辽宁大伙房水库沉积物中有机氯农药和多氯联苯的分布、来源及风险评价

利用GC-MS测定24个大伙房水库表层沉积物中有机氯农药和多氯联苯含量,主要揭示水库沉积物中有机氯农药和多氯联苯的残留特征.结果表明,HCHs的含量为0.70～3.48 ng.g-1,均值为（1.58±0.71）ng.g-1;DDTs的含量为0.85～4.94ng.g-1,均值为（1.94±0.82）ng.g-1;PCBs的含量为1.46～3.52 ng.g-1,均值为（2.42±0.64）ng.g-1.γ-HCH、β-HCH、DDE、DDT和PCB28百分含量较高.高百分含量γ-HCH和DDT表明目前仍在使用的林丹和工业滴滴涕产品;β-HCH、DDE和PCB28可能来自土壤中农药和多氯联苯残留.水库上游污染物含量明显高于水库下游,同时污染物高值点主要集中在浑河河口,表明水库上游浑河河流搬运是水库沉积物中污染物的主要输入来源,并影响污染物在沉积物中的分布.生态风险评价结果表明,沉积物中DDTs和γ-HCH存在较高的生态风险;沉积物中PCBs残留尚未对周围环境造成不利影响.

Distribution, Sources and Ecological Risk Assessment of Organochlorine Pesticides and Polychlorinated Biphenyl Residues in Surface Sediment from Dahuofang Reservoir, Liaoning

Twenty-four surface sediment samples collected in Dahuofang Reservoir were analyzed for organochlorine pesticides(OCPs) and polychlorinated biphenyl(PCBs) residues. The results showed that the recent occurrence levels in sediments were 0.70-3.48 ng·g^-1(with a mean of 1.58 ng·g^-1±0.71 ng·g^-1) for HCHs, 0.85-4.94 ng·g^-1(1.94 ng·g^-1±0.82 ng·g^-1) for DDTs, 1.46-3.52 ng·g^-1(2.42 ng·g^-1±0.64 ng·g^-1) for PCBs. The inputs of OCPs and PCBs could be attributed to the recent use of relevant products and the heavy historical application which preserved in agricultural soil in adjacent area. Contamination level of OCPs and PCBs in surface sediments decreased from upstream to downstream, and samples of higher contamination level were located in Hunhe river mouth, both of which indicated distribution of OCPs and PCBs in reservoir was influenced by riverine discharge. The ecological risk assessment suggested that the OCPs in the sediments of the study area might pose a bit high harm to the environment, while PCBs might pose little harm to the environment.