南宁城市内河水体和表层沉积物中有机氯农药分布特征

采用改进的固相萃取、加速溶剂萃取和气相色谱-电子捕获检测器，对广西壮族自治区南宁5条城市内河的水体和表层沉积物样品中7种痕量有机氯农药(OCPs)的残留状况进行了分析测定. 结果表明，南宁城市内河水体有机氯农药以HCHs为主，ρ(OCPs)为nd～0.141 μg/L. 5个点位沉积物中w(总OCPs)为2.13～2.80 μg/kg，均检出4,4′-DDE和4,4′-DDD，w(DDD)/w(DDE)<1，且DDTs在沉积物中的含量普遍高于HCHs. 各点位沉积物中有机氯农药各组分含量均低于美国环境保护署采用的无毒害风险浓度. 

Distribution Characteristics of Organochlorine Pesticides in Water and Surface Sediments from the Rivers of Nanning City

Residues of seven trace organochlorine pesticides (OCPs) in water and surface sediments from five rivers of Nanning City were determined with gas chromatography/electron capture detector (GC/ECD), and the samples were treated with improved solid phase extraction (SPE) and accelerated solvent extraction (ASE). The results indicated that HCHs were the dominant organochlorine components in the water, with concentrations ranging from nd to 0.141 μg/L. The total concentration of OCPs in the surface sediments ranged from 2.13 to 2.80 μg/kg in the five designated sampling sites. 4,4′-DDE and 4,4′-DDD were detected in all the sediment samples. The ratio of w(DDD)/w(DDE) was lower than 1. In general, the concentrations of DDTs were higher than those of HCHs. However, all concentrations of OCPs were lower than the Consensus-based Threshold Concentration formulated by the United States Environmental Protection Agency.