北京官厅水库周边土壤重金属与农药残留及风险分析
Heavy Metal and Pesticide Residues in Soils Around the Guanting Reservoir and Environmental Risk Assessment
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摘要: 对官厅水库周边土壤中Cu、Zn、Pb、Cr、Cd、N i、As、Co、HCHs和DDTs 10种污染物进行调查监测,并就其来源及环境风险进行评价,结果表明:Cd是该区域最主要的污染物,检测值为(0.68±0.17)mg.kg-1,相当于土壤环境质量一级标准的3.4倍,洋河和桑干河流域的土样已超过国家二级标准,对土壤造成了严重污染;土壤中仍有一定量的有机氯农药残留,并以DDT为主,约占农药残留总量的93%;历史上上游工业废水的排放以及农业生产中大量使用化肥和农药是该区重金属和农药污染的主要来源;全部样点的综合污染指数值均≥2,构成重度污染的样点超过65%,说明官厅水库周边土壤存在明显的多种污染物的复合污染。Abstract: Investigation and survey was carried out to determine heavy metals(Cu、Zn、Pb、Cr、Cd、Ni、As、Co) and pesticide residues(HCHs and DDTs) in soils around the Guanting Reservoir and their sources and environmental risks were analyzed as well.Results indicate that Cd is the major pollutant in this area,3.4 times as high as Grade Ⅰ criterion of the national standard for soil environment,with a mean of(0.68±0.17) mg·kg-1.The area of soils with Cd concentration(higher) than Grade Ⅱ criterion of the national standard accounts for about 40% of the whole study area.DDT is the main load of pesticide pollution in the soils,accounting for 93% of the total residue.Fertilizers and pesticides used in farming and industrial waste from upstreams are the major sources of soil pollutants in the region.The integrated pollution is more serious in the Yanghe River and the Sanggan River watersheds than in other areas,with Cd being the most serious factor.The integrated pollution index of all soil samples is higher than 2;and more than 65% of them higher than 3,being up to the level of serious pollution.These suggest that more attention should be paid to the soil integrated pollution induced by multi-pollutants in planning,protection and management of the water resource of the Guanting Reservoir in future.