北京东南化工区土壤有机氯农药污染特征和分布规律

采集北京原东南化工区表层土壤样品,测定了土壤有机氯农药(滴滴涕、六六六和六氯苯)残留浓度,结果表明化工区土壤有机氯农药浓度较高,滴滴涕和六六六平均浓度高达5470ng/g和2110ng/g,比一般农业和城市土壤中的浓度高出很多;某些点位甚至超过国家土壤三级标准,高浓度的点位主要集中在原农药厂的生产车间和存储点。六氯苯由于来源和挥发性跟滴滴涕和六六六不同,所以六氯苯残留在化工区土壤中的分布相对比较均匀。化工区土壤滴滴涕和六六六的异构体组成特征表明工业区土壤的有机氯农药降解速度较慢,滴滴涕残留来源于工业滴滴涕和三氯杀螨醇,而六六六主要来源于工业六六六。化工区的有机氯农药污染主要来自于原农药厂的生产和存储,重污染点位对周围化工厂的有机氯残留有一定的影响。由于高残留浓度和较低的降解速度,化工区土壤有机氯农药残留的环境风险值得进一步关注。

Characterization and Distribution of Organochlorine Pesticides in Soils from Beijing Southeast Chemical Industrial Zone

Concentrations of organochlorine pesticides (OCPs) were investigated in surface soils from Beijing southeast chemical industrial zone. Results indicated that average concentrations of HCHs and DDXs were 5,470ng/g and 2,110ng/g respectively,much higher than the concentrations in agricultural and urban soils. According to Chinese environment quality standard for soil,OCP concentrations in some soil samples exceeded the maximum allowable concentration obviously. The sampling sites with high OCP concentrations located at the production workshop and storage of the former pesticide factories. Deviations of HCB concentrations were much smaller than those of DDT and HCH concentrations because of the different source and volatilization capacity. Compositions of DDT and HCH indicated the degradation of OCPs in the zone was slow,DDT pollution was a mix of technical DDT and Dicofol and HCH pollution input was only due to technical HCH sources. OCP residues in the industrial zone were mainly from the production and storage of OCPs,the polluted sites caused the elevation of OCP concentrations in other factories. Because of high OCP residue levels and low degradation,environmental risk from chemical industrial zone should be further concerned.