贵州万山汞矿地区人发中汞的含量及其赋存状态的XAFS原位研究

Concentrations and XAFS speciation in situ of mercury in hair from populations in Wanshan mercury mine area, Guizhon Province

利用氢化物发生—原子荧光法测定了贵州万山汞矿地区人发中汞的含量。结果发现,该地区从事汞制剂操作的一线工人及居民的头发中汞含量远超过世界其它各地,其平均值为837 μg/g,说明该地区受污染状况非常严重。通过XAFS法测试了3组汞含量较高的头发样品。由XANES谱得出,虽然3组头发中汞的含量不同,但其中汞离子的价态是一致的。比较样品与参考样品的EXAFS谱得出,虽然3组头发样品中汞含量不同,但汞与其最近邻原子的键长是一致的,从而其配位情况也可能是相同的。通过比较所有样品的谱图可看出,头发样品与Hg(GS)_2的配位情况相似。

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 L_Ⅲ edge XAFS spectra. The Fourier transformed spectra indicate that the existing states of Hg in hair samples is not simply an inorganic form like HgCl_2 or HgO, but probably be 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.