Guidelines for the Assessment, Remediation and Management of Asbestos-Contaminated Sites in Western...

7/31/2019 Guidelines for the Assessment, Remediation and Management of Asbestos-Contaminated Sites in Western Australia

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Guidelines for the Assessment,

Remediation and Management

of Asbestos-Contaminated Sites

in Western AustraliaMay 2009


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Guidelines or the Assessment, Remediation and Management

o Asbestos-Contaminated Sites in Western Australia May 2009

1

Are these Guidelines relevant to you?

This document is primarily intended or contaminated sites regulators, auditors, and industry

consultants. However, parts may be useul to others, including:

Local Government Environmental Health Ocers and site workers Appndix B Managmnt

o Small-Scal Dmolition Asbstos Contamination and Appndix C Immdiat Rspons

Actions

Local government Sction 5.3 Ongoing Managmnt

Developers, owners, the public and local community members Ky Managmnt Mssags

and Chaptr 1 Introduction

For occupational health issues, advice should be sought rom WorkSae, Department o Commerce

on 1300 307 877. Detailed inormation is provided in the Commission or Occupational Saety and

Healths guidance note Occupational Saety and Health Management and Contaminated Site Work

2005, to be ound at:

www.commerce.wa.gov.au/WorkSae/PDF/Guidance_notes/Contaminated_Sites.pd

Additional asbestos inormation is available through the ollowing Department o Health and Australian

Saety and Compensation Commission sources:

www.public.health.wa.gov.au/2/867/2/asbestos.pm

www.saeworkaustralia.gov.au/NR/rdonlyres/1A198A7C-D0A7-40AD-964E-31673C695E92/0/

AsbestosCode.pd


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Preace

This document has been prepared by the Western Australian (WA) Department o Health (DOH)

to provide guidance or the investigation, remediation and management o asbestos-contaminated

sites, and it is based on both Australian and international best practices tailored to Western Australian

conditions. Asbestos is a major contamination issue in the State as a result o extensive past use.

The Guidelines include discussion on the character and toxicity o asbestos, its occurrence in

Western Australia, investigation procedures and criteria appropriate or dierent environmental

scenarios, and acceptable management strategies.

These Guidelines are likely to have the greatest application in urban situations but they are also

suitable or rural settings and mining and industrial sites in country areas.

Inquiries

Toxicology Branch

Environmental Health Directorate

Department o Health

PO Box 8172

PERTH BUSINESS CENTRE WA 6849

Phone: (08) 93884999

These Guidelines are available electronically at:

www.public.health.wa.gov.au/2/656/2/contaminated sites.pm


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Table o Contents

Prac 2

Figurs 5

Tabls 5

Ky managmnt mssags 7

1. Introduction 11

1.1 Role o the Department o Health 11

1.2 Asbestos-contaminated sites and health 11

1.2.1 Asbestos-contaminated sites in Western Australia 12

1.2.2 Nature o asbestos contamination 12

1.2.3 Risks rom asbestos contamination 13

1.2.4 Investigation criteria and clean-up goals 14

1.2.5 Air quality criteria 15

1.3 Assessment, remediation and management process 15

1.4 Consultative process 16

2. Prliminary sit invstigation 17

2.1 Site history investigation 17

2.2 Site inspection 182.2.1 Visual indicators 18

2.2.2 Characteristics o contamination 19

2.3 Sampling 19

3. Dtaild sit invstigation 20

3.1 DSI preparations 20

3.2 Sampling and analysis program 21

3.2.1 Acm as primary measure o asbestos contamination 21

3.2.2 Avoiding sampling invalidation by site activities 21

3.2.3 A ocus on judgmental sampling 21

3.2.4 Sampling Triggers and Densities 22

4. Sampling, monitoring and analytical mthods 24

4.1 Soil sampling 25

4.1.1 Hand-Picking (Emu-Bob) 25

4.1.2 Tilling 25

4.1.3 Screening 26

4.1.4 Test Pits and Trenching 27

4.1.5 Bore Samples 28

4.1.6 Stockpile Sampling 29

4.1.7 Determining Soil Asbestos Concentrations 31

4.1.8 Analytical Procedures 32


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4.2 Air quality monitoring 33

4.2.1 Air monitoring principles 33

4.2.2 Personal monitoring 344.2.3 Para-occupational sampling 34

4.2.4 Dust monitoring 35

4.3 Validation 36

4.4 Interpretation o results 37

4.5 Quality assurance/quality control 37

5. Risk assssmnt, rmdiation and managmnt 38

5.1 Human health risk assessment 38

5.1.1 Characterising the contamination 38

5.1.2 Determining exposure scenarios 38

5.1.3 Assessing the risk 39

5.2 Site remediation 40

5.2.1 Management in situ 41

5.2.2 Treatment on-site 43

5.2.3 Removal o-site 45

5.2.4 Air quality management 46

5.2.5 Validation 46

5.3 Ongoing management 47

6. Rporting 48

6.1 Soil Investigations 486.2 Air quality 49

7. Rrncs 50

Glossary 52

Appndix A Contaminated Sites Management Series

development o sampling and analysis programs 55

Appndix B Management o small-scale low-risk asbestos contamination 56

Appndix C Immediate response actions (IRAS) 59

Appndix D Contingency plans 61Appndix e Inormation brochure or owners and occupiers 62

Appndix F Case study: investigating and remediating an asbestos

contaminated site in Perth 64


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Key management messages

Background

In Western Australia (WA), asbestos was extensively used in building and other products into the

1980s. This legacy, combined with urban redevelopment and implementation o the Contaminated

Sites Act 2003 (CS Act), has resulted in asbestos-contaminated sites becoming an important human

health risk and management issue.

Characteristics o Asbestos Contamination

Asbestos is a contaminant that diers rom most others. In particular, its toxicology is such that it

primarily aects humans rather than being a risk to the environment. Inhalation o asbestos bres can

produce a range o lung-associated diseases, including cancers, sometimes resulting rom only low

levels o exposure.

Asbestos usually occurs discretely in an impacted area and will not degrade over time to orm less

harmul materials (i.e., it is very persistent). It can migrate through physical disturbance and this is

when its dangerous bres can be released.

Contamination Criteria

The Department o Health (DOH) takes a risk-based and, where necessary, conservative approach to

the uncertainties associated with protecting the public rom asbestos-contaminated sites. As a result,

the Guidelines employ the ollowing our general contamination criteria:

The investigation criterion or clean-up goal used by DOH is 0.001% asbestos in soil on a weight

or weight basis (w/w) or ree bre-related materials including brous asbestos and ree bre itsel;

Depending on site use, DOH applies at least 10-old higher criteria to asbestos-containing

materials (ACM) in sound condition, such as commonly ound asbestos cement ragments, since

these pose much lower risks to human health;

For remediation purposes, the top 10 cm o soil should also be made ree o visible asbestos

or ACM;

The asbestos air-quality limit or protecting the public around contaminated sites is 0.01 bres

per millilitre (/ml)(using the membrane lter method) as endorsed by the enHealth Council in

Management o asbestos in the non-occupational environment 2005document (enHealth 2005).

More inormation about the risk basis or and applications o these soil and air criteria are provided in

Sections 1.1.4 and 1.1.5, respectively.

Regulation

In WA the Department o Environment and Conservation (DEC) is the primary regulator o

contaminated sites and also the administrator o the CS Act. However, DEC seeks WA DOH advice

on all asbestos-related issues due to the signicance o asbestos exposure to human health.


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DEC has published extensive guidance on site contamination in its Contaminated Sites Management

Series (CSMS), although inormation on asbestos is limited.

The main national regulatory guidance or asbestos-contaminated sites is enHealth 2005, although

this document primarily provides general management principles.

DOH has developed these Guidelines to provide comprehensive practical guidance or environmental

sites consultants and auditors on the assessment, remediation and management o asbestos-

impacted sites in WA. The Guidelines are largely consistent with and build upon the enHealth 2005

and CSMS documents and hav th sam rgulatory status as th CSMS.

Any signifcant dpartur rom ths Guidlins should b outlind in dtail and ully justifd

in th appropriat sit rports.

DOH and DEC recommend a staged approach to contaminated site investigation and managementas per the CSMS, including or asbestos impacts. Figure 1 provides a generalised fow diagram o this

process.

Site Investigation

Key elements o the rst stage o the investigation, the Preliminary Site Investigation (PSI), are an

investigation o records and anecdotal material and a site walkover looking or signs o contamination.

Based on the PSI or other evidence, it may be necessary to report the site to DEC under the CS Act

as a known or suspected contaminated site and to consider the need or a Detailed Site Investigation

(DSI). A DSI and the associated extensive program o ollow-on work may not be necessary i the

contamination is conned to purely surace ACM (simple surace impact) or an in situ managementapproach is adopted.

The eectiveness o the PSI is critical to the subsequent management o the site. I asbestos

contamination is missed and is then accidentally disseminated across the site through earth

disturbance, a much larger area may require investigation and remediation. This would prove to be a

protracted and costly exercise. Appndix F Cas Study demonstrates the results o an inadequate

investigation.

When reporting the visual inspection results, it is critical that an inspectorcommnts spcifcally on

th prsnc or absnc o asbstos material and on the inspection methodology.

Any DSI and asbestos sampling programs should be ocussed and, where easible, use ACM as ameasure o total asbestos contamination. The sampling will help inorm any health risk assessment

and the selection o soil clean-up levels, i these are deemed necessary.

Management

Remediation options are preerred which minimise public risk, soil disturbance and also minimise the

amounts o contaminated material that are removed to landll.


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Management o asbestos in situ is encouraged, which may include covering the contamination with

clean ll and/or other protective or warning layers as well as registering a memorial on the sites

certicate o title. A common alternative o complete removal o asbestos rom a site oten involvesextensive and costly investigative and conrmatory sampling and is sometimes not eective. Also

whenever a licensed asbestos removalist is used or a structure potentially containing asbestos is

demolished, an environmental consultant should supervise the work to ensure site contamination

does not occur through poor practices.

These Guidelines also provide a simplied investigation and management approach primarily

or use by Local Government Environmental Health Ocers in dealing with single residential lots

possibly contaminated by asbestos dumping or poor demolition practices. This makes use o visual

contamination indicators, site knowledge and basic remediation measures or what is usually a low

risk situation. Details are provided in Sction 1.1.4 and Appndix B.

Consultation

All reporting and enquiries associated with contaminated sites in WA should be addressed to DEC in

the rst instance (Telephone Hotline 1300 762 982). DEC will seek advice rom or reer issues to DOH

as necessary in regard to public health.

In more complex cases, DOH is available via th accrditd sit auditor(i any) to provide general

advice on asbestos sampling and management proposals. Such an approach should include suitable

documentation outlining the relevant contextual inormation and details o the proposed approach.

DEC should be kept inormed. For urther inormation, contact the DOH Toxicology Branch on

08 93884999.

The proponent is also responsible or conducting public consultation during the whole investigative,

management and development process, depending on the size, complexity and sensitivity (or

instance i a child care centre is involved) o the undertaking. This should include inormation

provision and collection and complaint resolution.


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Figur 1 Sit Asbstos Invstigation and Managmnt Procss*

* This schematic is primarily or consultants and auditors, applies where a ormal process is required, and takes no

account o other contaminants. Note an auditor may not always be involved with a site.

Sit Rrral

Prliminary Sit Invstigation

Site History

Site Inspection

(see Chapter 2)

No Contamination Contamination

Arrang DeC Notifcation

(see Chapter 2)

Contamination Ill-DfndSimpl Surac

Impact

Option 1Managmnt In-situ:

Surface barriers

MOT/Brochure

Safe worker processes

(see Section 5.2.1)

Option 2Dtaild Sit Invstigation

(see Chapters 2 & 4)

Halth Risk Assssmnt

(see Section 5.1)

Prpar/Implmnt Sit

Rmdiation Plan

(see Chapter 5)

Conduct Validation

(see Section 5.2.5)

Rports Submittd to Auditor

(see Chapter 6)

Request or more data/work

i necessary

DeC

DOH


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1. Introduction

In 2005 the enHealth Council published its Management o asbestos in the non-occupational

environment 2005(enHealth 2005) to provide a nationally consistent approach to managing this

area o risk. This enHealth 2005 document provides important principles to build upon and tools to

use or asbestos contaminated sites.

These current Guidelines take the enHealth process urther by providing a consistent and

comprehensive approach to the assessment, remediation and management o asbestos-

contaminated sites in Western Australia. They consolidate and ormalise existing DOH asbestos

policies and take account o modern international scientic research and regulatory precedents.

The Guidelines should be used in conjunction with enHealth 2005 and the Department o

Environment and Conservation (DEC) Contaminated Sites Management Series (CSMS). However,

due to specic eatures o asbestos contamination, some guidance such as sampling and validation

procdurs may dir rom th gnral CSMS approach.

1.1 Role o the Department o Health

DOH has a key role in the regulation and management o asbestos in Western Australia via the

provision o expert health guidance and the administration o relevant asbestos legislation. For

contaminated sites, the responsibility is primarily advisory, based on legislative requirements and

administrative arrangements with DEC with respect to the Contaminated Sites Act 2003 (CS Act).DEC relies on DOH advice in regard to asbestos contamination and risk to human health. These

Guidelines are a joint publication o DOH and DEC and have th sam rgulatory status as

th CSMS.

Any dpartur rom ths Guidlins should b ully justifd and th application o

th approach xplaind.

Relevant legislation administered by DOH includes the Health (Asbestos) Regulations 1992. This

legislation imposes requirements or handling, demolition and removal o asbestos associated with

building structures at a site. WorkSae, Department o Commerce, is the licensing authority or such

removals (see www.commerce.wa.gov.au/WorkSae). Failure to manage asbestos, particularly duringdemolition activities, in accordance with the Regulations and existing guidance documents is the

origin o many asbestos-contaminated sites.

1.2 Asbestos-Contaminated Sites and Health

The toxic eects o asbestos are well recognised and primarily result rom the inhalation o ree bres.

Due to its toxicology, transport and degradation properties, and its physical orm, asbestos presents a

unique contamination challenge. In addressing this, DOH takes a practical and risk-based approach

wherever possible, and is conservative in situations o uncertainty.


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1. Introduction

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1.2.1 Asbstos-Contaminatd Sits in Wstrn Australia

There is a history o production and widespread use o asbestos materials in Western Australia.

Crocidolite asbestos, primarily used in asbestos-cement products, was extensively mined atWittenoom until the mine ceased operation in 1966. Imported amosite asbestos was also used

in these products until 1984, and chrysotile asbestos until 1987. Degradation and subsequent

dissemination o asbestos materials has required many sites to be subject to contamination

assessment and management in accordance with regulatory guidance. Adherence to these

Guidelines will help avoid costly and unnecessary delays associated with such activities including or

any redevelopment projects.

1.2.2 Natur o Asbstos Contamination

Contaminant asbestos can be in a range o orms, sizes and degrees o deterioration. For the

purposes o these Guidelines, the asbestos associated with contamination is divided into threegroups.

The rst is asbestos-containing material (ACM) which is in sound condition, although possibly broken

or ragmented, and the asbestos is bound in a matrix; or instance, asbestos encing or vinyl tiles. This

is also restricted to material that cannot pass through a 7mm x 7mm sieve. This sieve size is selected

because it approximates the thickness o common asbestos cement sheeting and or ragments to be

smaller than this would involve extreme mechanical action probably also associated with asbestos

bre release. The smaller ragments are covered by the third category described below. ACM usually

represents a low human health risk.

The second category is termed brous asbestos (FA) and encompasses riable asbestos material,

such as severely weathered ACM, and asbestos in the orm o loose brous material such as

insulation products. Friable asbestos is dened here as asbestos material that is in a degraded

condition such that it can be broken or crumbled by hand pressure. Both ACM and FA can oten be

detected visually.

The third group is called asbestos nes (AF). It includes ree bres o asbestos, small bre bundles

and also ACM ragments that pass through a 7mm x 7mm sieve. Both FA and AF have the potential to

generate or be associated with ree asbestos bres, which can pose a considerable inhalation risk i

made airborne.

Asbestos-Containing Material (ACM)ACM in soil is the most common orm o asbestos site contamination in Western Australia due to:

its historical widespread use as uncharacterised ll material or site landscaping; dumping o as

debris on vacant or development sites; and inadequate removal and disposal o asbestos products

during building demolitions. I identied beore urther dissemination or disturbance, the dumping and

demolition usually only results in readily rectiable surace contamination.

Fibrous Asbestos (FA) and Asbestos Fines (AF)

Sites are occasionally contaminated by asbestos brous material or ree bres, oten as a result o

mining, manuacture or distribution associated with asbestos products. Friable asbestos and very

small ragments may arise respectively rom severe weathering or damage associated with ACMcontamination.


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The identication and delineation o areas o AF contamination can be dicult because o poorer

visual indicators than ACM and FA and also analytical limitations associated with low levels o ree

asbestos bres in particular.

Naturally Occurring Asbestos (NOA)

Under the CS Act, in situ naturally occurring asbestos (NOA) is not considered contamination.

However, due to the serious health concerns associated with asbestos, aected areas should be

eectively managed in the short and long term. NOA is most likely encountered during geological

sampling and mining operations. Management measures similar to those or ree bre usually apply,

though DOH may require a site-specic approach.

1.2.3 Risks rom Asbstos Contamination

Asbestos poses a human health risk through the inhalation o its bres. I deposited in the lungs,the bres can initiate diseases that take many years to produce major health eects. These eects

include asbestosis, lung cancer and the normally rare cancer mesothelioma that aects certain

chest membrane linings. These impacts tend to be the result o higher levels o exposure, most oten

occupational, but mesothelioma can also result rom low level exposures.

The human health risk rom asbestos-contaminated soil varies considerably depending on the orm

o asbestos, its quantity and its exposure situation. For instance, large amounts o ree-bre asbestos

on the surace o a residential lot would be considerably more dangerous than asbestos incorporated

in a cement pipe buried beneath a commercial property. This is because the bre can more readily

be disturbed and inhaled in that residential situation and exposure theoretically may be or 24 hours a

day or a lietime.

An additional complication is the uncertainty associated with determining the degree and nature o the

asbestos contamination, and thereore also o the level o the resulting risk.

DOH has taken account o this variable, and oten uncertain risk, in developing these Guidelines

and applies more rigorous requirements in higher risk situations. DOH also bases its guidance and

investigation criteria on the ollowing practical positions, which are designed to manage human health

risks now and into the uture:

Overall, the potential health impacts posed by dierent asbestos minerals, such as chrysotile and

crocidolite, and bre dimensions can be treated as equivalent;

ACM may pose a uture ree-bre risk through its degradation, and thereore potential release o

asbestos bres;

The cancer risk rom asbestos should be kept as low as practical and preerably no more than one

occurrence in one million over a lietime or the exposed population. Mesothelioma is used here as

the most sensitive health impact o asbestos exposure.


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1. Introduction

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1.2.4 Invstigation Critria and Clan-up Goals

DOH has historically applied a contamination criterion or asbestos in soil o 0.001% weight or

weight (w/w) asbestos as cited in enHealth 2005. DOH has reviewed this criterion in light o extensiveresearch by Swartjes and Tromp in The Netherlands (2008). This study resulted in The Netherlands

introducing general regulatory investigation criteria o 0.01% w/w asbestos or brous asbestos and

0.1% w/w asbestos or non-riable ACM. The 0.01% criteria has the highest attendant risks but should

keep asbestos air levels below 0.001 /ml and probably around 0.0001 /ml. Using WHO (2000) risk

gures or mesothelioma, 0.0001 /ml corresponds to a lietime risk o 10-6 to 10-5 in the exposed

human population, which are risks that are broadly acceptable to DOH.

DOH has used these Dutch gures divided by a actor o 10 to derive investigation criteria or WA,

taking account o the greater dryness and dust-generating potential o local soils and the act that

DOH treats the mineralogical orms o asbestos as equivalent. The brous asbestos criterion applies

to FA and AF due to their ability to generate asbestos bre. DOH applies even higher criteria or theACM, depending on site use. These mirror the National Environmental Protection Measure (NEPM)

(1999) site uses and associated deault exposure ratios. These criteria are summarised below.

Soil asbstos invstigation critria

0.001 % w/w asbestos or FA and AF All site uses

0.01 % w/w asbestos or ACM Residential use, day care centres, preschools, etc.

0.04 % w/w asbestos or ACM Residential, minimal soil access

0.02 % w/w asbestos or ACM Parks, public open spaces, playing elds, etc.

0.05 % w/w asbestos or ACM Commercial/Industrial

The FA and AF criteria o 0.001% w/w remain xed or all site uses because the means to determine

concentration dierences at this level o detection is dicult.

These generic investigative criteria can also be used as soil clean-up goals or site-specic goals can

be developed i this is the chosen orm o remediation. The site-specic goals may be higher than

the investigative levels i any o a range o mitigating actors applies, such as the depth or orm o

contamination, binding or stabilising soil characteristics, or the nature o surace coverings.

For remediation o any contamination, the top 10 cm o soil should also be made completely ree o

visible asbestos, partly or risk reassurance purposes. This may be achieved by installing 10 cm o

clean ll or in the case o ACM or FA contamination by several cycles o hand-picking and ne raking

taking account o the procedure outlined in Sction 4.1.1 Hand-Picking (emu-Bob). However, DOHwould consider other means o managing that top 10 cm such as installing a long-term hardcover

over it.

DOH allows or a more qualitative approach to be applied to small low-risk sites, specically single

residential lots with ACM contamination as a result o on-site demolition or dumping. Such sites

should be assessed and managed in the rst instance by Local Government Environmental Health

Ocers in conjunction with DOH so that more ormal and demanding processes associated with the

Contaminated Sites Act 2003 (CS Act) may not be necessary.


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The management process or such sites is ully described in Appendix B and may be summarised as

ollows or the dierent levels o contamination:

ACM total sheet area < 10 cm2 (i.e. 3 x 3 cm) and with little associated past soil disturbance very low risk simply rmov all visibl ACM, including i practical atr gntly fn raking o

soil to 10 cm dpth to xpos any covrd ACM ragmnts;

ACM total sheet area > 10 cm2, or ACM occurrences with signicant soil disturbance, or buried

asbestos encing stumps low risk consult DOH with th xpctation o xcavating

th impactd and possibly all soil down to dpth o likly ACM pntration. For largr

quantitis o ACM, th risk may b highr and th sit may nd to b rportd to DeC

undr th CS Act.

1.2.5 Air Quality Critria

DOH recommends a 0.01 bres per millilitre (/ml) asbestos air quality limit to protect the public

around contaminated sites, which is the limit o detection using the membrane lter method. This

is the para-occupational limit endorsed in enHealth 2005, and remains the only practical limit and

methodology in use.

Based on the WHO risk estimates outlined in Sction 1.1.4 Invstigation Critria and Clan-up

Goals, 0.01 /ml o asbestos could result in an increased risk o 10-4 to 10-3 o an exposed person

developing mesothelioma during their lietime exposure. However, DOH applies this limit only in

the context o site asbestos-disturbing activities which primarily occur during site remediation.

Consequently, the period o exposure is likely to be at least 100-old less than in a lietime, resulting in

reduced risks o 10-6 to 10-5.

I asbestos-disturbing site activities may last more than 6 months, then more rigorous dust control

measures and better sampling and lower air quality limits should be applied.

Nuisance dust monitoring may be also necessary and can be used to complement asbestos

sampling, especially since it allows or more immediate responses to any ailures in dust management

measures. For nuisance dust, the National Environment Protection Measure (NEPM) 24-hour

guidance goal o 50 g/m3 or PM10 (particulate matter with an equivalent aerodynamic diameter o

10 m or less) should apply (NEPM 2003). Adherence to this limit can be used to help protect the

community against asbestos exposure, i the soil asbestos bre content is


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1. Introduction

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DOH uses the above document titles or convenience o reerence and because they are reasonably

explicit. Other titles could also be used and possibly combined. In the case o the SMP, it is expected

that it is included or prepared in conjunction with a Dust Management Plan (DMP). The SMP and/orSMVR may also need to include a commitment to and details o longterm uture management o the

site i asbestos remains in situ such as restrictions on land use/activities at a site.

All reports will need to be submitted or assessment by DEC, via an auditor i required by a planning

condition or Regulation 31 o the Contaminated Sites Regulations 2006. DEC may reer asbestos

or human health-related reports on to DOH with a request or advice. The auditor process and

adherence to these Guidelines may make routine reerrals to DOH less likely over time.

Environmental consultants employed to investigate and manage asbestos contamination should be

supervised by a lead consultant with appropriate asbestos credentials. The lead consultant should

normally have a minimum o 3 years continuous experience with asbestos soil contamination and

relevant tertiary qualications in environmental science, science or engineering.

1.4 Consultative Process

The proponent is responsible or undertaking appropriate public consultation throughout the site

investigation, remediation, management and development process. An outline o the recommended

communication process is provided in the Contaminated Sites Management Series Guideline

Community Consultation (DEC, 2006) and also in Public health consultation: a guide or developers

(Synnott and Katscherian, 2007). The extent o consultation will vary with the size, sensitivity and

complexity o the site, and stage o the development management process.

Consultation with stakeholders should be an interactive process where possible and not just anawareness-raising and inormation session. The need or this especially applies to asbestos, which

can be an emotional issue and hard to manage both technically and i it gains a political dimension.

I necessary in more complex cases DOH is available via th sit auditorto provide general advice

on asbestos sampling and management proposals. Such an approach should include appropriate

documentation outlining the relevant contextual inormation and details o the proposal. For urther

inormation, contact the Toxicology Branch on 93884999.


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2. Preliminary Site Investigation

18

Situations whr asbstos contamination may occur includ:

Industrial land, e.g., asbestos-cement manuacturing acilities, ormer power stations, and railand ship yards, especially workshops and depots;

Waste disposal or dumping sites, e.g., building waste;

Pre-1980s buildings or structures damaged by re or storm;

Land with ll or oundation material o unknown composition;

Sites where buildings or structures have been constructed rom ACM or where asbestos may

have been used as insulation material, e.g., asbestos roong, sheds, garages, reservoir roos,

water tanks, boilers;

Sites where pre-1980s buildings or structures have been improperly demolished or renovated,

or where relevant documentation is lacking;

Disused services with ACM piping e.g., water pipes, Telstra trenches or pits (usually within

1 metre o the surace).

2.2 Site Inspection

The initial site visual inspection or walkover provides the most important inormation on potential

exposure to asbestos bres and inorms the design o appropriate control measures.

Inspections should be grid-based as ar as practical in the rst instance to detect any visible asbestos.

The identied areas should then be surveyed in more detail along with suspect locations indicated asa result o the desktop study. enHealth 2005 (Appendix V: Sample inspection and investigation orm)

provides an asbestos visual inspection checklist. DOH recommends that such an approach be used

to assist the systematic collection o relevant data.

Site inspection methods should be adopted to prevent urther degradation or distribution o asbestos.

This may include: restricted on-site use o vehicles and equipment; minimal disturbance o stockpiled

or discarded materials; and the use o equipment and ootwear scrub-down areas.

2.2.1 Visual Indicators

Most potential asbestos contamination will be identiable i on the surace and in signicant quantities.

The main exception is ree bre which will be hard to identiy unless in bulk. An experienced inspectoris likely to identiy asbestos as such, but conrmation o representative samples by analysis is

appropriate i there is any uncertainty.

I the surace is heavily vegetated, then condence in the visual inspection will be lessened. Some

careul vegetation clearance may help to clariy the situation.

The inspection should also include any asbestos-containing structures, especially i in poor repair,

ootprints o demolished structures, and debris that has been dumped on the site, particularly

demolition waste.


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2.2.2 Charactristics o Contamination

The condition, quantities and location o the asbestos should be evaluated in general terms to inorm

initial remediation and management decisions. The ollowing basic approach is generally appropriate:

Where there is good historic inormation on the sources o the asbestos contamination, the

estimated surace area o contamination can be considered equivalent to the visually delineated

area o impact, and up to 1 m in all directions to account or uncertainty;

The depth o contamination may be inerred rom the desktop investigation, or later inormed

by targeted sampling. In either case, an additional 30 cm should be incorporated to account or

uncertainty;

The condition o ACM should be considered equivalent to the most degraded samples ound in an

area, noting that this may vary across dierent areas;

Where signicant amounts o ree asbestos bres may have been exposed over time, theimmediate surrounding area should also be considered contaminated.

The need or additional measures should also be considered as outlined in Appndix C Immdiat

Rspons Actions and Appndix D Contingncy Plans.

2.3 Sampling

Sampling during the PSI is not normally recommended, since either a management strategy may be

adequately dened based on other PSI investigation ndings or because it is evident that a detailed

site investigation (DSI) will be necessary anyway. Limited PSI sampling may be appropriate or the

ollowing reasons:

To conrm that asbestos is present, including as ree bre;

To roughly delineate the contaminations lateral and vertical extent;

To inorm the Sampling and Analysis Plan or the Detailed Site Investigation;

To obtain a preliminary idea o appropriate management options;

For air sampling, to ascertain what additional site-control measures are warranted or i immediate

response actions are required.

PSI sampling would most likely be surace hand-picking or targeted test pits. Any sampling should

be based on a written plan which takes account oSction 3.2 Sampling and Analysis Program.Inormation on common sampling methods or asbestos is provided in Chaptr 4 Sampling,

Monitoring and Analytical Mthods.


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3. Detailed Site Investigation (DSI)

20


A DSI is an investigation which conrms and delineates potential or actual contamination through a

comprehensive sampling program. The key elements o a DSI are outlined in the CSMS Reporting o

Site Assessments (DEC, 2001).

A DSI is not usually required by DOH or management purposes, although this will depend on

site-specic circumstances, especially the remediation approach proposed. A DSI should only be

undertaken when delineation o asbestos impacts must be accurate, such as i:

The remediation or management approach requires asbestos to be removed or relocated rom

an area;

Asbestos contamination is due to riable or ree-bre generating material;

Land uses are to be determined and delineated according to the extent and nature o asbestos

contamination.

A DSI may also help resolve uncertain ndings rom the PSI, or to help assess the likely eectiveness

o alternative remediation and management strategies.

A DSI is not necessary i the contamination is demonstrated to be ACM in limited quantities sitting on

the soil surace (simple surace impact). Hand-picking as outlined in Sction 4.1.1 may be sucient

to manage this type o contamination.

A DSI should normally only b undrtakn whn th ara o asbstos impact nds

to b wll dlinatd.

3.1 DSI Preparations

Any DSI should build upon the PSI and take account o any subsequent relevant site developments,

such as:

Any causes or evidence o urther site contamination:

Vandalism or degradation o structures containing asbestos;

Removal o asbestos structures;

Identiying new contamination areas, e.g. ollowing site excavations;

Cross-contamination by earthworks, transport o wastes, vehicular activity and wind or storm

damage to asbestos materials.

Changes in site conditions, surrounding environment and possible receptor exposures:

Adjacent developments or altered land usage;

Wind breaks, e.g., removal o nearby or site trees, ences or buildings;

Seasonal infuence;

Perormance o any Immediate Response Actions;

Community concerns, complaints and consultations;

Consultation undertaken with relevant stakeholders;

Any alterations to site development plans.


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3.2 Sampling and Analysis Program

The DSI should incorporate a site Sampling and Analysis Program (SAP) determined by the

contamination characteristics and intended uture site uses. The SAP should comply with CSMS

Development o Sampling and Analysis Programs (DEC, 2001). Asbestos specic sampling and

monitoring methods are outlined in Chaptr 4 Sampling, Monitoring and Analytical Mthods.

In developing a SAP, the ollowing important principles should be applied. The DOH approach

here and elsewhere in the Guidelines is to try to reduce the amount o sampling and to improve its

practicability, while taking account o the special contamination eatures o asbestos.

3.2.1 ACM as Primary Masur o Asbstos Contamination

The recommended way to detect and measure soil asbestos contamination is by using ACM when

present, unless FA and AF are also involved in signicant concentrations. ACM is the most commontype o asbestos contamination and, when exposed, can usually be readily detected visually and

concentrations calculated. By signicant FA and AF DOH means concentrations that might exceed

10% o the amount o asbestos as would be determined by using ACM alone. I AF arises rom co-

located ACM, DOH considers that this will not exceed 10% o the ACM even i the ACM is primarily

very small pieces arising rom severe mechanical action. An exception would be ACM damage

resulting rom power shaping tools, such as a circular saw.

I necessary or in doubt, sampling or ACM, FA and/or AF should occur and the ndings compared

against the relevant investigation criteria. The methodology or calculating asbestos concentrations is

outlined in Sction 4.1.7.

3.2.2 Avoiding Sampling Invalidation by Sit Activitis

Care is necessary during the DSI to ensure that sampling and monitoring results are not

compromised due to poor site management practices, specically:

Sampling should ollow removal o any asbestos material that may be actively generating asbestos

ree bres, such as exposed ACM products in poor condition;

Investigations should ollow any planned demolition o asbestos-containing structures or buildings,

or removal o asbestos rom within them, unless the demolition is closely monitored and the

associated removal site is proessionally validated;

All equipment operation, vehicle movements and dust during the sampling and monitoring regimeneed to be careully managed.

3.2.3 A Focus on Judgmntal Sampling

Judgmental sampling targets particular areas o a site based on known or likely contamination, which

is the preerred approach. It depends heavily on a thorough PSI and should refect the state o the

site at that time. Judgmental sampling can help avoid unnecessary broad area sampling. Judgmental

sampling may need to be augmented or substituted by grid sampling.

Grid sampling is most appropriate when asbestos contamination is widespread or may be present at

unknown locations. I the contamination is buried then test pits in particular and/or boreholes are used

or either the judgmental or grid-based regimes.


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The ollowing situations are especially relevant to judgmental sampling:

I contamination hot spots are identied by the PSI, a sampling strategy is required to conrm

their extent, which i indicated to be sub-surace should include test pits and stratied samplingmethods;

The SAP provides or opportunistic (discretionary) sampling to be conducted as necessary, or

example, when unexpected suspect asbestos products or unusual soil strata are encountered;

Areas that will remain covered by hardstand do not require sampling. However, i asbestos is likely,

its presence will be assumed unless sampling indicates otherwise. I sampling cannot readily meet

the recommended density because o hardstands, targeted sampling in key locations is suitable to

allow limited characterisation o sub-surace contamination;

I structures containing asbestos have been removed, the ormer ootprint should be investigated,

unless the removal was properly managed and documented. In addition to a visual inspection,sub-surace sampling should only be necessary i the structure was partially buried, or instance,

asbestos encing, or subsequent soil disturbance has occurred. Sampling below 30 cm depth

is not generally warranted. Sampling should extend laterally up to 50 cm outside the ootprint

perimeter, and include soak-wells. A sampling interval o 5-10 m along and within the ootprint

perimeter is recommended, aligned with any adjacent grid sampling pattern;

Disused sub-surace asbestos structures and products, such as ormer service trenches or piping,

may be localised areas o potential contamination. I not properly documented, these should

be delineated by sampling, although validation sampling would suce i structure removal is

undertaken.

3.2.4 Sampling Triggrs and Dnsitis

Greater sampling densities and sample volumes should generally be used or asbestos than

those considered appropriate or other contaminants. This is because asbestos can occur widely,

unpredictably and, as a discrete contaminant, asbestos can be hard to detect by conventional

sampling regimes.

Where grid sampling is appropriate, the density should be some multiple (see Table 1) o the

minimum density listed in CSMS Development o Sampling and Analysis Programs (DEC, 2001)

Appendix C(included in these Guidelines as Appendix A). The CSMS list was not designed or

asbestos sampling but DOHs experience is that it can provide a suitable guide or asbestos sampling

in conjunction with a multiplication actor (rom 0.5 to 2) depending on the likelihood o contamination.

In the case o judgmental sampling, the density selected will be primarily at the investigators

discretion, but should equal or exceed that proposed or grid sampling in Table 1 or each level o

asbestos likelihood. For localized higher risk contamination, a denser sampling regime should be

used, such as or investigating asbestos bres that may have been carried by rainwater into soil rom

large expanses o asbestos roong.


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Tabl 1 Triggrs and Typs o Asbstos Invstigations

Liklihood oAsbstos Typical Scnarios Invstigation Rgimn

Unlikely Grazing with no building history

Site with minimal pre-1987 history

Desktop/site walkover (DW)

No sampling without indicators

Possible Uncontrolled ll without mixed

building waste

Undeveloped site adjacent to urban

inll (& possible dumping)

DW. Judgmental &/or 0.5 x CSMS

grid sampling or any buried material

Suspect Uncontrolled ll with mixed building

waste

Soil linked to dumped ACM Industry associated with asbestos

Demolished structure ootprints

DW. Judgmental &/or 1 x CSMS grid

sampling or any buried material, with

at least 1 sample per nal lot

Likely Some sub-surace asbestos ound

Asbestos activities associated with

soil disturbance

Landll site

DW. Judgmental &/or 2 x CSMS grid

sampling or any buried material, with

at least 1 sample per nal lot

Known Identied asbestos but not

suciently delineated

DW. Judgmental at 2 x CSMS &

at least 1 sample per nal lot in

delineation zone

The rst three categories are primarily or asbestos screening purposes. They may i necessary

be undertaken in ull or in part at the PSI stage. The ourth category, Likely, may be or screening,

conrmation or delineation purposes, depending on the circumstances. Sampling associated with the

Known contamination is likely to be used or conrmation and precise delineation. Depending on the

ndings, it may be necessary to adopt a more detailed sampling regime or subsequent work, which

can build upon sample locations already used.


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4. Sampling, Monitoring and Analytical Methods

24

4. Sampling, Monitoring and Analytical

Methods

I appropriate, a Sampling and Analysis Program (SAP) should be implemented as outlined in Section

3.2 Sampling and Analysis Program, noting that ACM should be used as a contamination indicator

where practical. The SAP should be based on these Guidelines and as ar as possible on the CSMS

Development o Sampling and Analysis Programs (DEC, 2001).

Large area and/or localised sampling methods can be used, depending on the type o contamination

and purpose o the sampling. As will be discussed, some methods are not suitable or brous

asbestos (FA) or asbestos nes (AF). Large area methods include hand-picking, tilling and screening.Localised sampling includes using test pits, trenches and bore holes. Sampling and management are

not normally necessary or any asbestos deeper than 3 m since such soil is usually inaccessible to

most activities.

The SAP should include a written protocol and procedures or the proposed sampling. The methods

chosen should be demonstrated to be eective in previous investigations or trials. For instance, a

tilling method should detect and allow collection o most asbestos contamination or its particular

operational parameters.

An experienced asbestos investigator can determine which ragments clearly are asbestos (consistent

with weight-o-evidence) and decide their condition. I identication is at all in doubt, the ragments

should be assumed to be asbestos unless shown otherwise by laboratory analysis. Representative

ragments can be used or visual identication and analysis. Analysis is recommended or ragment

types that comprise the bulk o the suspect material.

Conclusions should be drawn in regard to ragment size distribution and relative proportions o

asbestos collected or any successive sampling passes. For instance, i ragments are all very small,

then there is a reasonable possibility that signicant amounts may be missed and may in act all into

the < 7 mm category and so be regarded as AF. For successive passes, i the amount ound in each

is quite large, (such as > 0.1 % w/w asbestos) and does not show a substantial sequential reduction,

then the contamination may be such that its quantication and remediation cannot be achieved by the

particular method.

Where asbestos contamination is ound, its quantication should relate to that particular immediate

grid area or volume. Care should be taken in any compilation o results not to permit averaging,

which might result in inappropriate dilution o the calculated level o contamination. For instance,

the level o contamination should not be determined across a whole large tilled area or one with an

unreasonably large grid size, such as 40 x 40 m.

In locations where asbestos exceeds the relevant investigation criteria, delineation o the impact

should ollow unless it is taken to be widespread and managed appropriately or addressed by

post-remediation validation. Any delineation sampling regimen will depend on the contamination

circumstances but should ensure the impacted area is condently captured, especially or higher

asbestos concentrations and bre-generating material.


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25

I the contamination is associated with a layer o uncontrolled ll, then the whole extent o the ll may

need to be considered impacted unless a strong argument or a more intensive sampling regime can

demonstrate otherwise.

For naturally occurring asbestos, such as may be ound on mining sites, the emphasis should be on

sampling those areas where soil or rock disturbance and thereore potential human health risk may

be likely, rather than delineating contamination zones.

4.1. Soil Sampling

4.1.1 Hand-picking (emu-Bob)

Hand-picking primarily reers to the visual inspection o the soil surace and manual collection o ACM,

as outlined in Table 2.

Tabl 2. Summary o Hand-picking Sampling Rcommndd Mthod

Procss

Can use a rake to sample down to a depth o 10 cm;

Most suitable or ACM, and possibly or low levels o FA;

Relevant where contamination is known or considered only to be on or near the soil surace

and may be attributed to a dened event;

Limited application or deeper contamination or i there is surace vegetation or debris. Raking

may be dicult except in sand;Used to characterise the extent and level o contamination, whilst concurrently reducing

its impact.

Implmntation

Locations and weights o asbestos material should be recorded;

Rake teeth should be < 7 mm spaced apart and > 10 cm long;

At least 2 passes o picking (and o raking i appropriate) made with 90o direction change

between each and using a grid pattern;

Material should not be urther damaged or buried by the process;

% contamination may be calculated as per Section 4.1.7, using 1 cm as soil depth or hand-

picking or using the rake teeth length as appropriate;

Final visual inspection o the area should not detect surace ACM.

4.1.2 Tilling

Tilling reers to a process o mechanically turning over surace soils to acilitate the presentation and

collection o asbestos ragments. The process and its implementation are outlined in Table 3.


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Tabl 3. Summary o Tilling Sampling Rcommndd Mthod

ProcssMost suitable or ACM, not or bre-generating materials;

Generally conducted across the entire zone o suspected impact;

Relevant or contamination within top 30 cm o soil;

Limited application or deeper contamination or i there is surace vegetation or debris;

Used to characterise the extent and level o contamination, whilst concurrently reducing

ACM impact.

Implmntation

Usually preceded by hand-picking;

Locations and weights o asbestos material should be recorded;

Soils should be pre-wet to the tilling depth, and the dust controlled;

Rotor blades should present ACM optimally or 1 or 2 spotters closely ollowing depending

on speed, till breadth and contamination level;

At least 2 passes with 90o direction change using a grid pattern;

Material should not be urther damaged or buried rom the process;

Evaluated areas normally cannot be considered representative o other locations;

Percentage contamination may be calculated as perSction 4.1.7, using an estimate o

the average impact depth as well as the area involved;

Final visual inspection o the area should not detect surace ACM.

4.1.3 Scrning

The term screening is applied to both the small-scale separation o ACM ragments rom localised

soil samples and the large-scale treatment o an area to detect and quantiy asbestos contamination,

with concomitant remediation. This Section deals with large-scale mechanical screening. The process

and its implementation are outlined in Table 4.


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Tabl 4. Summary o Scrning Sampling Rcommndd Mthod

ProcssMost suitable or minor ACM impact, not or bre-generating materials;

Other sampling methods are preerable because o potential dust/bre generation;

Generally conducted across the entire zone o suspected impact;

Relevant or larger volumes o reasonably accessible and delineated contamination;

Used to eectively characterise the extent and level o contamination, whilst concurrently

reducing ACM impact.

Implmntation

May be preceded by hand-picking i appropriate;

Oversized ACM may be removed by screening down rom larger mesh sizes to the nal

screening mesh;

Final mesh size o < 7 mm is recommended. Anything larger will require validation sampling as

outlined in Section 4.3;

ACM weights/concentrations should be closely correlated to locations or stockpiles to allow

re-sampling or segregation i required;

Impacted soil should not be mixed with other soil in a way that might compromise the

concentration calculations;

Soils should be pre-wet and procedure subject to strong dust/bre control and monitoring

measures as outlined in a Dust Management Plan;

Evaluated areas normally cannot be considered representative o other locations;

Percentage contamination may be calculated as per Section 4.1.7, using the weight o ACM

ound or a particular strata, area or volume;

Final visual inspection o the stockpile surace should not detect ACM.

Altrnativs to mchanical scrning that do not rquir xtnsiv dust managmnt

ar otn availabl and ar prrrd.

4.1.4 Tst Pits and Trnching

I asbestos extends below surace soils (>30cm), then sampling by test pits and trenches (TPs) are

most common and eective, especially i contamination distribution is uncertain. DOH recommends

use o TPs instead o boreholes (BHs) because buried ACM and FA can be more readily identied,

diering strata distinguished and there is more sampling fexibility. Specied large sample sizes

should be used or both methods with reliance put on visual methods o asbestos detection and

concentration calculation wherever possible. The process and its implementation are outlined in

Table 5.


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Tabl 5. Summary o Tst Pit/Trnching Sampling Rcommndd Mthod

ProcssSuitable or all asbestos types, but especially ACM, and FA i bre disturbance is manageable;

Relevant i contamination is buried and o unknown location and depth.

Implmntation

Sampling should be conducted to 30 cm below the likely lower limit o potential contamination

unless this is greater than 3 m;

Suspect asbestos material or construction debris should be targeted and all sample locations

noted;

Precautions are necessary to protect workers and public rom wall collapse or hole hazards,and potential bre release rom excavation/sampling.

ACM and FA

At least one 10 L sample rom each relevant stratum (or per 1 m depth) o one wall,

and discretionary samples rom other suspect spots;

Sample screened manually on-site through a < 7 mm sieve or spread out or inspection

on a contrasting colour material (recommended or FA);

Identied ACM and FA weighed to calculate asbestos soil concentration or individual samples

as per Section 4.1.7.

AF

At least one wetted 500 ml sample rom each relevant stratum or 1 m depth (i thick) o one wall,

and discretionary samples rom other suspect spots;

May be done with ACM/FA sampling, albeit at another wall position;

Whole sample submitted or laboratory analysis as per Section 4.1.8.

4.1.5 Bor Sampls

Although TPs are recommended, bore hole (BHs) sampling may be appropriate where physical

obstructions may limit soil access or generation o asbestos contaminated dust is a potential problem.

The sample taking and assessment is similar to that or TPs. The process and its implementation are

outlined in Table 6.


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Tabl 6. Summary o Bor Sampling Rcommndd Mthod

ProcssSuitable or all asbestos types;

Relevant i contamination is buried and o unknown location and depth.

Implmntation

Sampling should be conducted to 30 cm below the likely lower limit o potential contamination

unless this is greater than 3 m;

Suspect asbestos material or construction debris should be targeted and all sample locations/

depths noted.

ACM and FA

Corer diameter should be at least 15 cm;

At least one 10 L sample i practical rom each relevant stratum (or per 1 m depth) o core.

Cross-strata samples are permissible provided that asbestos detections are urther investigated;

Sample screened manually on-site through a < 7 mm sieve or spread out or inspection on a

contrasting colour material (recommended or FA);

Identied ACM and FA weighed to calculate asbestos soil concentration or individual samples

as perSction 4.1.7.

AF

At least one wetted 500 ml sample rom each relevant stratum (or per 1 m depth);

May be done with ACM/FA sampling;

Whole sample submitted or laboratory analysis as perSction 4.1.8.

4.1.6 Stockpil Sampling

Soil stockpiles intended or use on-site and o unknown quality should be assessed or asbestos

contamination. DOH adopts a conservative approach to stockpile assessment and use because o

associated uncertainties and risks.

I the stockpiles originated on the site rom areas not likely to be contaminated, or instance, no

indication o building activity or waste, the assessment can consist o a close visual examination

and hand-picking over the whole stockpile surace. I any asbestos is ound or the soil came rom

asbestos suspect areas on site, then the stockpiles should normally be considered contaminated.

These stockpiles and any imported soil, aggregate or crushed material o unknown quality should not

be used as clean ll without urther investigation and management i necessary.


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AS4964 provides guidance in regard to reporting the presence or not o asbestos. O the options

available, DOH considers that any asbstos dtctd should b rportd as such regardless o

its respirable status. This is particularly pertinent to any trace analysis, and the laboratory analysisshould be reported in the ollowing orm:

State the methods limit o detection;

Indicate i asbestos was detected or not detected, regardless o its orm;

I detected indicate the type o asbestos and provide a actual description;

I practical estimate the concentration o any asbestos;

State whether the analysis report is consistent with these Guidelines or not.

4.2 Air Quality MonitoringAir quality monitoring (AQM) or asbestos bre, dust and other contaminant emissions should be

considered during the DSI, remediation and site development processes. Asbestos bre and dust (as

a surrogate or asbestos bre) are o particular interest.

DOH considers that i best practice is used to control generation o dusts, atmospheric sampling

or asbestos bres adds little value to the evaluation or management o asbestos risks. However,

asbestos air sampling can help provide condence in those control measures, can be used to allay

community concerns in sensitive situations and may also be necessary or occupational purposes.

I required or public health reasons, then para-occupational sampling is considered the most

practical method to measure airborne asbestos at contaminated sites. Suitable guidance on relevant

sampling and assessment strategies is provided by enHealth 2005 (Appendix II, page 49). DOH also

supports the enHealth advice that dust levels should remain suciently low or measured asbestos

concentrations to be below the practical lower detection limit o 0.01 /mL.

Air sampling results should not b usd to conclude that there has been no asbestos bre release

rom soils or to justiy use o less stringent site management measures, because the sampling

methodology is not suciently accurate or representative or these purposes.

4.2.1 Air Monitoring Principls

The ollowing sections outline when various AQM methods may be relevant to the site investigation

and management process. In addition, the ollowing issues should be born in mind:The purpose o any air sampling should be clearly identied;

The AQM strategy should be developed by a person suitably experienced in asbestos sampling

and exposure assessment;

Monitoring or asbestos bres is not useul in real time or inorming management decisions about

the eectiveness o controls during asbestos disturbance due to analytical delays;

The membrane lter method is the only recognised and standardised measurement technique

regularly employed across Australia or the determination o airborne asbestos bre. It provides a

useul estimate o personal exposure to airborne asbestos bres;

Electron microscope techniques are preerred or low-level exposure situations in which the bresize and identication are important;


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Although transmission electron microscopy (TEM) is best suited to distinguish asbestos rom

non-asbestos bres, it examines a much smaller area o the collecting lter than scanning

electron microscopy (SEM) or phase contrast microscopy (PCM). TEM results are thereore lessreproducible and have greater uncertainty;

PCM is simple and inexpensive. The simplicity o the method allows or analysis to be perormed

on-site;

The resolution o PCM is poor and may miss many small bres that are observed using other

techniques. It also does not always distinguish asbestos rom non-asbestos bres. PCM can result

in a signicant underestimation and sometimes overestimation o the asbestos bre concentration

in air;

Asbestos sampling lters may become overloaded with dust in unavourable conditions and can

become unusable. They should be reported as such and not as nil or no asbestos detected;

The AQM arrangements should be modied i necessary in response to relevant changes in site

conditions, activities and monitoring results.

4.2.2 Prsonal Monitoring

Personal monitoring o asbestos in air to determine and help minimise potential workplace exposure

is an occupational health and saety issue. The WorkSae Division, Department o Commerce should

thereore be consulted prior to the implementation o any personal monitoring regime.

Personal monitoring is appropriate where signicant levels o airborne asbestos bres are possible,

as may be associated with the ollowing conditions:

Free asbestos bre contamination is present or is likely to exist within the soil and may be exposed

during the course o site works;

Site works will require extensive ground-disturbing activities in asbestos-impacted areas, including

tilling and mechanical screening;

Asbestos contamination is present at the soil surace and signicant vehicle or machinery trac

across the site is anticipated.

Personal monitoring results are also useul where there is uncertainty regarding the suitability or

eectiveness o adopted site management measures and may also help allay community concerns.

However, once representative data has been obtained, ongoing monitoring eorts may prove o little

value.

4.2.3 Para-occupational Sampling

Para-occupational sampling or asbestos can help demonstrate that past site activities are unlikely to

have increased risks to adjacent site users. The value o such sampling can depend on:

Stakeholder values and perceptions;

Constraints on available site management methods;

The nature o adjacent land-uses and potential receptors; e.g., a primary school versus an

industrial acility;

Community interest and/or complaints;

Perormance history.


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Care should be taken in using any licensed or other asbestos removalists associated with the

cleaning up or development o a site. Oten their emphasis will be on managing the occupational and

environmental risks at the time o the removal, with little consideration to remnant soil asbestos. Suchactivity unless closely supervised can lead to the generation and spread o asbestos contamination,

especially i subsequent soil disturbance occurs.

5.2.1 Managmnt In situ

Predisposing conditions

Asbestos is buried reasonably deeply, or example > 1.5 m;

Distribution o asbestos is dicult to determine;

Proponent does not wish to characterise the asbestos contamination;

Asbestos contamination covers a large area, or example > 2000 m2;

Contamination includes signicant FA or AF;

Site will largely be covered by hardstand;

Site is to be covered by clean ll or geotechnical or other purposes;

Likely associated requirement or a Memorial on Title (MOT) is not a concern.

In situ management primarily involves the isolation o the contaminated area with barriers and covers

so that it cannot be readily disturbed and thereore will not generate airborne bres. Potentially

aected parties should be inormed o the contamination and the arrangements in place to protect

them, including through a MOT, as discussed in Sction 5.3. Other in situ management measures not

described in these Guidelines are possible, such as cement injection stabilisation, which eectively

encapsulates the asbestos material.

DOH considers that a MOT associated with remediated sites is likely to become a common

occurrence and should not be regarded rom a human health risk perspective as a less acceptable

outcome.

The barrier or cover is usually a layer o clean ll (sand or soil). This ll should be demonstrated to

be ree o contamination. Nominally, the depth o the clean ll should be at least 1 m or public open

spaces and at least 0.5 m or all other uses, such as residential or commercial activities. The greater

depth or the public space is because o: the potential or deeper below-ground activity associatedwith such areas, such as irrigation systems and service trenches; the potential lower awareness o

the presence o the contamination; and the increased practicability o having such deep covers.

The 0.5 m cover may need to be increased to avoid contamination disturbance by subsequent

installation o sub-surace utilities below 0.5 m, unless any contamination excavated is properly

managed and not mixed in with material used or backlling.

For ACM contamination in bushland parks or nature reserves and where the area will be minimally

disturbed and subject to closer management, the cover may be 0.1 m o organic mulch. For instance,

mulch has been used in isolated or low-use areas o bushland where surace dumping o ACM has

occurred. However, any visible ACM should be removed rst and the mulch cover maintained in a

proactive manner. This usually requires an asbestos management plan or the area.


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Disadvantages

Asbestos remains on the site and will need to be properly managed;

Level o the site may need to be raised;

MOT will be necessary, except or clean ll covers > 3 m, which could adversely aect purchaser

perceptions.

5.2.2 Tratmnt On-sit

Predisposing conditions

Asbestos is not buried deeply, or example, < 1 m;

Asbestos contamination covers a large area, e.g., > 0.2 hectares, or some methods;

Extent o contamination is well delineated;

Contamination is not by asbestos ree-bres;

Need to avoid an MOT is important;

Adjacent properties are at some distance and/or are non-residential or do not involve sensitive

receptors, such as child care centres.

Treatment on-site is taken here to mean undertaking some physical treatment or manipulation o the

contaminated soil on-site, specically ACM hand-picking (possibly FA), tilling, screening or excavation

o the aected soil and burial on-site (all asbestos). For the rst three methods, any ACM collected

should be consolidated, properly packaged and disposed o at an approved landll.

An important outcom o th rmdiation is that th top 10 cm o soil should b r

o all visibl asbstos.

Hand-picking

Guidance on hand-picking or emu-bob o surace ACM is provided in Sction 4.1.1. This technique

can sometimes be used to remediate as well as to estimate the level o contamination associated with

surace soils. Remediation would be possible i the soil can be made ree o ACM. This may be only

possible i it is proven that the ACM is conned to surace soils, or instance, no deeper than 10 cm,

and that this has been substantially removed. Evidence o the depth o penetration may come romsampling and/or the desktop study.

Hand-picking may be used with care to remove FA material which is on the surace although

additional work should be undertaken to assess and manage likely asbestos ree-bres associated

with it.

The ACM removal process would involve at least three passes over the area collecting surace

and sub-surace ACM with a manual or mechanical rake capable o probing to 10 cm. The spacing

between the rake teeth should be at most 7 mm. The picking and raking should be done on a grid

basis and the ACM recovered weighed and its source location noted. I a pass across the impacted

area results in no ACM being ound then the soil can be considered eectively ree o ACM. Raking

may only be eective with very sandy soils.


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5. Risk Assessment, Remediation and Management

44

For either o these methods to work properly, it may be necessary to remove any covering vegetation,

whilst ensuring that the vegetation is clean o ACM beore disposal. Prior to vegetation clearing,

consideration should be given as to the need or a Clearing Permit to be obtained rom the DECunder the Environmental Protection (Clearing o Native Vegetation) Regulations 2004.

Tilling

Tilling using mechanical means may be an acceptable remediation methodology, or instance,

when the ACM contamination is demonstrated to be not more than 30 cm deep. The desktop study

and sampling may help to determine this. A detailed description o the process or surace ACM is

provided in Sction 4.1.2.

Tilling may be used in together with hand-picking and will require initial removal o surace vegetation.

A grid approach should again be used with a similar spotting, locating, weighing and calculation

approach used as outlined or hand-picking. Again, the top 10 cm o soil must be ree o ACM.

Screening

I undertaken properly, screening can be an eective remediation tool or ACM which provides

considerable condence that the processed soil achieves the required standard o cleanness. The

process is detailed in Sction 4.1.3.

A screen o eective nal mesh size o less than or equal to 7 x 7 mm should be used to ensure that

ragments o ACM panels do not pass through lengthways. Based on the amount o ACM retrieved

or a given volume o soil screened, the percentage o asbestos w/w can be calculated. I the levels o

small ragments are high, some sampling o the resulting stockpiles may be appropriate (seeSction

4.4) to ensure that the screening is eective.

I the 7 mm mesh size is impractical to use because o soil or other conditions, then a coarser

mesh size may be used, but this will need to be done in conjunction with sampling o the screened

stockpiles (see Section 4.3). The top 10 cm o screened installed soil must be ree o ACM.

Air quality management and monitoring are particularly important or screening procedures because

they have the potential to release considerable amounts o dust and possibly ree asbestos bre.

Consideration o the above on-site treatment options should take account o the ollowing actors:

AdvantagesNo contaminated soil needs to be moved o-site or disposal;

MOT is avoided ;

Sampling can be combined with remediation;

Risk is removed and no more management is required.

Disadvantages

Usually not suitable or high levels o contamination;

May not be suitable i there is considerable additional demolition debris;

May not be suitable or compacted soils or soils with high clay content;

In some cases, has potential to generate considerable dust which requires management and

monitoring to ensure there are no o-site impacts.


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47

5.3 Ongoing Management

Ongoing management reers to proper control and communication o inormation about asbestos

remaining on-site. As such, it is most relevant to remediation measures oManagement In situand

on-site burial.

A management plan will need to be developed and implemented on a long-term basis. This should be

included in the Site Management and Validation Plan that also outlines the remediation and validation

measures.

The ollowing elements should be considered in such a plan:

Arrangements to check the integrity o the covering barrier o the contaminated area i there is any

possibility o it being disrupted, or instance i the barrier is in the orm o a vegetative cover;

Arrangements or personnel associated with any uture work on the site to be warned and guidedin regard to the impacted area, including sae working practices and repairing any damage to the

barrier;

Development o an inormation brochure or existing or prospective owners and occupiers o the

site. A relevant template is provided in Appndix F Gnric Asbstos Soil Contamination

Factsht;

Arrangements or the local shire i possible or other responsible entity to make the brochure

available in perpetuity and to assist with the disposal o ACM i it is ound.

The inormation brochure should include details o: risks associated with asbestos; site history and

current circumstances; management arrangements; personal actions that may be appropriate, and

rom where additional inormation may be obtained.

Where ACM remains on the site and is managed, the land will be classied accordingly by DEC and a

memorial put on the title. The classication will be Remediated or restricted use. The restricted use

would consist o a warning that asbestos remains on site below ground and that precautions should

be taken not to disturb it. I disturbance is unavoidable then it should be done in a sae manner.


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6. Reporting

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6. Reporting

All asbestos-related reports should be presented primarily as outlined in the DEC guidance document

Contaminated Sites Management Series Reporting o Site Assessments 2001. The reports should

also refect the guidance provided in relevant chapters o these Guidelines as well as the ollowing

inormation:

Each report should outline the relevant training and experience o at least the supervising

environmental consultant;

I an approach varies rom these Guidelines, it should be ully detailed and justied, including by

providing inormation on precedents;

All reports should be as comprehensive as possible in regard to inormation, process and

decisions, to avoid misinterpretation;

Each report should be normally a stand-alone and should not rely on other documents or

contextual inormation or or interpretation;

Each report should investigate, outline and take account o any changes to site-associated

conditions that might aect the management process;

Where asbestos is not the only contaminant, any reporting relating to it should be clearly identied

and preerably discretely handled. This may deserve a specic report such as an Asbestos

Management plan;

For the PSI visual inspection it is critical to commnt spcifcally on th prsnc or absnc

o asbstos material and on the inspection method;

I a DSI is conducted, its report should include a statement as to why it was necessary as part o

the remediation and management process;

I a site is subject to a Mandatory Auditors Report, that report should comment on the compliance

with these Guidelines o the relevant site investigation and management activities;

The Site Remediation and Validation Report should include documentation arising rom the

disposal o removed asbestos or asbestos containing material at a suitable landll;

Incorporate photographs in reports since asbestos is oten identied visually.

6.1 Soil Investigations

O particular interest to DOH are details o the process and rationale associated with site

sampling, analysis and validation, and how the results are interpreted. This needs to be clear and

comprehensive especially or sites that are complicated or lack good historical inormation. The ull

raw data, including soil logs and laboratory results should be provided in appendices. Tables and

diagrams should be used to help summarise and interpret the data. Any asbestos concentration

calculations should be made explicit.


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