吉林市排污河底泥的污染状况及其生态风险评价

以吉林市排污河中底泥为主要研究对象,布置12个监测断面35个代表性采样点,采集并分析了河道内底泥样品中8种重金属及16种USEPA优先控制的多环芳烃的含量,并分别采用地质累积指数法(I_(geo))、潜在生态风险评价法(PERI)、沉积物质量基准法(SQGs)对排污河底泥中污染物进行了生态风险评价。结果表明,该排污河底泥中重金属及多环芳烃均不同程度超过松花江水系沉积物背景值,其中Hg、Pb、Cu、As、NAP、ANT超标倍数分别为87.5、10.2、6.18、5.90、115.6和228.5;I_(geo)显示Hg的生态风险最大,I_(geo)达到了5.82,而Cd和Ni的风险较小,这与PERI中Hg风险最大的结果一致;SQGs评价结果表明由重金属及多环芳烃引起的污染会产生生物毒性,且不利生物毒性将频繁发生;(3)以上结果说明,该排污河呈现以Hg为主要风险因子的重金属与多环芳烃复合污染现象,在今后应加强底泥监测和定期清淤,从而推动区域生态环境的治理与恢复。

Pollution and ecological risk assessment of sediments in sewage-received river of Jilin

Jilin is one of the most important chemical industry cities located in China's northeastern old industrial base.Heavy metals and polycyclic aromatic hydrocarbons (PAHs) have been detected in the sediments of different regions in China,but little is known about the sewage-received river of Jilin,whose pollution was very severe owing to long-time discharge of industrial and municipal wastewater.The aim of this study was to investigate the pollution of heavy metals and PAHs in sediments and to assess their ecological risks.A total of 35 sediment samples from 12 monitoring sections along this sewage-received river were collected for determination of the concentrations of 8 heavy metals (Hg,Pb,As,Cu,Zn,Cr,Cd,Ni) and 16 USEPA priority pollutant PAHs.Geoaccumulation index,H3/4kanson potential ecological risk index,and sediment quality guidelines (SQGs) were respectively used to assess the pollution and potential ecological risks of these pollutants in the sediments.The concentrations of heavy metals and PAHs were higher than the background values,especially those of Hg,Pb,Cu,As,NAP,and ANT.The geoaccumulation index indicated that the ecological risks of heavy metals in the sediments from high to low were as follows: Hg>Pb>As>Cu>Zn>Cr>Cd>Ni.The H3/4kanson potential ecological risk indexes of heavy metals were ranked as follows: Hg>As>Cd>Pb>Cu>Ni>Zn>Cr.SQGs indicated that adverse benthic impacts would occur frequently.The sediments were polluted by PAHs and heavy metals,especially Hg.