黄浦江表层水体中有机氯农药的分布特征

Distribution Characteristics of Organochlorine Pesticides in Surface Water from the Huangpu River

用双柱GC—ECD对黄浦江表层水体中的20种有机氯农药（OCPs）进行了分析，水体中ρ（OCPs）为87．28～148．97ng／L，含量较高的组分有β-BHC，δ-BHC，α—BHC，4，4’-DDT和七氯等，ρ（BHCs）高于ρ（DDTs），分别为42．13～75．47和3-83～20．90ng/L．组分分布特征表明，水体中BHCs主要为环境中的早期残留，在淀峰断面显示近期输入特征；水体中DDTs显示近期输入特征．高平潮时ρ（OCPs）低于低平潮，高平潮时大量长江水的涌入对黄浦江水体中的有机氯农药起到一定的稀释作用．水体中有机氯农药呈现较明显的季节性变化，丰水期含量高于枯水期，丰水期农田径流和土壤剥蚀作用的加强是导致水体中ρ（OCPs）升高的重要原因，说明黄浦江水体中有机氯农药的来源具有面源特征；水温升高加强了沉积物中有机氯农药的二次释放．与其他地区相比较，黄浦江表层水体中ρ（OCPs）较低，ρ（DDTs）和ρ（BHCs）均未超过地表水环境质量标准限值．

20 kinds of organochlorine pesticides （OCPs） in surface water from the Huangpu River in Shanghai, China were determined by GC-ECD with dual column. The total mass concentration of OCPs in surface water was 87.28- 148.97 ng/L. β-BHC, δ-BHC, α-BHC,4,4＇-DDT and heptachlor had higher mass concentration than other OCPs. The mass concentration of BHCs and total DDTswas 42.13 - 75.47 and 3.83 - 20.90 ng/L, respectively. Distribution characteristics of OCPs components showed that BHCs at present were mainly the early residue at most sections, but BHCs at Dianfeng section had some new input in near term. DDTs in water had some characteristics of new input in near term at most sections. Mass concentration of OCPs in water was distinguishing at different tide time, which were lower at high tide than at low tide. Inrush of abundant water from the Yangtze River diluted OCPs in water from the Huangpu River at high tide time. The seasonality of the mass concentration of OCPs was significant, and the level of OCPs in high flow season was higher than that in low flow season. Agricultural runoff and soil denudation enhanced in high flow season, and took more OCPs into the Huangpu River, which suggested that non-point source was one of the important sources of OCPs entering into the Huangpu River. Also, high temperature in high flow season strengthened secondary release of OCPs from sediment to water. Compared with other area, the mass concentration of OCPs in the Huangpu River was a bit lower. The mass concentration of DDTs and BHCs were both lower than the limited value defined by Environmental Quality Standards for Surface Water in China.