Laboratory Asbestos Testing and Respirable Fibres Will Fardon Business Development Manager

Transcription

1 Laboratory Asbestos Testing and Respirable Fibres Will Fardon Business Development Manager 9/12/2016 1

2 Overview Asbestos Brief Introduction Sampling, Sample Handling, Preparation Analysis Identification & Quantification Legislation and Standards What s new?

3 Asbestos Naturally occurring fibrous mineral silicates Earliest use 4,500 years ago strengthening earthenware Properties: sound absorption, tensile strength, its resistance to fire, heat, electrical and chemical damage Kills around 5000 workers each year, more than the number of people killed on the road Fibrous serpentine - Chrysotile (white) Amphiboles - Crocidolite (blue), Amosite (brown), Actinolite, Anthophyllite and Tremolite.

4 Asbestos Analysis Labs must be ISO for Asbestos ID Accreditation not required for Quantification Guidelines for ID given by Lab 30/HSG248 Guidelines for quantification Development and validation of an analytical method to determine the amount of asbestos in soils and loose aggregates: Addison et al.,

5 Asbestos Limits To what levels must samples be tested? Hazardous Waste limit 0.1% Short term exposure limit 0.6 f/ml over 10 mins Control limit 0.1 f/ml over 4 hours Addison dried soils with as little as 0.001% asbestos could release fibres at a concentration above the control limit. +44 (0)

6 Sampling Sample size now and future Double sealed containers Clear indication of suspected asbestos Sampling guidance in HSG248 Current discussions surround airborne fibres and fibre release, a risk which is increased when soil is dry

7 Identification Stage 1 Soil Screening and Identification Test must be UKAS accredited Sub-sample dried Examined under stereomicroscope Suspect materials/fibres/fibre bundles removed for identification Identification by Polarising Light Microscopy (PLM)

8 Identification Amosite RI Liquid 1.67 Straight Morphology Frayed Ends Purple-Gold dispersion staining colours

9 Quantification Stage 2 - Gravimetric Also called Hand Picking & Weighing LOD < 0.001% Bulk ACM removed and weighed % Asbestos content determined using guidelines in HSG264 Fine fraction examined and all fibres/fibre bundles removed and weighed

10 Quantification ACMs removed & weighed, % asbestos correction applied Example 89.46g soil containing: Chrysotile (Hard Cement mass 11.42g) From HSG264 max asbestos is 15% g Chrysotile (insulation lagging mass g) From HSG264 max asbestos is 85% g Total = (1.713g g)/89.46g = 1.92% Any loose fibres would be counted as 100% asbestos

11 Quantification Stage 3 - PCOM Performed where Gravimetric cannot but sample is positive Soil sample is mixed with water and filtered Filter is used for fibre counting by Phase Contrast Optical Microscopy (PCOM) All fibres counted, some discrimination for ACM/Non ACM

12 Quantification 1 5g fine soil into water with 1:200 ratio Shaken, settled and 1ml filtered Fibre counting as per HSG248, discriminating non-acm and types A/B Record fibre length and width for types A & B, calculate volume Calculate equivalent mass using density factors (HSG248) Calculate fraction used for analysis and report % asbestos as type A (Chrsotile) and type B (Amphiboles)

13 Documentation HSG248 The Analysts guide for sampling, analysis and clearance procedures HSG264 - Asbestos: The survey guide Both available as a free download from the HSE website

14 Updates New HSG248 draft version under review Potential changes to sampling volumes SCA Blue Book method for quantification V12 submitted for review (i2 on EIC review group)

15 So what comes next

16 Asbestos Dustiness in Soil Asbestos Dustiness

17 Asbestos Analysis Identification Quantification Does that give you the full picture? Can you accurately quantify the risk it represent?

18 Risk assessment What risk does that number actually represent? Current techniques give you a numeric result along with a qualitative description of the asbestos fibre type and ACM type Only part of the picture Requires further information and interpretation to help define the risk this represents What else can we do? What is it that represents a risk?

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20 Respirable Fibres Those which will penetrate beyond the terminal bronchioles into the gas exchange region of the lungs as these represent the significant risk to human health < 3µm Diameter, > 5µm length and an aspect ration (Length : Width) greater than 3 Not a dust but a long thin aerodynamic fibre

21 Respirable Fibres Can Cause Asbestosis and Mesothelioma with minimal exposure

22 If the soil is wet, then there is less chance of airborne fibres being released, but when dry, there is a significant risk of fibres becoming airborne Dry soils containing 0.001% asbestos could release fibres > current control limit of 0.1 fibres/ml Conditions: compressed air blown through the samples to produce respirable dust concentrations of > 5mg/m 3 Addison et.al

23 Based on a Standard Method BS EN : (0)

24 Method Principle Soil or bulk sample rotated in metal drum Constant air flow passed through equipment Generated dust with respirable fibres collected on a filter Dust on filter measured gravimetrically Airflow

25 Method Principle Respirable fibres analysed by standard PCOM method (HSG 248) Results reported as: Fibre Concentration (fibres/cm 3 ) Respirable Dust Concentration (mg/m 3 ) Respirable Fibres corrected to 4 mg/m 3 (UK exposure limit EH40)

26 Other options? Test sample DRY worst case scenario Test sample as received representative of sample as submitted Test sample with adjusted moisture mimic on site conditions Ultimately looking at an optimal moisture content required to control dust and fibre release

27 Benefits Adds in the extra level of detail you need to review risk on your site Quick response No additional site activity or deployment of monitoring equipment May provide significant cost savings over potentially unnecessary remediation/removal techniques

28 Thank you and questions +44 (0) i2 Analytical Ltd 7 Woodshots Meadow Croxley Green Business Park Watford Herts WD18 8YS