摘要:
采用ICP-MS测定了辽河26个支流表层沉积物间隙水中7种重金属(Pb、Cu、Cr、Zn、Ni、As、Cd)的含量,并应用间隙水毒性基准单位(IWCTU)和Nemeraw指数(NI)对间隙水重金属生态风险进行了评价;同时利用摇蚊幼虫活体生物毒性测试方法评估了辽河流域26个支流表层沉积物的综合毒性。研究结果显示,辽河支流表层沉积物间隙水7种重金属平均含量为:Pb 3.92μg·L-1,Cu 5.73 μg·L-1,Cr 7.21 μg·L-1,Zn 4.33 μg·L-1,Ni 4.48 μg·L-1,As 5.89 μg·L-1,Cd 0.29 μg·L-1,根据IWCTU值和NI值,柴河、养息牧、亮子河、凡河、付家窝堡、接官厅具有潜在的生态风险;综合毒性表征结果表明,柴河、长沟子河、付家窝堡、柳河、一统河、潮沟河表层沉积物对摇蚊幼虫具有较高毒性。结合重金属毒性和综合毒性分析,认为辽河流域支流表层沉积物毒性应该是由复合污染形成,而不仅仅是重金属污染。
Abstract:
Concentrations of Pb, Cu, Cr, Zn, Ni, As, and Cd in the interstitial waters of 26 surface sediments in Liaohe River were measured by ICP-MS. The ecological risks were assessed based on the Interstitial Water Criteria Toxicity Units (IWCTU) and Nemeraw Index (NI), respectively. Sediment toxicities of the samples were assayed using midge larva (Chironomus riparius) simutaneously. The results showed that averaged concentrations of the heavy metals in the interstitial water of sedimental samples were 3.92 μg·L-1, 5.73 μg·L-1, 7.21 μg·L-1, 4.33 μg·L-1, 4.48 μg·L-1, 5.89 μg·L-1, and 0.29 μg·L-1 for Pb, Cu, Cr, Zn, Ni, As, and Cd, respectively. And samples taken from Chai River, Yangximu River, Liangzi River, Fan River, Fujiawobao River, Jieguanting River showed potential ecological risks based on both IWCTU and NI values. By toxicity bioassay, samples from Chai River, Changgouzi River, Fujiawobao River, Liu River, Yitong River and Chaogou River exhibited stronger toxicities. Through integration, we suggested that the in vivo toxicities of the surface sediments from Liaohe River should be contributed by mixture of contaminants, rather than metals themselves.
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