Asbestos Fiber Transport from Facilities into the Community
1Cardno ChemRisk, Chicago, IL
Anders Abelmann PhD
A simulation study was conducted to evaluate the spatial dispersion of asbestos fibers from a point source. Asbestos fibers were released by cutting asbestos-containing cement pipe using a powered abrasive saw. Airborne samples were analyzed using scanning electron microscopy. The results provide a better understanding of the mechanism of airborne asbestos fiber transport.
Situation / Problem:
There has been recent scientific interest in historical community exposures to asbestos as a result of emissions from proximate industrial operations. Potential impacted populations include anyone residing within some distance of operations involving production or manipulation of asbestos-containing materials (ACM). While worker exposures to asbestos are reasonably well understood, there is a paucity of community exposure data.
We conducted an outdoor study where asbestos fibers were released through power sawing of cement pipe containing chrysotile (25%) and crocidolite (10%). Air samples were collected in a concentric pattern around the emission source at five distances including 8, 25, 50, 75 and 95 feet. The time involved in cutting the pipe was about 2 minutes per event and the total sampling time was 30 minutes. Samples were analyzed using scanning electron microscopy; fibers > 5 µm were counted and each detected fiber was characterized with respect to fiber type, length, width, and distance from the source.
Results / Conclusions:
Close to the source, the chrysotile:crocidolite ratio in the air samples was consistent with the bulk content of the cement pipe (5:2). Both chrysotile and crocidolite fibers are diluted or otherwise removed from the air quickly with distance, even when imparted with high initial momentum. The concentration of crocidolite fibers decreased more rapidly than chrysotile fibers. Fiber width appears to be an important determinant in fiber transport, but further research is needed to elucidate this relationship (e.g., through evaluating the relationship between the concentration of cement particles with distance compared to fiber length and distance, binding of asbestos fibers to cement, etc.).
Exposure Assessment Strategies
Risk Assessment and Management
Acknowledgements and References
List any additional people who worked on the project or provided guidance and support along with details on the role they played in the research. (Please include first name, last name, organization, city, state and country).
Joshua R. Maskrey, coauthor; Cardno ChemRisk, Pittsburgh, PA, USA
Jason T. Lotter, coauthor; Cardno ChemRisk, Chicago, IL, USA
Aaron M. Chapman, coauthor; Cardno ChemRisk, Washington, DC, USA
Melanie D. Nembhard, coauthor; Cardno ChemRisk, San Francisco, CA, USA
Steven F. Schlaegle, Bryan R. Bandli, Richard J. Lee, coauthors; RJ Lee Group, Monroeville, PA, USA
Dennis J. Paustenbach, coauthor; Cardno ChemRisk, San Francisco, CA, USA
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