贵州典型煤矿区土壤重金属污染与生态风险评价

Assessment of heavy metals pollution and potential ecological risks of typical mining area soils in Guizhou

【目的】探讨煤矿开采活动对周边土壤环境质量的影响.【方法】以贵州某典型煤矿为研究对象,对其周边农田土壤重金属元素Pb、Cd、Hg、As、Cu的含量进行分析,并采用单因子指数法、内梅罗综合指数法和潜在生态风险指数法对其污染程度和生态风险进行评价.【结果】除Cd、As元素外,Pb、Hg、Cu的含量均超过了贵州省土壤背景值,分别是贵州省土壤背景值的1.34、3.00和6.38倍,其中Cu的超标率为100%;单项污染指数分析表明,Cu的污染程度最严重,其次为Hg,重金属的污染程度大小依次为:Cu>Hg>Pb>Cd>As;综合污染指数分析表明,研究区采样点土壤综合污染指数均值为4.96,土壤整体污染程度为重污染等级,Cu和Hg是研究区土壤污染的主要因素.【结论】综合多种金属潜在生态风险指数RI,研究区RI值为190.86,整体表现为轻微生态危害等级,5种重金属元素的单项生态危害程度Eir依次为Hg>Cu>Cd>Pb>As,Hg、Cu、Cd是主要的潜在生态风险因素.

【Objective】To evaluate the mining on soil environmental quality.【Method】The typical mining area soils were used to analyze the content of heavy metals Pb,Cd,Hg,As,Cu.The pollution condition and ecological risk were assessed by single factor index method,Nemerow comprehensive index method and potential ecological risk index.【Result】The contents of Pb,Hg and Cu exceeded the soil background of Guizhou Province except Cd and As,which were 1.34,3.00 and 6.38 times of the soil background.The exceeding rate of Cu reached 100%.The single factor index showed that Cu was the most serious pollution heavy mental,then was Hg.The pollution degree of heavy metals arranged as CuHgPbCdAs.The average comprehensive pollution index was 4.96,which reached serious pollution degree according to Nemerow comprehensive pollution index,Cu and Hg were main factors of soil pollution in the mining area.【Conclusion】Considering the potential ecological hazard of multiple heavy metals,the RIis 190.86 which reaches light ecological hazard,the single ecological hazard degree arranges as Hg〉Cu 〉Cd 〉Pb〉As,the main ecological hazard factors are Hg,Cu and Cd.