安徽农田表层土壤中有机氯农药的分布及其组成

以安徽省寿县等19个地区的农田表层土壤(0～20 cm)为对象,采用超声波提取,气相色谱法/电子捕获检测器(GC/ECD)检测,分析了α-六六六、β-六六六、γ-六六六、δ-六六六、op′-DDE、pp′-DDD、α-硫丹和百菌清等8种有机氯农药(OCPs)在农田表层土壤中的分布及组成特征.结果表明： 19个取样点中8种有机氯农药残留的总含量范围为ND～23.75 μg·kg^-1,其中PP′-DDD、γ-HCH为主要污染物,平均质量浓度分别为13.83和13.49 μg·kg^-1.与1990年的调查结果相比,六六六平均值含量呈明显下降趋势；与国内外土壤相比,安徽省农田表层土壤中的六六六(HCHs)处于中等偏高的水平.安徽省农田表层土壤中OCPs、HCHs和pp′-DDD平均浓度分别为48.58、28.64和13.83 μg·kg^-1,均未超过《土壤环境质量标准》(GB 15618-1995)的一级土壤质量标准(<50 μg·kg^-1),污染较轻.

Distribution and composition of organochlorine pesticides in farmland top soils of Anhui Province

By using ultrasonic method and GC/ECD, this paper analyzed the distribution and composition of 8 kinds of organochlorine pesticides (alpha-HCH, beta-HCH, gamma-HCH, delta-HCH, op'-DDE, pp'-DDD, alpha-endosulfan, and chlorothalonil) in farmland top soils (0-20 cm) in 19 districts of Anhui Province, East China. The total concentration of the pesticides in the top soils ranged from 0 to 23.75 microg x kg(-1), among which, pp'-DDD and gamma-HCH were the major pollutants, with the mean concentration being 13.83 and 13.49 microg x kg(-1), respectively. As compared with the analyses in 1990, the present mean concentration of HCH had an obvious decreasing trend, but was still higher than that in the top soils in other regions of China and in other countries. The mean concentrations of OCPs, HCHs and pp'-DDD in the test top soils were 48.58, 28.64 and 13.83 microg x kg(-1), respectively, not surpassed the first grade level (< 50 microg x kg(-1)) of the China National Soil Environmental Quality Standards (GB 15618-1995), suggesting that the farmland top soils in these districts of Anhui Province were less polluted.