长三角部分地区土壤中22种有机氯农药的分布特征

针对长三角地区长期工业化对农业生态环境构成较大风险,本文利用气相色谱法对该地区不同利用类型土壤中22种有机氯农药进行测定,研究了有机氯农药的残留状况及其在4条土壤垂向剖面中的分布特征。结果表明,不同利用类型表层土壤中有机氯农药残留平均值为工业园区菜地(139.87 ng/g)工业园区荒地(103.1 ng/g)农业区传统菜地(26.27 ng/g)农业区水稻田(2.50 ng/g)。表层土壤中DDTs和HCHs是主要污染物,DDTs含量为0.14~485.73 ng/g(均值44.43 ng/g),HCHs含量为0.69~66.69 ng/g(均值7.73 ng/g),(DDD+DDE)/DDTs值表明该地区近期外源DDTs输入较少。土壤剖面样品分析表明,DDTs和HCHs的含量均随土壤深度增加而迅速降低,这与剖面土壤包气带岩性均以黏土和亚黏土为主,削弱了地表径流对有机氯农药的垂直迁移动力有关。本研究可为控制和改善该地区污染状况提供相关数据。

The Distribution Characteristics of 22 Organochlorine Pesticides in Soil from Sample Areas of the Yangtze River Delta

In order to evaluate the agricultural ecological environment risk caused by industrialization over a long period of time,the distribution characteristics of 22 organochlorine pesticide residues in the soils under different land use forms from four perpendicular profiles were analyzed using gas chromatography.Research results indicate that the mean concentrations of OCPs were in the order:vegetable land in industrial park(139.87 ng/g)> waste land in industrial park(103.1 ng/g)> vegetable land in agricultural areas(26.27 ng/g)> paddy field in agricultural areas(2.50 ng/g).DDTs and HCHs were still the primary pollutants of OCPs in the topsoils with DDTs concentrations of 0.14-485.73 ng/g(mean 44.43 ng/g) and HCHs concentrations of 0.69-66.69 ng/g(mean 7.73 ng/g).The ratio of(DDD+DDE)/DDTs indicated that there was almost no new input of pollution in this area.The concentrations of DDTs and HCHs tend to decrease gradually with the increase in the depth of soil profile.This trend is related to the fact that the rock types of zone of aeration in profile soil are mainly clays and sub-clays,which reduce the vertical transfer dynamics of organochlorine pesticides induced by the overland runoff.This study provides some references to the control and improvement of pollution conditions in the region.