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The Winston Churchill Memorial Trust of Australia

Risk Assessment of Asbestos-ContaminatedSoils: An International Perspective

Benjamin Hardaker – 2008 Churchill Fellow

I understand that the Churchill Trust may publish this Report, either in hard copy or on theinternet, or both, and consent to such a publication.

I indemnify the Churchill Trust against loss, costs or damages it may suffer arising out of anyclaim or proceedings made against the Trust in respect of or arising out of the publication ofany report submitted to the Trust and which the Trust places on a website for access overthe internet.

I also warrant that my final report is original and does not infringe the copyright of anyperson, or contain anything which is, or the incorporation of which into the final report is,actionable for defamation, a breach of any privacy law or obligation, breach of confidence,contempt of court, passing-off or contravention of any other private right or of any law.

Signed B. Hardaker May 2009

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Contact Details

Name Benjamin Hardaker

Address AECOM Australia Pty Ltd

Level 11, 44 Market Street, Sydney NSW 2000

Postal Address PO Box Q410, QVB Post Office, Sydney NSW 1230

Position Graduate Engineer

Environment, Water and Civil Infrastructure Group

Telephone +61 2 8295 3600

Facsimile +61 2 9262 5060

Email Benjamin.Hardaker@aecom.com

Project description To study how various jurisdictions assess the risk ofasbestos-contaminated soils to receptors in bothfragment and free asbestos fibre forms. This includedstudying source-pathway-receptor models, applicationof risk models and studying appropriate remediationtechniques to reduce the risk of contracting anasbestos-related disease.

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Acknowledgements

I gratefully acknowledge the Winston Churchill Memorial Trust for providing thisopportunity to complete this research. This opportunity has allowed the ASBINS(ASBestos IN Soil) workgroup to create relationships with leaders in the field to betterunderstand risk assessment of asbestos-contaminated soils.

Many thanks to all ASBINS’ contacts that provided a considerable amount of time andeffort to meet with me and discuss current and past research on the topic. Thank you foryour hospitality while on my visit.

I would also like to acknowledge the great amount of technical support my employer andcolleagues at AECOM Australia have provided. ASBINS, an AECOM Australiaworkgroup, has sustained the energy, support and network to continue this research forthe benefit of the Australian contaminated land industry.

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Executive Summary

The risk that asbestos-contaminated soils pose to receptors in Australia is relativelyunknown due to a lack of regulatory guidance. Risk is based upon a number of factorsincluding the type of asbestos (serpentine or amphibole), the concentration that areceptor is exposed to, the duration of exposure, the frequency of exposure, and the timesince first exposure (latency period). In comparison to countries such as the UnitedStates, United Kingdom and the Netherlands, Australia has remained idle incontaminated site clean-up of asbestos.

Epidemiological studies and risk models have been completed to determine negligiblerisk air concentrations of asbestos to which receptors can be exposed. The problemfound though is the lack of data in low concentration environments often experienced inpara-occupational or non-occupational settings, resulting in the need to extrapolate anumber of orders of magnitude lower than available data. This increases the uncertaintyand reliability of concentrations deemed of negligible risk.

Further to this challenge is the assessment of the exposure-pathway model whereasbestos migrates from soil to air. Jurisdictions have developed methods that aredeemed representative of conditions or scenarios where dust generation would causereceptors to be exposed to asbestos. Of great importance is their usefulness andrelevance to Australian conditions, but of course, their representativeness of exposure toasbestos.

While the challenge of developing a scientifically-defensible, ecologically sustainableASBINS (ASBestos IN Soil) process that may be accepted on a national basis isdaunting, the current wasteful and poorly justified practices cannot be allowed tocontinue. However, this is based upon social and political acceptance of there being a‘safe’ asbestos exposure level. Research in the Netherlands suggests there is an airconcentration of asbestos seen as being of negligible risk, although when compared withguidance values in the United Kingdom and United States a range of values exist.

This report provides a brief summary of current risk assessment tools available, includingrisk models used in the United States, United Kingdom and the Netherlands. Thesemodels are used for the determination of excess lifetime cancer risks to receptorsassociated with asbestos exposure. It is hoped that Australia can adopt some of theseprincipals in a regulatory form by including asbestos-specific information in the NationalEnvironmental Protection Assessment of Site Contamination Measure (NEPM), which iscurrently under review.

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Table of Contents

CONTACT DETAILS ................................................................................................................ IIACKNOWLEDGEMENTS........................................................................................................ IIIEXECUTIVE SUMMARY .........................................................................................................IVTABLE OF CONTENTS ...........................................................................................................VPROGRAMME.........................................................................................................................VILIST OF FIGURES ................................................................................................................VIIILIST OF TABLES..................................................................................................................VIIIACRONYMS............................................................................................................................IX1. INTRODUCTION ..................................................................................................................12. UNITED STATES OF AMERICA ..........................................................................................2

2.1 United States Environmental Protection Agency (US EPA) Asbestos TechnicalReview Workgroup (TRW) Summit, Las Vegas, Nevada..............................3

2.2 United States Environmental Protection Agency (US EPA) Region 9 Office, SanFrancisco, California....................................................................................3

2.3 California Environmental Protection Agency (CAL EPA), Oakland, California........ 52.4 United States Environmental Protection Agency (US EPA) Environmental Response

Team - West, Las Vegas, Nevada ...............................................................62.5 United States Environmental Protection Agency (US EPA) Region 10, Seattle,

Washington.................................................................................................92.5.1 North Ridge Estates ...........................................................................92.5.2 Region 10 Laboratory, Manchester, Seattle ...................................... 10

2.6 Massachusetts Department of Environmental Protection Agency (MassDEP),Boston, Massachusetts ............................................................................. 11

3. THE NETHERLANDS......................................................................................................... 123.1 Netherlands Ministry of Housing, Spatial Planning and Environment (VROM), Den

Haag, Netherlands .................................................................................... 133.2 Netherlands Organisation for Applied Scientific Research (TNO), Utrecht,

Netherlands............................................................................................... 133.3 Agrolab Analytical Laboratory, Deventer, Netherlands ........................................ 15

4. UNITED KINGDOM ............................................................................................................ 164.1 Institute of Occupational Medicine (IOM), Edinburgh, Scotland ........................... 174.2 Health and Safety Laboratories, Buxton, England ............................................... 174.3 British Occupational Hygiene Society (BOHS) Asbestos Contaminated Land

Seminar, London, England ........................................................................ 194.3.1 Woolston Riverside........................................................................... 194.3.2 Electricity Supply Board (ESB) Contamination Assessment and

Remediation 195. CONCLUSION.................................................................................................................... 216. RECOMMENDATIONS....................................................................................................... 247. REFERENCES ................................................................................................................... 25APPENDIX A – ADDITIONAL INFORMATION OBTAINED FROM THE UNITED STATES

ENVIRONMENTAL PROTECTION AGENCY .......................................................... 29APPENDIX B – ADDITIONAL INFORMATION OBTAINED FROM THE NETHERLANDS...... 32

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Programme

United States EnvironmentalProtection Agency (US EPA)Asbestos Technical Review(TRW) Workgroup Meeting

Building D, 4220 South Maryland Parkway, LasVegas, Nevada, United States.

United States EnvironmentalProtection Agency, Region 9

75 Hawthorne Street, San Francisco, California,United States.

California EnvironmentalProtection Agency (CALEPA)

1515 Clay Street, Oakland, California, UnitedStates.

AECOM Environment,Oakland

Suite 220, 300 Lakeside Drive, Oakland, California,United States.

United States EnvironmentalProtection Agency,Environmental ResponseTeam – West, Region 9

Building D, 4220 South Maryland Parkway, LasVegas, Nevada, United States.

United States EnvironmentalProtection Agency, Region 10

Suite 900, 1200 Sixth Avenue, Seattle,Washington, United States.

United States EnvironmentalProtection Agency, Region 10Laboratory

7411 Beach Drive East, Port Orchard, Seattle,Washington, United States.

Massachusetts Department ofEnvironmental ProtectionAgency (MassDEP)

1 Winter Street, Boston, Massachusetts, UnitedStates.

AECOM Environment,Westford

2 Technology Park Drive, Westford,Massachusetts, United States.

Netherlands Ministry ofHousing, Spatial Planningand the Environment (VROM)

Rijnstraat 8, Den Haag, the Netherlands.

Netherlands Organisation forApplied Scientific Research(TNO)

Princetonlaan 6, Utrecht, the Netherlands.

Agrolab, Deventer Handelskade 39, NL-7400 AR Deventer, TheNetherlands.

Institute of OccupationalMedicine (IOM)

Research Avenue North, Riccarton, Edinburgh,Scotland.

Faber Maunsell, Edinburgh Dunedin House, 25 Ravelston Terrace, Edinburgh,Scotland.

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Health and Safety ExecutiveLaboratories

Harpur Hill, Buxton, Derbyshire, England.

Bureau Veritas, Cranfield Unit 5, Trent House, Cranfield Technology Park,Cranfield, England.

British Occupational HygieneSociety (BOHS) AsbestosContaminated Land Seminar

Society for Chemical Industry, 14/15 BelgraveSquare, London, England.

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List of Figures

Figure 2.1 US EPA Framework for conducting risk assessment atSuperfund sites.

Figure 2.2 US EPA investigation results for adult cancer risk using theIRIS risk model.

Figure 2.3 An aerial photograph of a site showing areas of focus.Figure 2.4 The general arrangement for ABS with stationary air monitors

placed approximately 3.5m from ABS activities.

Figure 2.5 The fluidised bed asbestos separator developed by the USEPA.

Figure 3.1 The general risk assessment process used in theNetherlands.

Figure 3.2 Results showing the relationship developed between soil andair concentrations of asbestos.

Figure 4.1 The general approach currently adopted for assessing risksat contaminated soil sites in the United Kingdom.

Figure 4.2 The laboratory based soil dustiness testing apparatus.Figure 4.3 A view inside the rotating drum.

List of Tables

Table 3.1 Risk levels for concentrations of asbestos fibres >5µm inlength per cubic metre of air.

Table 3.2 Potencies of various asbestos fibre types.

Table 5.1 A risk matrix of regulatory and guideline values forasbestos in soil and air.

Table 5.2 Asbestos fibre potencies suggested in each risk model.

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Acronyms

ABS Activity-based sampling

ACM Asbestos-containing material

AS Australian Standard

ATSDR Agency for Toxic Substances and Disease Registry

ASBINS ASBestos IN Soil

BOHS British Occupational Hygiene Society

CARB California Air Resources Board

CALEPA California Environmental Protection Agency

CCMA Clear Creek Management Area

EA Environment Agency

ERT Environmental Response Team

HEPA High efficiency particulate air

HIL Health-based Investigation Level

HSL Health and Safety Laboratories

IRIS Integrated Risk Information System

ISO International Standards Organization

MassDEP Massachusetts Department of Environmental Protection

MPR Maximum permissible risk

MSDS Methods for the determination of hazardous substances

NATA National Association of Testing Authorities

NEPM National Environmental Protection (Contaminated SiteAssessment) Measure

NOA Naturally occurring asbestos

NR Negligible risk

PCM Phase contrast microscopy

PCMe Phase contrast microscopy equivalent

PLM Polarized light microscopy

PPE Personal protective equipment

x

SEM Scanning electron microscopy

SOP Standard operating procedure

TEM Transmission electron microscopy

TNO Netherlands Organisation for Applied Scientific Research

TRW Technical Review Workgroup (US EPA)

UKAS United Kingdom Accreditation Service

US EPA United States Environmental Protection Agency

VROM Netherlands Ministry of Housing, Spatial Planning and theEnvironment

WHO World Health Organization

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1. Introduction

A problem not only faced in Australia, but internationally is asbestos-contaminated soils.There is an increasing amount of information available on occupational exposure, wastemanagement and toxicology of bonded and friable asbestos, but there is great difficulty intranslating this information into forms that can be used in risk assessment. In comparisonto countries such as the United States, the United Kingdom and the Netherlands,Australia has remained idle in contaminated site clean-up of asbestos for some time now.

The risk that asbestos-contaminated soils pose to receptors in Australia is relativelyunknown due to a lack of guidance in regulatory form. Current guidance documents(enHealth Council, 2005; ACLCA, 2002) state that a site is deemed contaminated ifasbestos concentrations exceed 0.001% (w/w) in soil and 0.001 fibre/mL in air. The basisof these guidance values is unclear, with other jurisdictions providing a more sciencebased approach to risk assessment. Various studies have been completed on healtheffects relating to exposure of asbestos and also in modelling asbestos migration throughthe source-pathway-receptor model. This report provides a brief summary of current riskassessment tools available abroad, including various risk models used for thedetermination of excess lifetime cancer risks to receptors resulting from para-occupationaland non-occupational exposures.

Risk is based upon a number of factors, including the type of asbestos (serpentine oramphibole), the concentration that a receptor is exposed to, the duration that exposureoccurs for, the frequency of exposure, and the time since first exposure (latency period).Although each jurisdictions approach is specifically tailored to local conditions, Australiahas the ability to adopt parts of each process for use in risk assessment here.

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2. United States of America

The United States Environmental Protection Agency (US EPA) has recently released theFramework for Investigating Asbestos-Contaminated Superfund Sites1 (US EPA, 2008a).Figure 2.1 shows the general process outlining the use of activity-based sampling (ABS)in the framework to determine concentrations of asbestos in ambient air. Results obtainedfrom ABS are then combined with values contained within the Integrated Risk InformationSystem (IRIS)2 risk model for determination of the excess lifetime cancer risk. Generallyan action level corresponding to an excess lifetime cancer risk of 10-4 is used todetermine if remediation is required, although site-specific characteristics ultimatelydetermine the appropriate risk management level.

Figure 2.1: US EPA Framework for conducting risk assessment at Superfund sites(US EPA, 2008a, p. 4).

1 http://epa.gov/superfund/health/contaminants/asbestos/pdfs/framework_asbestos_guidance.pdf

2 http://www.epa.gov/iris/subst/0371.htm

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2.1 United States Environmental Protection Agency (US EPA) AsbestosTechnical Review Workgroup (TRW) Summit, Las Vegas, NevadaA week long meeting was held by the US EPA asbestos technical review workgroup(TRW) to share experiences of Superfund sites across the United States. It also involveddiscussing how the US EPA was to further refine the risk assessment process containedwithin the framework. Areas discussed for further research at the meeting includeinvestigating:

the relationship between surface area of asbestos fibres and adverse healthaffects resulting from exposure;

the effect of chemical composition, including surface and leachate compositions,due to the body ‘breaking down’ asbestos fibres and developing an asbestosrelated disease;

the importance of determining the retained dose rather than exposureconcentration;

the use of ABS confirmation sampling when fill is imported to a site during theremediation phase. This would be conducted after remediation has taken place toconfirm adequate remediation has occurred. Soil samples would still be takenbefore importing ‘clean’ fill onto the site;

how to approach sites where ABS produces non-detect results, but stationary airmonitoring upwind and/or downwind detects asbestos;

possible derivation of action or screening levels for air for the excess lifetimecancer risk range of 10-4 ~10-6 based upon current or proposed site usage; and

determination of uncertainty within the risk assessment phase.

2.2 United States Environmental Protection Agency (US EPA) Region 9Office, San Francisco, CaliforniaClear Creek Management Area (CCMA)3 was a recreational area available to residentsand visitors in California. Upon investigation it was found that naturally occurring asbestos(NOA) was present at the site. Initial investigations found that exposure scenariosincluded incidental (visitors) and continual (workers) exposures. A set of activities usingABS were developed by the US EPA to replicate activities conducted at the site withambient air measurements taken to determine concentrations of asbestos. An action levelcorresponding to an excess lifetime cancer risk of 10-4 was deemed appropriate with anacceptable risk range of 1 in 10 000 to 1 in 1 000 000. Concentrations of asbestosobtained through ABS using ISO 10312 (International Standards Organization, 1995)were then combined with IRIS risk model values to determine if an excess lifetime cancerrisk was present. Risk was calculated using the following equations:

3 http://epa.gov/region09/toxic/noa/clearcreek/index.html

4

IURxECELCR

time

exposureexposureexposure

ADxFxTxC

EC (after US EPA, 2008a)

where:

ELCR = excess lifetime cancer risk (unitless)

EC = average chronic daily exposure over a 70 year lifetime (f/mL)-1

C = measured asbestos concentration (f/mL)

Texposure = exposure time (hours/day)

Fexposure = frequency of exposure (days/year)

Dexposure =duration of exposure (years)

Atime = averaging time (lifetime)

IUR = IRIS inhalation unit risk (f/mL)-1

= 0.23 (f/mL)-1 for lifetime exposure

Figure 2.2: US EPA investigation results for adult cancer risk using the IRIS riskmodel (US EPA, 2008b, p. ES- 4).

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It was determined that for almost all activities except hiking, visiting the area five times ormore per year would result in an excess lifetime cancer risk of 10-4 being exceeded. Asthis was out of the US EPA’s acceptable excess lifetime cancer risk range the CCMA sitewas closed to the general public.

2.3 California Environmental Protection Agency (CAL EPA), Oakland,CaliforniaThere is still great debate between professionals as to specific characteristics of asbestosfibres such as length, width and type that cause adverse health effects. It is well knownthat asbestos is a carcinogen, but a definitive set of characteristics remains unavailablefor use in risk assessment. There is a general consensus though that the longer the fibre,the greater the potency.

There are a number of uncertainties present within the derivation of the IRIS cancer riskvalues for specific air concentrations. These include:

the use of phase contrast microscopy (PCM) to determine fibre characteristicsand concentrations. It has been debated that light microscope methods do notprovide the required analytical sensitivity. Transmission electron microscope(TEM) analysis is readily available in the United States, where phase contrastmicroscopy equivalent (PCMe) fibre counting rules are often used to correlateresults with IRIS risk values as PCM was used in the IRIS values derivation;

the possible over-estimation of asbestos concentrations when using indirectmethods to determine concentrations within air. This includes the need to convertfrom the mass of asbestos contained on the filtered media to a fibre concentrationwithin air;

the need to extrapolate to low concentrations, typically a number of orders ofmagnitude lower than concentrations seen in occupational environments, due to alack of data in non-occupational environments; and

the reliability of exposure data obtained in occupational exposure cohorts todetermine concentrations and types of asbestos. This also includes theapplicability of animal exposure studies.

It should be noted that the IRIS risk model does not differentiate between amphibole andserpentine fibre types. Concentrations obtained using the IRIS risk model may be furtherrefined in the future by reanalysing filter papers used in the original derivation of the IRISrisk values. This would be completed using TEM and a statistical analysis. CALEPA usesdifferent asbestos unit risk values, cancer endpoints and computational methods todetermine excess lifetime cancer risks at sites in the state of California.

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2.4 United States Environmental Protection Agency (US EPA)Environmental Response Team - West, Las Vegas, NevadaThe Environmental Response Team (ERT) helps develop sampling plans for bothasbestos in soil and air. ERTs focus is on anthropogenic sites, although the US EPA hasled the assessment of a number of NOA sites.

At Superfund sites a site history assessment is conducted, including the study of aerialphotographs, locating asbestos storage or dump locations, and whether ACMs weretransported through the site (e.g. Rail cars removing tailings from a mine site). From herea sampling plan for soil is developed using the program Visual Sampling Plan4 todetermine the number and location of soil samples. This program was developed by anumber of US government institutions for use on contaminated sites in the United Stateswith a soil detection limit for asbestos of 0.25% (w/w) (US EPA, 2008a; CARB, 1991).Composite samples are taken within each grid to determine areas of focus whenconducting ABS to Standard Operating Procedures - Activity Based Air Sampling forAsbestos5 (US EPA, 2007). Soils are classified and the site is portioned into grided areasof similar characteristics (i.e. asbestos concentration and soil classification). An exampleof a site separated into portioned areas is shown in Figure 2.3, where the red areas are ofhigh, yellow of medium, and blue of low concern.

Figure 2.3: An aerial photograph of a site showing areas of focus.

Meteorological data such as wind speed and direction is collected during sampling, butideally will also be collected for 6~12 months prior to sampling to determine worst-caseconditions. Personal sampling pumps are calibrated in the laboratory and again on-site.Depending on the required sensitivity, the amount of time required for sampling will bedetermined prior to sampling. The formula used for determining sampling time is:

4 http://vsp.pnl.gov/

5 http://www.ert.org/products/2084.PDF

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SAKA

Vgrid

filter (after US EPA, 2007)

where:

V = volume required to obtain desired analytical sensitivity (L)

K = number of grid openings observed during TEM analysis (unitless)

S = determined analytical sensitivity (structures/L)

Afilter = area of filter media (mm2)

Agrid = area of grid openings examined during TEM analysis (mm2)

It has been found that a 0.8µm pore size filter paper is sufficient for use with bothamphibole and serpentine fibre types and that it provides greater flow rates than smallerpore sizes. Typically a flow rate of 3.5~10 L/min should be used to ensure an adequatesample volume is collected. Problems with increased flow rates resulting in anunrepresentative sample being obtained may include:

increased backpressure across the filter;

large amounts of debris on the filter;

modification of asbestos structures or dislodgment from the filter; or

pumps faulting.

Stationary air monitors are placed upwind (one) and downwind (two) during ABSactivities, shown below in Figure 2.4. Perimeter samplers and background or reference airmonitors should be located well clear of ABS, with reference samplers being located wellaway from the site to determine background concentrations. Containment structures witha high efficiency particulate air (HEPA) filter or mist sprays may be used to suppress dustmigrating off-site if the location of testing is sensitive, but must be designed to ensure thatABS sampling is not affected.

Results obtained from grids where ABS has been conducted may be extrapolated to othergrids where ABS is not completed to reduce sampling volumes. This can only be donewhen similar soil types and asbestos concentrations are present. This is highlighted inFigure 2.3 where the site is portioned into areas of focus.

There are a number of analytical considerations that need to be taken into account whendeveloping ABS plans, including:

determination of the analytical sensitivity required for the site, and therefore theamount of air required to pass through the filters; and

the amount of grids to be viewed during TEM analysis to ISO 10312 (InternationalStandards Organization, 1995).

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If a low analytical sensitivity is required, a large amount of air is required to pass throughthe filter or a greater number of grids must be counted. For sampling to remain feasible ahigher flow rate would be desirable. To ensure a representative sample is obtained, itshould be noted that higher flow rates may result in:

increased debris other than asbestos obstructing the view of laboratory analystswhen analysing for asbestos;

the pump failing due to increased backpressure;

larger batteries being required; and

possible dislodgement or alteration of original forms of asbestos structures on thefilter.

Figure 2.4: The general arrangement for ABS with stationary air monitors placedapproximately 3.5m from ABS activities.

A large amount of debris on the filter paper may require an indirect sample analysis,although direct analysis is desirable for ease of analysis. The basic assumption of bothmethods is that the sample is evenly distributed on the filter, with indirect analysispossibly overestimating concentrations due to changes in asbestos matrices (i.e. the

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modification of matrices causing higher numbers of free fibres). Indirect analysis shouldonly be used if >25% of the filter paper is covered with debris. It should be noted thatunquantifiable errors may be introduced during indirect analysis due to the solutionneeding to be diluted for quantification.

Ultimately, risk assessment at the site is dependant upon the risk assessor and thesensitivity of the site. Separate risk calculations should be completed for each ABSactivity and for stationary air monitoring. These calculations are later combined todetermine excess lifetime cancer risk levels. Risk ranges for the site are developed takinginto account soil concentrations, soil type and proposed site usage using professionaljudgement.

Remediation may include the use of capping layers, excavation of portions of soil deemedto produce unacceptable concentrations of asbestos in air and appropriate sitemanagement to mitigate dust generation where possible. Under the new frameworkSuperfund sites are reviewed every 5 years to ensure the site still remains below theallowable cancer risk level and that soil disturbing activities in areas of contaminationhave not occurred.

2.5 United States Environmental Protection Agency (US EPA)Region 10, Seattle, Washington2.5.1 North Ridge EstatesNorth Ridge Estates6 is a residential subdivision developed on an ex-military recuperationbarracks located in Klameth Falls, Oregon. The military base was demolished in the late1970’s, resulting in a variety of ACMs being scattered across the site. No remedialmeasures were taken during the demolition phase with building footprints still visible atthe site. Chrysotile was found to be the predominant asbestos type found, althoughamosite was also been found in small quantities. No risk assessment was conducted priorto residential redevelopment, with large scale asbestos contamination, predominantlybonded ACMs, found on and below the soil surface. Of greatest concern is thedegradation of these bonded materials into more friable forms, with asbestos beingreleased into the ambient environment over time.

Preliminary investigations were conducted including intrusive soil investigations andstationary air monitoring to determine concentrations of asbestos. Soil samples wereanalysed using PLM, with no excessive levels of asbestos detected. Stationary airmonitoring results also only detected low levels of asbestos posing relatively low risk toreceptors.

Preliminary risk assessment at the site was completed using the Modified ElutriatorMethod7 (Berman & Crump, 2000) and ABS. Results from the preliminary investigationhave shown that a greater risk was present at the site than first thought. While a majority

6http://yosemite.epa.gov/r10/cleanup.nsf/4c5259381f6b967d88256b5800611592/6d3ab7def32c248a88256d3a007e7f53!OpenDocument

7 http://www.aeolusinc.com/Modified_Elutriator_Method.pdf

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of contamination is in bonded forms, friable materials would pose an increased risk asthey degraded over time. Of concern also were bonded materials that had weathered overtime and become friable. Initial risk reduction measures included identifying andremediating areas of known amosite containing materials and ‘emu bobbing’ of visibleACM pieces as an emergency response. Approximately 60 tonnes of ACM has beenremoved from the site, with an estimated 1500 tonnes still remaining. The handling ofchrysotile materials was seen as low risk, unless purposely broken or abraded. It has alsobeen observed that ACMs are migrating to the surface, requiring continual passes toremove ACMs.

An immediate response is not required as most materials are in a relatively bonded form,resulting in the option to conduct a more thorough risk assessment to determineappropriate remediation options for the site. Generally the site lies within the USEPAsgenerally accepted risk range of 10-4~10-6 at this stage, but would exceed this as ACMsdegraded over time and became friable.

2.5.2 Region 10 Laboratory, Manchester, SeattleThe fluidised bed asbestos separator is currently a tool under development by the USEPA. It is envisaged to be used in conjunction with ABS at Superfund sites, and is shownin Figure 2.5. It has been developed to determine approximate concentrations in air basedupon soil samples obtained from the field. 15L/min of air is forced through the ~20g soilsample, capturing the lighter materials on a cassette which may then be analysed forasbestos using TEM to ISO 10312 (International Standards Organization, 1995). Thismethod is still to be validated by the US EPA, although a standard operating procedure(SOP) is available.

Figure 2.5: The fluidised bed asbestos separator developed by the US EPA.

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2.6 Massachusetts Department of Environmental Protection Agency(MassDEP), Boston, MassachusettsCurrently the Massachusetts Department of Environmental Protection (MassDEP)asbestos in soil workgroup8 is creating asbestos in soil guidelines to be included in theMassachusetts Contingency Plan (MCP). Within these guidelines are a number of optionsavailable to assess risk including ABS, Modified Elutriator Method (Berman & Crump,2000) and determining levels at a site that are consistent with background levels.Providing options to assess risk allows contaminated land owners and/or consultants tochoose appropriate assessment and remediation techniques for a given site to ensure riskis below the required excess lifetime cancer risk level.

In Massachusetts there are currently no special waste facilities available for disposal ofasbestos containing soil or waste. Hence, it is a very expensive exercise to remediate asite. This has led to proposed soil concentration thresholds for reuse at landfill sites asgrading/shaping material (8000 mgACM/kgsoil) and daily cover (1000 mgACM/kgsoil). This isbased upon testing conducted at North Point Park, Cambridge9. ABS, the MassDEPSieve Method (MassDEP, 2007) and the Modified Elutriator Method were all used todetermine these threshold values for reuse.

8 http://www.mass.gov/dep/cleanup/compliance/asbest03.htm

9 http://www.mass.gov/dep/cleanup/compliance/AIS-results-081106.pdf

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3. The Netherlands

The Netherlands are currently the only jurisdiction to implement threshold levels forasbestos in soil and air, but also to derive a relationship between soil and airconcentrations. Threshold levels to which receptors can be exposed with negligible riskwere determined through a study completed in the late 1980’s looking at both human andanimal exposures. Current regulations (TNO, 2005) allow 100mg/kg (the sum of 1xserpentine and 10x amphibole fibre types) of asbestos in recycled waste materials andsoils in the Netherlands. Figure 3.1 shows the general tiered risk assessment approach.

Figure 3.1: The general risk assessment process used in the Netherlands(after TNO, 2005; Swartjes et al., 2003).

Preliminary investigationand desktop study

Exploratory survey

Soil conc.>100

mg/kg

Site-specific riskassessment

No furtheraction required

Air conc.>0.001f/mL

Remediationcompleted

No

Yes

Yes

No

Detailed survey

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3.1 Netherlands Ministry of Housing, Spatial Planning and Environment(VROM), Den Haag, NetherlandsApproximately a third of all buildings in the Netherlands contain asbestos, with anextensive inventory conducted of all government buildings. Schools may also beinventoried in the near future. All asbestos used in the Netherlands was imported, with atotal ban placed on the importation and use of asbestos in 1994 (European Communities,2007).

Risk communication campaigns are currently being developed by the Netherlandsgovernment to better educate the general public on the risks associated with asbestos-contaminated soils. There is still a mixed response from the community regardingcontaminated sites.

3.2 Netherlands Organisation for Applied Scientific Research (TNO),Utrecht, NetherlandsThe Netherlands are currently the only jurisdiction to provide in a regulatory formthreshold limits for excess lifetime cancer risk levels. Epidemiological and toxicologicalstudies were completed in the late 1980’s to determine allowable concentrations to whichhumans could be exposed (Montizaan & van der Heijden, 1989). Conclusions drawn fromthis study are outlined in Table 3.1.

Table 3.1: Risk levels for concentrations of asbestos fibres >5µm in length percubic metre of air (after Swartjes et al., 2003, p. 22).

Disease Risk Level Concentration of asbestos fibres>5µm in length per cubic metre of air1

1 in 1 000 000 (10-6) 10 – 100 (amphibole)100 – 10 000 (serpentine)

Mesothelioma1 in 10 000 (10-4) 1 000 – 10 000 (amphibole)

10 000 – 100 000 (serpentine)

1 in 1 000 000 (10-6) 100 – 1 000Lung Cancer2

1 in 10 000 (10-4) 10 000 – 1 000 0001 Analysed using scanning electron microscopy (SEM).2 Assuming 30% of the population are smokers.

It was found that asbestos fibres had differing potencies which depended upon theasbestos fibre type and length. A summary of potency values assigned to fibres is shownin Table 3.2.

Approximately twenty contaminated sites were used to develop ASBINS regulations in theNetherlands, with a summary provided in Table B.1 of Appendix B of raw data collected ateach site. This included collecting unique site characteristics such as types of ACMs, formof asbestos (bonded or friable), and included a range of levels of contaminationconcentrations, soil types and weather conditions. Soil concentrations were determined toNetherlands Standard NEN 5707 (TNO, 2005) where possible. Soil samples taken from

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across the site were based upon statistical methods outlined in NEN 5707 (TNO, 2005) todetermine the number and location of sampling locations. When a large range ofconcentrations of contamination were found at a site, the greatest contaminationconcentration was assumed across the entire site as a ‘worst-case’ scenario. If resultswere generally consistent, then a spatial average contamination concentration was used.

Table 3.2: Potencies of various asbestos fibre types (Swartjes & Tromp, 2008).Fibre Type Fibre Length PotencyChrysotile >5µm 1

Chrysotile <5µm 0.1

Amphibole >5µm 10

Amphibole <5µm 1

For the tier three site-specific risk assessment phase, laboratory data was obtained forworst case conditions. This included using highly friable materials during testing, providinga large soil surface area for air to be passed across to maximise asbestos emissions andby providing dry soil conditions. All laboratory testing was conducted by the NetherlandsOrganisation for Applied Scientific Research (TNO) and standardised by maintaining thesame staff on the project. No standard operating procedure was developed for theseexperiments.

Results from these experiments and previously completed epidemiological studiesallowed the derivation of negligible and maximum permissible risk levels for asbestos.These levels are:

negligible risk (NR) level (10-6 excess lifetime cancer risk level) = 1 000 fibre equivalents/m3

air = 0.001 fibre equivalents/mLmaximum permissible risk (MPR) level (10-4 excess lifetime cancer risk level) = 100 000 fibre equivalents/m3

air = 0.1 fibre equivalents/mL

A summary of data obtained from these experiments is shown in Figure 3.2 from whichthe 0.01% (w/w) soil intervention value was determined for the negligible risk level of0.001 fibre equivalents/mL.

15

Figure 3.2: Results showing the relationship developed between soil and airconcentrations of asbestos (Swartjes & Tromp, 2008; Swartjes et al., 2003).

Dispersion modelling was also used as semi-quantitative assessment tool using thePLUIM-PLUS model. Originally this model was used for modelling particulates of trafficemissions, but the model was modified slightly and it was assumed that the aerodynamicvelocity of asbestos fibres was <10µm. These results were then compared with stationaryair monitoring results to determine approximate air concentrations at given distances froma contamination point source. These results correlated well to provide a rough estimate ofair concentrations at a given distance from a contamination point source.

3.3 Agrolab Analytical Laboratory, Deventer, NetherlandsCommercial laboratories in the Netherlands are provided accreditation by TNO to quantifyasbestos in soil. Laboratories are also externally audited annually, with an inter-laboratoryvalidation being completed to ensure consistency in reporting. There are two basicassumptions of samples received by a laboratory; that samples are representative innature, and that free fibre contamination is homogeneous. Soil concentrations aredetermined to Netherlands Standard NEN 5707 (TNO, 2005). Of prime importance isassessing the forms of asbestos through a qualitative assessment and the ability for freefibres to be liberated from an ACM matrix. An analytical sensitivity of 1mg/kg (0.0001%(w/w)) is obtained through this method. Depending on the sample matrix, sample analysismay take between 0.5~8 hours. Soil samples are reduced using mechanical sieves andthe separate sieve fractions are analysed for asbestos. A more detailed outline of theprocess, including images, is provided in Appendix B.

16

4. United Kingdom

No regulatory value for acceptable concentrations of asbestos in air exist in the UnitedKingdom, although the World Health Organization (WHO) air quality guidelines forasbestos10 suggest 0.0005 fibre/mL as a negligible risk level (WHO, 2000). The generalapproach to assessing risk in the UK is shown in Figure 4.1.

Figure 4.1: The general approach currently adopted for assessing risks atcontaminated soil sites in the United Kingdom.

10 http://www.euro.who.int/document/aiq/6_2_asbestos.pdf

Preliminary investigation& desktop study

Site inspection(10m x 10m grids)

>0.1% w/w

Remediation occurs

Remediationadequate

Quantitativeassessment

Generallyfree fibresobserved

Risk assessmentconducted

Probably<0.001% w/w

Probably>0.001% w/w

Site cleared for use byEnvironment Agency

Yes

Yes

YesNoNo

No Unacceptablerisk present

Yes

No

17

Generally a 10-5 cancer risk level is deemed acceptable as an action level, with excesslifetime cancer risks being determined by the Hodgson and Darnton11 model (Hodgson &Darnton, 2000).

The Environment Agency (EA) suggests a case-by-case basis when asbestos in soil isdiscovered, with current regulations allowing 0.1% (w/w) of asbestos in waste materialsand soils (EPA, 2002). Any waste or soil material exceeding this value is classified ashazardous waste and must be disposed of appropriately.

Generally, most clients are interested in weather a site exceeds the European regulatoryvalue of 0.1% (w/w), with further analysis conducted to determine the extent of freeasbestos fibre contamination for low level contamination. Converting information obtainedthrough the quantification process into forms useful in risk assessment remains achallenge.

4.1 Institute of Occupational Medicine (IOM), Edinburgh, ScotlandIOM offers consulting services and a commercial laboratory to quantify asbestos in soilusing polarised light microscopy (PLM). No laboratory in the UK is accredited by theUnited Kingdom Accreditation Service (UKAS) to conduct quantification of asbestos in soilin low concentrations, with no regulatory document being available for this purpose. IOMreports on a ‘best practice’ basis using a method developed in-house: Development andValidation of an Analytical Method to Determine the Amount of Asbestos in Soils andLoose Aggregates12 (Davies et al., 1996). A small amount of other commerciallaboratories also quantify asbestos in soil using this method or other in-house methodsadapted from the above.

4.2 Health and Safety Laboratories, Buxton, EnglandCurrent risk assessment in the UK is based upon hazard identification. The challenge isconverting information obtained in the hazard identification phase to information useful inrisk assessment. Currently the Environment Agency (EA) is working on a document titledThe Way Forward that will provide guidance on how to assess the risk of asbestos-contaminated soil sites in the UK. This is soon to be released in the near future subject toapproval.

The Hodgson and Darnton (2000) model was developed by the Health and SafetyExecutive (HSE) for use in risk assessment in the UK. This model is based upon a meta-analysis of 23 studies and differentiates between the potency of chrysotile, amosite andcrocidolite fibre types. It has been used at a number of sites across the UK (Clay & Mailer,2008; Jones et al., 2005).

11 http://annhyg.oxfordjournals.org/cgi/reprint/44/8/565

12 http://www.hse.gov.uk/research/crr_pdf/1996/crr96083.pdf

18

The HSE, in conjunction with the EA, have also developed a soil dustiness test todetermine concentrations of asbestos that may be released to the air in worst-caseconditions. Figures 4.2 and 4.3 show the apparatus used in the laboratory-based test. Themethod still needs to be validated before use in industry but is due in the near future.

Figure 4.2: The laboratory based soil dustiness testing apparatus.

As the drum is slowly rotated, ribs within the drum wall cause dust emissions that aremeasured for asbestos. The method allows the determination of inhalable, thoracic andrespirable dust concentrations.

Figure 4.3: A view inside the rotating drum.

19

4.3 British Occupational Hygiene Society (BOHS) AsbestosContaminated Land Seminar, London, EnglandThe British Occupational Hygiene Society (BOHS) held an asbestos contaminated landseminar13 to update those involved with contaminated soil sites in the UK of the latesttools available and developments in risk assessment. A consistent message wasportrayed throughout the seminar presentations containing case studies - it wasimpractical to believe that all asbestos could be completely removed from a site. Byremoving all visible asbestos and conducting a site-specific risk assessment, sites wereremediated to either reduce the risk at operational sites for continued use orredevelopment.

4.3.1 Woolston RiversideThe Woolston Riverside site was a former shipyard located on the Itchen River,iSouthampton that was contaminated with asbestos due to previous site practices. Adesktop study was completed to determine the likelihood of contamination and anintrusive subsurface investigation conducted using trial pits and boreholes. A soilsampling plan was developed using the draft method MDHS AA (unpublished) andasbestos identified using HSG 248 Asbestos: The Analysts’ Guide for Sampling, Analysisand Clearance Procedures (HSE, 2005). Asbestos in soil was quantified using the IOMmethod (Davies et al., 1996) and the HSL soil dustiness test used to determine asbestosfibre generation in worst-case conditions (Clay & Mailer, 2008). Typically concentrationsof asbestos in soil were <0.1% (w/w). A comparison was also conducted between soilconcentrations and soil dustiness testing results to determine if there was a correlationbetween the two.

Using this information the Hodgson and Darnton model (2000) was used to determine theexcess lifetime cancer risk at the site before and after remediation. It was determined thatmechanical screening and soil washing was an appropriate remediation technique thathad previously proved successful in the Netherlands. Remedial targets for soil were set at<0.01% (w/w) and <0.0025 f/mL in air and achieved through these remediationtechniques. The site is now being redeveloped for residential reuse.

4.3.2 Electricity Supply Board (ESB) Contamination Assessment and RemediationAsbestos was used at many ESB power station sites throughout the twentieth centuryresulting in the need to remove an extensive amount of waste containing asbestos. In1968 any accessible asbestos was removed, including known areas on site where wastematerials had been dumped. The next phase of ESBs remedial works was to ensure ESBsites were below the agreed Irish and European Hazardous Waste classification value of0.1% (w/w) in soil (EPA, 2000). A more stringent threshold value of 0.01% (w/w) wasadopted based upon the regulatory value used in the Netherlands and on advice fromTNO.

13 http://www.bohs.org/eventDetails.aspx?event=166

20

Sites were initially investigated by completing a preliminary site investigation. Thisincluded the study of station records, interviews with past and present personnel andintrusive subsurface soil investigations. Investigation techniques such as trenching andcoring were used to obtain soil samples of approximately 1kg, which were assessed on-site for ease of assessment. The Netherlands Standard NEN 5707 (TNO, 2005) was usedto quantify soil asbestos concentrations.

During remediation 5m x 5m grids were marked out and the soil visually examined byhand. Large ACMs that were observed were removed manually using an emu pickingtechnique. Air monitoring was also conducted throughout remediation to MDHS 39/4Asbestos Fibres in Air Sampling and Evaluation by Phase Contrast Microscopy (PCM)under the Control of Asbestos at Work Regulations14 (HSE, 1995). Independent externalauditors would then validate remediated areas and label it as “asbestos safe” if soilconcentrations were below the agreed 0.1% (w/w). Quite often non-detect results of<0.001% (w/w) were obtained for soil samples (Tempelman et al., 2006). All results for airconcentrations were found to be below 0.01 f/mL.

14 http://www.hse.gov.uk/pubns/mdhs/pdfs/mdhs39-4.pdf

21

5. Conclusion

Much debate is still required between professionals as to developing a regulatory processfor assessing asbestos-contaminated soil sites in Australia. While the challenge ofdeveloping a scientifically-defensible, ecologically sustainable ASBINS process that maybe accepted on a national basis is daunting, the current wasteful and poorly justifiedpractices cannot be allowed to continue. This is vital to better understand risks toreceptors resulting from contaminated soil sites and to conserve natural resources wherepossible, provided it can demonstrated that no significant risk of harm is present.Regulatory guidance is available abroad, which is promising, but a great deal of researchis still required to determine its applicability and relevance to Australian conditions.

Each jurisdiction studied provide either a guideline or regulatory value for soil or airconcentrations of asbestos. A matrix of allowable soil and air concentrations is shown inTable 5.1. Air concentrations were been based upon epidemiological studies completed indeveloping each jurisdictions risk model, while soil concentrations were developedthrough practical testing in laboratory and on-site settings. This allowed a relationshipbetween soil and air concentrations to be developed.

Table 5.1: A risk matrix of regulatory and guideline values for asbestos in soil & air.Air Concentration For

Associated Excess LifetimeCancer Risk (fibre/mL)Jurisdiction Risk Model

10-6 10-5 10-4

Soil Conc.(% w/w)

United States(IRIS, 1993)

US EPAIRIS 0.000004 0.00004 0.0004 -

Netherlands(TNO, 2005) RIVM 0.001a - 0.1a 0.01

United Kingdom(WHO, 2000;EPA, 2002)

Hodgson &Darnton - 0.0005 - 0.1b

(0.001)c

Australia(ACLCA, 2002) - 0.001

(0.0005)d - - 0.001a Fibre concentration of ‘fibre equivalents’, where the fibre type and length defines its potency.b 0.1% (w/w) corresponds to the classification of asbestos as a Hazardous Waste under the European Waste Act.c 0.001% is a recommended value for which free fibre contamination can generate values of concern of respirableasbestos fibres (Addison et al., 1988).d 0.001 f/mL is the suggested practical fibre count limit, while 0.0005 f/mL is the suggested air thresholdconcentration (ACLCA, 2002; Imray & Neville, 1993).

Table 5.1 shows there are substantial differences in air concentrations between the IRISrisk model, and the RIVM and Hodgson & Darnton risk models for negligible risk levels of10-6 and 10-5 respectively. These studies have been based generally on the same cohortdata, with additional animal exposure assessments having also contributed. Of concernthough is the applicability of data used to come to the above conclusions. As a largeamount of human exposure data occurred in high concentration environments,assumptions have been made to extrapolate to very low orders of magnitude – in somecases four orders of magnitude. Variations in analytical tools used to determine fibreconcentrations, namely light and electron microscope methods, and also extrapolation

22

techniques (i.e. Linear or non-linear extrapolations, or a combination of the two) couldexplain these large variances.

Table 5.2 outlines how each risk model differentiates between the potency of amphiboleand serpentine fibre types. In the IRIS risk model, no differentiation is made betweenamphibole and serpentine fibres, whereas in the Hodgson and Darnton and RIVM riskmodels amphibole fibre types are weighted differently. Chrysotile generally appears to beless potent than amphibole fibre types, although the IRIS risk model does not take thisinto account. However, recent research conducted in the US tends to suggest thoughthere are differences in potency (Berman & Crump, 2008a; Berman & Crump, 2008b).

Table 5.2: Asbestos fibre potencies suggested in each risk model(BOHS (Burdett), 2009).

Model Chrysotile Amosite CrocidoliteUS EPA IRIS 1 1 1

RIVM 1 10 10Hodgson & Darnton 1 100 500

Specific to each jurisdictions risk assessment process soil and air-based risk assessmenttechniques have been developed. While some exposure-pathway assessment tools arestill in a formative stage and are still to be validated, it is a promising sign for Australia toadopt or use as a basis in developing a similar assessment technique. While it is knownthat the risk asbestos poses to receptors is through inhalation, the ability to create arelationship between soil and air concentrations of asbestos has allowed soil basedinvestigations to be used in the United Kingdom and Netherlands. While the United Statesopts for an air concentration determination process, the question is therepresentativeness of results obtained in the field, either by soil or air sampling. It wasfound that soil based assessment techniques were used in all methods, with the US EPAframework only aiming to detect approximate concentrations of asbestos to establishareas of focus of ABS. The Netherlands and United Kingdom methods based soilsampling programs upon statistics to determine the required location and number of soilsamples to be taken. Asbestos is a unique contaminant in that it does not migrate throughsoil or degrade over time, posing the question of the viability of developing a soil samplingprogram that is representative of site contamination. In any case, a large amount ofprofessional judgement is required in any of the above processes.

Analytical techniques are available for completing a site-specific risk assessment, but thechallenge of providing a technically and financially feasible solution is difficult as polarizedlight microscope (PLM) is the only NATA endorsed assessment tool available in Australia.Internationally recognised electron microscope methods have been developed fordetermining air concentrations using both SEM and TEM. The Netherlands Standard usesan adaptation of the ISO 14966 (International Standards Organization, 2002) method fordetermining soil concentrations. There is still some debate between professionals as towhether light microscope methods provide the analytical sensitivity required, although theNetherlands and United Kingdom are currently using PLM for quantification of asbestos insoil.

It is apparent in all methods that a large amount of professional judgement is required toconduct risk assessment. While a number of uncertainties still remain in each jurisdictions

23

approach, a defined end point is provided to determine whether remediation is necessaryto reduce excess lifetime cancer risks at a given site. Whether a case-by-case basis isused in Australia or an overarching assessment process developed, clarity is still requiredbetween government agencies and those conducting risk assessments as to a definedend-point. Answering the ‘how clean is clean enough?’ question is fundamental to the riskassessment of asbestos-contaminated soil sites across Australia.

24

6. Recommendations

An asbestos-specific regulatory document is required to provide a standard assessmentmethod with a defined end-point. This should include as a minimum guidance on fieldsampling techniques, analytical assessment and risk assessment methodologies, and ifrequired, remediation options for a site deemed a risk to human health. For this to bedeveloped further investigation will be required into the:

ability to adopt or develop a risk model similar in function to those developed inthe United States, Netherlands or United Kingdom for determining excess lifetimecancer risks. This may include developing a health-based investigation level (HIL)for soil and/or air, consistent with other carcinogenic contaminants outlined in theNational Environmental Protection Assessment of Site Contamination Measure(NEPM);

value and feasibility of studying the relationship between soil and airconcentrations of asbestos based upon laboratory and on-site testing of knowncontaminated soil sites in Australia. This would include developing a data bank ofsite-specific characteristics similarly completed in the Netherlands (refer to TableB.1, Appendix B);

financial and technical feasibility of PLM or SEM/TEM as a NATA endorsedquantitative assessment tool in determining soil and air concentrations ofasbestos; and

development of a centralised information sharing community that is focused onthe ASBINS issue. This will include further expanding the ASBINS network inAustralia between the public and private sectors, and collaborating withinternational experts in the field of risk assessment.

25

7. References

Addison, J., Davies, L.S.T., Robertson, A., Willey, R.J. (1988). The Release of DisturbedAsbestos Fibres from Soil. Institute of Occupational Medicine, Edinburgh, ReportTM/88/14.

Australian Contaminated Land Consultants Association Incorporated (ACLCA) (2002).Asbestos in Soils – ACLCA Code of Practice. Australian Contaminated Land ConsultantsAssociation Incorporated, New South Wales.

Berman, D.W. (2009). Final Soil Sampling Results and Preliminary Risk Assessment forthe North Ridge Estates Site Klamath Falls, Oregon. United States EnvironmentalProtection Agency, Region 10.

Berman, D.W., Crump, K.S. (2008a). A Meta-Analysis of Asbestos-Related Cancer Riskthat Addresses Fiber Size and Mineral Type. Critical Reviews in Toxicology, 38(S1): pp.49 – 73.

Berman, D.W., Crump, K.S. (2008b). Update of Potency Factors for Asbestos-RelatedLung Cancer and Mesothelioma. Critical Reviews in Toxicology, 38(S1): pp. 1 – 47.

Berman, D.W., Kolk, A.J. (2000). Draft: Modified Elutriator Method for the Determinationof Asbestos in Soils and Bulk Material, Revision 1. United States EnvironmentalProtection Agency, Region 8.

British Occupational Hygiene Society (BOHS) (2009). Asbestos Contaminated LandSeminar. Wednesday 25th February, Society for Chemical Industry (SCI), 14-15 BelgraveSquare, London.

California Air Resources Board (CARB) (1991). Method 435 – Determination of AsbestosContent of Serpentine Aggregate. California Environmental Protection Agency AirResources Board, California.

CDM Federal Programs Corporation (2008). Final Draft Feasibility Study Report NorthRidge Estates Site Klamath County, Oregon. United States Environmental ProtectionAgency, Region 10, Work Assignment No. 217-RICO-10BT.

Clay, J., Mailer, S. (2008). Asbestos Testing and Treatments in Soils. A Work in Progress.Ground Engineering, February 2008.

Co-operative Research Council for Contamination Assessment and Remediation of theEnvironment (CRC CARE) (2008). Asbestos in Soil Workshop. Friday 15th August,Citigate Central Hotel, 169 – 179 Thomas Street, Sydney.

Davies, L.S.T., Wetherill, G.Z., McIntosh, C., McGonagle, C., Addison, J. (1996).Development and Validation of an Analytical Method to Determine the Amount ofAsbestos in Soils and Loose Aggregates. HSE Contract Research Report No. 83/1996,Institute of Occupational Medicine, Edinburgh.

26

enHealth Council (2005). Management of Asbestos in the Non-OccupationalEnvironment. Australian Government, Department of Health & Aging and enHealthCouncil, Australia.

Environmental Protection Agency (EPA) (2002). European Waste Catalogue andHazardous Waste List. Environmental Protection Agency, Ireland.

European Communities (2007). Official Journal of the European Union. Office for OfficialPublications of the European Communities (Publications Office), ISSN 1725-2555,Volume 50, May 2007.

Health and Safety Executive (HSE) (2005). Asbestos: The Analysts’ Guide for Sampling,Analysis and Clearance Procedures. Health and Safety Executive, United Kingdom.

Health and Safety Executive (HSE) (2001). Methods for the Determination of HazardousSubstances 100 (MDHS 100) – Surveying, Sampling and Assessment of Asbestos-Containing Materials. Health and Safety Laboratory, Buxton, England.

Health and Safety Executive (HSE) (1995). Methods for the Determination of HazardousSubstances 39/4 (MDHS 39/4) – Asbestos Fibres in Air – Sampling and Evaluation byPhase Contrast Microscopy (PCM) Under the Control of Asbestos at Work Regulations..Health and Safety Laboratory, Buxton, England.

Health and Safety Executive (HSE) (unpublished). MDHS AA – Methods for theDetermination of Hazardous Substances: Asbestos Contaminated Land (Draft 6).Guidance on the Identification and Quantification of Asbestos in Contaminated Land.Health and Safety Executive, United Kingdom.

Hodgson, J.T., Darnton, A. (2000). The Quantitative Risks of Mesothelioma and LungCancer in Relation to Asbestos Exposure. Elsevier Science and British OccupationalHygiene Society, Epidemiology and Medical Statistics Unit, Health and Safety Executive,United Kingdom.

International Standards Organization (ISO) (2002). ISO 10496: 2002: Ambient Air –Determination of Numerical Concentration of Inorganic Fibrous Particles – ScanningElectron Microscopy Method. International Organization for Standardization, Switzerland.

International Standards Organization (ISO) (1995). ISO 10312: 1995: Ambient Air –Determination of Asbestos Fibres – Direct Transfer Transmission Electron MicroscopyMethod. International Organization for Standardization, Switzerland.

Jones, A.D., Cherrie, J.W., Cowie, H., Soutar, A. (2005). An Assessment of Risks Due toAsbestos on Farm Tracks and Rights of Way in South Cambridgeshire. Institute ofOccupational Medicine, Research Report TM/05/07, Edinburgh, United Kingdom.

Ladd, S. (2005). El Dorado Hills Naturally Occurring Asbestos Multimedia ExposureAssessment El Dorado Hills, California – Preliminary Assessment and Site InspectionReport Interim Final. United States Environmental Protection Agency, Region 9, SanFrancisco, California, Contract No. 68-W-01-012.

27

Massachusetts Department of Environmental Protection (MassDEP) (2007). Draft MADEP Sieve Method for the Determination of Asbestos Debris in Soil. MassachusettsDepartment of Environmental Protection, United States of America.

Massachusetts Department of Environmental Protection (MassDEP) (2006). Draft:Asbestos in Soil - Streamlining Regulation and Management. Massachusetts Departmentof Environmental Protection, Bureau of Waste Prevention and Waste Site Clean-Up.

Montizaan, G.K., van der Heijden, C.A. (1989). Appendix to Report No. 758473013 –Integrated Criteria Document Asbestos Effects. National Institute of Public Health andEnvironmental Protection.

National Environment Protection Council (NEPC) (1999). Assessment of SiteContamination National Environmental Protection Measure (NEPM). NationalEnvironment Protection Council Service Corporation.

National Occupational Health and Safety Commission (NOHSC) (2005). Guidance Noteon the Membrane Filter Method for Estimating Airborne Asbestos Fibres 2nd Edition[NOHSC:3003 (2005)]. Commonwealth of Australia, Department of Communications,Information Technology and Arts, Canberra, ACT.

Netherlands Organisation for Applied Scientific Research (TNO) (2005). NEN 5707: Soil –Investigation, Sampling and Analysis of Asbestos in Soil (translated to English by USEPA). Standardisation Centre, Netherlands Standards Institute.

Perry, A. (2004). A Discussion of Asbestos Detection Techniques for Air and Soil. Officeof Solid Waste and Emergency Response & Office of Superfund Remediation andTechnology Innovation, United States Environmental Protection Agency,

Standards Australia (2002). AS 4964 - Method for the Qualitative Identification ofAsbestos in Bulk Samples. Standards Australia.

Swartjes, F.A., Tromp, P.C. (2008). A Tiered Approach for the Assessment of HumanHealth Risks of Asbestos in Soils. Soil and Sediment Contamination, Volume 14, Issue 4,pp. 137 – 149.

Swartjes F.A, Tromp P.C, Wezenbeek J.M (2003). Assessment of the Risks of SoilContamination with Asbestos. National Health and Environmental Institute, Netherlands,RIVM Report 711701034/2003.

Tempelman, J., Colman, P., Scanlon, J. (2006). Management of Asbestos ContaminatedSites at ESB Power Stations, Focusing Primarily on Remediation. Electricity SupplyBoard, Ireland.

United States Environmental Protection Agency (US EPA) (2008a). Framework ForInvestigating Asbestos-Contaminated Superfund Sites. Office of Solid Waste andEmergency Response, United States Environmental Protection Agency.

United States Environmental Protection Agency (US EPA) (2008b). Clear CreekManagement Area Asbestos Exposure and Human Health Risk Assessment. UnitedStates Environmental Protection Agency, Region 9, San Francisco, California.

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United States Environmental Protection Agency (US EPA) (2007). Standard OperatingProcedures: Activity-Based Sampling for Asbestos. United States EnvironmentalProtection Agency, Environmental Response Team.

United States Environmental Protection Agency (US EPA) Integrated Risk InformationSystem (IRIS): Asbestos CASRN 1332-21-4 (accessed 20/03/2008)

Website: http://www.epa.gov/ncea/iris/subst/0371.htm

World Health Organization (WHO) (2000). Air Quality Guidelines for Europe, SecondEdition. World Health Organization Regional Office, Copenhagen, Denmark.

29

Appendix A – Additional information obtained from theUnited States Environmental Protection Agency

30

A.1 Tools used during activity-based sampling to collect data atcontaminated-soil sites.

Figure A.1: An air sampling pump used for determining air concentrations ofasbestos during ABS.

Figure A.2: A rotometer used for calibrating sampling pumps.

31

Figure A.3: A portable meteorological station.

32

Appendix B – Additional information obtained from theNetherlands

33

B.1 Quantitative assessment process of soil samples to NetherlandsStandard NEN 5707 (TNO, 2005).

The general quantitative assessment process in the Netherlands is as follows:

1. A 10kg sample is obtained from the field marked ‘asbestos containing’.

2. The sample is mechanically reduced using automated sieves for a 15 minuteperiod in a negative pressure containment structure. Air inside the containmentstructure is discharged to the atmosphere through a high efficiency particulate air(HEPA) filter.

3. Sieve fractions are transferred to separate vessels for mass determination.

4. Sieve fractions are weighed using an analytical balance.

5. Sieve fractions are initially analysed using a stereomicroscope. 100% of the sievefraction 2mm is examined, with the weight of the required sieve fraction <2mmbeing determined to achieve an analytical sensitivity of 1 mg/kg (0.0001% (w/w)).

6. Suspected ACMs are placed in a Petri dish for further examination.

7. Suspected ACMs are mechanically disturbed to obtain asbestos fibre samples.These fibres are placed on microscope slides in appropriate refractive oils forpositive identification using polarized light microscopy (PLM). Fibre types that canbe positively identified include chrysotile, crocidolite, amosite, actinolite,anthophylite and tremolite.

8. ACM samples are then compared with reference samples and the asbestospercentage is estimated by the analyst.

9. Expert advice is given by laboratory analyst as to the possibility of respirableasbestos in the sample. If three or more pieces of ACM are discovered in <2mmfraction, then >500µm fraction may be analysed further for respirable fibres usingscanning electron microscopy (SEM) at the clients discretion.

10. Sieves used for mechanical separation are decontaminated using a vacuummounted with a HEPA filter for reuse.

If the client requests that the respirable fraction be analysed, then the <500µm fractionmay be transported to a laboratory carrying SEM capabilities. The respirable fraction isanalysed to ISO 14966 (International Standards Organization, 2002).

34

Figure B.1: Sample obtained from the field marked ‘may contain asbestos’.

Figure B.2: Samples may be wet or dry, with analysisable to accommodate both forms.

35

Figure B.3: Structure that contains the soil sample duringmechanical sieving and stereomicroscope analysis.

Figure B.4: Mechanical sieves used to separate the 10kgsoil sample into sieve fractions.

36

Figure B.5: The remaining fine fraction <500µm from sample.

Figure B.6: Sieve fractions are placed into separate containers for analysis.

37

Figure B.7: The weight of each sieve fraction is determinedusing an analytical balance.

Figure B.8: Samples are initially observed using a stereomicroscope.

38

Figure B.9: Suspect ACMs are placed aside and individually weighed.

Figure B.10: Relevant details of the analysis are recorded on a reporting sheet.

39

Figure B.11: Asbestos types are positively identified using PLM.

Figure B.12: The fine fraction (<500 µm) is stored in a sealed bag for future freefibre analysis (at the client’s discretion).

40

Figure B.13: The sieves and work area are decontaminated using a vacuum cleanermounted with a HEPA filter.

41

Table B.1 – A sample of data collected to develop the relationship between soil and air concentrations of asbestos in the Netherlands.

Site Site characteristics Date Materials containing asbestos Asbestos concentration (mg/kg) Soil characteristics

Name Area(m2)

Volume(m3) Site type Type 1 Type 2 Type 3 Total Bound Unbound Fibres

<100 m Chrysotile Crocidolite Amosite Type Moisture content

Schijf machine shop

Schijf factory site

2,500

2,500

Top layer

Top layer

27-11-02

27-11-02

AC

AC

Weath’d AC

Weath’d AC

Fibre bundles

Fibre bundles

78-1,900

510-6,700

13-300

290

65-1,600

220-6,700

72-1,700

470-6,200

6-140

38-480

Sand

Clay

Dry-medium damp

Medium damp

Osdorp 1 soil tip

Osdorp 2 soil tip

Osdorp 3 soil tip

Tip, lab. sim.

Tip, lab. sim.

Tip, lab. sim.

Dec 02

Dec 02

Dec 02

AC

AC

AC

Fibres

1,200

45

180

1,200

45

180

0.2

940

45

140

210

38

0.2

Sandy

Sandy

Sandy

0% (dried out)

0% (dried out)

0% (dried out)

Goor 1 resid. area

Goor 2 resid. area

Goor 3 resid. area

Upper layer

Upper layer

Top layer, lab. sim

12 Dec 02

12 Dec 02

Jan 03

Loose asb.

Loose asb.

Loose asb.

Pulpy

Pulpy

Pulpy Fibre bundles

810-2,600

0.6-20

620 330

810-2,600

290 280 340

Frozen, 10-15%

Frozen, 10-15%

5%

IJmuiden playground 3,750 Upper layer 17 Aug 00 AC Board Insulating cord 16-800 6-780 10-16 Sand Dry

Klarendal site

Klarendal site

Klarendal site

1,500

1,500

1,500

Top layer

Top layer

Top layer

10 May 01

15 May 01

15 May 01

AC

AC

AC

58 (0-250)

58 (0-250)

58 (0-250)

58 (0-250)

58 (0-250)

58 (0-250)

58 (0-250)

58 (0-250)

58 (0-250)

Black earth

Black earth

Black earth

Dry

Damp

Damp

Beuningen car park 10,000 Upper layer 6 May 01 AC Board 32 (0-96) 24 8 (0-9) 8 Granulate Moist

Arnhem 1 tips

Arnhem 2 tips

33,000

33,000

Tips

Tips

15 Sep 99

Sep 99

Floor-cloth

Floor-cloth

Board

Board

Packing

Packing

32 (0-194)

32 (0-194)

32 (0-194)

32 (0-194)

16 (0-68)

16 (0-68)

Granulate

Granulate

Damp

Damp

Hedeman site Almelo 1

Hedeman site Almelo 2

Hedeman site Almelo 3

110,000

110,000

110,000

Upper layer

Upper layer

Upper layer

6 Dec 01

12 Dec 01

21 Jan 02

Insulation

Insulation

Insulation

2 (0.8-17)

2 (0.8-17)

2 (0.8-17)

2 (0.8-17)

2 (0.8-17)

2 (0.8-17)

<0.01

<0.01

<0.01

0.5

0.5

0.5

0.3

0.3

0.3

1.2

1.2

1.2

Damp

Damp

Damp

Voordrempt 1 rubble lot

Voordrempt 2 rubble lot

200

200

Tip

Tip

1999

1999

AC

AC

50-100

50-100

50-100

50-100

50-100

50-100

Rubble

Rubble

Moist

Moist

Emmeloord rubble lot 2,300 Tip 1996 AC 10-50 10-50 10-45 2-5 Rubble Moist

Amsterdam 1 ind. site

Amsterdam 2 ind. site

Amsterdam 3 ind. site

18,000

18,000

18,000

11,000

11,000

11,000

Top layer (0-1 m)

Top layer (0-1 m)

Top layer (0-1 m)

May/Jun 01

July 01

Aug/Dec 01

Insulation

Insulation

Insulation

Fibre bundles

Fibre bundles

Fibre bundles

1-9,600

130-52,000

1-340

1-9,600

130-52,000

1-340

Sand

Sand

Sand

Moistened

Moistened

Moistened

Spoil 27,000 700 Upper layer Jan 01 Insulation Fibre bundles 1,000-10,000 1,000-10,000 1,000-10,000 Spoil Wet

Wieringermeer 1 soillots

Wieringermeer 2 soillots

Tips

Tips

Jun/Aug 00

Jun/Aug 00

AC

AC

Board

Board

Insulation

Insulation

700 (1-5,300)

700 (1-5,300)

1-5,300

1-5,300

<5,300

<5,300

Earth

Earth

Moistened

Moistened