TY - JOUR
T1 - Evidence and reconstruction of airborne asbestos from unconventional environmental samples
AU - Webber, James S.
AU - Getman, Myron
AU - Ward, Tony J.
N1 - Funding Information:
Support for participation at the conference was provided by the Center for Environmental Health Sciences at the University of Montana. The authors thank collaborators Julie Hart and Terry Spear (Montana Tech) for the tree-bark sampling effort. The sediment-collection trip to Libby in 2002 would not have been possible without the aid of Mary Goldade of U.S. EPA Region 8. This work was supported in part by NIH COBRE grant P20 RR01760 from NCRR, and funding from the ATSDR.
PY - 2006/10/1
Y1 - 2006/10/1
N2 - The understanding of historical ambient asbestos concentrations is critical to exposure mapping and retrospective health impact studies involving asbestos related diseases. Two presentations at the University of Montana Center for Environmental Health Sciences Asbestos Conference (July 28, 2005) introduced novel methods for detecting evidence of past airborne asbestos contamination. In each of these studies, transmission electron microscopy was used to identify and measure asbestos fibers collected in samples from unconventional environmental sources. In the first study, paleolimnology, analytical transmission electron microscopy, particle-separation techniques, and empirical aerosol-sediment modeling were combined to provide the first measurements of airborne asbestos concentrations prior to the 1980s. In an upstate New York study area, airborne concentrations of chrysotile followed its 20th-century usage, with highest concentrations near mid-century (∼0.1 fibers/cm 3), followed by a decrease in the last quarter century. Airborne concentrations of anthophyllite asbestos (a contaminant from nearby talc mines and mills) increased from <0.004 to 0.022 fibers/cm3 from 1847 to 1995. In the second study, tree bark and core samples were collected from areas near the asbestos-contaminated vermiculite mine in Libby,MT. We originally hypothesized that trees in the areas surrounding the mine could serve as reservoirs for ambient amphibole fibers. Though gravimetric reduction of a tree core sample did not indicate the presence of amphibole fibers, transmission electron microscopy analysis of bark samples yielded substantial amphibole fiber concentrations ranging from 14 to 260 million amphibole fibers/cm2. Based on these preliminary results, we conclude that trees in the Libby valley can serve as reservoirs for amphibole fibers, and that a continued potential for exposure exists for those who harvest contaminated wood.
AB - The understanding of historical ambient asbestos concentrations is critical to exposure mapping and retrospective health impact studies involving asbestos related diseases. Two presentations at the University of Montana Center for Environmental Health Sciences Asbestos Conference (July 28, 2005) introduced novel methods for detecting evidence of past airborne asbestos contamination. In each of these studies, transmission electron microscopy was used to identify and measure asbestos fibers collected in samples from unconventional environmental sources. In the first study, paleolimnology, analytical transmission electron microscopy, particle-separation techniques, and empirical aerosol-sediment modeling were combined to provide the first measurements of airborne asbestos concentrations prior to the 1980s. In an upstate New York study area, airborne concentrations of chrysotile followed its 20th-century usage, with highest concentrations near mid-century (∼0.1 fibers/cm 3), followed by a decrease in the last quarter century. Airborne concentrations of anthophyllite asbestos (a contaminant from nearby talc mines and mills) increased from <0.004 to 0.022 fibers/cm3 from 1847 to 1995. In the second study, tree bark and core samples were collected from areas near the asbestos-contaminated vermiculite mine in Libby,MT. We originally hypothesized that trees in the areas surrounding the mine could serve as reservoirs for ambient amphibole fibers. Though gravimetric reduction of a tree core sample did not indicate the presence of amphibole fibers, transmission electron microscopy analysis of bark samples yielded substantial amphibole fiber concentrations ranging from 14 to 260 million amphibole fibers/cm2. Based on these preliminary results, we conclude that trees in the Libby valley can serve as reservoirs for amphibole fibers, and that a continued potential for exposure exists for those who harvest contaminated wood.
UR - http://www.scopus.com/inward/record.url?scp=33747639972&partnerID=8YFLogxK
U2 - 10.1080/08958370600835138
DO - 10.1080/08958370600835138
M3 - Article
C2 - 16920670
AN - SCOPUS:33747639972
SN - 0895-8378
VL - 18
SP - 969
EP - 973
JO - Inhalation Toxicology
JF - Inhalation Toxicology
IS - 12
ER -