四川阿坝州剖面大气中有机氯农药的污染特征

Contaminant characteristics of organochlorine pesticides in the atmosphere of Aba prefecture profile,Sichuan

采用聚氨酯泡沫-被动采样法(PUF-PAS)采集了阿坝剖面冬、夏季大气样,研究了高原地区大气中有机氯农药(OCPs)的组成、季节变化和海拔高度分布。结果表明大气中OCPs主要组成为HCHs、DDTs、七氯、艾氏剂、降解物狄氏剂与异狄氏剂,占OCPs总量的91%。剖面大气中OCPs既来自于大气长距离传输,又存在新的HCHs、DDTs和氯丹污染源输入。OCPs冬季含量(平均值2.35ng/m3)略高于夏季(平均值1.48ng/m3),其中HCHs、DDTs、七氯和七氯环氧冬季含量高于夏季,艾氏剂及降解产物狄氏剂与异狄氏剂、硫丹夏季含量高于冬季,而氯丹、六氯苯和九氯含量冬、夏两季相差不大。两季大气中OCPs浓度与高程线性相关系数(R2)平均值分别为0.11和0.10,OCPs浓度与高程无明显相关性,低海拔地区浓度低于高海拔地区。

Composition, seasonal variation and altitudinal distribution of organochlorine pesticides （OCPs） in the atmosphere of Aba prefecture profile have been studied by sampling the winter and summer atmospheres with polyurethane foam-passive sampling method （PUF-PAS）. The results showed that the main OCPs components in the atmosphere were HCHs, DDTs, heptachlor, aldrin, dieldrin and eldrin, together accounting for 91% of the total amount of OCPs. OCPs in the study area came not on ly from long distance atmospheric transmission, but also from the new input of HCHs and DDTs and chlordane sources. Mean concentration of OCPs, especially HCHs, DDTs, heptachlor and heptachloroepoxide in winter （2. 35 ng/m^3） was higher than that in summer （1.48 ng/m^3）. On the contrary, Aldrin, dieldrin and eldrin, endosulfan had higher concentrations in summer than in winter. The concentration of chlordane, HCB and nonachlor showed no marked differences. There were no obvious correlations between the atmospheric OCPs concentration and elevation in both seasons （linear correlation coefficient R^2 = 0. 11 and 0. 10）. Generally, low altitude areas had a lower OCPs concentration than the high altitude areas.