Site Investigation Report 10725-2 - Torfaen County Borough Council · 2011. 5. 5. · 10725/MJE/10) should be read in conjunction with this report. Reference to the desk study has

Intégral Géotechnique

Barratt Homes South Wales Cold Storage Depot, Llantarnam Road, Cwmbran Site Investigation Report 10725-2/GNS/10

Integral Géotechnique

CLIENT: Barratt Homes South Wales

PROJECT: Cold Storage Depot, Llantarnam Road, Cwmbran

TITLE: Site Investigation Report

JOB NO: 10725

DOCUMENT REF: 10725-2/GNS/10

Revision Purpose Description Originated Reviewed Authorised Date

0

Interim

GNS MJE HP Dec 10

Geotechnical Engineers:

Intégral Géotechnique (Wales) Limited Integral House 7 Beddau Way

Castlegate Business Park Caerphilly CF83 2AX

Tel: 029 2080 7991 Fax: 029 2086 2176

CONTENTS 1.0 INTRODUCTION 1.1 General

1.2 Proposed Development

1.3 Scope of Works

1.4 Limitations

2.0 THE SITE 2.1 Site Location and Description

2.2 Site Operations

2.3 Surrounding Land Use

2.4 Available Site Investigation Data

3.0 SITE HISTORY 4.0 SITE ENVIRONMENTAL SETTING 4.1 Physical Setting

4.2 Geology

4.3 Hydrology and Hydrogeology

4.4 Landfill Sites

4.5 Potential Contamination

5.0 PRELIMINARY CONCEPTUAL SITE MODEL 6.0 THE SITE INVESTIGATION 6.1 Fieldworks

6.2 Field Observations

6.3 Laboratory Chemical Testing

6.4 Groundwater Monitoring

6.5 In-situ Gas Monitoring

7.0 GROUND CONDITIONS

CONTENTS (CONTINUED)

8.0 CONTAMINATION 8.1 Averaging Areas

8.2 Soil Contamination

8.3 Soil Leachate

8.4 Ground Gases

9.0 REVISED CONCEPTUAL MODEL 10.0 RISK ASSESSMENT 10.1 Methodology

10.2 Source-Pathway-Receptor-Model

10.3 Human Health Risk Assessment

10.4 Risks to Vegetation

10.5 Groundwater Risk Assessment

10.6 Ground Gas Risk Assessment

10.7 Risks to Buildings and Materials Durability

10.8 Spoil Disposal

10.9 Uncertainties

11.0 ENGINEERING CONSIDERATIONS & RECOMMENDATIONS 11.1 Details of Proposed Development

11.2 Site Preparation

11.3 Foundations and Floor Slabs

11.4 Excavations and Formations

11.5 Access Roads and Car Parking Areas

11.6 Soakaway Potential

12.0 RECOMMENDED FURTHER WORKS

APPENDICES Appendix A Contaminated Land Definitions

Appendix B Windowless Sample Logs

Appendix C Falling Head Test Results

Appendix D Laboratory Chemical Test Results (Soils)

Appendix E Laboratory Chemical Test Results (Leachate)

Appendix F Laboratory Physical Test Results

Appendix G Groundwater Monitoring Results

Appendix H In-Situ Gas Monitoring Results

Appendix I Statistical Assessment of Chemical Results

CONTENTS (CONTINUED) FIGURES Figure 1 Site Location

Figure 2 Site Plan

COLD STORAGE DEPOT, LLANTARNAM ROAD, CWMBRAN 10725-2/GNS/10

INTÉGRAL GÉOTECHNIQUE (WALES) LIMITED Page 1

1.0 INTRODUCTION

1.1 GENERAL

Barratt Homes South Wales are proposing to redevelop the land at The Cold Stores off

Llantarnam Road, Cwmbran for residential end-use.

Intégral Géotechnique (Wales) Limited have been appointed as the Geotechnical

Engineers to undertake a site investigation to enable a geotechnical and

geoenvironmental appraisal of the site and provide a basis for design.

This report presents the findings of the site investigation and gives recommendations for

the design of foundations, floor slabs and other geotechnical and geo-environmental

aspects of the project.

1.2 PROPOSED DEVELOPMENT

The scheme comprises residential development the layout of which is unknown at

present.

1.3 SCOPE OF WORKS

The work instructed included a site reconnaissance visit and an intrusive site

investigation, followed by laboratory testing, and geotechnical and geoenvironmental

reporting.

A Desk Study for the site was previously undertaken and reported by Intégral

Géotechnique (Wales) Limited in October 2010. The desk study report (reference

10725/MJE/10) should be read in conjunction with this report. Reference to the desk

study has been made when compiling this report, and for ease of presentation and

understanding, sections of the desk study may be presented in this report. The desk study information was used to make an initial assessment of the site and to

design an investigation to be carried out by Intégral Géotechnique. The site investigation

was designed in accordance with BS10175, the Code of Practice for Investigation of

Potentially Contaminated Sites, and ‘Land Contamination: A Guide for Developers’

prepared by WLGA/EAW Land Contamination Working Group, July 2006.



1.3 SCOPE OF WORKS (CONTINUED)

The site investigation comprised:

• An intrusive investigation carried on 10 and 12 November 2010 comprising

windowless sampling following the coring of surface hard standing

• The installation of five combined groundwater/ground gas monitoring standpipes

at five windowless samples locations

• Sampling of soil/fill for laboratory chemical testing

• Sampling of natural soils for physical testing

• Leachate analysis on selected soil samples

• Ground gas monitoring and in situ permeability testing at the five standpipe

locations

1.4 LIMITATIONS

Access for the intrusive site investigation was limited at the time due to the existing

buildings present on site, the extensive number of underground services and dense

vegetation within the southern half of the site. The southern half of the site was not

accessible to the windowless sampling plant,, nor were intrusive investigations

undertaken within the footprint of any of the buildings.

This document is intended to be a working document for further development in

discussion with all concerned including the Local Planning Authority, the Environment

Agency Wales and the NHBC, as appropriate.

“Contamination” is taken throughout the report to mean the “presence of one or more

potentially harmful substances as a result of human activity”. The use of the term in this

way does not imply that harm is being or might be caused by the contamination. It should

be noted that “contamination” can have different meanings under different regulatory

regimes, for example, planning, building control and Part IIA of the Environmental

Protection Act 1990 (see Boxes 1 and 2 in Appendix A). Naturally elevated

concentrations of potentially harmful substances may also be of concern (see Box 1 in

Appendix A) and the significance of any that have been found is also evaluated in this

report.

It is important to recognise that there may be areas of contamination that have not been

found, or that contaminants are present at concentrations above those that have been

found. It is also important to recognise that contamination may be localised and that no

investigation, however comprehensive, is capable of finding such occurrences other than

by chance.



1.4 LIMITATIONS (CONTINUED)

The DEFRA/Environment Agency CLEA Model 2002, including the technical background,

generic conceptual models and model parameters, and the Soil Guideline Values derived

from this model, were withdrawn in August 2008. The model parameters and generic

conceptual models have been reviewed and the technical background updated to

incorporate the results of additional research, and new documents published that have

formed the basis of the new CLEA model. The new CLEA model (version 1.06) is being

adopted by regulators and consultants.

At the time of writing, there are only limited official Soil Guideline Values available for use

as Tier 1 soil screening values (arsenic, cadmium, nickel, mercury (elemental, inorganic,

and methyl), selenium, phenol and BTEX compounds). Atkins have updated their

ATRISKsoil screening values in line with the new CLEA guidance. Land Quality

Management (LQM), in conjunction with the Chartered Institute for Environmental Health

(CIEH), have revised their Generic Assessment Criteria for Human Health Risk

Assessment in line with recent changes to the CLEA methodology and have published a

new set of guideline values. Both Atkins ATRISKsoil and LQM/CIEH have derived

screening criteria in line with current UK guidance.

We have reviewed both sets of values and intend to use the most appropriate

assessment criteria as Tier 1 screening values until additional official screening criteria

are published. Where a published SGV is available, and considered appropriate, this will

be used in the first instance.

This report has been prepared for the use of Barratt Homes South Wales and their

advisors and should not be passed to others without the express consent of Intégral

Géotechnique (Wales) Limited.



2.0 THE SITE

2.1 SITE LOCATION AND DESCRIPTION

A detailed description of the site was provided in the initial Desk Study Report (reference

10725/MJE/10, dated October 2010).

A previously covered and obscured above ground storage tank (presumed DRO) was

identified within the southwest of the site (its location is detailed on Figure 2) during our

latest site reconnaissance visit. There was no significant evidence of excessive spillage

of fuel within the locality and the integrity of the tank looked maintained.

2.2 SITE OPERATIONS

The site operations have not changed since the completion of the Desk Study Report.

2.3 SURROUNDING LAND USE

The surrounding land use is the same as previously detailed in the Desk Study Report.

2.4 AVAILABLE SITE INVESTIGATION DATA The desk study report (reference 10725/MJE/10) previously provided by this practice

should be read in conjunction with this report.



3.0 SITE HISTORY

The recent history of the site was previously provided in our Desk Study Report.



4.0 SITE ENVIRONMENTAL SETTING

4.1 PHYSICAL SETTING

Details previously provided in our initial Desk Study Report Report (reference


4.2 GEOLOGY



4.3 HYDROLOGY, HYDROGEOLOGY AND FLOOD RISK



4.4 LANDFILL SITES



4.5 POTENTIAL CONTAMINATION

Details previously provided in our initial Desk Study Report Report (reference 10725/MJE/10, dated October 2010).



5.0 PRELIMINARY CONCEPTUAL SITE MODEL The preliminary conceptual site model/conceptual exposure model was provided in the

initial Desk study Report, and this will be reviewed following completion of the intrusive

site investigation works and laboratory chemical analysis.



6.0 THE SITE INVESTIGATION

6.1 FIELDWORKS

A site investigation was designed in accordance with BS5930:1999, the Code of Practice

for Site Investigations, BS10175, the Code of Practice for Investigation of Potentially

Contaminated Sites, and ‘Land Contamination: A Guide for Developers’ prepared by

Welsh Local Government Association (WLGA)/Environment Agency Wales (EAW) Land

Contamination Working Group, July 2006.

The site investigation was also designed to provide information to support and refine the

preliminary conceptual site model/conceptual exposure model that was detailed in the

initial Desk Study Report.

An investigation comprising nine windowless sample holes was carried out on 10 and 12

November 2010. Window sampling was chosen as the most appropriate intrusive form of

investigation at this stage since the site was still occupied, and this method would cause

the least disruption. The windowless sample holes were intended to provide information

on the shallow ground conditions and to take representative soil samples for laboratory

chemical/physical testing. In-situ strength testing (SPT/CPTs) was carried out during the

windowless sampling. Surface hardstandings were cored using a specialist diamond

coring drill at each location prior to sampling.

It is important to note that no windowless sample holes were undertaken within any of the

buildings, nor were holes sunk within the southern area of the site which was densely

vegetated and inaccessible.

Representative soil samples were taken from the windowless sample holes for laboratory

chemical testing and placed in the appropriate sample containers deemed suitable for the

analysis required. Strict protocols were adopted during this process to limit the cross

contamination of samples and included the use of sterile disposable gloves and stainless

steel sampling equipment cleaned with de-ionized water prior to sampling.

Gas monitoring standpipes were also installed within five of the windowless sample holes

(WS1, WS3, WS4, WS6 and WS9) to allow a programme of gas monitoring to be carried

out.

Following the installation of the standpipes a regime of ground gas monitoring was

commenced.



6.1 FIELDWORKS (CONTINUED)

Falling head permeability tests were later carried out on 3 December 2010 within the five

windowless sample holes installed with standpipes. Water was rapidly discharged into

the windowless sample hole, and rate of fall of the generated head measured over time.

The results of the falling head tests are presented in Appendix C

A programme of gas monitoring was commenced as soon as the site works were

complete.

The fieldworks were supervised by a qualified Geotechnical Engineer from Intégral

Géotechnique (Wales) Limited who also logged the windowless sample holes and

prepared their detailed engineering logs in accordance with the requirements of BS5930:

1999.

The approximate locations of the windowless sample holes are shown on Figure 2, while

their logs are presented in Appendix B.

6.2 FIELD OBSERVATIONS No visual or olfactory evidence of any contamination was observed during the drilling of

the windowless sample holes with the exception of a slight hydrocarbon odour noted in

WS8 at between 1.0m and 1.7m depth.

6.3 LABORATORY CHEMICAL TESTING

Representative soil samples were taken from the window sample holes across the site,

stored at the appropriate temperature and dispatched to the laboratories of STL for

laboratory chemical testing within 24 hours.

The samples were tested for a range of contaminants that reflects the historical use of the

site, the findings of the desk study and the preliminary conceptual site model/conceptual

exposure model. A list of the soil testing carried out is given below:



6.3 LABORATORY CHEMICAL TESTING (CONTINUED)

Beryllium Cadmium

Total Chromium Hexavalent Chromium (VI)

Copper Lead

Mercury Nickel

Vanadium Zinc

Arsenic Boron

Selenium Elemental Sulphur

Total Cyanide Total Sulphate

Sulphide Water Soluble Sulphate

pH Monohydric Phenol

PAH (Priority 16 by GC) TPH (aliphatic and aromatic split)

In addition, selected soil samples were tested for Loss on Ignition (LOI), Total Organic

Carbon (TOC) and asbestos.

The potential for leachate generation and migration off site or to groundwater was

identified as being potentially active. Therefore, selected samples were also tested for

their leachability characteristics for the same suite of contaminants as the soils (excluding

LOI, TOC and asbestos.

The results of all the soil and leachate testing are presented in Appendices D and E

respectively.

6.4 LABORATORY PHYSICAL TESTING

Selected samples were despatched to the laboratory of Geolab in Llanelli for

determinations of atterberg limits, moisture content and some routine durability chemical

testing.

The results of all the physical testing are presented in Appendix F.

6.5 GROUNDWATER MONITORING During return visits to site, the groundwater level within the standpipes installed on site

has been measured relative to ground level, the results of which are enclosed in

Appendix G.



6.6 IN-SITU GAS MONITORING (CONTINUED)

Gas monitoring standpipes were installed in five of the windowless sample holes and

these have been monitored at fortnightly intervals following completion of the fieldworks.

The gas monitoring programme commenced on 3 December 2010.

The concentration levels of methane, carbon dioxide and oxygen were measured in the

standpipes during each visit by using a GA2000 Landfill Gas Analyser. In addition, gas

flow rate and the atmospheric pressure at the time of the field measurements were also

recorded.

Gas monitoring was carried out over a range of atmospheric pressures to include at least

one reading in low and/or falling pressure, in accordance with the recommendations

made in CIRIA Report C665.

The results of the field gas monitoring undertaken to date (single visit) are presented in

Appendix H.



7.0 GROUND CONDITIONS A summary of the ground conditions encountered across the site is presented below in

Table 1.

TABLE 1 : SUMMARY OF GROUND CONDITIONS

Depth (m) From To

Stratum

0.0 0.1/0.25 MADE GROUND: Comprising surface hard standings of either tarmac or concrete or both.

0.1/0.25 0.35/1.0 MADE GROUND: Generally compact coarse granular materials seemingly used as “hard core” and comprising brown, grey, red brown, dark grey and black, slightly silty, slightly sandy, fine, medium and coarse angular and subangular gravel of sandstone, limestone, brick, slag and ash.

0.4/1.0 0.8/1.8 MADE GROUND: A predominantly cohesive made ground was recorded beneath the granular made ground in WS4, WS6, WS7, WS8 and WS9 and generally comprised firm, brown silty, slightly gravelly clay. The gravel typically comprised fine, medium and coarse, angular brick, ash, ceramic and sandstone.

0.8/1.8 1.0/4.4 SUPERFICIAL SOILS: The made ground deposits were generally underlain by a variable thickness superficial cohesive soils comprising soft, brown, grey, yellow brown and red brown, silty, slightly sandy, slightly gravelly CLAY, the gravel of which comprised fine, medium and coarse rounded and sub-rounded sandstone.

1.0/4.4 2.5/4.5 SUPERFICIAL SOILS: The natural shallow cohesive soils were generally underlain by a medium dense and dense, brown and light brown silty, slightly sandy to sandy GRAVEL comprising rounded fine, medium and coarse sandstone.

Surface tarmac or concrete was cored using specialist coring equipment at each

windowless sample location and found to be underlain by predominantly granular made

ground deposits containing variable quantities of angular sandstone, brick, slag, concrete,

bitumen and ash to depths of between 0.35m and 1.0m below ground level.

In five locations, this granular made ground was underlain by predominantly cohesive

made ground to a maximum depth of 1.8m in WS4. Generally the cohesive made ground

was seemingly confined to the eastern and southern areas of the site.



7.0 GROUND CONDITIONS (CONTINUED)

The made ground deposits were underlain by a poorly consolidated layer of cohesive

superficial soils typically described as soft, brown, yellow brown and red brown, silty,

sandy, slightly gravelly clay to depths of between 1.0m and 4.4m below ground level.

The cohesive superficial soils were underlain by generally competent, medium dense and

dense gravels to proven depths of between 2.5m and 4.5m depth below ground level.

The windowless sampling equipment refused in these materials and thus confirmed their

general competency.

The natural solid strata were only recorded within WS1 at 3.9m depth, with the natural

solid strata being described as stiff, red brown mottled teal and grey, slightly silty clay with

frequent mudstone lithorelicts. This deposit is believed to be the Raglan Marl group.

The groundwater levels identified on site during the drilling of the windowless sampling

holes were shallow and recorded at depths of between 0.5m and 1.85m below existing

ground level, which would suggest the presence of perched water in the made ground

and that the superficial soils are saturated.

This high groundwater table has been measured during a return visit to the site, where

after a settling period, the ground water levels were recorded at depths of between 1.0m

and 1.93m below ground level, indicating that the groundwater table presides in the

superficial soils.

It is difficult to gauge the stability of the ground conditions from windowless sample holes

drilled on site, but several of the holes collapsed during drilling and had to be re-drilled in

achieve the termination depth. Considering this, and the low strength of the upper

cohesive soils and the saturated nature of the gravel materials, it is considered that

instability within trenches/excavations formed on site will be extensive.

Falling head permeability tests were undertaken in five of the windowless sample holes in

which standpipes were installed. The response zone was generally below a depth of

1.0m. The head achieved when undertaken the test was artificially increased by raising

the test pipe 1.0m above existing ground level. The permeability values recorded during

the testing ranged between 1.0x10-3m/s and 2.1x10-6m/s.

It should be noted that this initial testing should only be regarded as indicative. If it should

be proposed to use soakaways for this site, then more extensive follow-up tests will be

required and should fully comply with BRE 365, in order to confirm the suitability of the

site and to satisfy the local authority.



8.0 CONTAMINATION

8.1 AVERAGING AREAS In order to assess the laboratory test results reliably and in context, the data have been

grouped into two averaging areas. An averaging area (or area of interest) is that area of

soil to which a receptor is exposed or which otherwise contributes to the creation of

hazardous conditions. This may be an area of historical industrial usage, a soil type, e.g.

made ground, or a specific proposed end use.

In the case of this analysis, the averaging area has been determined according to soil

type, with the made ground being the selected averaging area.

8.2 SOIL CONTAMINATION

As detailed in Section 1.4, the DEFRA/Environment Agency CLEA Model 2002, including

the technical background, generic conceptual models and model parameters, and the Soil

Guideline Values derived from this model, were withdrawn in August 2008. This included

the withdrawal of R&D Publication CLR 7 which detailed the statistical approach to be

adopted at the time for assessing site wide contamination. Subsequent to the withdrawal

of this document, CL:AIRE (Contaminated Land: Applications in Real Environments) has

published a document entitled ‘Guidance on Comparing Soil Contamination Data with a

Critical Concentration’, 2008. The CL:AIRE document includes guidelines on the use of

various statistical methods to assess the soil contamination concentrations, either

conducted in the context of the land use planning system or Part 2A of the Environmental

Protection Act 1990.

To conform to this new approach, we have implemented the use of the ESI Contaminated

Land Statistics Calculator developed by Environmental Simulations International (ESI)

Limited, which fully conforms to the CL:AIRE guidance.

In accordance with the CL:AIRE guidance, the results of the laboratory testing have been

compared to a critical concentration and if required, statistical analysis undertaken to

produce an Upper Confidence Limit (UCL0.95), against which the soil contamination

concentrations can be compared. If the Upper Confidence Limit (set as a default at 95%)

is achieved then the Null Hypothesis (i.e. the level of contamination is the same as, or

greater than the critical concentration) can be rejected and no further analysis or remedial

works are likely to be required at the site. If the Upper Confidence Limit is not achieved

then either further statistical data is required (comprising further chemical laboratory

analysis) or remedial action may be required.



8.2 SOIL CONTAMINATION (CONTINUED)

The published Soil Guideline Values for arsenic, cadmium, mercury, nickel, selenium,

phenol and BTEX compounds have been adopted as critical concentrations against which

soil contaminant concentrations can be compared. In the absence of additional published

SGVs, the Soil Screening Values (SSVs) derived by Atkins ATRISKsoil for a residential

with home grown produce end use and the Generic Assessment Criteria (GAC’s) derived

by Land Quality Management (LQM)/Chartered Institute of Environmental Health (CIEH)

have been adopted. These values have been derived by using the new CLEA 1.06

Model and using the revised and updated methodology and conceptual models.

The soil test results have been summarised and are shown in Appendix I

The results of the laboratory testing indicate that most of the analysed chemical elements

or compounds are present at concentrations below the appropriate thresholds. However,

the initial screening indicates that total chromium, lead, some speciated PAHs and

selected aromatic hydrocarbon fractions are initially contaminants of concern.

With regards to metalliferous contaminants, only total chromium and a single isolated

lead value have been detected at concentrations which exceed their relevant LQM or

ATRISK guideline values.

Total chromium was recorded at an elevated concentration in all of the eight analysed soil

samples with the recorded values being 9mg/kg and 26mg/kg which exceed the

conservative published LQM soil screening value of 4.3mg/kg. However, total chromium

typically comprises the less toxic, more stable chromium (III) and the more toxic

chromium (VI). Chromium (VI) was detected in the samples at a maximum concentration

of 1.0mg/kg (detection limit). Therefore it is likely that the total chromium concentrations

identified comprise mostly chromium (III). The LQM residential end use guideline for

chromium (III) is 3000mg/kg, whilst the guideline for hexavalent chromium is 4.3mg/kg.

Total chromium is therefore not considered to be a contaminant of concern at the site.

A single elevated concentration of lead was recorded from WS6 at 0.6m depth, with the

identified value of 231mg/kg exceeding the published Atkins ATRISKsoil screening value

of 166mg/kg. The recorded value is, however, significantly below the former SGV of

450mg/kg. The single elevated concentration is deemed to be an outlier and does not

belong to the general population of lead results.



8.2 SOIL CONTAMINATION (CONTINUED)

Elevated concentrations of several individual PAHs including benzo(a)anthracene,

benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene,

dibenzo(ah)anthracene and indeno(123cd)pyrene were recorded from four of the

windowless sample locations (WS5, WS6, WS8 and WS9), the values of which exceeded

their relative LQM screening values. The samples displaying elevated concentrations

were derived from deposits that often contained significant quantities of ash and clinker,

and it is these anthropogenic materials that account for the elevated concentrations of

individual PAHs.

Five soil samples were screened for speciated TPH (detailed aliphatic/aromatic split), of

which only a single soil sample from WS9 at 0.5m recorded any elevations of the

individual hydrocarbon fractions.

The elevated fractions included the aromatic bands C16-C21, C21-C35 and C35-C40, the

results of which only just exceeded their respective LQM guideline concentrations. No

other hydrocarbon fractions were elevated. The elevated fractions are indicative of the

presence of the heavier end hydrocarbons potentially including diesel fuel and oils.

A sample obtained from WS9 at 1.4m below the recorded hydrocarbon contamination did

not record any elevations potentially indicating that the TPH contamination is relatively

confined to the shallow soil profile.

None of the eight soil samples screened for asbestos recorded a positive identification.

8.3 SOIL LEACHATE We are currently awaiting the results of the scheduled leachate analysis and we will

assess these results once they are received.

8.4 GROUND GASES A single ground gas has been undertaken to date using a GA 2000 Gas Analyser. The

results of the gas monitoring programme are included in Appendix H. A summary of the

first set of results is given in Table 2 below.



8.4 GROUND GASES (CONTINUED)

Table 2: Summary of Ground Gas Results

Windowless Sample

Maximum Methane Concentration

(%)

Maximum Carbon Dioxide Concentration

(%)

Minimum Oxygen Concentration

(%)

Gas Flow Rate (l/hr)

WS1 0.0 0.2 20.10 0.0

WS3 0.0 0.4 19.40 0.0

WS4 0.0 1.6 17.90 0.0

WS6 0.0 0.1 20.40 0.0

WS9 0.0 0.3 20.00 0.0

The results show a maximum methane concentration of 0.0% and a maximum carbon

dioxide concentration of 1.6% to date. A maximum gas flow rate of 0.0l/hr has been

measured during the gas monitoring programme to date.



9.0 REVISED CONCEPTUAL SITE MODEL The preliminary conceptual site model/conceptual exposure model has been reviewed

and revised to reflect the findings of the site investigation and the results of the laboratory

testing of soils, soil leachate, groundwater and gas monitoring. Any previously identified

in-active pathways have been removed. Pathways identified as still active require

appropriate risk assessment or mitigation measures (see Section 10).



Table 6: Preliminary Conceptual Site Model/Conceptual Exposure Model

Site

Area/Zone Source Contaminant Receptor Pathway

Hazard Potential Active

Pathway and

Evidence?

Potential Risk Mitigation

Human Health –

Site End Users

Dermal Contact with soil

Ingestion of soil/dust

Inhalation of vapours

Human Health

Risks

Yes

Elevated

concentrations of

benzo(a)anthracene,

benzo(a)pyrene,

benzo(b)fluoranthene,

chrysene,

dibenzo(ah)anthracene

and

indeno(123cd)pyrene,

with a single elevated

concentration of lead.

Moderate Risk Assessment

required. Capping

of impacted soils will

be required within

proposed garden

areas.

Human Health –

Site Workers

(Construction and

Maintenance)

Dermal Contact with soil

Ingestion of soil/dust

Inhalation of vapours

Human Health

Risks

Yes

Elevated

concentrations of

benzo(a)anthracene,

benzo(a)pyrene,

benzo(b)fluoranthene,

chrysene,

dibenzo(ah)anthracene

and

indeno(123cd)pyrene,

with a single elevated

concentration of lead.

Moderate Risk Assessment

required. The

adoption of

appropriate PPE will

be required

Site wide Made ground

generated from

historical activities

on site

Metals, semi-

metals, non-

metals,

polyaromatic

hydrocarbons

Controlled Waters Leaching of contaminants

from made ground,

subsequent infiltration

through the made ground

and superficial deposits into

perched water, migration to

Reduction in water

quality

Awaiting the results of

leachate analysis

To be

confirmed

following

receipt of the

results of

leachate

To be confirmed

following receipt of

the results of

leachate analysis



alluvial groundwater and

lateral transport to surface

water

analysis

Neighbouring

Land

Leachate migration via

perched water or along

permeable service trenches

off site

Human Health

Risks/Land Quality


leachate analysis

To be

confirmed

following

receipt of the

results of

leachate

analysis

To be confirmed


the results of

leachate analysis

Building Materials Direct contact of concrete

with made ground

Building Materials

Durability

Yes

Potential for acidic

aggressiveness

associated with the

made ground

Moderate Risk assessment

required with

regards to proposed

foundation concrete

and building

materials in

accordance with

BRE SD1:2005

Controlled Waters Vertical migration to alluvial

groundwater

Lateral migration to surface

water

Reduction in water

quality

Perched water and a

shallow groundwater

table identified.

To be

confirmed

following

receipt of the

results of

leachate

analysis

To be confirmed


the results of

leachate analysis

Perched

Groundwater

Metals, semi-

metals, non-

metals,

polyaromatic

hydrocarbons

Neighbouring

Land

Lateral migration off site Human Health

Risks/Land Quality

Perched water and a

shallow groundwater

table identified.

To be

confirmed

following

receipt of the

results of

leachate

analysis

To be confirmed


the results of

leachate analysis

Ground Gas Methane, Human Health – Accumulation of gases in Human No Low Risk Assessment



associated with

made ground

and/or in-situ

natural gas

producing

materials

carbon dioxide Site end users,

construction and

maintenance

workers

Structures and

buildings

confined spaces, and/or

migration off site, leading to

asphyxiation, or risk of

explosion

Health/Buildings

and Structures

Maximum carbon

dioxide gas

concentration of 1.6%

recorded to date with

no flow detected

required in

accordance to

CIRIA report C665

to confirm findings.

Human Health –

Site End Users

Inhalation of vapours Human Health

Risks

Yes

Elevated

concentrations of

aromatic bands C16-

C21, C21-C35 and

C35-C40

Moderate Further risk

assessment

required.

Human Health –

Site Workers

(Construction and

Maintenance)

Inhalation of vapours Human Health

Risks

Yes

Elevated

concentrations of

aromatic bands C16-

C21, C21-C35 and

C35-C40

Moderate Further risk

assessment

required.

Appropriate PPE

should be adopted

as a precautionary

measure

Controlled Waters Migration of hydrocarbons to




water

Reduction in water

quality


leachate analysis

To be

confirmed

following

receipt of the

results of

leachate

analysis

To be confirmed


the results of

leachate analysis

Area within

vicinity of

WS9

Point Source –

shallow soils

impacted by

hydrocarbons

within the vicinity

of WS9

Hydrocarbons

– Fuel/oils

Neighbouring

Land

Migration of hydrocarbons to




water

Human Health

Risks/Land Quality


leachate analysis

To be

confirmed

following

receipt of the

results of

leachate

analysis

To be confirmed


the results of

leachate analysis

LLEWELLYN ROAD, PENLLERGAER 9867MJE/10


10.0 RISK ASSESSMENT

10.1 METHODOLOGY

The risk of pollution, health effects or environmental harm occurring as a result of ground

contamination is dependent upon three principal factors:

• The scale of the contamination sources;

• The presence of sensitive “receptors”, eg Humans: health of the general public,

site occupiers, redevelopment workers. Environment: flora, fauna, etc;

• The existence of migration pathways by which contaminants can reach the

sensitive receptors.

This section assesses each of these factors in order to evaluate the overall level of risk

and potential harm to receptors. The receptor may be human, a water resource, an eco-

system or construction materials. Pathways connecting a perceived hazard to a receptor

are referred to as exposure pathways.

The sources of contamination and the links connecting the hazards to the sensitive

receptors will represent the basis for the risk assessment.

10.2 SOURCE-PATHWAY-RECEPTOR MODEL

The preliminary conceptual site model was based on the findings of the desk study. This

was later reviewed and refined according to the findings of the site investigation, allowing

for the ground conditions encountered and the results of laboratory testing of soil and

groundwater. Any pathways considered to be inactive were removed from the model and

all remaining potentially active pathways require risk assessment.

The pathways shown as potentially active in the Revised Conceptual Site Model in

Section 9.0 above have been assessed below.

10.3 HUMAN HEALTH RISK ASSESSMENT 10.3.1 Site in its Present Condition The ground does not pose any risks to casual visitors or trespassers. The site is largely

covered by tarmacadam or concrete and is fenced off.



10.3 HUMAN HEALTH RISK ASSESSMENT (CONTINUED)

10.3.2 Future Site Users The contamination test results and investigation observations show elevated

concentration levels in the made ground (at shallow depth) of lead, speciated PAHs and

isolated TPH contamination within the vicinity of WS9

Since lead is a metallic element and is not volatile, and the elevated PAHs are also not

considered volatile, the only potentially active pathway by which a future site resident

could be exposed to the recorded contamination would be via dermal contact with, or

direct ingestion of, contaminated made ground.

It is therefore considered necessary to provide protective measures to remediate the site

in order to protect site end users. The proposed buildings and hardstanding areas will

sever the link between site end users and any remnant made ground sourced

contaminants.

The risks of site end users coming into direct contact with contaminated made ground are

therefore only applicable within proposed garden areas.

To sever the link between proposed site end users and the made ground deposits, it is

recommended that a clean and suitable cover system should be incorporated into the

proposed garden/landscaped areas. The proposed cover system would provide a barrier

between site end users and the remnant made ground sourced contamination, subject to

correct specification and installation.

We understand that the site may be raised by in the region of a 1.0m above existing site

level as part of either a flood protection measure or for the facilitation of drainage.

Providing the imported materials are classified as inert, and suitable for use on a

residential site, then this raising of the site will sever the link between site end users and

the made ground sourced contamination.

As a minimum requirement, we recommend that the imported soils are screened for a

suite of chemical contaminants prior to importation onto site, with the concentrations of

such determinants being below DEFRA and EA published SGVs, or other appropriate

guidance (ATRISK/LQM) based on a residential end use. Further verification of soil

quality will be required during the importation and placement of the materials.




If the site is not raised then ultimately, the thickness of imported cover systems within

proposed garden areas will be dependent on the requirements of the Local Environmental

Health Officer, but we envisage that a minimum thickness of 600mm should be placed.

Level requirements may then dictate that some materials will require off-site disposal to

achieve the levels necessary and provide the appropriate cover.

The investigations undertaken on site have also identified the presence of TPH

contamination within the vicinity of WS9 at shallow depth. This contamination appears to

be confined to the shallow soil profile, but will require further investigation.

The TPH contamination should be considered volatile in nature, and will present a risk to

site end users from inhalation pathways, which will not be retarded by the provision of the

proposed capping system. It is difficult at this stage to assess the actual risks, and further

works will be required to delineate the vertical and lateral extent of any hydrocarbon

contamination within the vicinity of WS9.

Dependent on the nature and extent of any hydrocarbon contamination, mitigation

measures could include localised removal and bioremediation, off site disposal, or the

use of gas vapour protective membranes within proposed plots local to the sources of

contamination.

The above ground fuel storage tank noted within the south-western area of the site will

require decommissioning in accordance with established industry practice, and visual

inspection of the soils within this area will be required, followed by appropriate validation

sampling and testing.

If soil excavation is required, the removal of hydrocarbon impacted materials should be

undertaken under the supervision of a suitably qualified professional. The excavated

materials could be stockpiled on a suitably impermeable surface (concrete hardstanding

or impermeable plastic sheeting) and over sheeted to reduce the potential for leachate

generation as a result of rainfall infiltration.

Validation sampling and analysis will be required within the areas of hydrocarbon

removal, with samples being obtained from the impacted and excavated soils, and also

from the sides and base of the resultant excavations to prove the satisfactory removal of

the impacted soils.




Any groundwater found to be impacted by hydrocarbons within the excavations will

require removal and processing, the method of which will be dependent on the quantities

of impacted groundwater. For small quantities it is probable that the impacted

groundwater could be removed by using a tanker and hose, and disposed of off site. If

larger quantities are encountered it will be necessary to mobilise settlement and baffled

fuel interceptors to site. It should be possible to dispose of water treated in this way to

adopted sewers under licence with the waste collected in tankers and disposed of off site

to a licensed treatment facility.

The future development of the site will involve the formation of excavations within the

made ground deposits and natural soils, and as such there is an increased risk of ground

workers/site operatives encountering contamination, including hydrocarbon impacted

soils/groundwater.

All excavations should be regularly checked for safe atmospheres.

Normal good hygiene practices should be adequate to protect the health and safety of

redevelopment workers, and should include:

• Minimum handling of materials;

• Washing of hands prior to all meal breaks, which should be taken in a designated

clean area;

• The use of standard protective clothing such as boots, overalls and gloves, where

considered relevant.

• Vapour masks should be made available when working in excavations and

workers should be made aware of the risks associated with hydrocarbon

contamination.

• Masks which protect the users face from splashes of hydrocarbon impacted

waters should also be made available

• Site designated a no smoking area.

In dry weather, inhalation of dust and gases should be avoided preferably by the use of

dust suppression techniques to minimize fugitive emissions and minimisation of exposed

materials at any particular time.

Additionally, a system should be established by which any ‘unusual’ materials that may

be encountered are reported rapidly to the site management, so that the appropriate

action may be taken, following specialist advice if necessary. An unusual material may be

identified on site by colour, odour or physical nature.




Reference should be made to the Health and Safety Executive document “Protection of

Workers and the General Public during the development of contaminated land” for

detailed guidance on these matters.

10.4 RISKS TO VEGETATION

No elevated concentrations of phytotoxic contaminants have been identified on site. It

should, however, be noted that the proposed capping within garden areas should

incorporate a suitable growth medium for the proposed planting.

10.5 GROUNDWATER RISK ASSESSMENT

We are currently awaiting the results of the scheduled leachate analysis, and following

receipt of this information we will provide a detailed assessment with regards to the risks

controlled waters.

Given the high groundwater table encountered, and the nature of on site contamination,

an allowance for a period of groundwater monitoring, sampling and testing should be

allowed for.

10.6 GROUND GAS RISK ASSESSMENT

The single result of the gas monitoring programme undertaken to date indicates a

maximum methane concentration of 0.0% and a maximum carbon dioxide concentration

of 1.6%. A maximum gas flow rate of 0.0l/hr was measured during the gas monitoring

programme.

As no flow was detected during the gas monitoring to date, we have conservatively

adopted a gas flow rate of 0.1l/hr in calculation of the Gas Screening Value.

In accordance with CIRIA Report C655 a Gas Screening Value (GSV) of 0.0016l/hour has

been calculated. This GSV corresponds to a Characteristic Situation 1 which does not

require any special gas protective measures. Such a scenario applies to multi-storey

buildings (in excess of two storeys).

For low rise buildings (two storeys or less) this GSV corresponds to a green classification

when utilising the NHBC traffic light system (when assuming a 150mm void and

suspended floor slabs), which again does not require any special gas protective

measures.



10.6 GROUND GAS RISK ASSESSMENT (CONTINUED)

It is important to note that this assessment is based on a single gas monitoring result and

should be considered preliminary. The risk assessment will be reviewed following

completion of the gas monitoring programme.

10.7 RISKS TO BUILDINGS AND MATERIALS DURABILITY

10.7.1 Concrete Classification A summary of the laboratory chemical test results for the chemicals monohydric phenol,

sulphur, total sulphate, water soluble sulphate, sulphide and pH, which may adversely

affect the durability of building materials is presented in Appendix I.

Evidence to date does not indicate any specifically aggressive conditions, but it would be

reasonable to expect a degree of sulphate and acidic aggressiveness from the made

ground.

In accordance with BRE Digest SD1:2005 and adopting the assessment procedure

specified therein for brownfield sites, the laboratory chemical test results indicate a

characteristic value (taking the mean of the two highest results) for water soluble sulphate

of 215mg/l.

Using Table C2 of BRE Digest SD1:2005, this characteristic value corresponds to Design

Sulphate Class DS-1.

The groundwater regime of the site has been assessed as ‘mobile’ and a characteristic

pH value of 7 has been determined (adopting the lowest test result). The Design Sulphate

Class has been modified to give a site ACEC class of AC-1.

10.7.2 Water Services Water pipes will need to be protected from contamination within the ground. In particular

the presence of PAH and TPH should be addressed when selecting pipe materials.

Measures to protect the pipes will include clean backfill to trenches and possibly

alternative material selection. Reference should be made to WRAS document 9-04-03.

The final design and selection of the pipe and associated backfill should be agreed with

the appropriate Regulator prior to installation.



10.8 SPOIL DISPOSAL

Under the Landfill Regulations (2002) all spoil materials should be classified if they

require disposal to a landfill facility. To determine the appropriate type of landfill site,

there will need to be a characterisation of the materials in relation to the Waste

regulations.

The made ground materials are tentatively classified as stable non reactive hazardous

waste but specialised testing will be required once earthworks design and volumes are

known.

Locally soils impacted by hydrocarbons may be classified as hazardous. Basic Characterisation For each waste intended to be landfilled, the following information will be required, either

separately or as part of the Duty of Care waste transfer note, or Special Waste

consignment note:

• Source and origin

• Standard Industry Code (SIC), process producing waste

• Treatment applied or reason not considered necessary

• Composition (including Waste Acceptability Criteria (WAC) leaching tests

hazardous and inert waste where necessary)

• Appearance

• European Waste Catalogue (EWC) Code

• Hazardous properties (if hazardous waste and applicable)

• Not a waste prohibited from landfill (i.e. not corrosive, flammable etc)

• The class of landfill that waste is suitable for (i.e. hazardous)

• Likely behaviour of the waste in the landfill

• Whether waste can be recycled

The basic characterisation is the responsibility of the waste producer. The waste

contractor may undertake all or part of the process of basic characterisation – including

the WAC analysis. It will still be the responsibility of the waste producer to ensure that the

information is correct.

In the absence of any detailed assessment of the likely areas and types of soils that may

be generated for disposal (based on the ground conditions, remediation proposals and

soil materials encountered at the site) the following tentative classification is proposed,

based on the made ground materials.



10.8 SPOIL DISPOSAL (CONTINUED)

Source and origin Cold Storage Depot, Llantarnam Road, Cwmbran

Standard Industry Code (SIC), process producing waste 45.11

Stratigraphic horizon Made Ground Natural Ground

Treatment applied or reason not considered necessary Segregation applied at

point of excavation

Segregation applied at

point of excavation

Composition (including WAC leaching tests for hazardous and inert waste where necessary)

Refer to Section 7.0 Refer to Section 7.0

Appearance (smell, colour, consistency and physical form)

Non odorous locally odorous (hydrocarbons)

Brown/grey brown/dark grey and black

Both heterogeneous and homogenous

Granular and cohesive

Non odorous

Brown/orange brown/yellow brown/red brown

Reasonably homogenous

Cohesive over granular

European Waste Catalogue (EWC) Code 17.05

Soil (including excavated soil from contaminated sites), stones and dredging spoil

17.05

Soil (including excavated soil from contaminated sites), stones and dredging spoil

Not a waste prohibited from landfill (i.e. corrosive, flammable etc)

No No

The class of landfill that waste is suitable for (i.e. hazardous)

Stable Non-reactive Hazardous Waste in Non-hazardous Landfill

Inert (where not impacted by hydrocarbons)

Likely behaviour of the waste in the Landfill Stable Stable

Whether waste can be recycled Yes Yes

This preliminary classification will require more definitive assessment and confirmation

when detailed designs are produced detailing the likely areas of waste disposal if

required. Alternatively, at construction stage any materials identified by the developer as

waste will require Waste Acceptance Criteria (WAC) testing and characterisation prior to

pre-approval from the landfill operator and ahead of export to tip.

It is recommended that a sustainable development strategy is adopted which reduces to a

practicable minimum the need for export of waste to a licensed tip.



10.8 SPOIL DISPOSAL (CONTINUED)

In order to minimise disposal, the materials generated should be segregated and

examined, with appropriate testing as necessary, to enable the materials to be sorted or

treated into lower classifications, with the resultant benefit of potentially generating re-use

rather than disposal.

10.9 UNCERTAINTIES It is important to recognise that there may be areas of contamination within the site that

have not been found or that contaminants may be present at concentrations above those

that have been found. It is also important to recognise that contamination may be

localised and that no investigation, however comprehensive, is capable of finding such

occurrences, other than by chance.

The existing buildings have not been inspected as part of the investigations reported here

for asbestos or other contaminants.

The near-surface drainage patterns have not been fully established.

The ground beneath the buildings has not been examined but on present evidence the

existing floor slabs are in good condition and there is no evidence of any pits, basements

or past spills of potential contaminants. Some degree of made ground material should be

expected beneath the existing floor slabs.

It should be noted that cold storage depots often have two floors (a ground bearing floor

slab and a suspended slab, with the lower floor slab providing insulation. Extensive pipe

work is often routed beneath the floor slabs, with these services often clad extensively

with asbestos.



11.0 ENGINEERING CONSIDERATIONS AND RECOMMENDATIONS

11.1 DETAILS OF PROPOSED DEVELOPMENT

The scheme comprises residential development the layout of which is unknown at

present.

11.2 SITE PREPARATION Detailed material and building inventories together with structural surveys will be required

to ensure safe and efficient demolition strategies and subsequent material management

and re-use strategy. The existing buildings will require a detailed asbestos survey and

subsequent demolition in a controlled manner. Allowances should be made for removing

buried structures associated with the past usage of the site, including foundations of the

existing buildings, inspection pits, any above and below ground tanks, underground pipe

works, interceptors and site drainage.

All redundant footings, services and surface hardstandings associated with the former

buildings will need to be broken out with the resulting debris crushed and screened to a

structural specification, typically 150mm maximum particle size. All excavated materials

should be screened for unsuitable materials such as timber, metal etc. The most reliable

way to achieve a formation cleared of underground obstructions associated with the past

site usage would be to excavate the previously developed areas to a depth of

approximately 1.5m. The resulting spoil would be screened and crushed to a 6F2

standard and re-laid in controlled and compacted layers in accordance with DTp

Specification for Highways Works.

The exposed formations should be checked and any soft spots/areas should be removed

and replaced with well compacted site won or imported granular fill material.

The reduced levels should be brought up to the required levels with well compacted

imported granular materials. Department of Transport (DTp) Type 1 sub base, or similar

approved, could be used, and should be compacted in layers, in accordance with the

current DTp Specification for Highway Works.

Excavating and processing the ground to approximately 1.5m depth, will also have the

additional benefit of exposing, and being able to appropriately deal with, any hitherto

undetected ‘hot spots/areas’ of hydrocarbon contamination. Any soft spots identified

during preparation works should be removed and backfilled with clean granular material

in accordance with the DTp Specification for Highway Works.



11.2 SITE PREPARATION (CONITNUED)

A contingency should be allowed for the possible presence of loosely backfilled former

tanks or inspection pits (associated with vehicular maintenance). These and any other

‘soft spots/areas’ should be removed and replaced with well compacted acceptable

granular materials, as described above.

The materials required to achieve finished levels, i.e. fill materials, topsoil, road

construction materials etc. should be acceptable site processed or imported materials.

Any shortfall in quantities shall be made up with clean, inert, granular imported materials

in accordance with an agreed specification. These materials will need to be placed and

compacted to achieve structural performance standards.

All the investigation, remediation and engineering works should be fully supervised by

appropriate qualified and experienced geotechnical engineers. All physical and chemical

testing will be subject to certification procedures with full documentation by appropriate

Consulting Engineers and regulators such as the Local Authority’s Environmental Health

Department, the Environment Agency and the NHBC.

Any buried services running within the site should be traced and either disconnected and

removed or diverted prior to site works commencing

The dense trees and vegetation within the southern area of the site will require

appropriate clearance subject to TPO’s etc. A detailed Japanese Knotweed survey

should be undertaken during this process, and if any is found, suitably treated,

11.3 FOUNDATIONS AND FLOOR SLABS

Both the made ground and cohesive superficial deposits, owing to their physical nature,

are not considered suitable founding horizons for the proposed structures, and as such

should be fully penetrated by the chosen foundation arrangement. It should also be

recognised that a significant amount of ground disturbance will arise when the existing

development of buildings and infrastructure are removed.

Several foundation options have been considered for the proposed structures, the details

of which are provided below.

Traditional Trench Fill Foundations The main problems with adopting such a foundation solution would be the problems

arising from the excavation of the foundation trenches and the presence of a variable and

rising water table.



11.3 FOUNDATIONS AND FLOOR SLABS (CONTINUED)

The trench sides are likely to become rapidly unstable and require shoring to maintain an

open excavation. Furthermore, it is recommended that foundations are excavated in

sections to retain some stability, meaning that foundation concrete will require pouring in

sections, making for a slow build programme.

In addition, the trenches would need to extend to depths of between 1.0m and possibly

up to 4.4m below existing ground level. This fact and the anticipated instability may mean

that significantly large volumes of mass poured concrete may be required, probably

making this foundation solution impractical and uneconomical.

Standing water observed in the trial pits excavated during the site investigation indicates

that significant dewatering of foundation trenches may also be required.

If trench fill foundations are proposed in some areas (where the made ground and

cohesive superficial soils are thinner) mass concrete strip/trench fill foundations could be

used and founded within the competent in-situ granular soils. An allowable bearing

pressure of 100kN/m2 can be used to design foundations in these materials. At this

intensity of loading, and in these competent materials the total settlements should not

exceed 25mm and any angular distortions caused by differential movements should be

less than 1:750.

Any soft spots encountered in foundation trenches should be excavated out and the

foundation over deepened until more competent soils are encountered.

To protect against the effects of frost heave and thermal shrinkage, foundation formations

should be a minimum of 900mm below finished ground level.

Owing to the presence of mature trees and vegetation located to the south of the site,

foundations may require deepening in accordance with NHBC Chapter 4.2.

Suspended floor slabs would be required with this approach.

Raft Foundation An alternative to trench fill/pier foundations could be the use of an engineered raft

foundation.




The made ground below any proposed raft foundation should be excavated out and

screened to remove any unsuitable materials such as large, typically boulder sized

inclusions of concrete, brickwork, metal and timber etc. The processed and acceptable

made ground can then be placed back in the resultant excavation in thin well compacted

layers, in accordance with the current DTp Specification for Highways Works.

A suitable bed of Type 1 sub base or similar approved material should be laid on top of

the re-engineered made ground, and again compacted and placed in a controlled manner

compliant with the Specification for Highways Works.

The thickness of such materials should be determined by a suitable qualified structural

engineer and will depend somewhat on the chosen design of the raft foundations.

For preliminary purposes, the proposed rafts should be designed to an allowable

maximum bearing pressure of 40kN/m2, with an average pressure of less than 30kN/m2.

At this intensity of loading, the total settlements should not exceed 25/30mm and any

angular distortions caused by differential movements should be less than 1:750.

Plate load tests and/or dynamic probing of any fill materials placed and the proposed

formation will be required in order to confirm the adequacy of the earthworks prior to

floating the raft.

Pile Foundations/Vibro compaction treatment Given the economic considerations of the above foundations, and the possible difficulties

that may be encountered when constructing the above foundation types, it may be

prudent to adopt a piled foundation arrangement or ground treatment by vibro methods of

treatment supporting reinforced strip footings.

Pile Foundations

Provided that the piles are taken down into suitably competent in-situ materials then pre-

cast concrete driven or cast in-situ augered/driven piles could be used and taken down to

appropriate sets.

Shell and auger boreholes will be required to provide geotechnical information on the

shallow to medium depth soils.

The advice of a specialist piling contractor should be sought regarding the specific design

and load bearing capacity of any piles. Any load capacity contribution from the made

ground or cohesive superficial deposits should be ignored in the pile design.




Allowances should be made for a negative skin friction within any uncompacted made

ground or soft in-situ soils.

Allowances should again be made by the piling contractor for the removal of any buried

structures and the ease of piling through the made ground, cohesive superficial soils,

granular soils and solid strata at depth that may be encountered during the piling works.

Allowance should also be made for suitable pile testing.

Vibro compaction treatment Consideration may also be given to ground improvement, which could be achieved with

vibro-compaction. This method would involve the construction of closely spaced stone

columns using bottom feed systems, beneath the load bearing areas of the buildings.

The stone columns should extend as far as possible through the made ground and soft to

firm predominantly cohesive shallow superficial soils and into the competent granular

soils at depth. The aim is to ensure 'stiffening' of the ground, thereby spreading and

dissipating the new development bearing stresses to minimise any differential settlements

within the underlying soils.

If the use of vibro-compaction is to be considered further it is strongly recommended that

a suitably experience specialist vibro-stabilisation contractor be contacted to explore this

technique further.

Removal and/or pre-loosening during site preparation may be necessary to ensure

penetration of the vibro-compaction probe through areas of more compact made ground.

Following successful ground treatment works, reinforced concrete strip foundations with

suspended floor slabs or could be utilised.

The ground treatment works, if adopted after further review, should be such that an

allowable bearing pressure in the range of 100-125kN/m2 could be achieved 600mm

below the surface of the site suitable for an appropriately designed reinforced concrete

beam or strip footing.

Within the prepared ground at the proposed foundation formations, and at this intensity of

loading, the total settlements should not exceed 20mm and any angular distortions

resulting from differential settlements should be less than 1 in 750.




Upon completion of the vibro stabilisation works, properties may be founded using

reinforced strip or raft foundations designed in line with design requirements of the

specialist vibro piling contractor.

Ground slabs should be of suspended construction and incorporate the suitable gas

protection/vapour resistant membranes and ventilated sub floor voids. This provision will

be confirmed subject to the completion of the gas monitoring recommended in this report.

As detailed for piling, shell and auger boreholes will be required to investigate the deeper

ground conditions prior to finalising design.

11.4 EXCAVATIONS AND FORMATIONS

It is difficult to gauge trench stability and ease of excavation based on the penetration of

windowless sample equipment. However, we consider that excavation should be

possible with normal soil excavating machinery. Allowances should be made for the use

of more powerful machinery and the use of pneumatic/hydraulic breakers, where the

potential for remnant buried obstructions (buried services, old foundations, pits etc) within

the made ground exist, or where excavations into the dense natural superficial soils are

anticipated.

Excavations to depths of typically 1.0m are likely to encounter significant groundwater

inflows. Perched pockets of groundwater associated with buried foundations and other

structures should be anticipated. Some of these influxes of groundwater (if contaminated

by organic materials) should be treated/removed using appropriate tanker and hose, or a

specialised filtered free phase separator leading to the hydrocarbon product being

removed from the perched water.

If excavations are required to extend to greater depths, then variable and possibly

considerable quantities of groundwater should be anticipated, particularly within the

saturated gravel horizon at depth. Such water ingress should be adequately controlled at

all times to ensure stability and protection of the temporary and permanent works

Some pit side instability within the heterogeneous made ground deposits should be

anticipated. The stability of trenches within the made ground is likely to rapidly

deteriorate over time, and excavations may require shoring to maintain an open

excavation. Trenches extending into the natural gravels are also likely to rapidly become

unstable owing to the progressive influxes of groundwater.



11.4 EXCAVATIONS AND FORMATIONS (CONTINUED)

Any trenches to depths greater than 1.2m and required to be entered by personnel should

be made safe in line with health and safety requirements, or temporarily battered back at

gradients of typically 30 degrees.

Any ‘soft spots/areas’ encountered in the formations should be removed and replaced

with well compacted imported granular materials.

The exposed formations within the in-situ materials will be susceptible to damage,

loosening and deterioration by wet weather and site traffic. They should therefore be

protected by blinding concrete, or a 200mm thick layer of hardcore, immediately after

exposure.

11.5 ACCESS ROADS AND CAR PARKING AREAS

Following the site strip there are likely to be variations in the strength of the materials at

the formation levels. It is recommended that for design purposes, a California Bearing

ratio (CBR) value of between 1% (made ground) and 2% (natural shallow cohesive soils)

could be assumed for the in-situ soils subject to confirmation by in-situ testing. After

appropriate site preparation as outlined in Section 11.2 above a CBR of 5% should be

achievable.

Where the granular materials are re-used to reinstate and raise the site area 5% CBR

values are considered achievable. Lesser quality materials may necessitate the use of a

capping layer.

After proof rolling the formations, all the ‘soft spots/areas’ should be removed and

replaced with well compacted imported granular materials. Such materials should be to

the approval of the local highway authority and should be compacted in layers, in

accordance with the DTp Specification for Highways Works.

11.6 SOAKAWAY POTENTIAL Soakaway testing to British Standards required to show regimes was not attempted but in

situ falling head permeability tests were undertaken in the installations constructed in five

of the window sample holes.

Soakaway testing was attempted in the more permeable strata.



11.6 SOAKAWAY POTENTIAL (CONTINUED)

Location Test Section Result Comments

(m) (m/s)

WS1 1.0 – 3.36 8.2 x 10 -4

WS3 1.0 – 3.56 1.5 x 10 -4

1.8 X 10-5 Initial result more indicative of installation effects rather than ground. Adopt second result

WS4 1.0 – 4.0 4.8 x 10 -5

WS6 1.0 – 3.84 2.1 x 10 -6

WS9 1.0 – 3.2 1.4 x 10 -3

Generally the upper superficial materials are of low permeability as they are

predominantly clay based. They may possess some macro permeability due to the

nature of the backfilling but infiltration could cause further settlement and loss of material.

The gravelly strata at depth are more permeable but are often saturated possibly with a

sub artesian or even artesian head seasonly or during heavy rainfall periods.

In view of the above, the use of infiltration may not be applicable within drainage design if

levels remain at current levels as the drainage systems will essentially be flooded and

there will be insufficient head to facilitate infiltration. However, if levels are raised then

this might permit the use of trench type soakaway systems providing adequate storage is

provided. However, sustainable drainage systems including swales and attenuation

basins should be considered to attenuate surface run off, subject to appropriate design.





12.0 RECOMMENDED FURTHER WORKS

The following further works are recommended following clearance of the site.

• Undertake investigations in the unexplored areas currently vegetated.

• Undertake research into building construction and then intrusive investigations of

floor areas and construction together with contamination surveys.

• Undertake trial pitting across the site to obtain better coverage, particularly in

those areas previously inaccessible (beneath the footprint of the former buildings

and within the densely vegetated area in the south).

• Undertaken a number of soil infiltration tests within trial pit excavations in

accordance with BRE 365.

• Drill a series of shell and auger boreholes across the site to investigate the nature

of the soils/rocks at depth and provide the necessary parameters for vibro-

treatment/pile design.

• Detailed laboratory analysis will be required in those areas previously

inaccessible.

• Further delineation of areas in which hydrocarbons were previously identified will

require investigation and laboratory analysis.

APPENDIX A

CONTAMINATED LAND DEFINITIONS

Box 1: Contamination and contaminated land in a planning context Annex 2 of Planning Policy Statement 23 (3) states that:

� To avoid confusion with the statutory term “contaminated land” and its definition [i.e. in Part IIA of

the Environmental Protection Act 1990] and to reflect the different context of planning control, this

Annex uses the wider term “land affected by contamination”. This is intended to cover all cases

where the actual or suspected presence of substances in, on or under the land may cause risks to

people, property human activities, or the environment, regardless of whether or not the land meets

the statutory definition in Part IIA.

Annex 2 also states:

� Potentially hazardous substances, such as radon, methane or elevated concentrations of metallic

elements may also be present in the ground due to the underlying geology. Since these may pose a

risk to human health or to the environment, their presence is a material consideration.

Box 2: The Building Regulations – Approved Document C(4) Contamination is dealt with in requirement C1 which concerns `Preparation of site and resistance to

moisture'.

C1(1) requires that: The ground to be covered by the building shall be reasonably free from any material that might

damage the building or affect its stability, including vegetable matter, top-soil and pre-existing

foundations.

C1(2) requires that: Reasonable precautions shall be taken to avoid danger to health and safety caused by

contaminants on or in the ground covered, or to be covered by the building and any land associated

with the building.

C1(3) requires that:

Adequate sub-soil drainage shall be provided if it is needed to avoid –

(a) the passage of ground moisture to the interior of the building;

(b) damage to be building, including damage through the transport of water-borne contamination to

the foundations of the building.

Contaminant is defined as (C1(4)):

Any substance which is or may become harmful to persons or buildings, including substances

which corrosive, explosive, flammable or radioactive or toxic.

The “building and land associated with the building” means: The building and all land forming the site subject to building operations which includes land under

the building and the land around it which may have an effect on the building or its users.

Requirement C1(2) applies to new construction and under Regulation 6, whenever there is a

“material change of use” of the whole building. “Material change of use” is defined in Regulation 5.

APPENDIX B

WINDOWLESS SAMPLE LOGS

APPENDIX C

FALLING HEAD TEST RESULTS

APPENDIX D

LABORATORY CHEMICAL TEST RESULTS (SOILS)

APPENDIX E

LABORATORY CHEMICAL TEST RESULTS (LEACHATE)

APPENDIX F

LABORATORY PHYSICAL TEST RESULTS

APPENDIX G

GROUNDWATER MONITORING RESULTS

APPENDIX H

IN-SITU GAS MONITORING RESULTS

APPENDIX I

STATISTICAL ASSESSMENT OF CHEMICAL RESULTS

FIGURES

APPENDIX A

CONTAMINATED LAND DEFINITIONS

Box 1: Contamination and contaminated land in a planning context Annex 2 of Planning Policy Statement 23 (3) states that:

� To avoid confusion with the statutory term “contaminated land” and its definition [i.e. in Part IIA of

the Environmental Protection Act 1990] and to reflect the different context of planning control, this

Annex uses the wider term “land affected by contamination”. This is intended to cover all cases

where the actual or suspected presence of substances in, on or under the land may cause risks to

people, property human activities, or the environment, regardless of whether or not the land meets

the statutory definition in Part IIA.

Annex 2 also states:

� Potentially hazardous substances, such as radon, methane or elevated concentrations of metallic

elements may also be present in the ground due to the underlying geology. Since these may pose a

risk to human health or to the environment, their presence is a material consideration.

Box 2: The Building Regulations – Approved Document C(4) Contamination is dealt with in requirement C1 which concerns `Preparation of site and resistance to

moisture'.

C1(1) requires that: The ground to be covered by the building shall be reasonably free from any material that might

damage the building or affect its stability, including vegetable matter, top-soil and pre-existing

foundations.

C1(2) requires that: Reasonable precautions shall be taken to avoid danger to health and safety caused by

contaminants on or in the ground covered, or to be covered by the building and any land associated

with the building.

C1(3) requires that:

Adequate sub-soil drainage shall be provided if it is needed to avoid –

(a) the passage of ground moisture to the interior of the building;

(b) damage to be building, including damage through the transport of water-borne contamination to

the foundations of the building.

Contaminant is defined as (C1(4)):

Any substance which is or may become harmful to persons or buildings, including substances

which corrosive, explosive, flammable or radioactive or toxic.

The “building and land associated with the building” means: The building and all land forming the site subject to building operations which includes land under

the building and the land around it which may have an effect on the building or its users.

Requirement C1(2) applies to new construction and under Regulation 6, whenever there is a

“material change of use” of the whole building. “Material change of use” is defined in Regulation 5.

APPENDIX B

WINDOWLESS SAMPLE LOGS

APPENDIX C

FALLING HEAD TEST RESULTS

PERMEABILITY TEST DATA

PROJECT JOB No.

TYPE FALLING

DATE 03.12.10 TIME 10.3 hrs

BOREHOLE NUMBER WS 1 TEST No. 1

3.36 m From top of casing

3.36 m From top of casingOK

0.076 m

0.050 m

0.00 m

L/D Ratio 31.1

2.36 m


1.00 m

1.04 m

0.00 m

HG TEST 2.04 m

Depth of water below top of casing Head of Water Ratio

t t h H = (Hg - h) H/H0(mins) (s) (m) (m)

0 0 0.00 2.0 1.00

0.5 30 1 60 0.62 1.4 0.70

1.5 902 120 1.03 1.0 0.503 180 1.33 0.7 0.354 240 1.59 0.5 0.225 300 1.70 0.3 0.1710 600 1.81 0.2 0.1115 900 1.92 0.1 0.0620 1200 1.96 0.1 0.0425 1500 1.99 0.1 0.0230 1800 2.00 0.0 0.0245 270060 3600

TEST SECTIONLength L = 2.36 m Area A = 0.5680 m2

INTAKE FACTORRefer to BS 5930 Figure 7

Type Special

F =

F = 4.09

TIME LAGT = Time from start of test when h = 0.37 ho

See graph opposite

T = 750 s

PERMEABILITY

K = A / ( F * T )

K = 1.85E-04 m/s

COMMENTS

Soil in casing (m) L

Depth of casing (mBGL) hc

Height of casing above ground level huc

Ground water level (mBGL) HG

Hole in Soil below base of casing (m) L

Elapsed Time

Water level at start of test below top of casing ho

Cold Store Llantarnam 10725

Piezometer diameter (m) d

Depth of borehole at start of test (mBGL) hi

Depth of borehole at end of test (mBGL) he

Borehole diameter (m) D

D*2.32*Π*(L/D)loge[1.1(L/D)+((1+1.1(L/D)2)0.5]

Borehole WS 1

0.10

1.000 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

Time (secs)

LOG

H/H

o 0.37 H/H0

TRENDLINE


PROJECT JOB No.

TYPE FALLING

DATE 03.12.10 TIME 11 hrs




0.076 m

0.050 m

0.00 m

L/D Ratio 33.7

2.56 m


1.00 m

1.04 m

0.00 m

HG TEST 2.04 m



0 0 0.00 2.0 1.00

0.5 30 1 60 0.21 1.8 0.90

1.5 902 120 0.53 1.5 0.743 180 0.82 1.2 0.604 240 0.96 1.1 0.535 300 1.02 1.0 0.5010 600 1.17 0.9 0.4315 900 1.28 0.8 0.3720 1200 1.31 0.7 0.3625 1500 1.34 0.7 0.3430 1800 1.39 0.7 0.3245 2700 1.41 0.6 0.3160 3600



Type Special

F =

F = 4.36


See graph opposite

T = 7900 s

PERMEABILITY

K = A / ( F * T )

K = 1.79E-05 m/s

COMMENTS






Elapsed Time







D*2.32*Π*(L/D)loge[1.1(L/D)+((1+1.1(L/D)2)0.5]

Borehole WS 3

0.10

1.000 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000 4250 4500 4750 5000

Time (secs)

LOG

H/H

o 0.37 H/H0

TRENDLINE


PROJECT JOB No.

TYPE FALLING

DATE 03.12.10 TIME 11.30 hrs




0.076 m

0.050 m

0.00 m

L/D Ratio 39.6

3.01 m


1.00 m

1.90 m

0.00 m

HG TEST 2.90 m



0 0 0.00 2.9 1.00

0.5 30 1 60 0.59 2.3 0.80

1.5 902 120 0.93 2.0 0.683 180 1.24 1.7 0.574 240 1.52 1.4 0.485 300 1.86 1.0 0.3610 600 2.03 0.9 0.3015 900 2.18 0.7 0.2520 1200 2.31 0.6 0.2025 1500 2.50 0.4 0.1430 1800 2.61 0.3 0.1045 2700 2.68 0.2 0.0860 3600 2.72 0.2 0.06



Type Special

F =

F = 4.94


See graph opposite

T = 1650 s

PERMEABILITY

K = A / ( F * T )

K = 4.75E-05 m/s

COMMENTSInitial curve reflects made ground.






Elapsed Time







D*2.32*Π*(L/D)loge[1.1(L/D)+((1+1.1(L/D)2)0.5]

Borehole WS 4

0.10

1.000 250 500 750 1000 1250 1500 1750 2000

Time (secs)

LOG

H/H

o 0.37 H/H0

TRENDLINE


PROJECT JOB No.

TYPE FALLING





0.076 m

0.050 m

0.00 m

L/D Ratio 37.4

2.84 m


1.00 m

1.93 m

0.00 m

HG TEST 2.93 m



0 0 0.00 2.9 1.00

0.5 30 1 60 0.82 2.1 0.72

1.5 902 120 1.07 1.9 0.633 180 1.22 1.7 0.584 240 1.34 1.6 0.545 300 1.39 1.5 0.53

10 600 1.56 1.4 0.4715 900 1.72 1.2 0.4120 1200 1.84 1.1 0.3725 1500 1.90 1.0 0.3530 1800 2.03 0.9 0.3145 2700 2.03 0.9 0.3160 3600 2.09 0.8 0.29



Type Special

F =

F = 4.72


See graph opposite

T = 2800 s

PERMEABILITY

K = A / ( F * T )

K = 2.15E-06 m/s

COMMENTS






Assumes infiltration to gravel horizon only






Elapsed Time


D*2.32*Π*(L/D)loge[1.1(L/D)+((1+1.1(L/D)2)0.5]

Borehole WS 6

0.10

1.000 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000

Time (secs)

LOG

H/H

o 0.37 H/H0

TRENDLINE


PROJECT JOB No.

TYPE FALLING





0.076 m

0.050 m

0.00 m

L/D Ratio 29.5

2.24 m


1.00 m

1.00 m

0.51 m

HG TEST 2.00 m



0 0 0.51 1.5 1.00

0.5 30 1 60 1.04 1.0 0.64

1.5 902 120 1.36 0.6 0.433 180 1.61 0.4 0.264 240 1.82 0.2 0.125 300 10 600 15 900 20 1200 25 1500 30 1800 45 2700 60 3600



Type Special

F =

F = 3.94


See graph opposite

T = 130 s

PERMEABILITY

K = A / ( F * T )

K = 1.05E-03 m/s

COMMENTS






Test may be more reflective of made ground rather than natural soils.






Elapsed Time


D*2.32*Π*(L/D)loge[1.1(L/D)+((1+1.1(L/D)2)0.5]

Borehole WS 9

0.10

1.000 50 100 150 200 250 300 350 400 450 500

Time (secs)

LOG

H/H

o 0.37 H/H0

TRENDLINE

APPENDIX D

LABORATORY CHEMICAL TEST RESULTS (SOILS)

APPENDIX E

LABORATORY CHEMICAL TEST RESULTS (LEACHATE)

APPENDIX F

LABORATORY PHYSICAL TEST RESULTS

APPENDIX G

GROUNDWATER MONITORING RESULTS

Field Gas Monitoring ResultsSite: Cold Store Job No: 10725

Date: 03.12.10 Weather: Cloudy/Icy

Name of Engineer: RH Barometric Pressure (Millibars): On Arrival During Monitoring End of Monitoring Ambient Temp1009 1008 1008 1ºC

Water level Well Base Level Methane (CH4) Oxygen Carbon Dioxide Carbon Monoxide Hydrogen Sulphide Peak Gas Flow VOC Vapours TimeBorehole No. (mbgl) (mbgl) LEL (%) Average (%) Peak (%) O2 (%) CO2 (%) CO (ppm) H2 S (ppm) (l/per hr) (ppm > background)

WS 1 1.04 2.36 0.00 0.00 0.00 20.10 0.20 0.00 0.00 0.00 0.00 12.15

WS 3 1.31 2.56 0.00 0.00 0.00 19.40 0.40 0.00 0.00 0.00 0.00 13.00

WS 4 1.90 3.01 0.00 0.00 0.00 17.90 1.60 1.00 0.00 0.00 0.00 13.30

WS 6 1.93 2.84 0.00 0.00 0.00 20.40 0.10 0.00 0.00 0.00 0.00 14.00

WS 9 1.00 2.24 0.00 0.00 0.00 20.00 0.30 0.00 0.00 0.00 0.00 14.45

Notes:

1. Instrument Used: GA 2000 Gas Analyser2. Typical Accuracy: Gas 0-5% Volume 5-15% Voume 15%-FS Gas 0-FS

%CH4 +/- 1% +/- 1% +/- 3% CO +/1 10%FS%CO2 +/- 2% +/- 1% +/- 3% H2S +/1 10%FS%O2 +/- 1% +/- 1% +/- 3%

3. LEL = Lower Explosive Limit4. N/R = No Reading Taken


APPENDIX H

IN-SITU GAS MONITORING RESULTS

Field Gas Monitoring ResultsSite: Cold Store Job No: 10725

Date: 03.12.10 Weather: Cloudy/Icy

Name of Engineer: RH Barometric Pressure (Millibars): On Arrival During Monitoring End of Monitoring Ambient Temp1009 1008 1008 1ºC

Water level Well Base Level Methane (CH4) Oxygen Carbon Dioxide Carbon Monoxide Hydrogen Sulphide Peak Gas Flow VOC Vapours TimeBorehole No. (mbgl) (mbgl) LEL (%) Average (%) Peak (%) O2 (%) CO2 (%) CO (ppm) H2 S (ppm) (l/per hr) (ppm > background)

WS 1 1.04 2.36 0.00 0.00 0.00 20.10 0.20 0.00 0.00 0.00 0.00 12.15

WS 3 1.31 2.56 0.00 0.00 0.00 19.40 0.40 0.00 0.00 0.00 0.00 13.00

WS 4 1.90 3.01 0.00 0.00 0.00 17.90 1.60 1.00 0.00 0.00 0.00 13.30

WS 6 1.93 2.84 0.00 0.00 0.00 20.40 0.10 0.00 0.00 0.00 0.00 14.00

WS 9 1.00 2.24 0.00 0.00 0.00 20.00 0.30 0.00 0.00 0.00 0.00 14.45

Notes:

1. Instrument Used: GA 2000 Gas Analyser2. Typical Accuracy: Gas 0-5% Volume 5-15% Voume 15%-FS Gas 0-FS

%CH4 +/- 1% +/- 1% +/- 3% CO +/1 10%FS%CO2 +/- 2% +/- 1% +/- 3% H2S +/1 10%FS%O2 +/- 1% +/- 1% +/- 3%

3. LEL = Lower Explosive Limit4. N/R = No Reading Taken


APPENDIX I

STATISTICAL ASSESSMENT OF CHEMICAL RESULTS

SUMMARY OF LABORATORY CHEMICAL TEST RESULTS

Job Number: 10725 Site: Cold Storage Depot, Llantarnam Client: Barratt South Wale

Number of Samples

Minimum Concentration

Maximum Concentration

Guideline Concentration Source

(mg/kg) (mg/kg) (mg/kg)Beryllium 8 0.20 1.10 51 LQMCadmium 8 0.02 4.80 10 SGVChromium 8 9.00 26.00 4.3 LQMHexavalent Chromium 8 1.00 1.00 4.3 LQMCopper 8 5.70 34.00 2330 LQMLead 8 8.20 231.00 166 ATRISKMercury 8 0.03 0.89 1 SGVNickel 8 1.90 24.00 130 SGVVanadium 8 10.00 27.00 75 LQMZinc 8 39.00 323.00 3750 LQMArsenic 8 0.40 5.20 32 SGVBoron 8 0.10 2.21 291 LQMCyanide 8 1.00 1.00 34 ATRISKSelenium 8 0.70 0.70 350 SGVElemental Sulphur 8 0.10 2.70 5000 EATotal Sulphate 0 0.00 0.00 2000 BRESulphide 8 1.00 1.00 250 EAMonohydric Phenol 8 1.00 1.00 420 SGVpH 8 7.00 12.00 5 -Acenaphthene 8 0.30 3.30 210 1%SOM LQMAcenaphthylene 8 0.10 1.50 170 1%SOM LQMAnthracene 8 0.10 10.00 2300 1%SOM LQMBenzo(a)anthracene 8 0.10 20.00 3 1%SOM LQMBenzo(a)pyrene 8 0.10 13.00 0.8 1%SOM LQMBenzo(b)fluoranthene 8 0.10 15.00 6 1%SOM LQMBenzo(ghi)perylene 8 0.10 11.00 44 1%SOM LQMBenzo(k)fluoranthene 8 0.10 14.00 9 1%SOM LQMChrysene 8 0.10 28.00 6 1%SOM LQMDibenzo(ah)anthracene 8 0.10 4.10 0.8 1%SOM LQMFluoranthene 8 0.10 21.00 260 1%SOM LQMFluorene 8 0.40 5.30 160 1%SOM LQMIndeno(123cd)pyrene 8 0.10 12.00 3.2 1%SOM LQMNaphthalene 8 0.10 1.30 1.5 1%SOM LQMPhenanthrene 8 0.50 16.00 92 1%SOM LQMPyrene 8 0.10 18.00 560 1%SOM LQMAliphatic C5-C6 5 0.10 0.20 30 1%SOM LQMAliphatic C6-C8 5 0.10 0.10 73 1%SOM LQMAliphatic C8-C10 5 10.00 10.00 19 1%SOM LQMAliphatic C10-C12 EPH 5 10.00 10.00 93 1%SOM LQMAliphatic C12-C16 EPH 5 10.00 129.00 740 1%SOM LQMAliphatic C16-C35 EPH 5 20.00 1960.00 45000 1%SOM LQMAliphatic C35-C44 EPH 5 10.00 903.00 45000 1%SOM LQMAromatic C5-C7 5 0.10 0.10 65.00 1%SOM LQMAromatic C7-C8 5 0.10 0.10 120 1%SOM LQMAromatic C8-C10 5 10.00 10.00 27 1%SOM LQMAromatic C10-C12 EPH 5 10.00 10.00 69 1%SOM LQMAromatic C12-C16 EPH 5 10.00 18.00 140 1%SOM LQMAromatic C16-C21 EPH 5 10.00 294.00 250 1%SOM LQMAromatic C21-C35 EPH 5 11.00 1025.00 890 1%SOM LQMAromatic C35-C40 EPH 5 11.00 1025.00 890 1%SOM LQMMonohydric Phenol 8 1.00 1.00 420 SGVElemental Sulphur 8 0.10 2.70 5000 EATotal Sulphate 0 0.00 0.00 2000 BREWater Soluble Sulphate (g/l) 8 0.04 0.22 0.5 BRESulphide 8 1.00 1.00 250 EApH 8 7.00 12.00 5 -

Note: All concentrations in mg/kg unless stated

Exceedence Representative US95 concentration exceeds guideline concentration

BU

ILD

ING

M

ATE

RIA

LS

DU

RA

BIL

ITY

Determinand

ME

TALS

SE

MI-M

ETA

LS

&

NO

N-

ME

TALS

PA

HTP

H

Integral Geotechnique (Wales) Limited

LABORATORY CHEMICAL TEST RESULTS SUMMARY

10725 Cold Storage Depot, Llantarnam

METALS, SEMI-METALS & NON-METALS

No. Location Depth (m) Arsenic as As, dry weight

Boron as B, hot water sol

dw

Beryllium as Be, dry weight

Cadmium as Cd, dry weight

Chromium as Cr, dry weight

Hexavalent Chromium as

DW

Copper (Total BG Spec)

Lead (Total BG Spec)

Mercury as Hg, dry weight

Nickel as Ni, dry weight

Selenium as Se, dry weight

Vanadium as V, dry weight

Zinc as Zn, dry weight

(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg)

1 WS1 0.5 0.4 0.3 0.2 4.8 9 1 6.7 14 0.89 1.9 0.7 10 3232 WS5 0.4 3.9 0.4 0.9 0.02 15 1 33 22 0.08 24 0.7 23 573 WS6 0.3 0.4 1.8 1.1 0.09 9 1 13 231 0.07 3.3 0.7 11 864 WS6 0.6 4.7 0.5 0.8 0.02 15 1 22 37 0.1 20 0.7 26 685 WS7 0.5 5.2 0.4 0.8 0.02 16 1 20 28 0.1 22 0.7 27 826 WS8 0.5 4.7 2.21 0.8 0.02 14 1 34 67 0.1 23 0.7 26 1357 WS8 1.2 0.4 0.1 0.6 0.02 15.3 1 9.2 15 0.03 21.2 0.7 24 458 WS9 0.5 1.2 0.3 0.2 0.02 26 1 5.7 8.2 0.03 16 0.7 12 39

Soil Guidance value (SGV) 32.0 291.0 51.0 10.0 4.3 4.3 2330.0 166.0 1.0 130.0 350.0 75.0 3750.0

Source of SGV SGV LQM LQM SGV LQM LQM LQM ATRISK SGV SGV SGV LQM LQM




INORGANIC CHEMICALS & OTHERS

No. Location Depth (m) Cyanide (Total), dry weight

Loss on ignition, dried

solids

Monohydric phenols dw pH

Sulphate as SO4, Water

SolubleSulphide Sulphur

(Elemental)TOC (Ignition in

O2)

(mg/kg) (%) (mg/kg) (pH units) (g/l) (mg/kg) (mg/kg) (%)

1 WS1 0.5 1 6.4 1 12 0.035 1 0.1 4.32 WS5 0.4 1 3.7 1 10 0.154 1 0.2 6.23 WS6 0.3 1 5 1 8.2 0.133 1 2.7 4.54 WS6 0.6 1 5.4 1 7.2 0.039 1 0.3 1.85 WS7 0.5 1 5.5 1 7.3 0.056 1 0.4 2.36 WS8 0.5 1 7.3 1 7 0.049 1 2.7 2.27 WS8 1.2 1 1.8 1 7 0.038 1 0.2 0.48 WS9 0.5 1 2 1 9.2 0.215 1 0.1 2.5

Soil Guidance value (SGV) 34.0 10.0 420.0 5.0 0.5 250.0 5000.0 6.0

Source of SGV ATRISK WAC SGV - BRE EA EA WAC




POLY AROMATIC HYDROCARBONS (PAH)

No. Location Depth (m) Acenaphthene mg/kg 313

Acenaphthylene mg/kg 313

Anthracene mg/kg 313

Benzo(a)anthracene mg/kg 313

Benzo(a)pyrene mg/kg 313

Benzo(b)fluoranthene mg/kg 313

Benzo(ghi)perylene mg/kg 313

Benzo(k)fluoranthene mg/kg 313

Chrysene mg/kg 313

Dibenzo(ah)anthracene mg/kg

313

Fluoranthene mg/kg 313

Fluorene mg/kg 313

Indeno(123cd)pyrene mg/kg 313

Naphthalene mg/kg 313

Phenanthrene mg/kg 313

Pyrene mg/kg 313

(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg)

1 WS1 0.5 0.6 0.1 1.3 1.5 0.7 1.4 0.5 0.7 1.3 0.2 3.3 0.7 0.5 1 3.8 2.42 WS5 0.4 3.3 1.5 10 20 13 15 11 14 28 4.1 21 5.3 12 1.3 16 183 WS6 0.3 1.2 0.6 3.5 7.7 6.2 9.4 2.8 3.8 8.4 1.3 16 1.7 3.1 0.3 11 114 WS6 0.6 0.4 0.1 0.2 0.5 0.5 1.2 0.4 0.5 0.8 0.2 1.2 0.4 0.4 0.3 0.8 15 WS7 0.5 0.4 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.1 0.1 0.2 0.4 0.1 0.2 0.5 0.16 WS8 0.5 0.9 0.7 1.7 6.1 6.3 9.8 3.2 4.3 8.1 1.4 8.9 1.3 3.4 0.6 6.7 5.87 WS8 1.2 0.3 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.7 0.1 0.2 1 0.18 WS9 0.5 1 0.3 3.3 7.7 5.3 8.6 2.3 4.1 7.8 1 17 1.2 2.6 0.1 12 11

Soil Guidance value (SGV) 210.0 170.0 2300.0 3.1 0.8 5.6 44.0 8.5 6.0 0.8 260.0 160.0 3.2 1.5 92.0 560.0

Source of SGV 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM




TOTAL PETROLEUM HYDROCARBONS (TPH)

No. Location Depth (m) Aliphatic C5-C6 Aliphatic C6-C8 Aliphatic C8-C10 Aliphatic C10-C12 EPH

Aliphatic C12-C16 EPH

Aliphatic C16-C35 EPH

Aliphatic C35-C44 EPH Aromatic C5-C7 Aromatic C7-C8 Aromatic C8-C10 Aromatic C10-

C12 EPHAromatic C12-




C40 EPH(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) -

9 WS7 0.5 0.2 0.1 10 10 10 22 12 0.1 0.1 10 10 10 10 14 1410 WS8 0.5 0.2 0.1 10 10 10 43 33 0.1 0.1 10 10 10 10 11 1111 WS8 1.2 0.1 0.1 10 10 129 221 56 0.1 0.1 10 10 10 10 18 1812 WS9 0.5 0.17 0.1 10 10 66 1960 903 0.1 0.1 10 10 18 294 1025 102513 WS9 1.4 0.19 0.1 10 10 10 20 10 0.1 0.1 10 10 10 10 19 19

Soil Guidance value (SGV) 30.0 73.0 19.0 93.0 740.0 45000.0 45000.0 65.0 120.0 27.0 69.0 140.0 250.0 890.0 890.0

Source of SGV 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM 1%SOM LQM


FIGURES

FIGURE 1 - SITE LOCATION

NORTH

Cold Storage Depot, Llantarnam, Cwmbran

1000m

SITE LOCATION

Intégral House7 Beddau WayCastlegate Business ParkCaerphillyCF83 2AXTel: 029 2080 7991Fax: 029 2086 2176


Window Sampling Location Crown Copyright Reserved

FIGURE 2 - SITE LAYOUT

NORTH

Cold Storage Depot, Llantarnam, Cwmbran

APPROXIMATE SITE BOUNDARY

TP1

TP4

TP5

TP3

TP2

TP6

Intégral House7 Beddau WayCastlegate Business ParkCaerphillyCF83 2AXTel: 029 2080 7991Fax: 029 2086 2176


WS 1

WS 6

WS 5

WS 2

WS 8

WS 9 WS 4

WS 3

WS 7

Area inaccessible due to dense vegetation

Documents

Site Investigation Report 10725-2 - Torfaen County Borough Council · 2011. 5. 5. · 10725/MJE/10) should be read in conjunction with this report. Reference to the desk study has