新乡市地表水沉积物中HCHs和DDTs的分布特征及生态风险

Distribution and Risk Assessment of HCHs and DDTs in Sediments from Xinxiang Surface Water

利用GC-ECD测定了新乡市地表水沉积物中的有机氯农药六六六(HCHs)、滴滴涕(DDTs)的含量,分析其可能来源并进行生态风险评估。结果表明:新乡市地表水沉积物中∑HCHs和∑DDTs的含量范围分别为1.13～8.12ng·g-1dw(平均为2.88ng·g-1dw)和2.38～22.67ng·g-1dw(平均为8.07ng·g-1dw)。HCHs和DDTs的组成特征表明,新乡市地表水沉积物中的DDTs主要来源于历史上DDTs的使用,同时存在局部地区三氯杀螨醇的使用,而HCHs主要来源于林丹的使用。根据沉积物中HCHs和DDTs的质量评估标准,新乡市地表水沉积物中HCHs未对生态构成威胁,而DDTs存在生态风险。

This work investigated contamination status of the HCHs and DDTs in sediments from surface water, Xinxiang City. Sediments used in this study were collected from 18 sites in surface water of Xinxiang in January 2007. The levels and distribution patterns of the HCHs and DDTs in samples were investigated by the technique of soxhlet extraction followed by the analysis of gas chromatography（GC）coupled with a electron capture detector（ECD）. In addition, the potential sources as well as ecological risks of HCHs and DDTs were analyzed. The concentrations of ∑HCHs（α-, β-, γ-and δ-HCH） and ∑DDTs（p, p′-DDT, o, p′-DDT, p, p′-DDE and p, p′-DDD） in sediments ranged from 1.13 ng·g^-1 to 8.12 ng·g^-1（average, 2.88 ng·g^-1 dw） and 2.38 ng·g^-1 to 22.67 ng·g^-1 dw（average, 8.07 ng·g^-1 dw）, respectively. The compositional analysis of DDTs suggested that historical usage of technical DDTs was the main reason for DDTs residues in the sediments from surface water of Xinxiang, while fresh DDTs inputs from dicofol application were likely to occurred in this region. The ratios of HCHs isomers indicated the present of lindane in the area. Compared with some published guideline values of OCPs in sediments, the concentrations of HCHs were at safe levels while the residues of DDT would pose adverse biological effects in this studied area.