Distribution of organochlorine pesticide residues and potential genotoxicity in surface sediments from Lake Taihu

采用GC-ECD对太湖表层沉积物中的有机氯农药含量进行了定性定量分析.太湖20个采样点均有不同程度的有机氯农药检出,16种有机氯农药总量为4.22-460.99ng/g(dw),北部湖区、湖心区以及沿岸区等均有高值点出现,与沉积物有机质含量、氮磷营养盐含量分布并不一致.检出率最高的有机氯农药组分为DDTs、HCHs.DDTs含量检出顺序为p,p'-DDT﹥p,p'-DDD﹥p,p'-DDE,说明环境中可能仍然具有DDT输入特征;HCHs中α-HCH,γ-HCH检出相当,β,δ-HCH检出较高,主要为早期残留.结合鼠伤寒沙门氏菌/哺乳动物微粒体酶系(Ames)试验研究太湖典型湖区表层沉积物中有机污染物的遗传毒性,初步确定可能的生态风险因子.;The present distribution of organochlorine pesticides(OCPs) in surface sediments from Lake Taihu had been quantitatively analyzed by GC-ECD. OCPs were detected in all 20 samples, and total concentrations for 16 kinds of OCPs components ranged from 4.22 to 460.99ng/g(dw). Not only the northern part but also the center and the edge of the lake had higher concentrations, which was inconsistent with the distribution of organic carbons, nitrogen and phosphorus in surface sediments. DDTs, HCHs were the highest in all the detected compounds of OCPs in 20 samples. In DDTs, the residual level of p,p'-DDT was much higher than p,p'-DDE and p,p'-DDD, which showed there maybe new pollution sources recently. In HCHs, the contents of α-HCH and γ-HCH were similar, while β,δ-HCH had much higher residues caused by earlier use of this compound. The genoxicity of the typical locations were examined by the Ames test, and the genotoxic results were combined with the chemical analysis to determine the most responsible stressers for genotoxicity in the surface sediments of Lake Taihu.