Dr Phil Studds Ramboll Asbestos in Soils

Asbestos in Soils
Dr Phil Studds
Ramboll
phil.studds@ramboll.co.uk

CONTENTS
General Background
• what is it?
• where does it come from?
• why do we care?
Case Study
• UK legislation & guidance for:
• initial laboratory testing
• standard assessments
• Bespoke Trials
• Remediation options
• Risk Communication
• Conclusions

What Most Relevant is it? Reports
• Asbestos is a naturally occurring
fibrous rock mineral
• Mined commercially in Russia,
Canada, Australia, Africa, USA,
Cyprus, China, Brazil, Italy….
• 6no. fibrous types of asbestos
• Excellent physical properties
-Chemical resistance
-Resistant to fire
-Acoustic & condensation protection
• Used extensively in the UK until
the late 1990s

Most Relevant Types Reports
• Chrysotile – White
•2000 BC – found in clay pots
in Finland
• 300 BC – oil lamp wicks in
Greek Acropolis
• Amosite – Brown
• Crocidolite – Blue
• brown & blue more
hazardous
• Apparent colour
not a good indication
of type
• 100 AD – woven table cloths
& handkerchiefs
• 1700s – purses, coats, shirts,
books
• 1800s – theatre safety
curtains and fire fighting
clothes
• 1828 – first US patent for
steam engine
• 1900s – food purification
filters, gas mask filters, hospital
air filters, surgeon’s thread,
tooth paste filler, cigarette tips
and artificial snow

Asbestos Cement
roofing sheets
'Preformed' Thermal
Pipe Insulation
Floor Vinyl (with
Asbestos Paper Backing)
Brakes containing
Asbestos Rope
Products
Bakelite toilet
containing Bonded
Asbestos
Asbestos thermal
insulation debris
(contamination).

Asbestos fire blanket Pieces of AIB Perforated AIB ceiling
tiles damaged around
the light fitting
Suspended AIB
ceiling tiles in a corridor
Asbestos containing
floor tiles in a corridor
Asbestos cement

How does it end up in the ground?
Only very minor natural sources of asbestos in the UK – Cornwall
Chrysoltile
Asbestos contamination by anthropogenic sources
• Processing asbestos – dust fallout of debris from nearby works,
i.e. factory, Armley, Leeds
• Demolished buildings and clearance of buildings containing ACMS
– poor site practice
• Buried pipes/ducts
• Fly tipping
• Intentionally placed in the ground (farmers/power stations)
• Landfill disposal
• Cross contamination – importation of impacted soils

Who is at risk & why do we care
Current Users
–Recreational Activities
–Residents
- Largest single industrial killer
in the UK
- Over 4,000 deaths /yr in UK
rising to 10,000 deaths /yr
–Workers
Contractors involved in re-profiling the site
–Earthworks / enabling works
–Cut and Fill operation and muck shift
–Pilling Contractors
–Services / Drainage Gangs
–House builders
HSE Statistic
every week on average...
- 4 plumbers die
- 20 tradesmen die
- 6 electricians die
- 8 joiners die

1. Mesothelioma
2. Lung cancer
3. Asbestosis
4. Diffuse pleural thickening

ASBESTOS IN SOIL
CASE STUDY – HOBMOOR SCHOOL,
BIRMINGHAM

Case study - Introduction
New School site at Yardley
• Client – Balfour Beatty Construction
Limited,
• PFI Contractor for 10 Birmingham
Schools
• New Hobmoor School
• Site Context
• Soft landscaping, sports areas,
significant cut and fill
• Previously developed land - industrial
• Historic review and site visit established significant volumes of
demolition rubble from prefabricated buildings across the site
• Surrounding residential area

Case Study
Initial Assessments
• Significant demolition rubble
across the site
• Asbestos Containing Materials
(ACM) encountered during
site clearance
• Specialist Survey (Specialist
Contractor) undertaken -
sampling, perimeter air
monitoring
• Asbestos cement –
chrysotile
• Asbestos insulating board
- amosite
• ACM located in the top
100 – 150mm of top soil

Regulations
Most Relevant Reports
• The Health and Safety at Work Act 1974
• The Asbestos Licensing Regulations 1983
(as amended)
• The Asbestos (Prohibition) Regulations
1992 (as amended)
•The Control of Asbestos at Work
Regulations 2002
•The Control of Asbestos Regulations 2006
• Construction (Design and Management)
Regulations 2007

UK Guidance
No definitive guidance for
concentrations in soil.
• ICRCL Guidance Note 64/85 “Asbestos on Contaminated Sites”
published 1990
• If obvious ACM present – treat as contaminated
• Addison et al, HSE Contract Report 83/96
• Introduce idea of testing for free fibres
• Hazardous Waste Regulations
• 0.10%wt asbestos in soil – threshold for hazardous waste

Sampling and Analysis
• ≥1 kg samples
• Bulk ID
– presence/absence of asbestos minerals
• First stage of quantification
• Weigh soil sample
– lab specifically accredited for soils
• Pick out ACMs, describe type e.g. chrysotile cement
• Weigh ACMs
• Use standard asbestos contents to calculate % asbestos
• Second stage – quantify loose fibre content using optical
microscopy (f/ml)-

Laboratory Analysis
Gravimetric w/w percentage asbestos in soil
• Cheap easy to obtain result
• Limited value and difficult to interpret number because it calculates %
concentration of asbestos in ACMs as a % of whole soil sample
• Lead to large overestimate of asbestos content, e.g.:
• Thermal insulation – 6-85%
• Asbestos Boards – 37-97%
• Resin – 30-70%
• Basic gravimetric analysis not appropriate for assessing waste
classification or potential risk to human health
• Risk - How to relate hazard (ACMs) to risk (from respirable asbestos
fibres)?
• Remediation - How to effectively plan remediation (or do nothing)
scheme without all necessary information

Dustiness Testing
• Measures the propensity of the material
to release airborne dust.
• It is a comparative measurement.
• Carried out by applying a standard set
of measurement conditions and
selecting a defined fraction (e.g.
respirable).
• European Standard EN15051 method
• Range of dustiness values extend over 5
orders of magnitude.
• Replicates the worse case airborne
release – only used for difficult sites

Detection of Airborne Fibres
Scanning Electron Microscopy

Assessment of Data
• No UK Tier 1 SGV defined for concentrations (or percentage) of
asbestos in soils – i.e. levels regarded as NOT representing
SPOSH
• EA/Defra, IOM, EIC + others working on this.
• Dutch Guidelines -

Assessment Difficulties cont…
• Test methods for fibre release – (meaningful tests required).
• Typical background asbestos fibre counts in outdoor urban air 1
0.0001f/ml
• HPA advise on an unofficial environmental limit of 0.0005f/ml
• But standard air fibre monitoring equipment gives a 0.01f/ml
detection limit! (SEM – 0.001 f/ml)
• Modelling Tools – once site specific exposure data is gathered,
how are the risks evaluated? There is currently no public
available modelling to assess soil source asbestos exposure
(1) – Health Effects Institute US

Assessing Risk - Summary
• Impact from asbestos should be assessed like any other soil
contaminant (i.e. S-P-R), except;
• Impact occurs as discrete fragments
• Potential for exposure increases with time as material breaks down
with time
• Hazard assessment based on % w/w crude and does not relate to
concentration of air borne fibres, the real risk
• Risk from exposure to airborne asbestos from soil dependent on:
• Asbestos content in soil;
• Type of asbestos present;
• Matrix of soil (clay or sand dominated), moisture content
• Site use and exposure duration/behaviour of receptor

Case Study
RISK MANAGEMENT – PHASE 1
• Pollutant linkages identified – during
construction and operation of the site
• Free fibres, friable materials (asbestos
cement, AIB)
• Remedial Options Appraisal
1. Dig & dump (vegetation strip)
- >£800 000
2. Handpick ACMs and cap and with
imported top soil (300mm) + marker
layer ~£0.5M
3. Assess risks of reusing top soil in situ
• Developed a bespoke methodology
• Comprehensive worldwide review of
asbestos legislation & guidelines

Case Study
BESPOKE ASSESSMENTS – ARE TOP SOILS
SUITABLE FOR REUSE ON SITE?
I
OBJECTIVES
All ACM has been removed from the top soil
as far as reasonably practicable.
II
There is no significant amount of residual
free fibres within the top soil.
OBJECTIVE TESTING
III
Vigorous disturbance of the soil, greater
than the worst case envisaged during
school operation, will not generate
detectable levels of asbestos fibres in
outdoor air.
Soil Screening
Soil Fibre Analysis
Air Monitoring
I, III, IV, V
II
III, V
IV
Vigorous disturbance of the soil, greater
than the worst case envisaged during
school operation, will not generate
detectable levels of asbestos fibres in
indoor air.
Indoor Air Experiment
IV, V
V
There will be no significant load of asbestos
fibres into the environment during future
school operations.

Case Study
INDOOR AIR EXPERIMENT
• Estimate potential air fibre release during
school operation e.g. soil derived indoor
dust
• Simulate realistic and real time situation –
worst case
• Purpose built 12m 3 sealed enclosure with air
lock entry
• Vigorous disturbance of soil (5mins for every
15mins over a 1h period) – generate dust
• Air monitoring and testing
• Phase Contrast Optical Microscopy (PCOM)
analyses
ACM impacted soils
generating dust in a school
building

Case Study
SOIL FIBRE ANALYSIS
• Analysis of “screened soils” for “free
fibres”
• Samples sent to specialist lab - Institute
of Occupational Medicine (IOM) in
Edinburgh
• Qualitative analysis – binocular &
Polarised Light Microscopy (PLM)
• Quantitative analysis (% w/w) –
Quantitative Phase Contrast Microscopy
• No detected “free fibres”
• Vigorous disturbance of soils does not
generate secondary asbestos fibres
• Specific to conditions on the Hobmoor
site – soil type, asbestos type etc.

Soil Remediation
• Ex situ soil
treatment – hand
picking
• Waste exemption
for re-use on site –
deep burial and
capping
• Suitable for use,
risk-based target
• Validation of
stockpiles

• The principal method
- disposal to landfill or capping.
• Segregate
Soil Remediation
• Reduce the volume of soil going to
landfill
• Allow a reduction in the
classification of the soils to nonhazardous
• Allow the retention of treated soils
on site
• Savings of at least 30%, >60%
compared to straight disposal to
landfill.

Case Study
SOIL SCREENING
• Hand picking of asbestos cement and AIB fragments
• Licensed contractor, HSE approved methodology
• Trommel sieving (14mm mesh)
• Air monitoring across the perimeter of the site & in “Control Zone”

Case Study
RISK COMMUNICATION
• Asbestos is an emotive subject
• “Perceived” hazards and risks
• Stakeholder Management was key to
the success of this project
• Balfour Beatty
• Health & Safety Executive
• Environment Agency
• Birmingham City Council Contaminated
Land Officer
• Environmental Health Departments
• School Board of Governors
• Complex air monitoring – confidence
to neighbours

Case Study
CONCLUSIONS
• Screened top soil – fit for purpose
• Reused in soft landscape without
capping layer
• Site Specific & Bespoke risk
assessment methods developed and
implemented
• Worst case activities simulated and
tested
• No residual fibres detected
• Concluded residual risks Low
• Risk Communication undertaken

Case Study – Conclusions cont.
• In total 80 soil samples were analysed and 14 were identified with
visible ACM debris, all of which were less than 0.05% by weight of
the sample.
• No free fibres were detected in any of the 11 samples tested.
• Results of all air monitoring - below detection limit of the
standard HSE method i.e.