Concentrations and XAFS speciation in situ of mercury in hair from populations in Wanshan mercury mine area, Guizhou province

Human hair samples were collected in 2000 and 2003 from mercury mine area in Wanshan, Guizhou and analyzed by measuring the amount of total mercury using hydride generation-atomic fluorescence spectrometry. Average Hg concentration in the sample was found to be 837 μg/g, much higher than those from other areas in the world, which shows a serious pollution of mercury in this area. A preliminary study was made to determine the existing states of mercury in hair samples by employing the X-ray absorption fine structure spectroscopy (XAFS). Although the Hg concentrations in the hair samples differs from each other, the valence states and local structure of Hg remain alike in view of the results obtained from the Hg LIII edge XAFS spectra. The Fourier transformed spectra indicate that the existing states of Hg in hair samples is not simply an inorganic form like HgCl2 or HgO, but probably in a more complex state. The bond lengths of Hg and coordinations are approaching for the three hair samples when considering XAFS spectra. Comparing with standard compounds, the XAFS spectra of the hair samples are most similar to Hg(GS)2, which means that the mercury in hair is more likely to bond with S as in Hg(GS)2, but more orderly. (authors)