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CHEMICAL ANALYSIS OF WORLD TRADE CENTER FINE PARTICULATE MATTER FOR USE IN TOXICOLOGICAL ASSESSMENT
Citation:
McGee, J K., Chen, Lung Chi, Cohen, Mitchell D, G. Chee, C. M. Prophete, N. H. HaykalCoates, S Wasson*, T L. Conner, D L. Costa, AND S H. Gavett. CHEMICAL ANALYSIS OF WORLD TRADE CENTER FINE PARTICULATE MATTER FOR USE IN TOXICOLOGICAL ASSESSMENT. ENVIRONMENTAL HEALTH PERSPECTIVES 111(7):972-980, (2003).
Description:
Chemical Analysis of World Trade Center Fine Particulate Matter for Use in Toxicological Assessment
John K. McGee1, Lung Chi Chen2, Mitchell D. Cohen2, Glen R. Chee2, Colette M. Prophete2, Najwa Haykal-Coates1, Shirley J. Wasson3, Teri L. Conner4, Daniel L. Costa1, and Stephen H. Gavett1.
1National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA; 2Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, NY, USA
3National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA;
4National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA.
Abstract
The catastrophic destruction of the World Trade Center (WTC) on September 11, 2001 caused the release of high levels of airborne pollutants into the local environment. To assess the toxicity of fine particulate matter (< 2.5 mm in diameter; PM2.5) which may impact the health of workers and residents in the area, we collected fallen dust samples on September 12 and 13 from sites within a half-mile of Ground Zero. Samples of WTC dust were sieved, aerosolized, and size-separated, and the PM2.5 fraction was isolated on filters. Here we report the chemical and physical properties of PM2.5 derived from these samples, and compare them with PM2.5 fractions of three reference materials which range in toxicity from relatively inert to acutely toxic (Mount Saint Helens PM, Washington DC ambient air PM, and residual oil fly ash). X-ray diffraction of very coarse sieved WTC PM (< 53 mm) identified calcium sulfate (gypsum) and calcium carbonate (calcite) as major components. Scanning electron microscopy confirmed that calcium-sulfur and calcium-carbon particles were also present in the WTC PM2.5 fraction. Analysis of WTC PM2.5 using X-ray fluorescence, neutron activation analysis, and inductively coupled plasma - atomic emission spectrometry showed high levels of calcium (range 22 - 33%) and sulfur (37 - 43% as sulfate), and much lower levels of transition metals and other elements. Aqueous extracts of WTC PM2.5 were basic (pH range 8.9 - 10.0) and had no evidence of significant bacterial contamination. Levels of carbon were relatively low, suggesting that combustion-derived particles did not form a significant fraction of these samples recovered in the immediate aftermath of the destruction of the towers. Since gypsum and calcite are known to cause irritation of the mucus membranes of the eyes and respiratory tract, inhalation of high doses of WTC PM2.5 could potentially cause toxic respiratory effects.