东北黑土区小流域耕地土壤重金属污染特征及健康风险评价：以海沟河小流域为例

为探究城市化进程、农业生产等对黑土环境质量的影响,分析黑龙江省海沟河小流域表层(0～20cm)土壤重金属累积状况与生态风险,采用US EPA模型评价土壤重金属污染健康风险。结果表明:1)海沟河小流域耕地土壤重金属元素平均含量为Cu 16.334mg/kg,Zn 70.684mg/kg,Hg 0.063mg/kg,As 0.05mg/kg,Pb 24.486mg/kg,Cd 0.213mg/kg,Ni 21.775mg/kg和Cr 49.649mg/kg,其中单因子污染指数、综合污染指数、地积累指数均表明研究区土壤重金属已开始积累和富集,其中以Hg和Cd的污染较重。2)单因子生态风险指数Er表明45.59%和47.06%样点Hg的风险分别处于中等和强级别,Cd则分别为60.29%和39.71%。综合生态风险指数RI表明中等风险等级样点所占比率较高为69.12%,说明研究区土壤重金属潜在生态风险危害已形成,其中Hg和Cd贡献最大。3)健康风险评价结果表明,经口摄入暴露途径更容易引发致癌或非致癌风险。8种重金属中As、Cr、Cd及Ni具有致癌风险。

Heavy metal pollution characteristics and its health risk assessment in a mollisol watershed of Northeast China: Taking Haigou watershed as study case

To explore the impact of urbanization and agricultural production on the environmental quality of black soil, the heavy metal accumulation characteristics and its potential ecological risk in Haigou watershed, a small mollisol watershed in Heilongjiang Province in Northeast China was investigated. The health risk was then analyzed by using US EPA model. The results showed that: 1)The average contents of heavy metals were Cu 16. 334 mg/kg, Zn 70. 684 mg/kg, Hg 0. 063 mg/kg, As 0. 05 mg/kg, Pb 24. 486 mg/kg, Cd 0. 213 mg/kg, Ni 21. 775 mg/kg and Cr 49. 649 mg/kg. The single factor pollution index, Nemero pollution index and terrestrial accumulation index all indicated heavy metals were accumulating and aggregating in soil, among which Hg and Cd pollutions were more serious. 2)Er, the single-factor ecological risk index, showed that 45. 59% and 47. 06% of samples were in medium and strong Hg risk class, respectively. And 60. 29% and 39. 71% of samples were in the risk of Cd pollution. RI, the comprehensive ecological risk index, demonstrated 69. 12% samples were in intermediate risk level, which showed potential ecological hazards and Cd and Hg were the major contributors. 3)The health risk assessment indicated exposure of oral intake was more likely leading to carcinogenic or non-carcinogenic risk. There was no non-carcinogenic risk and whileCr, Cd and Ni could lead to carcinogenic risk.