA prior to the discontinuation of surface water being provided to Site. This is further evidence for historical PFAS impact to the Sports Fields related to irrigation of recycled water.

Fire Ground Laundry

A sample of water collected from a potable-water tap in the Fire Ground laundry (SW034) reported a PFOS concentration of 0.04 µg/L. This concentration is below screening levels for drinking and primary contact recreation. No other PFAS compounds were detected above the LOR.


11.5 Summary of key sources These sources have been assessed and the summarised in Table 11-1. An assessment value of 0.1 µg/L PFAS was applied to identify local minor sources because 0.1 µg/L corresponds to the PFAS concentration in the recycled water and is an order of magnitude above the resulting broad diffuse plume of impacted groundwater.

Table 11-1 Summary of known and potential PFAS source areas following field investigation

CSR Area Comment

Considered a source

area Major or minor

source area

VT0067 Fire Ground and nearby wetlands Confirmed PFAS presence in surface water, groundwater, sediment and soil

Yes Major

Fire Station/Ornamental Lake Confirmed PFAS presence in surface water, groundwater, sediment and soil

Yes Minor

Storm-water drains Confirmed PFAS presence in surface water discharge suggests PFAS sorption onto drain pipes

Yes Minor

VT0192 Fire Ground Water Filter Wash-down Area and UST (CER01) and ASTs

Low PFAS presence in groundwater below 0.1 µg/L

No

VT0365 Former STP Confirmed PFAS presence in surface water, groundwater, sludge/sediment and soil

Yes Minor

Sports Fields Confirmed PFAS presence in soil and grass

Yes Minor

Bushfire zone Confirmed PFAS presence in groundwater and surface soil

Yes Minor


No PFAS detected in sediment and pore water above laboratory LOR

No

VT0363 Sullage Pit Confirmed PFAS presence in groundwater and surface water

Yes Minor

VT0365 Closed Rifle Range Road landfill Confirmed PFAS presence in groundwater above 0.1 µg/L

Yes Minor

VT0366 Closed outdoor swimming pool landfill

Confirmed PFAS presence in groundwater above 0.1 µg/L

Yes Minor

Communications school Confirmed PFAS presence in nearby groundwater (VT0366)

Potential Minor

VT0380 Closed indoor swimming pool landfill

No evidence of PFAS in groundwater

No

VT0191 UST (CER2) Low PFAS presence in groundwater below 0.1 µg/L

No

VT0369 USTs (CER03) Confirmed PFAS presence in groundwater above 0.1 µg/L

Yes Minor

VT0370 Former Petrol Station USTs Low PFAS presence in groundwater below 0.1 µg/L

No

VT0371 Filling Station USTs Confirmed PFAS presence in groundwater above 0.1 µg/L

Yes Minor

VT0372 Demonstration Building AST Confirmed PFAS presence in groundwater above 0.1 µg/L

Yes Minor

VT0373 Ward Room AST Low PFAS presence in groundwater below 0.1 µg/L

No

VT0374 Powerhouse Confirmed PFAS presence in nearby groundwater (VT0371)

Potential Minor

VT0367 Coal loading area Low PFAS presence in groundwater below 0.1 µg/L

No

VT0368 Former dry-cleaning facility Confirmed PFAS presence in groundwater above 0.1 µg/L

Yes Minor


11.6 Transport pathways

11.6.1 Groundwater/Soil Impact Interfaces Two primary exposure pathways exist for PFAS impacts in groundwater:

Surface water infiltration and migration through the soil profile, bringing with it dissolved phase PFAS from unsaturated soils

Movement of groundwater through PFAS impacted saturated soils contributing to the groundwater dissolved phase

To assess the contribution of soil in the saturated zone to the interpolated groundwater plume, the quantity of PFAS soil impact which resides in the saturated zone was interpolated across the site, as shown on Figure 29 in Appendix A. The interpolation shows only three areas where there is a groundwater/PFAS soil impact interface; the Former STP, the Fire Station and Fire Ground wetlands. Further, the fact that the majority of PFAS soil impacts are residing in the vadose zone (discounting unidentified sources residing in the saturated zone), the primary exposure pathway to groundwater is via surface water infiltration. However, it is noted that uncharacterised areas of soil impact at the Fire Ground and closed Rifle Range Road landfill may be sources of PFAS adsorbed to soils in the saturated zone. A secondary transport pathway may exist in the form of preferential pathways created by inappropriate monitoring well installation; it was noted during this investigation that several existing monitoring wells had unusually large screened intervals (some as much as 6 metres), this may have inadvertently cross-connected perched water and the groundwater proper in areas such as the Fire Ground. In consideration, groundwater PFAS impacts are mostly residual and the extent of dynamic mass addition is minimal.

11.6.2 Groundwater/Surface Water Interaction Areas of interpolated extent of groundwater PFAS impacts indicates that groundwater/surface water interaction could take place in the wetlands near the Fire Ground and on the eastern foreshore of the Site. Given the intensity of impact at the Fire Ground wetlands this is likely to be the main area of groundwater/surface water interaction and soil/surface water interaction.

11.6.3 Volumetrics Cases and Source Area Persistence To assess mass difference between the impacts contained in the saturated zone and those contained in the vadose zone volumetrics cases were developed for total PFAS soil impacts. The mass difference was used to infer source area potential and persistence. The logic of comparing masses between source areas was that by assuming similar leaching rates, areas with larger masses available for leaching would persist longer than areas with lower masses of PFAS, i.e., the groundwater plume will persist longer in areas with higher saturated soil impacts. This is also important when comparing dissolved-phase mass to saturated soil mass, indicating that on a total mass basis the majority of PFAS is bound to soils. The inferred mass of total PFAS in each source area was considered as part of ranking for the PMAP. However, stored mass was not the controlling factor. For example, more PFAS was inferred to be stored in the South Creek wetlands, but that area was ranked lower for remediation in the PMAP because it was not practical to excavate the PFAS-impacted soils in that area.

Mass differences were also evaluated to provide an indication of the potential management measures which may be required to mitigate source areas where migration in groundwater and/or surface water may be taking place.

Soil whole of Site:

- Total PFOS in soil = 57 kg in 746,000 m3 of soil

- Total PFOS in saturated zone = 11 kg in 110,000 m3 of soil

- Total PFOS in vadose zone = 47 kg in 636,000 m3 of soil

- Percentage of PFOS impact in saturated zone = 19%


- Total PFOA in soil = 0.06 kg in 5,600 m3 of soil

- Total PFOA in saturated zone = 0.04 kg in 3,500 m3 of soil

- Total PFOA in vadose zone = 0.02 kg in 2,000 m3 of soil

- Percentage of PFOA impact in saturated zone = 66%

- Total PFHxS in soil = 3 kg in 160,000 m3 of soil

- Total PFHxS in saturated zone = 0.7 kg in 29,000 m3 of soil

- Total PFHxS in vadose zone = 2.3 kg in 131,000 m3 of soil

- Percentage of PFHxS impact in saturated zone = 23%

Groundwater whole of Site

- Total PFOS in groundwater = 2.2 kg in 9,800,000 m3 of water

- Total PFOA in groundwater = 0.1 kg in 2,700,000 m3 of water

- Total PFHxS in groundwater = 1.7 kg in 21,850,000 m3 of water

- Total PFOS+PFHxS in groundwater = 4.8 kg in 28,400,000 m3 of water

The total proportions of PFOS, PFOA and PFHxS contained in the dissolved phase as compared to that contained in the solid phase is in the saturated zone is:

- PFOS = 20%

- PFOA = 550% (i.e. there is five times more PFOA in groundwater than in soils in the saturated zone)

- PFHxS = 74%

Note that there is no indication that transformation of PFAS compounds is occurring, and in the absence of such data indicating this it is unsafe to assume so. PFOA is present because it was a component of the source material (3M Lightwater and Ansulite), and due to greater solubility than PFOS it is therefore more mobile.

11.6.4 Evaluation of PFAS fluxes via surface-water drain flows PFAS were detected in samples of surface water collected from drains discharging ephemerally onto the Site along the northern and western Site boundaries and discharging ephemerally from into the tidal creeks or directly into Hanns Inlet. The mass flux of PFAS at each sampled discharge point was estimated to evaluate the relative contribution from each sampling location in response to rain events. Note that these mass fluxes are based on storm events that reflected average monthly rainfall for the August 2018 sampling event. Mass fluxes will vary depending upon the yield contributing to flow in the drain system, which will vary throughout the year and between years.

For each sampling location the flow rate of water was evaluated qualitatively (no flow to high flow), which was combined with the reported total concentration of the 28 PFAS compounds analysed to estimate the mass flux of total PFAS at the location. Details of the evaluation are presented in Table 11-2.

Calculated flux of total PFAS coming onto the Site was approximately 0.12 gm/day, which reflected flows from one location on the northern boundary and one on the western boundary.

Results from the PFAS flux evaluations indicate that total mass discharge into the tidal creeks or directly into Hanns Inlet was approximately 0.8 gm/day of total PFAS. Hence, total discharge is approximately seven times the total mass flux calculated for flows coming onto the Site, which reflects on-Site contribution to PFAS mass carried in the storm-water crossing the Site. On a relative basis the two highest estimates of PFAS flux discharge occurred from Outflow 8 (HC945) and Outflow 9 (HC164), which flank the closed outdoor swimming pool landfill located south of the Communications School.


Table 11-2 Evaluation of PFAS flux at drain sampling locations

Drain Feature Aurecon Sample ID

Flow Estimate

from Field Sheet

Indicative flow rate

(L/s)

Indicative flow rate (m3/day)

Concentration PFOS+PFHxS

(µg/L)

Approximate Daily Flux

PFOS+PFHxS (gm/day)

Approximate Annual Flux

PFOS+PFHxS (gm/year)

Concentration 28 PFAS

(µg/L)

Approximate Daily Flux Total 28

PFAS (gm/day)

Approximate Annual Flux

Total 28 PFAS

(gm/year) INFLOW LOCATIONS

Inflow 3 SW021 Moderate 10 864 0.13 0.11 41 0.13 0.01 2 Inflow 6 SW023 Moderate 10 864 0.01 0.009 3.2 0.01 0.00001 0.0

TOTAL 0.12 44.2

0.01 2.0 OUTFLOW LOCATIONS

Outflow 8 (HC945) SW001 Moderate 10 864 0.239 0.206 75.4 0.456 0.394 143.8 HC886 SW002 Low 0.5 43.2 0.011 0.0005 0.2 0.017 0.001 0.3 Outflow 6 (HC665) SW003 Low 2 172.8 0.03 0.005 1.9 0.158 0.027 10.0 Outflow 9 (HC164) SW004 Moderate 10 864 0.42 0.363 132.5 0.603 0.521 190.2 HC955 SW005 Low 1 86.4 0.023 0.002 0.7 0.03 0.003 0.9 Outflow 7 (HC911) SW006 Low 1 86.4 0.54 0.047 17.0 0.636 0.055 20.1 Outflow 5 (HC786) SW007 Low 1 86.4 0.013 0.001 0.4 0.021 0.002 0.7 Outflow 4 (HC787) SW008 Very low 0.1 8.64 0.017 0.000 0.1 0.023 0.000 0.1 HC679 SW009 Low 1 86.4 0.018 0.002 0.6 0.023 0.002 0.7 HC1003 SW010 Low 1 86.4 0.026 0.002 0.8 0.036 0.003 1.1 HC980 SW011 High 20 1728 0.035 0.060 22.1 0.046 0.079 29.0 HC1014 SW012 Low 1 86.4 0.19 0.016 6.0 0.253 0.022 8.0 HC628 SW013 Low 1 86.4 0.122 0.011 3.8 0.149 0.013 4.7 HC978 SW017 High 20 1728 0.06 0.104 37.8 0.1 0.173 63.1 HC772 SW018 No flow 0.01 0.864 0.791 0.001 0.2 0.97 0.001 0.3 HC544 SW029 Low 1 86.4 0.27 0.023 8.5 0.28 0.024 8.8 HC420 SW030 Low 1 86.4 0.08 0.007 2.5 0.27 0.023 8.5

TOTAL 0.851 311

1.34 490


11.7 Receptors of concern The refined list of potential receptors based in the delineation of sources and assessment of pathways is summarised in Table 11-3

Table 11-3 Refined list of potential human and ecological receptors

Potential Receptor Exposure media Potentially complete

exposure pathway

Above Tier 1 Risk

Assessment ON-SITE HUMAN RECEPTORS

Base Workers or Trainees

SOIL/VEGETATION/CONCRETE: dermal contact with and ingestion of this media at the Fire Ground/South Creek wetlands, Fire Station/Ornamental Lake, Former STP, Sports Fields, Sullage Pit and other minor sources1

Yes No

SURFACE WATER: dermal contact with and ingestion of this media at the Fire Ground (during training Leak-Repair-Live Unit) and Hanns Inlet (during exercises in and on the Inlet)

Yes No

GROUNDWATER No No SEDIMENT/SLUDGE/BIOSOLIDS No N/A

Intrusive construction workers

SOIL/VEGETATION/CONCRETE: dermal contact with and ingestion of this media, and inhalation of dust at the at Fire Ground/South Creek wetlands, Fire Station/Ornamental Lake, Former STP, Sports Fields, Site land boundaries, Sullage Pit and other minor sources1

Yes Yes

SURFACE WATER Yes Yes

GROUNDWATER Yes Yes SEDIMENT/SLUDGE/BIOSOLIDS Yes N/A

Site visitors SOIL/VEGETATION/CONCRETE: dermal contact with and ingestion of this media at the Fire Ground/South Creek wetlands, Fire Station/Ornamental Lake, Former STP, Sports Fields, Sullage Pit and other minor sources1

Yes No

SURFACE WATER No3 N/A GROUNDWATER No N/A SEDIMENT/SLUDGE/BIOSOLIDS No N/A

Temporary on-Site residents

SOIL/VEGETATION/CONCRETE No N/A SURFACE WATER No3 N/A GROUNDWATER No N/A SEDIMENT/SLUDGE/BIOSOLIDS No N/A

Permanent on-Site residents

SOIL/VEGETATION/CONCRETE No N/A SURFACE WATER No N/A GROUNDWATER No N/A SEDIMENT/SLUDGE/BIOSOLIDS No N/A

Childcare attendees SOIL/VEGETATION/CONCRETE No N/A SURFACE WATER No N/A GROUNDWATER No N/A SEDIMENT/SLUDGE/BIOSOLIDS No N/A

1 Refer to Appendix A - Figures 27F for extent of impacted soil. 2 Existing administrative controls and PPE are in place to prevent exposure. 3 While some reported results for surface water exceeded the recreational screening level, this screening value is based on lifetime consumption of 0.2L every day, which is not likely to occur due to the low likelihood of long-term exposure to site workers, occupants and visitors.


Refined list of potential human and ecological receptors, continued

Potential Receptor Exposure media Potentially complete

exposure pathway

Above Tier 1 Risk

Assessment OFF-SITE HUMAN RECEPTORS

Off-Site residents SOIL/VEGETATION/CONCRETE No N/A SURFACE WATER No N/A GROUNDWATER No N/A SEDIMENT/SLUDGE/BIOSOLIDS No N/A

Western Port Bay fish consumers

FISH Yes No

ON-SITE ECOLOGICAL RECEPTORS On-Site terrestrial biota

SOIL/VEGETATION/CONCRETE: Potential direct contact with and uptake (and bioaccumulation) from media in Fire Ground/wetlands, Fire Station/Ornamental Lake and Former STP

Yes Yes4

SOIL/VEGETATION: Potential direct contact with and uptake (and bioaccumulation) from media in Sports Fields, Sullage Pit, land boundaries

Yes No

SURFACE WATER: Potential direct contact with and uptake (and bioaccumulation) from media in the Fire Ground/wetlands and nearby creeks, Fire Station/Ornamental Lake, Former STP, Sullage Pit, storm-water drainage system and Hanns Inlet

Yes Yes5

GROUNDWATER: Potential direct contact with and uptake (and bioaccumulation) from media1

Yes No criteria6

SEDIMENT/SLUDGE/BIOSOLIDS: Potential direct contact with and uptake (and bioaccumulation) from these media

Yes No criteria7

On-Site aquatic biota (including Hanns Inlet)

SOIL/VEGETATION/CONCRETE: Potential direct contact with and uptake (and bioaccumulation) from media in Fire Ground/wetlands, Fire Station/Ornamental Lake and Former STP4

Yes Yes

SURFACE WATER: Potential direct contact with and uptake (and bioaccumulation) from media in the Fire Ground/wetlands and nearby creeks, Fire Station/Ornamental Lake, Former STP, Sullage Pit, storm-water drainage system and Hanns Inlet5

Yes Yes

GROUNDWATER: Potential direct contact with and uptake (and bioaccumulation) from media in the Fire Ground wetlands (crabs, pipis and worms impacted by discharge)

Yes Yes

SEDIMENT/SLUDGE/BIOSOLIDS: Potential direct contact with and uptake (and bioaccumulation) from these media

Yes No criteria7

OFF-SITE ECOLOGICAL RECEPTORS Off-Site terrestrial biota8


Off-Site aquatic biota (Western Port Bay)


1 Refer to Appendix A - Figures 27F for extent of impacted soil 4 Direct contact ecological screening criteria (public open space) not exceeded, but indirect contact ecological screening criteria (industrial/commercial) was exceeded 599% species protection screening level exceeded for bioaccumulation but not 95% species protection screening level for direct contact, 6Groundwater ecological criteria are for marine and freshwater protection, which are not directly applicable to terrestrial biota (such as grass and trees) 7Note detects of PFAS in sediments from Fire Ground oil-water interceptor, Ornamental Lake, South Creek near closed Rifle Range Road landfill and storm-water drainage system, but no sediment guidance values in the NEMP 8 Note that this is defined as an off-Site exposure scenario (i.e., the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site


11.8 Refined Conceptual Site Model The assessment of known and potential human and ecological receptors based on the risk assessment presented in Section 11 is summarised in Table 11-4. Cross-sectional visualisations of key sources are provided in Appendix J.

Focussing on the main source of PFAS-impacted soils, Figure 11-8 presents cross section of the refined CSM for the main source area located at the Fire Ground and South Creek wetlands south of the Fire Ground. Key points shown on the figure are loss of PFAS-impacted water from the Fire Ground lagoon via leakage to groundwater, via over-topping of the lagoon, and discharge via the lagoon drainpipe into the South Creek wetlands south of the Fire Ground. Leakage from the lagoon is inferred to be leaching PFAS from soils that had been impacted by leakage from the former unlined and clay-lined settling ponds. This leakage and discharge has impacted soils and groundwater in the wetlands, which has resulted in biota in the wetlands and Hanns Inlet being exposed to PFAS above the screening levels

Figure 11-8 Visualisation of the Refined CSM – Fire Ground & Tidal Flats

Notes: (1) lagoon former overflow of PFAS-impacted water (blocked off in 2017) (2) clayey estuarine sediments within thin sand layers (3) semi-confined Brighton Group aquifer of clays with thin sand and gravel layers (4) leakage of PFAS-impacted lagoon water that also leaches PFAS from unsaturated soils previously impacted by leakage from the

former unlined and clay-lined settling ponds.


Table 11-4 Assessment of known and potential human and ecological receptors

Pathway not complete and / or relevant for this receptor Tier 1 screening level not exceeded Potentially complete pathway, but PFAS screening levels not exceeded at receptor Tier 1 screening level exceeded Complete pathway with potential exposure above Tier 1 screening level at receptor Tier 1 screening level not available Potentially complete pathway, but no Tier 1 screening level

Exposure Media Exposure Pathway

Human Receptors Ecological Receptors

Off-Site On-Site Off-Site1 On-Site2

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Soil (Fire Ground and wetlands straddling the South Creek)

Inhalation of dust or particulates Incidental Ingestion Dermal Contact Direct Contact or Uptake Bioaccumulation or Secondary Poisoning #

Soil (Fire Station and Ornamental Lake)


Soil (Former STP and West Creek)


1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. # There is the potential for movement on-site and off-site for mobile wildlife (birds, mammals, reptiles), this risk is considered low and acceptable.


Assessment of known and potential human and ecological receptors, continued Pathway not complete and / or relevant for this receptor Tier 1 screening level not exceeded Potentially complete pathway, but PFAS screening levels not exceeded at receptor Tier 1 screening level exceeded Complete pathway with potential exposure above Tier 1 screening level at receptor Tier 1 screening level not available Potentially complete pathway, but no Tier 1 screening level




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Soil (Sports Fields)

Inhalation of dust or particulates

Incidental Ingestion Dermal Contact Direct Contact or Uptake Bioaccumulation or Secondary Poisoning

Soil (Site land boundaries)



Soil (potential minor sources in operational area)



1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields.






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Soil (Sullage Pit)



Groundwater

Ingestion (potable use)

Incidental Ingestion (non-potable use) Dermal Contact (potable and other uses) Direct Contact or Uptake ##

Surface Water (Fire Ground including Leak-Repair-Live facility, Fire Ground lagoon, South Creek wetlands and South Creek)

Incidental Ingestion + +

Dermal Contact + +

Direct Contact or Uptake

Bioaccumulation or Secondary Poisoning 1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. ## Groundwater ecological criteria are for marine and freshwater protection, which are not directly applicable to terrestrial biota (such as grass and trees). + The result for the sample from the Leak-Repair-Live facility at the Fire Ground was below screening levels for primary contact recreation, but the result reported for the Fire Ground lagoon was above the PFOS screening level for primary contact recreation. 3






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Surface Water (Fire Station and Ornamental Lake)4

Incidental Ingestion

Dermal Contact


Bioaccumulation or Secondary Poisoning

Surface Water (Former STP including West Creek)4


Dermal Contact



Surface Water (Sullage Pit)


Dermal Contact

Direct Contact or Uptake +++ +++

Bioaccumulation or Secondary Poisoning 1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. 4 There are no screening criteria available for PFHxA, however these levels are in excess of PFOA human health screening criteria in surface water at the Fire Ground and Former STP and groundwater at the Fire Ground. +++ 99% species protection screening level exceeded for bioaccumulation but not 95% species protection screening level for direct contact.






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Surface Water (Closed Rifle Range Road Landfill and nearby South Creek)


Dermal Contact



Surface Water (storm-water drainage system)


Dermal Contact



Surface Water (Hanns Inlet)


Dermal Contact

Direct Contact or Uptake *** +++ +++

Bioaccumulation or Secondary Poisoning 1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. ++ Existing administrative controls and PPE are in place to prevent exposure. The screening value is based on consumption of 0.2L every day over decades, which is not likely due to the transient nature of construction works. +++ 99% species protection screening level exceeded for bioaccumulation but not 95% species protection screening level for direct contact. *** Multiple non-detects below LOR at entrance to Hanns Inlet indicate incomplete pathway to Western Port Bay. Note that permanent surface water was not observed on-Site at any other locations (some of the storm-water flows indicated in the table are ephemeral).






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Incidental Ingestion ++

Dermal Contact ++



Sediment (Fire Station and Ornamental Lake)5


Dermal Contact ++



Sediment (Sullage Pit)6


Dermal Contact ++


Bioaccumulation or Secondary Poisoning 1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. 5 There are currently no reliable criteria for Tier 1 assessment of sediment, but PFAS was detected in sediments in these areas. 6 There are currently no reliable criteria for Tier 1 assessment of sediment, PFAS was not detected above LOR in sediments in these areas. ++ Existing administrative controls and PPE are in place to prevent exposure.






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Sediment (storm-water drainage system)5


Dermal Contact ++



Sediment (Hanns Inlet)6


Dermal Contact ++



Sludge/biosolids (Former STP lagoons)5


Dermal Contact ++


Bioaccumulation or Secondary Poisoning 1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. 5 There are currently no reliable criteria for Tier 1 assessment of sediment, but PFAS was detected in sediments in these areas. 6 There are currently no reliable criteria for Tier 1 assessment of sediment, PFAS was not detected above LOR in sediments in these areas. ++ Existing administrative controls and PPE are in place to prevent exposure.






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Fish (Hanns Inlet) Ingestion 1 Note that this is defined as an off-Site exposure scenario (i.e. the biota are located off-Site when in contact with media). Fauna, such as birds and mammals, that can move on and off Site are covered in the on-Site Terrestrial Biota scenario as the exposure scenario occurs on-Site. 2 Hanns Inlet is part of the investigation area and considered to be on-Site for this exposure pathway assessment. 3 Includes users of Sports Fields. 4 Limited sample size resulted in LOR above screening level. ++ Existing administrative controls and PPE are in place to prevent exposure.


12 PFAS Management

12.1 Identified risk management measures The risk management framework advocated in Schedule B2 of the ASC NEPM was used to assess generic (Tier 1) risks to human and ecological receptors. Following the decision flowchart in the ASC NEPM (see Figure 12-1), detailed investigation and laboratory analysis was performed34, the CSM was refined (see Section 5), and screening criteria for the intended land use were exceeded. Based on the characterisation of the key source areas of PFAS impact to soil (Fire Ground and South Creek wetlands areas), it is considered that there is sufficient information to devise risk-based remediation strategies without the need to pursue further and more detailed site-specific assessment of risk to human health and/or ecological receptors.

Figure 12-1 ASC NEPM general process flowchart (Green highlight indicates path followed for the DSI)

34 The commissioning of the DSI works in part represents a departure from the systematic investigation process advocated in Schedule B2 of the ASC NEPM in that no prior preliminary site investigations (PSI), specific to the investigation of potential PFAS impacts, have been conducted and / or formally reported, and Defence has not contracted Aurecon to undertake any such PSI works or the production of a PSI report.


The requirements for the implementation of risk mitigation measures and the nature of such mitigation measures will be addressed in the PMAP which is to be prepared after finalisation of the DSI report.

Management of risks associated with Site sources of PFAS through the PMAP would involve a combination of engineering and administrative measures. Using the findings from the source-pathway-receptor linkages set out in the refined CSM, measures will be implemented to manage risk. The intent of these measures would be to either remove a source or receptor, or cut the pathway of exposure between a source and associated receptor. A compilation of risks (based on preclusion of beneficial use) and potential management measures are presented in Table 12-1.

Table 12-1 Precluded beneficial uses and potential management measures

Beneficial Use Potential Management Measures


Source reduction (for example, excavation of PFAS-impacted soils at the Fire Ground or the Fire Station / Ornamental Lake. Standard Defence

construction environmental management plan requirements.


Administrative control: Implement standard Defence OHS and construction environmental management plan requirements.


Source reduction (for example, excavation of PFAS-impacted soils at the Fire Ground or the Fire Station / Ornamental Lake.


Administrative control: no groundwater extraction for irrigation.


Administrative control: no groundwater extraction for stock watering.


Administrative control: no groundwater extraction for industrial water use.

Groundwater SEPP: Primary contact recreation (including intrusive workers) On-Site

Administrative control: no groundwater extraction for primary contact recreation (such as filling or topping up swimming pools with groundwater).


Source reduction (for example, excavation of PFAS-impacted soils at the Fire Ground or the Fire Station / Ornamental Lake. Standard Defence construction environmental management plan requirements (reduce erosion of PFAS-impacted soils that could enter waterways).

Water SEPP: Aquatic plants and animals (99% species protection) Off-Site

Not from Site PFAS sources, as off-Site preclusion based on detects in surface water in some Council drains flowing onto the Site.


Administrative control: no taking of biota (including fish) for human consumption in Naval waters (including Hanns Inlet).


Administrative control: no primary contact recreation (including swimming) in the Fire Ground Lagoon and South Creek or filling of swimming pools from these water features.


12.2 Data gaps and additional monitoring

12.2.1 Data gaps The main data gaps include:

Refining the vertical extent of impacted soils beneath the Fire Ground lagoon, Ornamental Lake at the Fire Station, and the lagoons at the Former STP

The nature and extent of impacted soils beneath the Fire Ground lagoon will be investigated further as part of decommissioning and remediation of the Fire Ground after the new fire-training facility is constructed and commissioned. It is anticipated that additional soil sampling will be undertaken as part of decommissioning the Fire Ground lagoon. Results from the additional soil sampling could be used to refine the Site CSM and understanding of PFAS sources at the Fire Ground

The Ornamental Lake is to be re-built and part of the construction and remediation will be to excavate and manage PFAS-impacted sediments and underlying soils. The deepest soil samples in this area were collected at 0.2 m so further work may be required to refine the vertical extent of impacted soils. The new lake will be constructed after PFAS-impacted soils are excavated and assessed for on-Site re-use

The Former STP lagoon remediation work is to involve excavating the biosolids and managing the biosolids on-Site. Underlying soils will need to be assessed to evaluate the extent of excavation necessary to validate the excavation prior to backfilling. Interpolation of soil PFAS concentrations indicates a larger area of PFAS impact surrounding the former STP area, however as soil sampling in this area was opportunistic (i.e. co-located with monitoring well installation and incidental soil samples) the lateral extent of PFAS impacts in soils remains to be defined.

The Sullage Pit monitoring wells were only sampled in one round, further groundwater monitoring is recommended to improve statistical confidence in results from this area. However, it is noted that the groundwater monitoring wells may be dry

There is a gap in the knowledge about the human health and ecological risks of PFAS-impacted sediment and biosolids. As such, there are no current guidelines in the NEMP for these media. The ANZBP proposed screening levels based on the FSANZ TDI may be included in future revisions of the NEMP and sediment guidance values may be reported

All of the above data gaps will be addressed in the design and implementation of the PMAP.

12.2.2 Additional monitoring Monitoring will be set out in the PMAP Ongoing Monitoring Plan (OMP). The OMP will detail a sampling plan that will allow detection of any significant changes in groundwater levels or quality after removal of source materials. In addition, the OMP will set out the approach to collecting data to evaluate trends of PFAS concentrations in groundwater. Evaluation of these trends will provide guidance on the need to implement mitigation measures if (to be established) trigger levels are exceeded.


13 Conclusions and next steps

13.1 Conclusions The fundamental goals of the DSI were to:

Determine the nature and extent of AFFF PFAS impacted media

Evaluate the risk posed by such impact to human health and / or the environment; and

Evaluate the requirement to undertake further, more detailed site-specific risk assessment studies and / or implement strategic site management strategies.

13.1.1 Determine the nature and extent of AFFF PFAS impacted media The DSI results show that the main primary PFAS soil source areas are:

The Fire Ground

Wetlands nearby to the Fire Ground straddling South Creek (South Creek wetlands), which historically received PFAS discharges from the Fire Ground.

A lesser primary PFAS source area of impacted soil and sediment is at the Fire Station and nearby Ornamental Lake.

Minor soil source areas were identified at the following locations:

Former STP and associated settling lagoons

Sports fields irrigated with Class C recycled water

Sullage Pit

While not contributing significantly to the PFAS load to receptors, other minor sources (based on elevated surface water or groundwater results) were identified at the closed Rifle Range Road landfill, closed outdoor swimming pool landfill, stormwater drain piping, some of the aboveground or underground petroleum storage tanks, the former dry-cleaning facility, coal loading area, and the Fire Ground Water Filter Wash-down Area. Figure 13-1 shows the locations of these key source areas.

Figure 13-1 Summary of key PFAS sources, transport pathways and receptors


An isolated area of PFAS soil impact near the north-eastern land boundary was identified where a bushfire occurred in the 1990’s where AFFF residue may have been present in firefighting equipment (either Base or CFA).

Samples from the remainder of the Site reported non-detect to negligible PFAS concentrations in soil that were not indicative of source areas.

The nature and extent of PFAS-impacted media reflects migration of PFAS away from the identified source areas via surface water and groundwater. The lateral and vertical extents of detected PFAS was generally defined around each source area except for the primarily vertical extent of impact below the Fire Ground lagoon where access for intrusive investigations beneath the lagoon was limited due to access restrictions.

The principal PFAS component of these soil impacts is PFOS, where the total interpolated PFOS mass in soil is an order of magnitude above PFHxS total mass and three orders of magnitude above PFOA total mass. The majority of this mass is contained in shallow soils around the Fire Ground and nearby wetlands.

All results for soil samples recovered during the Aurecon DSI and the prior Golder works programs were below the Tier 1 screening level for PFOS for the relevant land use scenarios, except for some results reported for soil samples collected in the South Creek wetlands, which exceeded the indirect and direct toxicity screening level for ecosystem protection and the screening level for intrusive/maintenance works. For the objectives and purposes of the DSI, it is considered that adequate delineation of the extent of PFAS impact at each of the main sources of PFAS at the Site has been achieved.

The interpolated volumetric mass of total PFAS in Site soils as defined by the extent of the analytical data set is estimated as:

- Total PFOS in soil = approximately 60 kg in 750,000 m3 of soil

- Total PFOA in soil = approximately 0.06 kg in 6,000 m3 of soil

- Total PFHxS in soil = approximately 3 kg in 160,000 m3 of soil

The majority of the observed PFOS and PFHxS is present within the unsaturated (vadose) zone soils (~80%), whilst the majority of the PFOA is observed in the saturated zone soils (~66%).

The Site is situated at the bottom of the local water catchment. Hence, from the higher portions of the water catchment surrounding the Site, both surface water and groundwater pass through the Site before discharging to either Site drainages or directly into Hanns Inlet.

Details of potential pathways via surface water and groundwater between sources and receptors include:

Surface water generally flows along topographical gradients and flows in a general south-easterly direction along the creeks (West Creek, South Creek and East Creek), which in turn discharge to Hanns Inlet

Groundwater flow at the Site occurs in a general southerly to easterly direction and discharges into Hanns Inlet. At the Fire Ground, groundwater flows to the southeast. Groundwater from the Site flows away from the adjacent residential and community land areas of Crib Point, Bittern and Somers, which are predominantly located (up- and cross-hydraulic gradient) to the west, north and east of the Site

Groundwater quality is generally poor and not suitable for potable use. Groundwater is not extracted for any beneficial use on-Site.

As shown on Figure 13-1, groundwater impacted by Site derived PFAS sources is not migrating towards off-Site groundwater wells located east, west and north of the Site. These areas are located hydraulically up- or cross-gradient from the Site sources of PFAS. Therefore, a complete groundwater pathway does not exist between Site sources of PFAS and groundwater users located west and north of the Site.

The lateral and vertical extent of PFAS-impacted groundwater has been defined up to discharge points into surface waters either within the Site creek systems or directly to Hanns Inlet. The PFAS plume originating at the Fire Ground migrates towards and discharges into South Creek via the shallow alluvial/estuarine aquifer or into Hanns Inlet via preferred pathways in the Brighton Group aquifer. At the Fire Station and Ornamental Lake, PFAS-impacted groundwater discharges into Hanns Inlet. In the marina area, a source of PFAS, which may originate from the Sports Fields that historically received Class C recycled water, has impacted groundwater that is migrating through both the fill aquifer and the uppermost saturated interval of the


Brighton Group aquifer, which discharges into Hanns Inlet. Visualisation of the plume (refer to Section 11) highlighted potential minor sources including the Sullage Pit, the closed Rifle Range Road landfill, the closed outdoor swimming pool landfill, some former fuel storage areas, and the former dry-cleaning facility. These areas were identified as potential minor sources due to PFAS detects in the groundwater above anticipated levels in the groundwater plume. However, there is no evidence of AFFF storage or use in these areas from desktop review and interviews. Overall, these are minor contributions to the PFAS mass loading and are not sources which warrant any future remedial intervention or management but will be subject to ongoing monitoring.

PFHxS groundwater impacts originating from the identified source areas are forming a contiguous plume across the Site, whilst PFOS groundwater impacts are confined to a plume covering the western extent of the base infrastructure with two smaller isolated plumes in the eastern area of the base adjacent to Hanns Inlet. PFOA groundwater impacts are confined to a small contiguous plume between the Fire Ground and the wetlands straddling South Creek near the Fire Ground.

The interpolated volumetric mass of total PFAS in Site groundwater as defined by the extent of the analytical data set is estimated as:

- Total PFOS in groundwater = approximately 2 kg in 9,800,000 m3 of water

- Total PFOA in groundwater = approximately 0.1 kg in 2,700,000 m3 of water

- Total PFHxS in groundwater = approximately 2 kg in 21,850,000 m3 of water

With regards to the distribution of PFOS between soil and groundwater, of the total PFOS mass in soil, 19% of this is residing in the saturated zone, and of the PFOS mass in the saturated zone 20% of that is the total PFOS mass in dissolved in groundwater. This is consistent with the relatively slow movement of PFOS in groundwater that has been observed and the confinement of the PFOS plume to the western section of the base. Without source area abatement these impacts are likely to continue, however the results indicate migration in groundwater is slow and the extent of physical attenuation could be high.

Surface water within the Site is primarily impacted with Site-derived PFAS, however PFAS-impacted surface water was reported entering the Site via Council drains from unknown off-Site source(s) at two locations along the northern and western Site boundaries. In response to local rain events, the calculated approximate flux of total PFAS entering the Site from these unknown off-Site source(s) is approximately 0.12 gm/day (120 mg/day). Impacted Site surface water discharges to tidal creeks that drain to Hanns Inlet or directly into Hanns Inlet through the storm-water system and outflows. The calculated flux of total PFAS discharging into the tidal creeks or directly to Hanns Inlet is approximately 0.8 g/day (800 mg/day).

Surface water in the western and central portions of Hanns Inlet is impacted by PFOS. Results for samples collected from the water column in these areas exceeded the Tier 1 direct toxicity screening level for PFOS for 99% species protection in marine ecosystems. PFAS was not detected in the eastern portion of Hanns Inlet (at the opening of Hanns Inlet into Western Port Bay).

Overall the findings of the DSI identify a relatively low but diffuse total mass of PFAS predominantly within the soil, surface water and groundwater at the Site.

13.1.2 Evaluate the risk posed by such impact to human health and the environment

Based on the findings of the DSI, the following conclusions are made in respect of risk to human health and the environment:

Human Health

The investigation and sampling of groundwater indicates that there is no evidence of a complete pathway between Site sources of PFAS to off-Site groundwater users (considered to be east, north, west and south-west of the Site) from Site-derived PFAS impacts. Consequently, there is no potential risk to human health

There is no realistic potential for PFAS-impacted groundwater and surface waters to discharge and impact upon on-Site permanent residential areas and the Child Care Centre


There is no evidence of adverse risk to consumers of edible fish caught within the confines of Hanns Inlet, although it is identified that access to these wasters for fishing purposes is strictly prohibited

There is no evidence of any adverse risk to on-Base non-intrusive workers or Site visitors.

Intrusive/maintenance workers:

− Reported residual PFAS impacts in soils at the Fire Ground and South Creek wetlands, surface water at the Fire Ground lagoon, and groundwater at the Fire Ground/South Creek pose an unacceptable risk to workers undertaking intrusive works.

− Note that the residual risk would be low and acceptable because intrusive/maintenance works would be undertaken under standard Defence OHS and construction environmental management plans.

− These administrative controls would manage the risk posed by intrusive works across the Site including works conducted within the key PFAS source areas (Fire Ground and wetlands, Fire Station / Ornamental Lake and Former STP) and address any uncertainty of PFAS impact in other areas at the Site.

Environment

There is evidence of potential risk to the environment (on-Site receptors) by direct exposure and bioaccumulation / secondary poisoning to PFAS-impacted soils and surface waters at the Fire Ground, creek system and neighbouring wetlands, Fire Station / Ornamental Lake, and the former STP

There is evidence of potential risk to the environment (on-Site receptors) by direct exposure and bioaccumulation / secondary poisoning to PFAS-impacted groundwater discharging to wetlands

The primary driver of risk is discharge of PFAS-impacted waters and groundwater to the receiving marine environment within Hanns Inlet, and the potential for adverse impacts to marine biota, although Aurecon notes no adverse risk to consumers of edible fish caught within the confines of Hanns Inlet was identified.

Victorian beneficial uses of land, surface water, and groundwater











The risks posed by these precluded beneficial uses can be mitigated to low and acceptable levels through a combination of engineering and administrative controls, which are set out in the PMAP.

13.1.3 Evaluate the requirement to undertake further, more detailed site-specific risk assessment studies and / or implement strategic site management strategies.

Based on the characterisation of the main source areas of soil impact (Fire Ground and South Creek wetlands; and the Fire Station / Ornamental Lake area), it is considered that there is sufficient information to devise risk-based remediation strategies without the need to pursue further and more detailed site-specific assessment of risk to human health and/or ecological receptors.


The DSI has been completed in accordance with the NEPM and PFAS NEMP. The current extent of PFAS contamination in terms of sources, pathways and receptors has been defined and therefore the objectives of the DSI have been met

13.2 Next steps Consistent with the protocols developed by Defence, the findings of the DSI will be used in the preparation of the PMAP, and as part of the PMAP an OMP will be developed. The primary focus of the PMAP will be on the implementation of appropriate measures to address the risk posed by ongoing discharge of Site-derived PFAS into Hanns Inlet. . In addition, potential management options, such as a combination of engineering and administrative controls, will be set out in the PMAP to mitigate the Site conditions that have precluded beneficial uses of land, surface water, and groundwater.

The PMAP and OMP will also address the data gaps and material areas of uncertainty identified by the DSI as discussed in Section 12. Aurecon is currently developing the PMAP, which will be endorsed by the appointed Environmental Auditor and EPA Victoria prior to implementation.


14 Statement of limitations Aurecon performed the services in a manner consistent with the normal level of care and expertise exercised by members of the environmental profession. No warranties express or implied, are made. It should be noted that some information provided in this report is reliant on information provided by third parties such as Department of Defence and various State and Commonwealth government departments. Aurecon takes no responsibility for the quality/accuracy of information provided by third parties.

The outcome of this report is limited to information supplied for the activities associated with the scope of works only. It is intended that this assessment provides a description of the identified PFAS sources, pathways and receptors and recommendations on how to address and manage any issues at the location in question.

Soil and rock formations are often variable, resulting in heterogeneous distribution of PFAS across a Site. PFAS concentrations may be estimated at chosen sample locations, however, conditions between sample Sites can only be inferred on a basis of geological and hydrological conditions and the nature and the extent of the PFAS. Boundaries between zones of variable PFAS concentrations are often indistinct, and therefore interpretation is based on available information and the application of professional judgement. Aurecon uses best judgement acquired from working on similar Sites and makes recommendations based solely on the results obtained.

We note that this report has been prepared for the use of Defence only and is based on information provided by Defence. Aurecon takes no responsibility and disclaims all liability whatsoever for any loss or damage that Defence may suffer as a result of using or relying on any such information or recommendations contained in this report, except to the extent Aurecon expressly indicates in this report that it has verified the information to its satisfaction. This report does not provide a complete assessment of the environmental status of the Site, and it is limited to the scope defined herein. Should further information become available regarding the conditions at the Site, including previously unknown likely sources of PFAS, migration pathways or receptors, Aurecon reserves the right to review the report in the context of the additional information.

The findings, observations and conclusions expressed by Aurecon are not, and should not be considered as an opinion concerning the commercial feasibility of the property or asset. The report may contain various remarks about and observations on legal documents and arrangements such as contracts, supply arrangements, leases, licences, permits and authorities. A consulting scientist can make remarks and observations about the technical aspects and implications of those documents and general remarks and observations of a non-legal nature about the context of those documents. However, as consulting scientists, Aurecon is not qualified, cannot express and should not be taken as in any way expressing any opinion or conclusion about the legal status, validity, enforceability, effect, completeness or effectiveness of those arrangements or documents or whether what is provided for is effectively provided for. They are matters for legal advice.


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Standards Australia AS/NZS 5667.11 1998, Water Quality – Sampling, Part 11, Guidance on Sampling of Groundwaters, Sydney.

Stockholm Convention (2009), Stockholm Convention on Persistent Organic Pollutants (POPs) – Text and Annexes, United Nations Environment Programme, Stockholm, Sweden.

US Environmental Protection Agency (US EPA) (2014), Emerging Contaminants – Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) – Emerging Contaminant Fact Sheet, National Service Center for Environmental Publications, March 2014.

US Environmental Protection Agency (2018) https://www.epa.gov/pfas/basic-information-pfas#exposed accessed 14 August 2018.

Victoria Environment Protection Authority (2000), Groundwater Sampling Guidelines, Publication 669, State Government of Victoria, Melbourne.

Victoria Environment Protection Authority (2006), Hydrogeological Assessment (Groundwater Quality) Guidelines, Publication 668, State Government of Victoria, Melbourne.

Victoria Environment Protection Authority (2016), Incoming water standards for aquatic ecosystem protection: PFOS and PFOA, Publication 1633, State Government of Victoria, Melbourne.

Western Australia Department of Environment Regulation (2017), Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS), Government of Western Australia, Perth.

https://www.epa.gov/pfas/basic-information-pfas#exposed

A

Figures

Appendix A Figures

B

Sampling Methods

Appendix B Sampling Methods

C

Borehole Logs

Appendix C Borehole Logs

D

Photographic Record

Appendix D Photographic Record

E

Field Data

Appendix E Field Data

F

Summary of Laboratory

Results

Appendix F Summary of Laboratory Results

G

Laboratory Certificates

Appendix G Laboratory Certificates

H

QA/QC Results

Appendix H QA/QC Results

Compliance with the Sampling and Analysis Quality Plans

While the intrusive investigation generally complied with the SAQPs, there were several variations from the SAQPs, which are detailed below. The variations to the SAQPs are considered minor, do not have any impact on achieving the objectives of this investigation and do not alter any of the assessments, conclusions or recommendations made within this report.

Of the stormwater drains discharging into Hanns Inlet, the third sampling location for surface water and sediment (SW003) only had a sample of surface water collected as only rock armouring was present at the mouth of the drain so no sediment could be collected (refer to site photographs). However, sediment samples were collected from nearby locations (within 10 m). Therefore, the lack of sediment sample at the originally intended location did not significantly impact the evaluation of PFAS entering Hanns Inlet.

Samples of surface water and associated sediment were proposed to be collected from drain outlets into Hanns Inlet. However, one of the proposed 21 sampling locations was not sampled because the sampling locations were either covered by heavy vegetation or the drain outfalls into Hanns Inlet were buried. However, sufficient samples were collected from nearby drains to characterise surface water discharging into Hanns Inlet and associated sediment.

Out of 93 monitoring wells eight wells were dry during each of the groundwater monitoring events. Of the dry wells four wells are located in the Fire Ground and two wells at located at the closed Stony Point landfill.

Out of 93 monitoring wells, three wells could not be located due to incorrect coordinates provided by others.

During rounds one and four of groundwater monitoring, GW01-VT0366, GW01-VT0367, GW03-VT0371, and GW02-VT0373 were unable to be located and are assumed to have been covered in fill or destroyed from Site construction and maintenance. Further, the objective of the fourth GME was to collect groundwater samples from the new wells and wells located along flow paths through these new wells. The noted wells were not in the areas of interest for the fourth GME.

Additional samples were collected beyond the scope of the SAQP:

Additional soil samples were collected at the Fire Ground and Fire Station to further evaluate the extent of PFAS impact because PFAS was detected in each of the SAQP soil samples collected at those areas

Additional samples of biosolids were collected from two of the three lagoons at the former STP as these lagoons had dried out during the time of undertaking the DSI.

Additional grass and soil samples were collected at the sports fields to evaluate potential impact from the irrigation with PFAS-impacted Class C recycled water.

The following field tasks outlined in the SAQPs for initial works and to address data gaps were not completed.

Installation of additional deeper wells along the western boundary was not undertaken after Aurecon became aware that private wells north and west of the Site had been sampled and PFAS was not detected.

Soil samples from the paddock northwest of the former STP lagoons were not collected because these samples were intended to evaluate if biosolids excavated from the lagoons had been placed in that area. Aurecon was informed by Base staff that the lagoons had never been cleaned out, and accordingly no sampling was undertaken within this area.

I

Pre-DSI Laboratory Certificates

Appendix I Pre-DSI Laboratory Certificates

J

Cross Sectional Diagrams

Appendix J Cross Sectional Diagrams

K

Survey Data and Reports

Appendix K Survey Data and Reports

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Document prepared by

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Investigation of per- and poly-fluoroalkyl substances at ......The Site is between Somers and Bittern / Crib Point, approximately 70 km south of Melbourne, Victoria. The Site surrounds