鄱阳湖流域农田重金属污染的生态风险评估

选择乐安河-鄱阳湖段典型重金属污染区作为研究区,采用不同方法对各样点土壤及其蔬菜农产品的重金属污染及其危害进行评价.结果表明:各样点土壤中重金属含量最高的元素为Cu,最高值达423.124 mg·kg^-1; 不同评价方法得出乐安河上游至中游区域土壤中重金属Cu呈极度污染状态,存在严重的生态风险隐患; 各样点蔬菜重金属Cd含量均超过《无公害蔬菜安全要求》中规定的标准值(0.050 mg·kg^-1); 农产品样品对Cd的富集系数都超过0.100,最高值达3.254; 内梅罗综合污染指数法的评价得到78.57%的农产品重金属Cd为重度污染; 健康风险指数评价进一步表明各样点大部分农产品中的Cd超出安全基准值1.0,且样品中Cd的目标致癌风险T_R(0.003 2～0.013 2)均超过了美国环保署推荐的可接受风险值(10^-6～10^-4)和国际辐射防护委员会推荐的最大可接受风险值(5.0×10^-5).

The Ecological Risk Assessment of the Heavy Metals Pollution on the Typical Wetland and Farmland of Poyang Lake

Some typical heavy metal pollution areas in the farmland of Lean River and Poyang Lake are selected as the study area.And the heavy metals pollution on the soils and the vegetables is evaluated by using different evaluation methods and the risk degree of vegetables to human health is evaluated.The results indicates that the highest content of copper was up to 423.124 mg·kg^-1.The results of different evaluation methods indicate that the heavy metal of copper in the soils were all extremely polluted,which have serious ecological risk.The contents of cadmium in all vegetables exceeded the standard value(0.05 mg·kg^-1)of safety requirements for non-environmental pollution vegetables.The results of Enrichment Coefficient of heavy metals in vegetable show that the value of BAF of cadmium surpassed 0.10,and the highest value of which is up to 3.254.The Nemero’s Comprehensive Pollution index indicates that 78.57% of vegetables is severely polluted by Heavy metal of cadmium.And the health risk index in vegetables further show that the contents of cadmium in most vegetables in all kinds of sampling sites are beyond the safety reference value of 1.0.The target risk(T_R)value(0.003 2～0.013 2)of cancer exceeded the acceptable risk value(10^-6～10^-4)which were recommended by US EPA and surpassed the highest acceptable risk value of 5.0×10^-5 which recommended by ICRP,and cadmium is a carcinogen substance in the all samples.