asbestos analysis of soil and rock
TRANSCRIPT
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Asbestos ContaminationSloppy or improper Asbestos Removal jobs can leave asbestos contamination in surrounding soil
Why Look for Asbestos in Soil/Rock?
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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
Why Look for Asbestos in Soil/Rock?
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Asbestos ContaminationContamination from “Past Use (or current use!) Sites” such as manufacturers of asbestos containing products, auto repair sites, etc.
Why Look for Asbestos in Soil/Rock?
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Asbestos Contamination from Events or Disasters such as 9/11 and Katrina
Why Look for Asbestos in Soil/Rock?
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Naturally Occurring Asbestos
Why Look for Asbestos in Soil/Rock?
First gained large scale publicity with the Libby Montana Vermiculite Issue
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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
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El Dorado County, CA
Oak Ridge High School soccer field construction disturbs amphibole asbestos.
Naturally Occurring Asbestos
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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.
Naturally Occurring Asbestos
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NOA – not just a California problem
Naturally Occurring Asbestos
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Naturally Occurring Asbestos (NOA) affects more than 30 square miles of Staten Island
Naturally Occurring Asbestos
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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
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Scales of Non HomogeneityThe 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?
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Scales on Non Homogeneity
The Fine Picture
Obtaining a representative sub-sample in the lab is important
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Scales on Non Homogeneity
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.
The Very Fine Picture
Low mag stereoscopic view of play sand
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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”.
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Limitations of Standard PLMLimitations 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, semi-
quantitative 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 SoilQuantitative Sieving Method, to be promulgated (hopefully Summer 2007)
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The soil is sub-sampled (only particles < 16mm)Wet sieved through a 60 mesh (250 micron) sieveOnly the >250 micron fraction is analyzedStereoscope (20X) used to quantify, and PLM used to identify
Region 1 Screening Protocol
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1. Sample is dried at 60o C2. Weigh (1Kg dry start
weight minimum)3. Sieve Stack
• 6.3 mm sieve• 4.75 mm sieve• 2.0 mm sieve
MA DEP Sieve Method
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4) Wet sieve into 3 fractions5) Transfer each fraction to its own
disposable tray
MA DEP Sieve Method
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6) Dry and weigh all fractions7) Each fraction undergoes a
stereoscopic examination to extract all suspect debris.
8) For each fraction, homogenous suspect material is placed into separate weighing dishes and analyzed separately.
9) If any material contains >1% asbestos by PLM then it is considered ACM.
MA DEP Sieve Method
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• 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
MA DEP Sieve Method
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Pilot Study Results
Samples above proposed action limit
MA DEP Sieve Method Performance
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Split Samples demonstrate the problems associated with a non homogenous matrix
MA DEP Sieve Method Performance
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MA DEP Sieve Method
Pros
Relatively quick and easy
Finds obvious asbestos common sensically, by hand picking it outat low mag
Cons
Relies on stereoscope (20X) to find suspect ACM
Fine material (<2mm) is typically not analyzed
Therefore unconsolidated asbestos goes undetected
Summing Up
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Scenario 2:Scenario 2:
Naturally Occurring Asbestos (NOA)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 435California Air Resource Board (CARB) Method 435Determination of Asbestos Content of Serpentine AggregateDetermination 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%).
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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.
CARB Method 435
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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.
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• 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.
CARB Method 435
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TEM CARB Method for SoilTEM CARB Method for SoilCARB 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.
CARB Method 435 “Plus”
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Following the standard milling,
TEM CARB MethodA known mass of sample is weighed out and brought into solution
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After sonication,the sample is filtered through a 0.4 micron filter
TEM CARB Method
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TEM CARB Method
Analyzed by TEM at 20,000X
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• 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
TEM CARB Method
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TEM CARB MethodPerformance at 0.1%
0.24
0.13
0.37
0.060.04
0.09
0
0.1
0.2
0.3
0.4
0.5
Lab 1 Lab 2 Lab 3 Lab 4 Lab 5 Lab 6
Spiked Sample 1 – Chrysotile 0.1%
Round Robin Analysis by TEM to 0.1% Sensitivity
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0.07
0.01 0.00
0.08
0.14
0.27
0
0.1
0.2
0.3
0.4
Lab 1 Lab 2 Lab 3 Lab 4 Lab 5 Lab 6
Round Robin Analysis by TEM to 0.1% Sensitivity
Spiked Sample 2 – Actinolite 0.1%
TEM CARB Method Performance at 0.1%
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Blind Test with Spiked SamplesPLM and TEM
Chrysotile
Actinolite
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Blind Test with Spiked SamplesPLM and TEM
Chrysotile
Actinolite
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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
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Elutriator Method
Tumbler apparatus filled with soil
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Tumbler inside enclosed humidity chamber
Elutriator Method
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Elutriator MethodAir Cassettes on top of the elutriator stack.
Isokinetic sampling to catch only the respirable fraction of fibers released from the soil
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Summing Up: Summing Up:
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)
The right answer depends on the question.The right answer depends on the question.
