长江流域岸边土中OCPs的残留特征、来源及风险评价

Residue characteristics, sources and risk assessment of organochlorine pesticides in riparian soils of the Yangtze River Basin

选取长江流域干流及支流周围的土壤作为研究介质,分析表层土壤中13种有机氯农药(OCPs)的含量,用同分异构体比值法和主成分分析法解析其来源,并对土壤中的OCPs进行风险评估.结果表明,长江流域表层土壤中Σ13OCPs的含量范围为8.94~77.79ng/g,平均含量是24.55ng/g,主要成分是六HCHs和DDTs.OCPs的含量水平表现为上游与下游相近,且二者均小于中游,在世界范围内处于中等水平.土壤中的HCHs主要来自于林丹的历史残留;DDTs主要来自于三氯杀螨醇的近期输入和工业DDTs的非法使用.健康风险评价表明,中游地区的风险高于上游及下游地区,特别是在城陵矶、南嘴和湘阴3个地区,土壤中OCPs对儿童的致癌风险Risk综合处于10^-6~10^-4,存在一定的致癌风险.

The soils around the main stream and the tributaries of the Yangtze River Basin were selected as the research medium,and the contents of 13organochlorine pesticides(OCPs)in the topsoil were analyzed.The sources were analyzed by isomer ratio method and principal component analysis,and the health risk assessment was discussed.The results showed that the concentration ofΣ13OCPs in the surface soil of the Yangtze River Basin ranged from 8.94 to 77.79ng/g,with an average content of 24.55ng/g.BHC(HCHs)and DDTs were the dominant components.The concentration level of OCPs was similar between upstream and downstream,but the level in midstream showed higher than that in upstream and downstream.However the level of OCPs concentration in Yangtze River Basin showed that is at a medium level in the world.The HCHs in the soil were mainly from the historical residues of lindane,while DDTs were mainly derived from the recent import of dicofol and the illegal use of industrial DDTs.The health risk assessment in the midstream was higher than that in the upstream and downstream of Yangtze River Basin.The Risk value of carcinogenic risks ranged from 10-6 to 10-4 in Chenglingji,Nanzui and Xiangyin,which indicated that there were certain carcinogenic risks to children in these three areas.