个旧矿区周边水稻土重金属生态风险及预警

摘要

Heavy metal pollution in the surrounding soil of mining area has great harm to agricultural products and human health.The ecological risk assessment and early warning of paddy soils in Gejiu mine area were conducted by calculating potential ecological risk index (RI),geoaccumulation index (Igeo)and ecological risk warning model (IER)based on the concentrations of a range of heavy metals (Pb,Cd,As,Zn,Cu,and Cr).The re-sults showed the sequence of different RI was Cd>As>Cu>Cr>Pb>Zn.The average potential ecological risk indexes for single heavy metals (Eri)of Cd and As were more than 40 and 94. 4%in the “medium risk”or above level category.The sequence of different Igeo was Cd >As >Pb >Cr>Cu >Zn,Cd and As had 94. 4% in the“moderate-intensity”or above level category.Ecological risk assessment results showed that 66. 7%were in the“no ecological risk warning”category and 33. 3% were in the “high ecological risk warning”category.Compre-hensive analysis indicated that the region was mainly dominated by cadmium and arsenic in soil.The corresponding soil remediation measures should be taken in the area with high ecological risk assessment level.The monitoring should be strengthened in the no ecological risk warning area in order to prevent pollution.%矿区周边土壤重金属污染对区域农产品和人体健康危害极大，为对个旧市大屯镇稻田土壤重金属的潜在生态风险进行定量评价及预警分析，计算了6种重金属元素（Pb、Cd、As、Zn、Cu和Cr ）的综合生态风险指数（RI）、地累积指数（Igeo ）和生态风险预警指数（IER ）。结果表明：研究区域6种重金属平均风险指数的大小顺序为：Cd＞As＞Cu＞Cr＞Pb＞Zn，Cd和As元素的生态风险指数平均值＞40，94．4％的土壤样品处于中等风险以上水平；重金属元素的Igeo顺序为Cd＞As＞Pb＞Cr＞Cu＞Zn，Cd和As元素有超过94．4％的土壤样品处于中等污染以上水平。生态风险预警评价结果显示，66．7％采样点处于生态风险无警级别，33．3％采样点处于生态风险重警级别。综合分析认为，该区域主要是以Cd和As为主的土壤重金属复合污染，对已经达到生态风险重警级别的区域应该采取相应的土壤修复措施，对无警区域应该加强监控防止污染。