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asbestos analysis and implications for site development Right - - PowerPoint PPT Presentation

The new Blue Book method of asbestos analysis and implications for site development Right Solutions Right Partner www.alsglobal.com 1 Right Solutions Right Partner Asbestos in Soil Over 4000 people die of asbestos related diseases


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1 Right Solutions · Right Partner

Right Solutions • Right Partner www.alsglobal.com

The new ‘Blue Book’ method of asbestos analysis and implications for site development

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2 Right Solutions · Right Partner

Asbestos in Soil

  • Over 4000 people die of asbestos related diseases each year
  • Asbestos is a Class 1 carcinogen
  • Proven link with respiratory diseases: asbestosis, mesothelioma, bronchial

carcinoma, pleural plaques (and recently ovarian cancer)

  • Can remain latent for 15 – 40 years
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Asbestos In Soil Risk of asbestos on Brownfield Sites

  • Buried asbestos uncovered during site clearance
  • Site activity causes breakdown of bound ACM
  • Airborne fibres generated from soil
  • Carried on vehicle wheels
  • Carried on clothing of site personnel
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4 Right Solutions · Right Partner

Asbestos in Soil Respirable fibres

  • The greatest risk to human health is from the respirable fibres, not the bound

ACM

  • Respirable fibres are defined as small fibres that can be inhaled into the

lower regions of the lung, with the following dimensions:

  • Longer than 5 um, <3 um diameter, and have aspect ratios of at least 3:1
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Quantifying Asbestos - Limits of Detection

What limit should be considered an acceptable risk?

  • HSE Control Limit for exposure to asbestos is 0.1 fibres/ml for a continuous average
  • ver a four hour period
  • Addison et al (1988) ‘The Release of Dispersed Asbestos Fibres from Soils showed

that airborne fibre concentrations could be very high (> 20 f/ml), and even 0.001% of asbestos in a dry loose mixture was capable of producing airborne respirable asbestos concentrations in excess of the 0.01 f/ml clearance limit

  • This value has never been ratified by any regulatory body
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Analytical Methods summary – Identification

  • Gross visual screening for ACM only – not acceptable to UKAS
  • Detailed screening using a x 40/x80 standard optical microscope and

remove fibrous material

  • Identification of asbestos type by Polarising Light Microscopy (PLM) as per

HSG 248

  • Laboratories must be accredited to ISO 17025 for this analysis
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Asbestos Identification in Soil

Initial visual examination

  • Spread out entire sample
  • Examine for ACMs

– Remove and dry for ID

  • Subsample soil for ID

– Dried for ID Stereomicroscopy Dried sample examined at x40 – x80 Suspect fibres removed for PLM Polarised Light Microscopy Place fibre in RI Liquid Observe a range of fibre characteristics

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Identification of Asbestos In Soil

  • Polarised Light Microscopy (PLM) – crossed polars
  • Birefringence: “The numerical difference between the highest and

lowest Refractive Index of a mineral”, visible as interference colours.

  • Extinction: Fibres disappear from view or ‘extinguish’ at four positions

each 90° apart.

  • Most fibres extinct when parallel with polariser or analyser
  • Actinolite and Tremolite have slight ‘angle’ of extinction.
  • Elongation: Relationship between fibre shape and optical properties
  • Length Slow: The slow ray of the mineral is parallel with the length of

the mineral

  • All asbestos fibres are length slow apart from Crocidolite
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Analytical Methods Quantification

  • Quantification of ACM only by gravimetric measurement to 0.1%
  • Quantification of smaller ACM and fibre bundles by gravimetric to 0.001%
  • Quantification by dispersion and fibre measurement using Phase Contrast

Microscopy (PCM) - dispersed fibres - to 0.001%

  • SEM or TEM - limited commercial availability
  • Fibre release test – very limited commercial availability, time consuming and

expensive

  • Respirable fibres in respirable dust - NEW
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Asbestos In Soil - Quantification

  • Dispersed Free Fibres
  • Fibre counting and sizing
  • Portion of fine fraction mixed

with water

  • Aliquots removed and filtered
  • Filter dried and cleared using

acetone

  • Filters evaluated at x500 – x600

magnification – Non-asbestos fibres discriminated using modified PCOM – Asbestos fibres measured (length and width) – Calculate mass of each fibre – Calculate mass % in sample

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Asbestos in Soil- Quality - External

  • Identification

– Annual UKAS assessment – AIMS External QC scheme

  • Run by HSL
  • Quarterly
  • Quantification

– Annual UKAS assessment – AISS External QC scheme

  • Run by HSL
  • Four rounds so far

(plus pilot round)

  • Limited number of

labs participating

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Asbestos in Soil

  • The industry has difficulties with knowing what to do on site, best practice for

sampling, which tests should be requested, and interpretation of the data.

  • There is significant variation in laboratory testing methods for quantification
  • f asbestos.
  • So what is the industry doing about this?
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Asbestos in Soil - Industry Initiatives

  • An updated version of HSG 248 The Analysts guide for Sampling, Analysis

and Clearance procedures, (HSE 2005) is in progress.

  • Draft version now available
  • Dr Martin Gibson of HSE is responsible for this update
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Asbestos in Soil – Industry Initiatives

  • EIC (Environmental Industries Commission) asbestos subgroup set up in 2010
  • CIRIA PSG set up in Jan 2012 after appointment of contractor (LQM & IOM) to

produce clients’ guide

  • The document (200+ pages) was published March 2014: ‘Asbestos in soil

and made ground: a guide to understanding and managing the risks’

  • Comprehensive document, and highlighted areas where more information

was required

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Asbestos in Soil – Industry Initiatives

  • Joint Industry Working Group (JIWG) set up in Nov 2011
  • Secretariat by CL:AIRE, and chaired by Steve Forster of IEG Technologies, -

their aim is to build on the CIRIA document and produce a CoP by the end of 2015

  • Representatives on the PSG from consultants, landowners, lawyers,

developers, labs, the regulators and insurers

  • Working closely with the regulators – EA, DEFRA, HSE and UKAS
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Asbestos in Soil – Industry Initiatives

  • Additional information to be provided in the CoP:
  • Background levels of asbestos in 400 soils
  • Information on fibre release rates from a wide range of soil types and

asbestos concentrations

  • An algorithm helping to predict risk from any particular site
  • A recommended, robust method for identification and quantification of

asbestos in soils

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Asbestos in Soil – Industry Initiatives

  • Blue book methods
  • Also known as MEWAM – methods for the examination of water and associated

materials

  • Written by the Standing Committee of Analysts (SCA) – several working groups
  • Published by the Environment Agency, currently still on their website
  • Over 200 methods, widely recognised by industry and the regulators
  • Far more methods for water, but solids working group set up in 2001
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Blue Book Method

  • Stage 1: Identification – HSG 248 the Analyst’s guide for Sampling, Analysis and

Clearance Procedures (2005)

  • Stage 2: Quantification – gravimetric for ACM and fibre bundles
  • Stage 3: Quantification – dispersion, followed by measurement and counting using

PCM for dispersed free fibres

  • Laboratories should be accredited to ISO 17025 for this method as each stage

involves some fibre discrimination, but so far, this is not mandatory

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Benefits

  • Standardisation of Laboratory Approach
  • Standardisation of Output
  • Assurance of Quality & Robustness of Results.