巢湖东半湖沉积物中有机氯农药的残留特征及风险评价

采样测定了巢湖东半湖4个样点的表层沉积物中有机氯农药(OCPs)的含量.结果表明,11种有机氯农药在样品中被检出,总含量为8.26～31.73 ng·g~(-1);OCPs在沉积物中的垂直分布从上往下大体呈递减趋势;且OCPs的最高含量都出现在上层沉积物中,说明巢湖东半湖沉积物中有机氯农药主要集中在0～3 cm的表层.根据分析,DDTs来自于早期残留或者施用农药后的长期风化残留.沉积物风险评估表明,巢湖东半湖表层沉积物中的有机氯农药存在一定的生态风险.

Residues Character and Risk Evaluation of Organochlorine Pesticides in Sediments in the East Area of Chaohu

Persistent organochlorine compounds including organochlorine pesticides (OCPs) were widely used in industry and agriculture. To study the contamination status of organochlorine pesticides(OCPs)in surface sediments of Chaohu, the sediment samples were collected from four different sites in the east area of Chaohu and analyzed for HCH isomers, DDT isomers, aldrin, dieldrin, endrin, HCB, endosulfan isomers (α and β), heptachlor epoxide, endosulfan sulfate, heptachlor, α-chlordane, β-chlordane, and their eco-environmental risk was evaluated also. The results indicated that 11 kinds of OCPs were detected in the samples, and the total concentrations of OCPs were 8.26～31.73 ng·g~(-1); The vertical distribution of OCPs in the sediments presented descending trend from the upper to the lower layer; The highest concentrations of OCPs were found in the upper layer sediments, which showed that the OCPs in the sediments of the east area of Chaohu had the phenomenon of surface enrichment. According to the analysis, the DDT class(DDTs) pollution came from early residues or in long-term weathering after application of pesticides. Compared with the deposit risk evaluation value, the residues of organochlorine pesticides in the surface sediments of the east area of Chaohu Lake were in certain ecology risk.