东洞庭湖湖滨带土壤重金属健康风险评价

Health rick assessment on soil heavy metals in the lakeside of East Dongting Lake

以东洞庭湖湖滨带为研究区域,系统调查分析其土壤中的重金属污染状况,并进行致癌风险评价和非致癌风险评价。东洞庭湖湖滨带土壤中的重金属As、Hg、Cd、Cu、Zn、Ni、Cr的平均含量分别为19.31、0.0113、0.989、50.29、125.7、43.9和93.36 mg/kg,已全部超过了洞庭湖背景值,其中As、Hg和Cd的最大含量分别已超过洞庭湖背景值的5倍、5倍和20倍之多,说明东洞庭湖湖滨带土壤已经受到一定程度的重金属污染。致癌风险评价结果表明,As为当地主要的致癌物,Cd属于安全的范围,叠加后的致癌总风险指数平均值成人的为1.6810-5,儿童的为1.0410-6,在鹿角港口区、岳阳市区和城陵矶港口区相对较高,是平均值的1.3至2.6倍。非致癌风险评价结果显示,Hg、Pb、Cu、Zn、Cr、Ni的非致癌风险指数均远小于1,不会对当地居民健康构成威胁。叠加后的非致癌总风险指数平均值成人的为1.7910-1,儿童的为1.0910-2,在漉湖芦苇场、团州农场、君山旅游区较高。

The soil pollution by heavy metals was studied, and the carcinogenic and non-carcinogenic risks were assessed using the US-EPA risk models in the lakeside of East Dongting Lake. The average contents of As, Hg, Cd, Cu, Zn, Ni and Cr in soil were 19.31 mg/kg, 0.0113 mg/kg, 0.989 mg/kg, 50.29 mg/kg, 125.7 mg/kg, 43.9 mg/kg and 93.36 mg/kg, respectively, and they all exceeded the background values of Dongting Lake. The observed highest contents of As,Hg and Cd were 5, 5 and 20 times of the background values of Dongting Lake, respectively. These indicated that soils have been polluted by heavy metals in the lakeside of East Dongting Lake. The results of carcinogenic risk assessment also showed that As was the major carcinogenic element, while Cd was below the safety range in the study area. The average values of total carcinogenic risk indices were 1.6810^-5 for adults and 1.0410^-6 for children, respectively. The indices were 1.3 to 2.6 times of the regional averages in the Lujiao port, the Chenglingji port and the Yueyang suburb. The non-carcinogenic risk values of elements of Hg, Pb, Cu, Zn, Cr and Ni were less than 1, and were not expected to be harmful to the local community. The average values of the total non-cancerous risk indices were 1.7910^-1 for adults and 1.0910^-2 for children, respectively, and they were shown relatively high in the reed fields of Lu Lake, the Tuanzhou farm and the tourism area of Jun Moutain.