兴仁高砷煤矿区沉积物污染特征及重金属潜在生态风险评价

Pollution Characteristics of Surface Sediments and Potential Ecological Risk Assessment of Heavy Metals inHigh Arsenic Coal Mine Area in Xingren

为评价兴仁高砷煤矿区水体沉积物的污染水平及其生态风险,以贵州省表生沉积物背景值作为基准评价沉积物污染水平,采用Hakanson潜在生态风险指数法评价了沉积物中重金属的环境生态风险。结果表明:交乐、潘家庄和小尖山煤矿区水体沉积物均表现出低pH值,高SO2-4、As、Fe等特征。与贵州表生沉积物背景值相比,交乐煤矿区水体沉积物中Fe、As和Hg平均值分别超过背景值4082倍、358.8倍和19.3倍;潘家庄煤矿区水体沉积物中Fe、As和Hg平均值分别超过背景值3478倍、8.3倍和0.55倍;小尖山煤矿区水体沉积物中Fe、As和Hg平均超过背景值2457倍、5.6倍和0.65倍。利用潜在生态风险指数法分析表明:交乐、潘家庄和小尖山煤矿区水体沉积物主要受到As、Hg污染。交乐、潘家庄和小尖山煤矿区水体沉积物各重金属的潜在生态风险指数(Eir)从高到低依次为As>Hg>Cd>Cu>Pb>Cr>Zn,As>Hg>Cd>Cu>Pb>Zn>Cr,As=Hg>Cd>Cu>Pb>Cr>Zn。生态风险指数(RI)交乐>小尖山>潘家庄,交乐沉积物中重金属生态风险程度为很强风险,潘家庄和小尖山沉积物中重金属生态风险程度为中等风险。

Geochemical backgroundof supergene sediments inGuizhou was used as a benchmark to assess the pollution levels of surface sediments in the high arsenic mining area of Jiaole,Panjazhuang and Xiaojianshanin Xingren,and the potential ecological risk of heavy metals were evaluated by Hakanson method.The results showed that the pollution characteristics of the sediments inJiaole,Panjazhuang and Xiaojianshanwere low pH and high contents of SO2-4,As and Fe.The average values of Fe,As and Hg in Jiaolewere 4082 times,358.8times and 19.3times than the values of Geochemical backgroundof supergene sediments inGuizhou,respectively;3478times,8.3times and 0.55 times in Panjiazhuang,respectively;and 2457 times,5.6times and 0.65 times in Xiaojianshan,respectively.Potential ecological risk indices（Eir）indicated that the sediments in three study sites were seriously polluted by As and Hg,with the pollution degree of As〉Hg〉Cd〉Cu〉Pb〉Cr〉Zn in Jiaole,As〉Hg〉Cd〉Cu〉Pb〉Zn〉Cr in Panjazhuang and As=Hg〉Cd〉Cu〉Pb〉Cr〉Zn in Xiaojianshan,respectively.The values of potential ecological risk indices（RI）were Jiaole〉Panjiazhuang〉Xiaojianshan,with very high ecological risk for Jiaole and moderate ecological risk for Panjiazhuang and Xiaojianshan.