铅锌矿区农田土壤重金属污染现状与评价

Current Situation and Assessment of Heavy Metals Pollution in Farmland Soils around a Pb-Zn Mine

调查研究了福建省西部某铅锌矿区附近的农田(2.34 hm^2)土壤中Cd、Pb、Zn、Cu的污染状况,并探讨了4种重金属在矿区农田土壤上空间分布的变异状况。结果表明:调查区土壤Cd、Pb、Zn和Cu含量均超过福建省土壤背景值。土壤重金属单因子污染指数与地累积污染指数评价结果基本一致,Cd的污染程度最严重,Pb和Zn的污染程度次之,Cu的污染程度最轻。调查区土壤重金属的内梅罗综合污染指数平均值为9.13,重度污染的农田数占总数的97.44%,表明调查区农田土壤受重金属综合污染严重。土壤中Cd的潜在生态危害风险较高,Pb、Zn和Cu的潜在生态危害风险很低。不同田块土壤Cd、Pb、Cu、Zn含量的变幅分别达21.5、10.6、5.8和10.8倍,表明矿区农田土壤重金属空间分布的高度复杂性。

An investigation over an agricultural field（2.34 hm^2）near a Pb-Zn mining area in western Fujian Province was carried out,the pollution degree and the potential ecological risks of cadmium（Cd）,lead（Pb）,zinc（Zn）and copper（Cu）in the surface soils were evaluated,and the spatial distribution of the heavy metals was discussed.The results showed that the contents of Cd,Pb,Zn and Cu in the soils of the investigated area all exceeded the background values of the soils in Fujian Province,showing exogenous pollution of the metals.The results of single factor pollution index of soil heavy metals and soil cumulative pollution index are basically the same,the soils have heavily polluted with Cd,moderately polluted with Pb and Zn,slightly polluted with Cu.The average value of the integrated pollution index of heavy metals in the investigation area was 9.13,and the number of heavily polluted farmland was 97.44%of the total,indicating that the farmland soil in the survey area was seriously polluted by heavy metals.The potential ecological risks of Cd in the soils are very strong while those of Pb,Zn and Cu in the soils are weak.The contents of Cd,Pb,Cu and Zn in the soils of different field blocks differed by 21.5,10.6,5.8,and 10.8 times,respectively,indicating great spatial distribution variation of heavy metal contents in the fields of the mining area.