海河流域沉积物中典型重金属的生态风险评估及验证

沉积物重金属污染及其生态风险评估日益受到关注,而沉积物质量基准是开展生态风险评估的有力工具。本研究通过物种敏感度分布法(species sensitivity distributions, SSD)和急慢性毒性比(acute to chronic ratios, ACR)推导了镍、铜、锌、镉和铅的沉积物质量基准(sediment quality guideline, SQG)。在获得合理的重金属沉积物慢性毒性数据的基础上,采用S-Logistic模型拟合镍、铜、镉和铅的慢性SSD曲线,采用S-Gompertz模型拟合锌的慢性SSD曲线。得到镍、铜、锌、镉和铅沉积物质量基准低值(sediment quality guideline low value, SQGlow)分别为18.6、69.9、107、1.26和38.4 mg·kg~(-1),应用ACRs,得到相应的沉积物质量基准高值(sediment quality guideline high value, SQGhigh)分别为167、226、556、10.1和384 mg·kg~(-1)。与加拿大和澳大利亚重金属沉积物基准值具有一定的可比性。选择花翅摇蚊(Chironomus kiiensis)、伸展摇蚊(Chironomus tentans)和霍甫水丝蚓(Limnodrilus hoffmeisteri)3种底栖生物作为受试生物,验证基准值对海河流域沉积物重金属毒性的预测能力。结果表明,利用SQGs预测沉积物毒性的总准确率为76.2%,3种底栖生物验证准确率从高至低为:花翅摇蚊>伸展摇蚊>霍甫水丝蚓。

Ecological Risk Assessment and Verification of the Typical Heavy Metals for Sediment of Haihe River Basin

Heavy metals, such as copper, cadmium, lead, zinc and nickel, are widely detected in freshwater sediment of China, and they receive much attention on their ecological risks to benthic organisms. Sediment quality guideline (SQG) is an efficient tool for evaluating the ecological risks of contaminants in sediment. In this study, we investigated the feasibility to derive SQGs of the five heavy metals using the methods of species sensitivity distribution (SSD) and acute to chronic ratios (ACR). The chronic toxicity data to freshwater benthic organisms for copper, cadmium, lead, zinc and nickel in sediments were collected from literatures. With the developed strict screening principles, reliable toxicity data were selected to fit the SSD models by nonlinear regression. The sediment quality guideline low values (SQG_low) for nickel, copper, cadmium and lead were obtained from the S-Logistic model, and that of zinc was obtained from the S-Gompertz model. Due to the lack of acute toxicity data for the five heavy metals in sediments, ACRs were applied to estimate the sediment quality guideline high values (SQG_high). The SQG_low values for nickel, copper, zinc, cadmium and lead were 18.6, 69.9, 107, 1.26 and 38.4 mg kg^?1, and the SQG_high values were 167, 226, 556, 10.1 and 384 mg kg^?1, respectively. They were comparable to the SQG values used in Canada and Australia. In order to verify the capacity of the obtained SQGs to predict sediment toxicities, Chironomus kiiensis, Chironomus tentans and Limnodrilus hoffmeisteri were employed to test the toxicities of the sediments collected from Haihe River. The results demonstrated that 76.2% of the tested samples had the same results predicted by the SQGs, and the order of the accuracy for benthic organisms was Chironomus kiiensis > Chironomus tentans > Limnodrilus hoffmeisteri.