万山稻米汞含量分布特征及影响因素研究

Distribution and Influencing Factors of Mercury in Rice Grains in Wanshan

运用冷原子荧光技术（CVAFS）对贵州万山汞矿区主要河流范围内稻米总汞（THg）含量进行了测定，并从区域层面对稻米THg的分布特征及影响因素进行了研究。结果表明：万山汞矿区主要流域内稻米THg含量范围为2.838-295.534 ng·g-1，平均含量为50.819 ng·g-1，67.5％的样品已经超出GB 2762-2005中所规定的粮食污染物限量标准20 ng·g-1（总汞）。在水平空间分布上，6个检测区域的稻米THg含量均随着与汞矿核心区距离加大而降低，但是不同区域之间的降低变化幅度不尽相同。通过对稻米THg与土壤THg、SiO2、Al2O3、总铁（TFe2O3）、总硫（TS）、总磷（TP）、总氮（TN）、有机质、pH进行相关性分析发现，稻米THg与TS、TN、有机质、pH表现出显著的正相关性，与SiO2显著性负相关，但未发现与土壤THg之间有显著的相关性。

Total mercury（THg）concentrations in rice grains from Wanshan, Guizhou province, which was impacted by Hg mining, were mea-sured using a CVAFS method. THg concentrations in the rice grains showed a clear spatial pattern and were highly related to the inputs of Hg derived from mining. Concentrations of THg in rice grains in major basins of Hg mining ranged from 2.8 ng·g-1 to 295 ng·g-1 with an av-erage of 50.8 ng·g-1. Approximate 67.5%of rice samples showed THg concentrations exceeding the national standards（THg=20 ng·g-1）. Rice THg concentrations tended to decrease from central Hg-mined areas to less polluted ones. However, the decreasing rates of THg con-centrations in rice were quite different in the six areas. Rice THg concentrations were significantly positively correlated with TS, TN, organic matter, and pH, but negatively with SiO2. Rice THg had no correlation with soil THg concentrations.