Download Asbestos Analysis of Soil and Rock

Asbestos Analysis
of Soil and Rock
Ed Cahill
EMSL Analytical Inc.
845-469-8671
[email protected]
1
Why Look for Asbestos in Soil/Rock?
Asbestos
Contamination
Sloppy or improper Asbestos
Removal jobs can leave
asbestos contamination in
surrounding soil
2
Why Look for Asbestos in Soil/Rock?
Asbestos Contamination
Demolition of Buildings Without
the Proper Removal of ACM
prior can leave a trail of
asbestos contamination all the
way to the landfill
3
Why Look for Asbestos in Soil/Rock?
Asbestos Contamination
Contamination from “Past Use
(or current use!) Sites” such as
manufacturers of asbestos
containing products, auto repair
sites, etc.
4
Why Look for Asbestos in Soil/Rock?
Asbestos Contamination from
Events or Disasters
such as 9/11 and Katrina
5
Why Look for Asbestos in Soil/Rock?
Naturally Occurring Asbestos
First gained large
scale publicity with
the Libby Montana
Vermiculite Issue
6
Naturally Occurring Asbestos
Naturally Occurring /
Unnaturally Exported
Vermiculite was processed in blast
furnaces and sent throughout the
country and abroad for a multitude of
uses. The raw ore was also exported
for processing off site
7
Naturally Occurring Asbestos
El Dorado County, CA
Oak Ridge High School
soccer field construction
disturbs amphibole
asbestos.
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Naturally Occurring Asbestos
Naturally Occurring Asbestos
Serpentine (including
Chrysotile asbestos) is the
state rock of California.
The aggregate used for
roadbeds, rail beds, and on
construction sites of all types
is always a question mark.
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Naturally Occurring Asbestos
NOA – not
just a
California
problem
10
Naturally Occurring Asbestos
Naturally Occurring Asbestos (NOA) affects more than 30 square miles of
Staten Island
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Why is Soil and Rock Different
from Other Samples?
The problems with soil:
- obtaining a representative sample in the field
- obtaining a representative sub-sample in the lab
- varying particle sizes prohibit making proper slide
mounts
ALL of these come down to a problem of lack of
Homogeneity
12
Scales of Non Homogeneity
The Big Picture
• Obtaining representative
•
•
samples in the field can
be difficult.
Samples tend to be very
non-homogeneous
especially over the large
areas that are typical in
NOA related cases.
How many samples for a
baseball field or 100 miles
of road or rail bed?
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Scales on Non Homogeneity
The Medium Picture
• How deep to go?
• What layers to include?
14
Scales on Non Homogeneity
The Fine Picture
Obtaining a
representative
sub-sample in the
lab is important
15
Scales on Non Homogeneity
The Very Fine Picture
Large particle size makes it
difficult to get good slide
mounts for light microscopy
or grid preps for TEM. The
presence of rocks, sticks,
even sand sized quartz
crystals are a problem
when analysis is at higher
magnifications.
Low mag stereoscopic view of play sand
16
Soil is Different
• Soil and Rock are
problem matrices for
field and lab
personnel alike.
• Without special
care asbestos can be
overlooked.
• Careful sampling
plans can reduce
inconsistencies, and
carefully define “what
is the sample”.
17
Limitations of Standard PLM
EPA PLM Method (EPA/600/R-93/116)
Method for the Determination of Asbestos in Bulk Building Materials
• As the title suggests and the method explains, this is a
method for relatively homogenous bulk building
materials, not soil.
• The final version of this method is quite flexible though
and matrix modification prior to analysis is described
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Solutions
The analytical approach will vary
depending on the potential source of
asbestos:
• “Fugitive Asbestos” from sources such as
•
•
demo and construction, illegal dumping, bad
removal jobs, etc.
NOA (Naturally Occurring Asbestos)
Special circumstances like Libby, WTC, Katrina
in New Orleans
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Scenario 1
Asbestos Contamination in Soil
In scenarios with visible pieces of suspect ACM in the soil, sieving is
often the best choice.
• EPA Region 1 Screening Protocol
“Protocol for Screening Soil and Sediment Samples for
Asbestos Content” used by the EPA Region 1 Lab
- This is a low tech screening method, semiquantitative at best.
- Been around since 1994, revised ’97 and ’99
- Stereoscopic (20X mag) estimate of % Asbestos
•
MA DEP Sieve Method for the Determination of Asbestos Debris
in Soil
Quantitative Sieving Method, to be promulgated
(hopefully Summer 2007)
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Region 1 Screening Protocol
„
„
„
„
The soil is sub-sampled (only particles < 16mm)
Wet sieved through a 60 mesh (250 micron)
sieve
Only the >250 micron fraction is analyzed
Stereoscope (20X) used to quantify, and PLM
used to identify
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MA DEP Sieve Method
1. Sample is dried at 60o C
2. Weigh (1Kg dry start
weight minimum)
3. Sieve Stack
• 6.3 mm sieve
• 4.75 mm sieve
• 2.0 mm sieve
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MA DEP Sieve Method
4)
5)
Wet sieve into 3 fractions
Transfer each fraction to its own
disposable tray
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MA DEP Sieve Method
6)
7)
8)
9)
Dry and weigh all fractions
Each fraction undergoes a
stereoscopic examination to
extract all suspect debris.
For each fraction, homogenous
suspect material is placed into
separate weighing dishes and
analyzed separately.
If any material contains >1%
asbestos by PLM then it is
considered ACM.
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MA DEP Sieve Method
• The total weight of all the ACM found in all
layers is divided by the total starting weight
to determine the final percent.
• This method determines the % of ACM
(not the % asbestos) in the soil sample.
• The proposed standard for Massachusetts
is 150mgACM/KGsoil
25
MA DEP Sieve Method
Performance
Pilot Study Results
Samples above proposed action limit
26
MA DEP Sieve Method
Performance
Split Samples
demonstrate
the problems
associated
with a non
homogenous
matrix
27
MA DEP Sieve Method
Summing Up
Pros
Relatively quick and easy
Finds obvious asbestos common sensically, by hand picking it out
at low mag
Cons
Relies on stereoscope (20X) to find suspect ACM
Fine material (<2mm) is typically not analyzed
Therefore unconsolidated asbestos goes undetected
28
Scenario 2:
Naturally Occurring Asbestos (NOA)
In scenarios where there is no visible evidence of
ACM contamination or if it is suspected that there
may be NOA in the soil or rock.
California Air Resource Board (CARB) Method 435
Determination of Asbestos Content of Serpentine Aggregate
The sample is milled and then analyzed by PLM using a 400 or 1000
point count (0.25% or 0.1%).
29
CARB Method 435
The sample is:
• dried in a drying oven and material >3/8” is removed by sieving
• Milled at liquid nitrogen temperature at minus 200 degrees C (-300oF) for
approximately 4-8 minutes (depending on the sample make up) in order to
reduce the nominal particle size to 75 microns.
30
CARB Method 435
• After milling the sample
is analyzed by a PLM
400 or 1000 point count
(0.25% or 0.1%).
• The CARB Method has
an abbreviated PLM
method in it but the
more comprehensive
EPA 600 method is
recommended after the
milling.
31
CARB Method 435
• One of the main advantages of the CARB
Method over the sieving methods is that it
enables detection of unconsolidated (loose
and unbound from matrix) asbestos fibers.
• Unfortunately the resolution of the light
microscope is only about 0.25 microns.
•
Asbestos fibers/bundles with widths less
than this are not detected.
32
CARB Method 435 “Plus”
TEM CARB Method for Soil
CARB Milling followed by TEM Mass Analysis by EPA 600
Section 2.5
• Milled sample is put into suspension, filtered and
analyzed.
• Analysis is performed at up to 20,000X
• Identification of asbestos using X-Ray Analysis
and SAED (selected area electron diffraction)
• Results are given in percent asbestos by mass
• Varying levels of analytical sensitivities are offered.
33
TEM CARB Method
A known mass of
sample is weighed out
and brought into solution
Following the
standard milling,
34
TEM CARB Method
After sonication,the sample is filtered
through a 0.4 micron filter
35
TEM CARB Method
Analyzed by TEM
at 20,000X
36
TEM CARB Method
• By carefully measuring the lengths
and widths of any asbestos
fibers/bundles detected, the individual
fiber masses are calculated.
• The individual weights are then totaled
and a mass percent is determined
37
TEM CARB Method
Performance at 0.1%
Round Robin Analysis by TEM to 0.1% Sensitivity
0.5
Spiked Sample 1 – Chrysotile 0.1%
0.37
0.4
0.3
0.24
0.2
0.13
0.09
0.1
0.06
0.04
0
La b 1
La b 2
La b 3
La b 4
La b 5
La b 6
38
TEM CARB Method
Performance at 0.1%
0.4
Round Robin Analysis by TEM to 0.1% Sensitivity
Spiked Sample 2 – Actinolite 0.1%
0.3
0.27
0.2
0.14
0.1
0.08
0.07
0.01
0.00
0
La b 1
La b 2
La b 3
La b 4
La b 5
La b 6
39
Blind Test with Spiked Samples
PLM and TEM
Chrysotile
Actinolite
40
Blind Test with Spiked Samples
PLM and TEM
Chrysotile
Actinolite
41
One Final Approach
The Elutriator Method - Superfund EPA 540-R-97-028
• With this method a soil sample is gravimetrically tracked through sieving
into course and fine fractions
• The fine fraction is then tumbled in a closed chamber and any
respirable dust generated is collected on air cassettes
• Analysis is performed by ISO 10312 counting rules
This method is peer reviewed and acceptable for risk assessment
studies
42
Elutriator Method
Tumbler apparatus
filled with soil
43
Elutriator Method
Tumbler inside enclosed humidity chamber
44
Elutriator Method
Air Cassettes on top of
the elutriator stack.
Isokinetic sampling to
catch only the respirable
fraction of fibers
released from the soil
45
Summing Up:
The right answer depends on the question.
I see building material debris in the soil. Does it have asbestos and
if so how much? Do I need to dispose of it as hazardous waste?
• PLM by MA DEP Sieving Method to give % ACM in soil
• PLM by modified MA DEP Sieving Method to give % Asbestos in
Soil
I don’t necessarily see suspect asbestos but I think it might be
there either from contamination (ex brake shops) or from NOA.
• PLM CARB 435 (down to 0.25% or 0.1%)
• TEM CARB 435 (EPA 600 Mass Analysis)
Does the Soil Contain Respirable Fibers?
• EPA 540-R-97-028 Superfund Method (Elutriator)
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Asbestos Analysis
of Soil and Rock
Ed Cahill
EMSL Analytical Inc.
845-469-8671
[email protected]
47