黑河重金属空间分布及与大型底栖动物的关系

为探究河流水体和表层沉积物重金属分布特征及其与大型底栖动物的响应关系,于2019年8月在黑河上、中游不同区域采集底栖动物、水体及表层沉积物样品,测定了8种重金属(Cr、Cu、Ni、Pb、Zn、Cd、Hg、As)的含量,利用多元统计法分析了底栖动物、水体及表层沉积物重金属空间分布特征,并运用综合污染指数、潜在生态风险指数...

Space distribution of heavy metals and its relationship with macrozoobenthos in the Heihe River,Northwest China

A study of exploring the distribution characteristics of heavy metals between river water and surface sediments and analyzing the response to macrozoobenthos were carried out different areas in August 2019 in the upper and middle reaches of the Heihe River. The contents of eight heavy metals (Cr, Cu, Ni, Pb, Zn, Cd, Hg and As) were determined for macrozoobenthos, water and surface sediments samples in this study. The spatial distribution characteristics of heavymetals in macrozoobenthos, water and surface sediments were analyzed by multivariate statistical method. Moreover, the pollution risk of heavy metals in river water and surface sediments was evaluated by comprehensive pollution index and potential ecological risk index. Finally, the relationship between macrozoobenthos and river water and surface sediments was analyzed by correlation analysis. The results showed that heavy metal concentrations was low in river water and the spatial variation was not significant. The average values of w(Mn), w(Zn), w(Cr), w(Ni), w(Cu), w(Pb), w(As), w(Cd) in surface sediments were 1.36, 2.26, 2.66, 2.10, 1.98, 1.85, 1.89 and 3.33 times higher than the background values of water and soil respectively, and the spatial differences were significant, Cu, Cr and Ni in the surface sediments may come from the application of pesticides and fertilizers and the discharge of industrial wastewater. Cd, Pb and Mn may come from the superposition of slag and its leachate and natural background; as and Zn may be related to the discharge of domestic and industrial wastewater. The pollution level of heavy metals in water was very low and the pollution of heavy metals in surface sediments was mainly caused by Cd, Cr, Zn and Ni. Furthermore, the spatial variation trend was as follows:upstream tributary > upstream main stream > middle stream. The RI values of Mn and Cd in surface sediments were 17.20 and 12.30, respectively, which belonged to high risk level. What's more, other elements were at low risk level. The macrozoobenthos biomass and diversity showed spatial difference distribution and the density of Basommatophora was positively correlated with as in water body. The density of Coleoptera, Hemiptera and Basommatophora and the three biodiversity indexes were significantly correlated with heavy metal content in surface sediments, which could be used as potential indicators of heavy metal pollution in river water and surface sediments in the upper and middle reaches of Heihe River.