卡房锡尾矿库重金属污染特征及生态风险评价

Heavy Metal Pollution Characteristics and Ecological Risk Assessment of Kafang Tin Tailings Pond

研究尾矿库重金属的污染特征及其生态风险是保障周边环境及人体健康的重要前提.对卡房锡尾矿库中重点关注的“五毒”重金属(As、Cr、Cd、Pb和Hg)进行全量和形态的测定,分析其分布特征;采用地累积指数法、潜在生态风险指数法和风险评价准则法从全量和形态两方面对尾矿库重金属的污染状况、潜在生态风险进行探究.结果表明,从重金属全量的角度,As在空间分布上存在差异且污染严重;Cd、Hg、Cr和Pb在空间分布上较均匀,Cd和Hg污染轻微,Cr和Pb污染可控.从重金属形态的角度,As、Cr、Pb和Hg在尾矿中以残渣态为主、环境污染风险较低,Cd在尾矿中以可氧化态为主,环境污染风险较高.为此,卡房锡尾矿库应加强尾矿中As污染管控,关注尾矿中Cd的潜在污染风险,全库Hg、Pb和Cr污染风险总体可控.

To study the pollution characteristics and ecological risks of heavy metals in tailings ponds is an important prerequisite for protecting the surrounding environment and human health.The total amount and morphology of five“toxic”heavy metals(As,Cr,Cd,Pb,and Hg)in Kafang tin tailings pond were determined.Based on the aforementioned,we analyzed the distribution characteristics of heavy metals.The potential ecological risks of heavy metals in tailings ponds were studied from the aspects of total amount and morphology.Sample data were analyzed using the geo-accumulation index method,potential ecological risk assessment method,and risk assessment criteria.The results showed that,from the perspective of the total amount of heavy metals,the spatial distribution of As was different,and the pollution was serious;the spatial distribution of Cd,Hg,Cr,and Pb was relatively uniform;the pollution of Cd and Hg was slight;and the pollution of Cr and Pb was controllable.From the perspective of the morphology of heavy metals,As,Cr,Pb,and Hg in tailings were mainly in the residual state and had low environmental pollution risk,whereas Cd in tailings was mainly in an oxidizable state and had high environmental pollution risks.Therefore,Kafang tin tailings pond should strengthen the control of As in tailings and pay attention to the potential pollution risks of Cd in tailings and the overall pollution risks of Hg,Pb,and Cr in the entire reservoir were controllable.