| Mapping and Prediction of Coal Workers' Pneumoconiosis with Bioavailable Iron Content in the Bituminous Coals Xi Huang,1 Weihong Li,1 Michael D. Attfield,2 Arthur Nádas,1 Krystyna Frenkel,1 and Robert B. Finkelman3 1Department of Environmental Medicine and NYU Cancer Institute, New York University School of Medicine, New York, New York, USA; 2Division of Respiratory Diseases Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA; 3U.S. Geological Survey, Reston, Virginia, USA Abstract
Based on the first National Study of Coal Workers' Pneumoconiosis (CWP) and the U.S. Geological Survey database of coal quality, we show that the prevalence of CWP in seven coal mine regions correlates with levels of bioavailable iron (BAI) in the coals from that particular region (correlation coefficient r = 0.94, p < 0.0015) . CWP prevalence is also correlated with contents of pyritic sulfur (r = 0.91, p < 0.0048) or total iron (r = 0.85, p < 0.016) but not with coal rank (r = 0.59, p < 0.16) or silica (r = 0.28, p < 0.54) . BAI was calculated using our model, taking into account chemical interactions of pyrite, sulfuric acid, calcite, and total iron. That is, iron present in coals can become bioavailable by pyrite oxidation, which produces ferrous sulfate and sulfuric acid. Calcite is the major component in coals that neutralizes the available acid and inhibits iron's bioavailability. Therefore, levels of BAI in the coals are determined by the available amounts of acid after neutralization of calcite and the amount of total iron in the coals. Using the linear fit of CWP prevalence and the calculated BAI in the seven coal mine regions, we have derived and mapped the pneumoconiotic potencies of 7,000 coal samples. Our studies indicate that levels of BAI in the coals may be used to predict coal's toxicity, even before large-scale mining. Key words: bioavailable iron, calcite, coal, chronic obstructive pulmonary disease, COPD, pneumoconiosis. Environ Health Perspect 113:964-968 (2005) . doi:10.1289/ehp.7679 available via http://dx.doi.org/ [Online 15 April 2005]
Address correspondence to X. Huang, Department of Environmental Medicine and NYU Cancer Institute, New York University School of Medicine, 550 First Ave., PHL Room 802, New York, NY 10016 USA. Telephone: (212) 263-6650. Fax: (212) 263-6649. E-mail: xihuang@env.med.nyu.edu This project was supported by grant OH 03561 from the National Institute for Occupational Safety and Health and in part by National Institute of Environmental Health Sciences Center grant ES00260. The authors declare they have no competing financial interests. Received 18 October 2004 ; accepted 14 April 2005.
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