某区域内矿区土壤重金属污染与生态风险评价

Evaluation of Soil Heavy Metal Pollution and Ecological Risk in a Mining Area

探究区域内矿区土壤重金属变化并对其进行污染评价,旨在为该区域环境保护及污染治理提供一定的理论依据,以期实现矿山地质环境保护与矿产资源开发并行的矿业绿色发展。以铅、锌、镉、砷含量为评价指标,结合《土壤环境质量标准》(GB 15618—2018),采用重金属单因子污染指数法与内梅罗综合污染指数法进行重金属污染评价,并对该区域矿区潜在生态风险作出评定。结果表明,A矿区土壤各重金属含量的变异系数为149.05%~211.42%,B矿区土壤各重金属含量变异系数为60.88%~118.58%;A矿区土壤重金属均出现超标现象,其中铅、锌和镉含量超标较为严重,超标率在72%以上,而砷含量超标现象则相对较轻,超标率为36.36%;B矿区土壤铅和锌含量均未出现超标,超标率为0,而砷和镉含量则出现不同程度的超标,其中砷含量超标率为92.31%,镉含量超标率为65.38%;两个矿区土壤各重金属含量均超背景值的现象,超背景值比例为42.31%~100.00%。A矿区土壤以铅、锌和镉污染为主,而B矿区土壤中砷和镉的污染较为严重。两个矿区土壤重金属综合污染指数均属重度污染,A矿区生态风险综合指数为很强生态风险危害,而B矿区为中等生态风险危害。

This paper explores the changes of heavy metals in the soil of mining area and evaluates the pollution,aiming to provide certain theoretical basis for environmental protection and pollution control in this area,so as to realize the green development of mining industry in parallel with geological environmental protection and mineral resources development.With the contents of lead,zinc,cadmium and arsenic as evaluation indexes and combined with the Soil Environmental Quality Standard(GB 15618-2018),the heavy metal pollution was evaluated by the single factor pollution index method and the Nemero comprehensive pollution Index method,and the potential ecological risk of the mining area was evaluated.The results showed that the coefficient of variation of each heavy metal content in the soil of Mining Area A was 149.05%to 211.42%,and that of the soil of mining area B was 60.88%to 118.58%.The heavy metals in the soil of mine A all exceeded the standard,amongwhich the lead,zinc and cadmium content exceeded the standard seriously,with the exceeding rate of over 72%,while the arsenic content exceeded the standard relatively mild,with the exceeding rate of 36.36%.The content of lead and zinc in the soil of Mining Area B did not exceed the standard,and the exceeding rate was 0%,while the content of arsenic and cadmium exceeded the standard to different degrees,among which the exceeding rate of arsenic content was 92.31%and the exceeding rate of cadmium content was 65.38%.The content of all heavy metals in the soil of the two mining areas exceeded the background value,and the proportion of the above background value was 42.31%~100.00%.The soil in Mining Area A is mainly polluted by lead,zinc and cadmium,while the soil in mining area B is seriously polluted by arsenic and cadmium.The comprehensive pollution indexes of soil heavy metals in both mining areas are heavy pollution.The comprehensive ecological risk index of Mining area A is strong ecological risk hazard,while that of mining area B is medium ecological risk hazard.