浙西某地石煤矿山周边耕地土壤重金属污染与生态风险评价

Assessment of Farmland Soil Heavy Metal Contamination and Ecologic Risk in a Western Zhejiang Stone-like Coal Mine Periphery

以浙西某石煤矿山及周边农田表层土壤为研究对象,运用潜在生态风险指数法综合评价其潜在生态危害程度。结果表明,Cd、Hg、Cu、As、Zn、Ni、Pb、Cr等8种重金属元素平均含量均高于中国土壤背景值,相关性分析表明,除Cd与Cr呈显著的正相关关系,其余元素两两呈极显著正相关关系;潜在生态风险评价表明研究区土壤环境RI平均值为250.38,属强生态危害程度,Cd元素是构成潜在生态风险的主要因素。地表水检测表明矿坑内地表水呈强酸性,Cd、Zn、Cu含量超标,以Cd超标最严重。周边农作物安全评价得出,该区农产品甘蔗Cd严重超标,农产品质量安全存在较大风险;自然修复石煤矿山地表水Cd含量超标程度高,邻近地区土壤及地表水易受影响,存在生态风险。石煤矿山周边土壤及农产品重金属含量超标严重,建议石煤矿山生态环境修复应采用自然恢复和人工修复相结合的办法,做好石煤矿山废水、废渣处理,减少因淋滤作用对地下水、土壤造成的影响。

Taking a stone-like coal mine and peripheral farmland topsoil as the subject investigated has used potential ecologic risk index method comprehensively assessed its potential ecologic hazard level.The result has shown that the average content of Cd,Hg,Cu,As,Zn,Ni,Pb and Cr 8 heavy metal elements are all higher than Chinese soil background values.The correlation analysis has shown,besides Cd and Cr presented significant positive correlativity,other elements are presented very significant correlativity in pairs.Potential ecologic risk assessment has shown that study area soil environment RI average is 250.38,belongs to strong hazard level,while Cd is the main constituent element.Surface water test has shown that the mine surface water presents highly acidic,content of Cd,Zn and Cu overproof,Cd especially serious.Safety assessment of peripheral crops has worked out that Cd in sugarcane is seriously overproof,thus rather large quality safety of crops existed.As a whole,naturally rehabilitated stone-like coal mine surface water Cd content overproof level is high,peripheral soil and surface water are easy to be impacted and ecologic risk existed.Stone-like coal mine peripheral soil and crops heavy metal content seriously overproof,thus stone-like coal mine entironment rehabilitation natural and artificial combined method is proposed,mine liquid and solid wastes treatment and disposal should be well done to reduce impacts from eluviation on groundwater and soil.