新疆地表水体重金属生态风险评估

摘要

系统分析新疆主要地表水体中重金属暴露特征,并基于可利用的毒性数据,采用安全阈值法(MOS10)评价了水体中6种典型重金属对水生生物的生态风险.结果表明:新疆地表水重金属暴露浓度平均顺序为Ni＞Zn＞Cu＞Cr＞Cd＞Pb,均值都未超过世界卫生组织(WHO)饮用水健康标准.重金属生态风险评价结果表明,短期暴露下,6种重金属的MOS10均大于1,Cr、Cd、Cu、Pb、Ni和Zn暴露浓度超过影响10％的水生生物的概率分别为9.95％、9.40％、9.40％、1.72％、6.08％和0,说明6种重金属对水生生物的短期生态风险较小;长期暴露下,Zn的MOS10大于1,Cr、Cd、Cu、Pb和Ni的MOS10均小于1,Cr、Cd、Cu、Pb、Ni和Zn暴露浓度超过影响10％的水生生物的概率分别为15.40％、12.01％、24.80％、15.70％、98.25％和0,说明Zn的生态风险较低,Cr、Cd、Cu、Pb和Ni对水生生物具有长期潜在的生态风险,且6种重金属对水生生物的生态风险大小依次为Ni＞Cu＞Pb ＞Cr＞Cd＞Zn.%The exposure characteristics of heavy metals in surface aquatic environments of Xinjiang area were analyzed,the safety threshold method was employed to evaluate the ecological risks of 6kinds of typical heavy metals.The results showed that the average order of heavy metals exposure concentration was Ni＞Zn＞Cu＞Cr＞Cd＞Pb,all heavy metals under the health standards for drinking water of WHO.The ecological risk assessment of heavy metals showed that MOS10 of six heavy metals were more than one,the probability of exposure concentrations (Cr,Cd,Cu,Pb,Ni and Zn) more than the concentrations of affecting 10％ aquatic organisms were 9.95％,9.40％,9.40％,1.72％,6.08％ and 0,the ecological risk to aquatic organisms was negligible for a short time respectively.Nevertheless,for a long time,MOS10of Zn were more than one,MOS10 of Cr,Cd,Cu,Pb and Ni were less than one,respectively.The probability of exposure concentrations (Cr,Cd,Cu,Pb,Ni and Zn) more than the concentrations of affecting 10％ aquatic organisms were 15.40％,12.01％,24.80％,15.70％,98.25％ and 0,which revealed that ecological risk of Zn was negligible,and ecological risks of Cr,Cd,Cu,Pb and Ni were higher on aquatic organisms,and the ecological risk of six main heavy metals was in order Ni＞Cu＞Pb ＞Cr＞Cd＞Zn.