湖南洞庭湖水系重金属健康风险评价

为了掌握洞庭湖水系重金属健康风险状况，采用美国环境保护署推荐的水环境健康风险评价模型，对洞庭湖水系重金属通过饮用水途径引起的健康风险进行评价。结果表明：重金属总健康风险在2．27×10-5-1．004×10-4a-1之间，平均为4．87×10-5a-1，未超过关国环境保护署推荐的最大可接受风险水平1×10-4a-1；重金属健康风险从大到小的顺序为：As、Cd、Pb、Cu、Zn，湘江、资水、沅江、洞庭湖、澧水，丰水期、枯水期；As为主要风险污染物；1988年以来，洞庭湖水系“四水”重金属健康风险均呈增加趋势，其中湘江和资水分别增加了13．34和5．07倍，因此，加强洞庭湖流域特别是湘江和资水重金属的污染治理是降低洞庭湖水系重金属健康风险的有效途径。

Health risk assessment of heavy metals in Dongting Lake water system in Hunan Province, China

In order to investigate the health risk of heavy metals in the Dongting Lake water system, we used the water environmental health risk assessment model recommended by the United States Environmental Protection Agency （USEPA） to assess the health risk of heavy metals that pass through drinking water supply routes in the Dongting Lake water system. The results show that the total health risk value of the heavy metals ranged from 2. 27 ×10-5 per year to 1. 004×10-4per year, with an average value of 4. 87×10-5per year, not exceeding the maximum acceptable risk level 1 ×10-4per year recommended by the USEPA. The heavy metals, rivers, and seasons can be ranked by risk in descending order, as follows： As, Cd, Pb, Cu, and Zn; the Xiangjiang River, the Zishui River, the Yuanjiang River, Dongting Lake, and the Lishui River; and the wet season, and the dry season. The main risk pollutant was As. The four-water health risk values of heavy metals in the Dongting Lake water system have increased since 1988, and the values of the Xiangjiang River and the Zishui River increased by 13.34 and 5.07 times, respectively. Therefore, strengthening the control of heavy metal pollution in the Dongting Lake Basin, especially in the Xiangjiang River and the Zishui River, is an effective way to reduce the health risk associated with heavy metals in the Dongting Lake water system.