被认为造成了地球最大的大灭绝——它在2.5亿年前杀死了70%以上的植物和动物——的火山爆发在今天仍然正在夺走生命。这是一项新的研究得出的结论，该研究首次证明了中国一个地区的煤的丰富的硅石成分可能与煤的挥发性物质相互作用，从而导致高得不寻常的肺癌发病率。这项研究有助于解决这种癌症之谜，它发表在了ACS的半月刊《环境科学与技术》上。
David Large及其同事指出，中国云南省宣威县的一些地区的不吸烟女性有全世界最高的肺癌发病率——是中国其他地方的20倍。该地区的女性用敞开的燃煤炉为家庭取暖和做饭，这些炉子并不把烟排往室外。科学家认为来自燃烧的煤的室内排放导致了癌症，但是还不清楚为什么该地区的癌症发病率比其它地区高这么多。此前的研究表明了在煤烟中的称为PAHs的某些挥发性物质与该地区的肺癌之间的联系。
这组科学家发现在宣威县的一些地区使用的煤的硅石（一种可疑致癌物）含量是美国的煤的10倍以上。他们指出，硅石可能与PAHs联合起来让煤变得更致癌。这组科学家还发现了这种高硅石含量的煤形成于2.5亿年前，当时大规模的火山喷发让硅石沉积在了形成宣威煤的泥炭中。（生物谷Bioon.com）
生物谷推荐原始出处：
Environ. Sci. Technol., 2009, 43 (23), pp 9016–9021 DOI: 10.1021/es902033j
Silica-Volatile Interaction and the Geological Cause of the Xuan Wei Lung Cancer Epidemic
David J. Large*?, Shona Kelly?, Baruch Spiro§, Linwei Tian, Longyi Shao?, Robert Finkelman#, Mingquan Zhang, Chris Somerfield?, Steve Plint?, Yasmin Ali? and Yiping Zhou
Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham, NG7 2RD, U.K., Division of Epidemiology and Public Health, University of Nottingham, Nottingham, NG7 2RD, U.K., Department of Mineralogy, Natural History Museum, Cromwell Road London, SW7 5DB, U.K., School of Public Health, Chinese University of Hong Kong, Hong Kong SAR, China, State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China, The University of Texas at Dallas, F021, Richardson, Texas 75080-3021, and Yunnan Institute of Coal Geology Prospection, Kunming, 650218, China
Parts of Xuan Wei County, Yunnan Province, China have the highest known lung cancer mortality in nonsmoking women. This high mortality displays a clear spatial relationship to the mines producing coal from the uppermost Permian. Geochemical, petrographic, and grainsize analyses were undertaken on a set of coal samples from Xuan Wei. Results demonstrate that the single geochemical property that makes this coal unusual is its high concentration of quartz (13.5 wt %) of which 35?55% occurs as <10 μm grains. We propose the potential for silica?volatile interaction (PSVI) as a new method for assessing the combined influence of silica and volatile organic matter and use this as a basis for re-evaluating existing ecological data. Published lung cancer mortality values are more strongly correlated with PSVI values for Xuan Wei coal than with volatiles or silica alone and the PSVI values measured are distinct from those of other coals. Finally we propose that the localization of this epidemic to Xuan Wei results from enhanced weathering of the local Emeishan basalts as a consequence of geochemical perturbations at the Permo-Triassic Boundary.
