长江下游表层沉积物中有机氯农药的残留状况及风险评价

2005年3—4月在长江下游安庆段—南通段共采集表层沉积物样品28个,使用加速溶剂萃取、气相色谱/质谱法测定了样品中的有机氯农药(OCPs)，包括六氯苯(HCB)、氯丹、滴滴涕(DDTs)、艾氏剂、狄氏剂、异狄氏剂、七氯和灭蚁灵等14种目标化合物. 结果表明:长江下游表层沉积物中的HCB和DDTs的检出率都为100%，DDTs是样品中OCPs的主要组分，其残留以降解代谢产物DDD和DDE为主. w(HCB)平均值为3.240 μg/kg (0.048～30.300 μg/kg)，w(DDTs)平均值为8.100 μg/kg(0.336～32.830 μg/kg). 在长江下游不同采样点的OCPs含量差异很大，部分支流入江口和城市排污口附近样品中的w(DDTs)或w(HCB)出现高值. 沉积物中DDTs的来源主要与农用土壤风化流失和上游沉积物迁移、输送有关. 与沉积物风险评估值对比,长江下游表层沉积物中的DDTs存在一定的生态风险. 

Residues and Risk Evaluation of Organochlorine Pesticides in Surface Sediments from the Lower Reaches of the Yangtze River

Twenty-eight surface sediment samples were collected at a section of the lower reaches of the Yangtze River(from Anqing to Nantong) from March to April in 2005.The samples were extracted by accelerated solvent extraction(ASE) and analyzed with gas chromatography/mass spectrometry.Fourteen kinds of organochlorine pesticides(OCPs),including Hexachlorobenzene(HCB),Chlordane,DDTs,Aldrin,Dieldrin,Endrin,Heptachlor and Mirex,were determined.The detection rates were 100% for HCB and DDTs.DDTs were the primary OCPs...