某工业园周边农田土壤重金属污染特征及潜在风险评价

Characteristics and potential risk assessment of heavy metal pollution in the arable soils around an industrial park

为探究某工业园周边农田土壤重金属污染及潜在风险状况,系统采集了园区周边农田15个表层土壤,通过测定土壤的pH值及重金属Pb、Cu、Zn、Cd、Cr、Ni含量,并借助Pearson相关性分析和主成分分析等方法,及内梅罗综合指数污染法和Hakanson潜在风险评价指数法等评价方法,进一步揭示重金属的污染特征及潜在风险。研究结果表明:该工业园周边农田中Pb、Cu、Zn和Cd的平均含量超过了我国农用地风险筛选值,Cd的平均含量甚至超过管制值,该地区土壤已不适合作为农用地用途;距离工业区较近的土壤中重金属浓度较高,研究区土壤中重金属污染来源与工业园关系密切;内梅罗综合指数污染法评价表明所有采样点的土壤均为重度污染,各金属元素的潜在风险指数从大到小依次为Cd>Pb>Cu>Ni>Cr>Zn,其中Cd是对潜在生态风险指数贡献最大的金属元素。人体健康风险评估表明,Pb、V和As对人体造成非致癌风险显著,As存在很大的致癌风险。周边工矿活动等人为活动对土壤的重金属贡献份额达71.99%,自然源贡献为17.06%。整体来看,研究区土壤呈现极高生态风险水平,应当对该区域土壤污染采取一定的调控措施。

In order to explore the soil pollution and potential risk of heavy metals in farmland around an industrial park, 15 surface soils are collected from farmland around the industrial park.By measuring the pH value and heavy metals Pb, Cu, Zn, Cd, Cr and Ni in the soil, and using Pearson correlation analysis and principal component analysis, and Nemero index method and Hakanson potential risk assessment index method to further reveal the pollution characteristics and potential risks of heavy metals.The results show that the average content of Pb, Cu, Zn and Cd exceeded the risk screening value of agricultural land in China, and the average content of Cd even exceeded the control value.The soil in this area is not suitable for agricultural land use.The concentrations of heavy metals in soil near the industrial zone are higher, and the sources of heavy metal pollution in soil in the study area are closely related to the industrial zone.The evaluation of Nemerow comprehensive index pollution method show that all the soil samples are severely polluted, and the potential risk index of each metal element in descending order is Cd>Pb>Cu>Ni>Cr>Zn, among which Cd is the metal element with the greatest contribution to the potential ecological risk index.The contribution of human activities to soil heavy metals is 71.99%,and that of natural sources is 17.06%.On the whole, soil in the study area presents a very high level of ecological risk.Therefore, some regulation measures should be taken to control soil pollution in this area.