Silica-volatile interaction and the geological cause of the Xuan Wei lung cancer epidemic.
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 microm 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.
Large
David J
DJ
Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham, NG7 2RD, U.K. david.large@nottingham.ac.uk
Kelly
Shona
S
Spiro
Baruch
B
Tian
Linwei
L
Shao
Longyi
L
Finkelman
Robert
R
Zhang
Mingquan
M
Somerfield
Chris
C
Plint
Steve
S
Ali
Yasmin
Y
Zhou
Yiping
Y
D002681:China / Q000453:epidemiology; D003031:Coal; D005260:Female; D055593:Geological Phenomena; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology* / Q000401:mortality; D012822:Silicon Dioxide / Q000009:adverse effects*; D014481:United States; D014835:Volatilization
D003031:Coal; D012822:Silicon Dioxide