南方丘陵区河流表层沉积物重金属污染评价

Ecological risk assessment and source analysis of heavy metals in surface sediments of rivers located in the hilly area of southern China

采样分析南方丘陵山区瓯江、钱塘江、闽江、九龙江沉积物中重金属含量,并对其来源及生态风险进行研究.结果显示,沉积物中Mn、Zn、As、Cd、Pb、V在九龙江有较高浓度,Ni、Cu在钱塘江浓度最高,Cr、Sb在瓯江浓度最高,而Al、Co和V的最高浓度分布在闽江.但重金属含量空间差异不显著.SQGs、Igeo和EF评价显示,Cd在研究区沉积物中污染最为严重,呈中度至重度污染,其次是Mn、Zn、Pb,其在研究区部分地区存在轻度污染,其他重金属处于无污染状态.RI评价显示,研究区河流沉积物存在极高重金属潜在生态风险,尤其是Cd.相关分析和PCA分析显示,Zn、As、Cd、Pb来自于自然过程、矿业开采及农业生产过程,Cr、Ni、Sb来自于工业生产过程产生废水,Al、Co和V来自于自然过程,而Cu则来源于混合源.pH值、TP、TN和LOI是影响水体中重金属含量的重要因子.本研究为河流生态系统的健康和保护提供重要依据.

Heavy metals are characterized with toxicity,persistence and bioaccumulation,can exert significant adverse effect on the health of human beings and other organisms through food chain.In aquatic ecosystem,sediment is both the sink and the source of heavy metals.Thus,it’s of great importance to study heavy metals in surface sediment to keep the aquatic ecosystem in good condition.In this study,the spatial distribution,source analysis,and corresponding ecological risk of heavy metals in surface sediments of four main rivers(Minjiang River,Qiantangjiang River,Oujiang River and Jiulongjiang River)in the hilly area of southern China was analyzed.Our results showed that the relative higher values of metal group of Mn-Zn-As-Cd-Pb were observed in Jiulongjiang River.Moreover,the highest values of metal group of Ni-Cu,Cr-Sb,Al-Co-V were found in Qiantangjiang River,Oujiang River and Minjiang River,respectively.However,no significant difference of the heavy mental contents were tested among the four rivers(P>0.05).Pollution assessment based on SQGs,Igeo and EF exhibited that sediments were moderately or seriously polluted by Cd and some sites were slightly polluted by Mn,Zn,and Pb.In addition,the RI assessment showed that heavy metals in sediments of our studied rivers posed extreme high potential of ecological risks.Multivariate analysis indicated that Mn,Zn,As,Cd and Pb mainly came from natural process,agricultural and mining activities;Cr,Ni and Sb may mainly come from instrial wastewater While industrial wastewater and Al,Co,V may mainly derived from natural process.And Cu derived from multiple sources above.By RDA analysis,the pH,TP,TN and LOI were the main environmental factors influencing heavy metal concentrations in the sediments.This study can provide important information for the protection of river ecosystem.