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Indoor Environment Connections Article 011509 V2


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Indoor Environment Connections Article 011509 V2

  1. 1. Asbestos in Soil Methods I wanted to start off this brief technical summary with an item that appeared in the January 2009 Indoor Environment Connections publication… “Asbestos in Soil; The State of the Issue, Tom Laubenthal, Sean Fitzgerald, Alan Seagrave, P.G. In this session, Laubenthal and Seagrave will describe the nature of asbestos contamination in soil. This issue has perplexed the industry for years. What constitutes a contaminated soil? How does one go about sampling and then analyzing soil for the presence of asbestos? Is the asbestos in the soil from site pollution or from naturally occurring sources? When performing a site clean up for asbestos, what constitutes “clean?” These are all questions that many in the asbestos control industry wrestle with on a regular basis often with little guidance from the regulatory community or well-defined industry practices. This session will be broken into three portions. The first will be an overview of the issues and the nature of the problems encountered. The second section will be the laboratory perspective; past and current lab analysis perspectives and data interpretation. The third section will describe the current asbestos-in-soil analysis method being developed by the ASTM (D-22.07).” Tom and Alan are well-respected colleagues and friends. This plug for their presentation at the upcoming EIA conference is well-deserving and might even earn me a cold beer at the next ASTM committee meeting. Their topic, summarized here, has been the subject of debate among laboratory professionals and regulators for years. I strongly encourage you to attend this session for a more comprehensive review of this subject. So what’s the big deal about asbestos in soil? I mean, doesn’t the mineral originate in the ground?! Isn’t “asbestos in soil” redundant? For that matter, is “Naturally Occurring Asbestos” redundant? Isn’t asbestos only a problem in the air? There are, of course, multiple sources of regulations dictating how a bulk sample can be handled and analyzed for asbestos… isn’t that good enough? Consider also the questions posed in Tom and Alan’s abstract above. Like most issues surrounding anything asbestos, the answers can be quite complex. What methods are available to the environmental professional for such investigations? Currently there are several methods. They include a) EPA Region I Proprietary Method for the Analysis of asbestos in Soils, Sludges, and Sediments, b) CARB 435 Analysis of Asbestos in Serpentine Aggregate, c) EPA 600 04-004 The Vermiculite Attic Insulation method (though obviously this has its utility as its title suggests), d) various Libby Amphibole proprietary methods, e) EPA 540-R-97-028 Draft: Modified Elutriator Method openoffice-in.doc 1 of 8
  2. 2. Asbestos in Soil Methods for the Determination of Asbestos in Soils and Bulk Materials, Revision 1, f) EPA 600 R-93-116 Asbestos in Bulk Building Materials, g) MA DEP Method for Asbestos in Soil, and h) various modified methods from North America and abroad that employ PLM, SEM, TEM, and XRD. The current off-the-shelf choices for field sampling regimens and analytical testing methods may prove effective for some investigations, but then be completely useless for others. Furthermore, the ability to make effective engineering decisions based on laboratory results from these methods is questionable due to the wide range of variations in site and sampling circumstances, not to mention the vast extremes of ‘soil’ matrix definitions. As an asbestos remediation or design professional how would you employ a lab result in ppm (mg/kg), fibers/gram, gram/cm2, or % by weight? As a risk assessor how do you interpret these results? Remember, that most ‘bulk’ asbestos methods (ex. EPA 600) and the interpretation of that data are specifically designed for Asbestos in Bulk Building Materials. Many ambiguous definitions abound for ‘soil’. Is it the loamy stuff that I plant my tomatoes in the back yard? Is it the potting ‘soil’ that is mixed with vermiculite? Is it the loose earth mixed with building material debris that we find in some building crawl spaces? Is it something totally different like industrial waste-stream sludge? Was ‘soil’ sampled with large fractions of vegetative matter, or with fractions of miscellaneous components like bottle caps, broken glass, and other obvious non-asbestos containing trash. Other more specific definitions look for ‘aggregate serpentine mineral’. So what method is best for your study? Good question. The industry, in conjunction with regulators, has often had to quickly devise methods that suit the needs of select investigations (ex. Libby and other vermiculite studies, El Dorado California, etc.) Though these may be effective for short-termed projects, some lack validation studies, peer review, and the more rigorous input of a wide range of laboratory, regulatory and engineering professionals. ASTM once ‘rescued’ the industry with a series of recognized sampling and analytical methods for another complex matrix. As such, asbestos in surface dust investigations (ex. ASTM D5755, D6480 etc.) have become quite common as part of a comprehensive openoffice-in.doc 2 of 8
  3. 3. Asbestos in Soil Methods approach to building surveys and remediation studies. Those methods, developed in the 1980s and proposed in the 1990s, in conjunction with the demands of the industry, continue to evolve and have been employed in countless high-profile cases. A Guidance document (D7390.07) is also now available through ASTM to provide data interpretation to professionals. Under the auspices of Sub-Committee D22.07 (Asbestos Sampling and Analysis), ASTM is working to release a recognized method for soil investigations in the near future. Will this method supersede the other analytical methods? No. Will this method set the standard for future development of ancillary methods for an even wider range of ‘asbestos in soil’ methods? That is part of the intent of the sub-committee. As a foundational resource, other methods and procedures can grow from this to be utilized in various applications. Some method particulars… • The method covers a procedure to identify asbestos in soil, to provide an estimate of the concentration of asbestos in the sampled soil (dried), and can optionally provide a concentration of asbestos reported as the number of asbestos structures per gram of soil. • The method produces results that may be used for evaluation of sites contaminated by construction, mine and manufacturing wastes, deposits of naturally-occurring asbestos and other sources of interest to the investigator. • The method utilizes a combination of PLM and TEM analytical techniques and utilizes recognized qualitative and quantitative protocols. • The method has an analytical sensitivity down to <0.25% asbestos by weight and has allowances for even better limits of quantitation. • The method defines soil as “top layer of the earth’s surface consisting of rock and mineral particles”. • The method accounts for other contaminants and interferences. • The method employs dry sieving separation techniques and has an appendix for wet sieving procedures as well. • The method is based upon gravimetric fractions and estimated weight percents and asbestos structures per gram results. • The method recognizes asbestos identified as bulk building material as well as asbestos mineral free from any known source or origin. • The method has a detailed regimen for the collection of samples at and below the surface of the site. openoffice-in.doc 3 of 8
  4. 4. Asbestos in Soil Methods Some examples… Case Study 1: Crawl-Space Investigation. An institutional building owner contracted for remediation of ACM insulation on the pipes within a basement crawl-space. The small containments that preceded the removal did not properly account for the ‘soil’ floor space. For that matter, neither did the building survey that was used in the building’s O&M plan. Subsequent clearance testing continued to reveal ‘mysterious’ sources of asbestos in the air. Further sampling of this base earth revealed buried and surface contamination of asbestos insulation throughout various depths of soil. After a partial ‘clean-up’ by removing a modest few centimeters of surface soil, no visible insulation was apparent. Air samples, however, continued to yield ‘failing’ results by TEM. By employing the ASTM method, it was determined that the fine fraction of soil had substantial free fibers of asbestos well below the optical resolution of PLM. Finally, it was found that a level of 20cm of earth should be removed and a layer of ‘encapsulating’ cement used to remove and control the problem. Case Study 2: Illegal Dumping. An abandoned industrial site was found to have several tons of illegally dumped construction debris. Not only were the piles of demolition debris visible, but it was obvious that someone had tried to cover the evidence by partially bulldozing the piles into the soil. Initial sampling and analysis by an EPA 600 PLM method at a local lab found little ACM. As such, only visible surface debris was removed under controlled conditions. However, when it came to removing ‘buried’ debris without controls, air samples revealed levels of asbestos that exceeded worker limits. Indeed, a more diligent approach revealed that most ACM had deteriorated into unrecognizable ‘soil’. Utilizing a systematic approach of sampling at various surface and associated depths around the site, and establishing baseline counts away from the site, a target threshold value for ‘acceptable removal’ was established by local regulators and other stakeholders. Case Study 3: Catastrophic or Episodic Release. It was well documented that clean-up efforts in Lower Manhattan after 9/11 required the careful attention to surface dust from the collapse and resulting fire plume be addressed in any remediation plan. But what about local playgrounds and roof-top gardens after rain and other actions ‘removed’ the visible dust? Before this ASTM method was developed, similar protocols revealed asbestos at re- entrainable levels in these areas. Fine fraction analysis by TEM revealed how much asbestos was embedded in the soil. openoffice-in.doc 4 of 8
  5. 5. Asbestos in Soil Methods Case Study 4: Building Site Due Diligence. A construction site for a new building in a busy area of Virginia was rather benign until a worker noted an obvious vein of white-grey fibrous rock that had been exposed during site excavation. Tons of this ‘rock’-laden earth was transported along busy highways in populated areas. The earth was considered ‘clean- fill’ where it had been deposited. Initial laboratory analysis quickly revealed amphibole asbestiform mineral deposits that were never investigated in the initial site evaluations. A comprehensive study using the rudiments of this ASTM method revealed a gradient of naturally occurring asbestos mineral throughout the site and neighboring sites. Controls were quickly implemented. There are many other scenarios (indeed there may be countless situations not covered here) where asbestos in soil is an issue. To conclude, this subject still stirs debate, field sampling and analytical methods have not always met each situation of circumstance, the proposed method has the ability to provide comprehensive analytical data that can be readily duplicated in various lab settings while additional consensus standards develop. Acknowledgements: Jim Millette, PhD, MVA and Chairman of ASTM D22.07, Owen Crankshaw, RTI, Alan Seagrave, PG, Bureau Veritas, Andy Oberta, The Environmental Consultancy, Tom Laubenthal, ETI, Ed Cahill, EMSL, and Mark Floyd FASI. Author Info: Frank Ehrenfeld, Laboratory Director for International Asbestos Testing Laboratories since 1992, oversees over 30 scientists at the commercial environmental and materials testing laboratory in New Jersey. Mr. Ehrenfeld is involved in all aspects of the technical operations of IATL. He is active as a member of several industry organizations including ASTM D22.07 (Asbestos Sampling and Analysis) and is recognized as an expert on micro-analytical techniques. Please reach Frank at openoffice-in.doc 5 of 8
  6. 6. Asbestos in Soil Methods Figure 1: Typical Soil Investigation Scenario from ASTM E1368 - 05e1 Standard Practice for Visual Inspection of Asbestos Abatement Projects. Figure 2: Field Sample Collection openoffice-in.doc 6 of 8
  7. 7. Asbestos in Soil Methods Figure 3: Dry Sieving Apparatus Figure 4: Wet Sieving Soil Fractions openoffice-in.doc 7 of 8
  8. 8. Asbestos in Soil Methods openoffice-in.doc 8 of 8