PFAS for Councils

Are we there yet? Challenges with

PFAS assessment, management and

remediation

Andrew Kohlrusch | Environmental Scientist

Social challenges – media coverage

• Patrick Breysse, director of the CDC’s National Centre for

Environmental Health described PFAS “one of the most seminal

public health challenge for the next decades”, according to the

Bloomberg news agency – The Guardian 18/10/17

• The chemical industry doesn’t want you to be afraid of Teflon

pans. You should be – salon.com

• Watered down warning signs for council – Katherine Times

(February 2018)

• Unclear if morass duck is on or off the menu – Gippsland Times

(22 January 2018)

• Forrestfield Airport Link toxic soil dump creates headache for

WA Government – ABC News 19/10/17

Regulatory challenges

• Lots of guidance – NSW EPA, WA DWER, enHealth, Vic EPA

• No accepted limits for re-use of soil contaminated with low

levels of PFAS

• NEPM??

• NEMP/ANZECC?

• NSW EPA

• Fire training facilities, power stations, petrochemical storage

facilities, metal plating facilities, ports

• Auditor guidelines – The auditor must check that

contamination by PFAS has been considered in the

assessment of contamination.

• No regulation of sites under CLM Act – yet

Information challenges

• PFAS surveyed in dolphins, fish

and water in the Port River and

Barker Inlet

• Highest levels of PFAS

• All fish sampled were safe to eat

• nothing to say that they are

unhealthy because of it

• Dolphins are flourishing and

highest numbers ever recorded

Technical challenges

Human health

• GHD and others have undertaken a robust review of available

studies to derive toxicity criteria for human health using methodology

consistent with that adopted in Australia

• US EPA, Danish, Australian and German guidance different

outcomes

• The NEPM methodology to determine soil criteria for various land

uses using these toxicity criteria

But:

- Significance of dermal exposure not well understood

- Uptake in garden produce and bioaccumulation in food chain (e.g.

seafood) not well understood – sediments and fish may act as

sinks for PFAS

Technical challenges

Terrestrial ecosystems

• Limited information on:

- How environmental factors modify the toxicity of PFOS and PFOA

- Bioavailability (e.g. effect of carbonaceous material, CEC).

Sediments:

• PFAS can accumulate in sediments. There is some information

available, but limited information on toxicity to various organisms

in sediments and role of bioaccumulation.

• Chemical extraction may overestimate bioavailable contaminant.

Surface water:

• Investigation levels are less than laboratory levels of reporting

Lack of toxicity criteria for other PFAS compounds. Possible other

compounds could add 100% - 300%

Investigation challenges

• Complex assessments – on and off site

• Guidelines are changing and inconsistent between states

• Mobility can lead to large plumes from source

• Affected sites.

• Difficult to treat – especially when in soil and groundwater,

lots of silver bullets

• Difficult to decide what is safe, what can be managed,

what doesn’t need management

• Precursors

• Precautionary/responsible approach?

Investigation considerations

Plants and animals (fish):

• Prediction is uncertain; low criteria for waters. Measure

directly if criteria exceeded. Draw on new information as it

becomes available Precautionary/responsible approach?

Groundwater

• Almost inevitable. Easier and more defensible to rely on

direct measurement rather than prediction

• Soil contamination can result in groundwater

contamination

Investigation considerations

Human health: drinking water. Consider flux if local

exceedance.

Ecological: surface water: difficult to conclude no effect;

difficult to predict; consider flux; measure receiving water or

biota

Ecological: shoreline: Effect may be seen at shoreline prior

to dilution; consider extent of effect.

Ecological: sediment: effect on biota difficult to predict.

Measure fish. Gap

Plant and animal uptake from irrigation water or soil: difficult

to predict: measure directly.

Time

Stakeholder engagement

“Traditional” site assessment approach

• Soil

• Groundwater

• Soil vapour

• (human health risk assessments)

• (fate and transport modelling)

PFAS site assessment approach

• Soil

• Groundwater

• Soil vapour

• Fate and transport modelling

• Surface water

• Sediment

• Biota – domestic consumption, foodweb, commercial produce

• Sediment toxicity studies - pore water and toxicity of pore water

• Complex human health and ecological risk assessments –

toxicology

• Community and stakeholder engagement

Investigation expectations

• Start outside

• Stakeholder engagement plan

• Regulatory advice – state of flux

• Investigation not limited to the site – access agreements

• More aspects to be covered

• It will cost more and take longer

• Uncertainty of the outcome

• Use the investigation as screening levels

• Duty to report

• Source area management

Stakeholder engagement

• NEPM guidance

• Experienced team

• Controlled/uncontrolled messages

• NSW EPA, Health, other regulatory agencies

• Perception of risk

• Communication – technical/empathetic

• Plan, plan, plan

PFAS site assessment approach - CSM

RAAF Base Pearce

• PSI and DSI

• Two phases of DSI => HHERA

• Key objectives

• What are sources?

• How is PFAS migrating from base?

• What/how is affected?

• 17 potential PFAS source

areas have been investigated,

both on base and off base

• Site auditor

RAAF Base Pearce

• Ecological values and

community reliance on

groundwater

• Soil, groundwater, sediment,

surface water, biota sampling

• Over 1000 samples collected

• Stakeholder engagement –

community, base and

regulatory agencies

Jervis Bay Range Facility/HMAS CRESWELL

• PSI and DSI

• Two DSI

phases

• Stakeholder

engagement

• Site auditor

Jervis Bay Range Facility/HMAS CRESWELL

• Ecological values and

community use of surface

water

• PFAS has been recorded in

soil, sediment, surface water

and groundwater onsite at

concentrations above the

health-based guidance values

• To date over 500 samples

have been collected

PFAS site assessment approach - CSM

• Oakey investigation

Source: AECOM 2017

Oakey

Key elements

• Sampling of over 100 residential bores.

• Sediment, surface water and pore water sampling

• Targeted drilling and hydrogeological modelling

• Interim management responses

• Stakeholder engagement – community, regulators

• Biota sampling => human health and ecological risk

assessments

Source: AECOM 2017

Remediation and management

May include:

Soil & infrastructure

• Avoid exposure to site occupants, workers or visitors

• Avoid leaching to groundwater & surface water

Sediments & surface water

• Avoid unacceptable impacts to ecological systems

• Protection of human health

Groundwater

• Protection of human health

• Protection of ecosystems

Informed from

conceptual

site model

Remediation decision process

Need to consider…..

• Existing risk posed to human health and the environment

• Risk to human health and the environment following

implementation

• Sustainability – social, environmental, economic

• Acceptability to stakeholders - particularly from a regulatory

perspective

Remediation/management options

Current available treatment and disposal options:

• Surface water treatment – possible

• Groundwater in-situ treatment – impractical

• Groundwater pump and treat – impractical other than as

hydraulic containment

• Soil and sediment treatment: only high temperature

treatment or immobilisation

• Landfill disposal: uncertain in most states; some states

setting criteria

• Sewer disposal: uncertain in most states; issue for water

authorities.

Remediation and management – mass delineation

• Source delineation - where is the mass?

• PFAS complex properties and interactions with various media

• Highly soluble

• Affinity to sorb to clays, organic carbon, concrete

• Slow release from source

• E.g. Significant proportion of the total mass may be addressed by

active & targeted remediation & management at the source zone E.g. >95% PFAS

total mass

Soil remediation options

• Much research being undertaken in Australia and internationally

• Challenging due to the strength of carbon-fluorine bonds

• Some treatments involving transformation of PFAS may result in toxic by

products that are not yet known or well understood

• Cost of field scalable treatment may be prohibitive – seem promising at a

trial level but not yet implemented on a commercial scale

• Currently few practicable remediation options available in Australia other

than:

o Capping and containment – including stabilisation

o Excavation and onsite or offsite treatment in a high temperature thermal

treatment system

• Landfill disposal may be possible but may not be an appropriate disposal

method

Appears to be the most practicable and effective

approach for many sites - limited to source areas where

the magnitude of the area & volume are manageable

Soil management options (cont.)

PFAS contaminated soil encountered during construction activities:

• Practicable solution required whereby contaminated soil can be excavated

and managed in a timely manner while minimising risk

• Options include:

– Reinstatement of soil to the excavation

– Placement of soil at another location on the site with the same or higher

risk contamination profile

– Containment of soil on-site

– Offsite disposal or on/offsite treatment

Appear to be the most practicable approach for many construction projects

Water management & treatment options

• Goal to achieve very low concentrations that can either be discharged to sewer,

stormwater or surface waters, or reinjected to an aquifer

• Viable field scalable technologies include:

o Adsorption (e.g. GAC, resins, ion exchange polymers, MyCelx™,

MatCARE™, RembindTM)

o Nanofiltration

o Reverse osmosis

• Adsorption results in a separation and concentration of PFAS in a residual solid

phase that must be treated / disposed of – e.g. high temperature thermal

• May be used as part of a groundwater pump and treat strategy, although much

of the mass may remain adsorbed within the aquifer

• There are other laboratory tested technologies (e.g. ScisoR) that are now

reaching field trial stages

Favoured due to lower cost and more manageable waste stream

N

PFAS

source

zone

Surface water pathway

Containment

Removal

In-situ treatment

Ex-situ treatment

Institutional controls

- Restricted use

- Alt water supplies

Monitoring & natural

attenuation

Water treatment

Risk assessment

Hydraulic controls

Water treatment

Secondary source

removal Stakeholder engagement

Receptors

PFAS mg/L

PFAS management options?

PFAS management options?

Banning the domestic use of groundwater

All domestic bore water use is banned in Zones 2 to 4. This includes

using groundwater for drinking, watering gardens, washing cars and

other domestic purposes. This will minimise the risk to bore water

users and prevent the spread of contamination through pumping. The

sites from which the contamination has occurred are being cleaned up

under the most robust contaminated land management legislation in

Australia.

Key messages

• Decisions typically made on the basis of contaminant concentrations, but must

also consider mass flux – ‘rate of mass flow per unit area’

• Significant proportion of the total mass often addressed by managing the

secondary release at the source zone

• Excavation, encapsulation and/or stabilisation are the most practicable options

- landfill a more viable option as criteria are established

• Adsorption is favoured water treatment option and is field proven

• Groundwater pump and treat challenging due to the mass remaining adsorbed

within the aquifer and the volume of water to be treated

• Technical challenges and considerations of sustainability (inc. cost) make a

‘clean-up to the extent practicable’ approach applicable

www.ghd.com