人工湿地底泥中特征重金属的空间分布及生态风险评价

采集武河湿地沉积物,采用四酸消解法(HCI-HNO3-HF-HCIO4)对样品进行处理,测定武河湿地沉积物中6种重金属(As、Cd、Cu、Hg、Pb和Zn)的含量,分析其空间分布特征,并采用内梅罗综合污染指数法、潜在生态危害指数法和ERL/ERM评价法评价重金属的环境风险。结果表明,武河湿地表层沉积物中重金属含量大多高于环境背景值,空间分布差异性较小。内梅罗综合污染指数按由大到小依次为Hg、Cd、As,Zn、Cu、Pb,Hg的内梅罗综合污染指数最大为3.74,综合污染程度最为严重。潜在生态风险评价表明,湿地沉积物中潜在生态危害指数(RI)为743.91,属Ⅴ极强生态危害。ERL/ERM评价结果显示,湿地沉积物中Cu、Hg含量高于ERM值,对水生态系统有很强毒性;As、Zn的含量介于ERL和ERM之间,可能会对水域生物产生一定的毒性。

The Spatial Distribution and Ecological Risk Assessment of Characteristics Heavy Metals in the Artificial Wetland Sediment

The study collected Wuhe wetland sediments and used four acid digestion methods (HCL-HNO3-HF-HC104) to process samples,content of 6 kinds of heavy metals (As,Cd,Hg,Pb,Zn) and spatial characteristics in the sediments were determined and analyzed.The environment risk of heavy metals further was evaluated by the method of the Nemerow Pollution Index method,Potential Ecological Harm Index and the ERL/ERM.The results showed that the heavy metals in surface sediments of Wuhe Wetland content were mostly higher than those of environment background values,and the spatial distribution difference was smaller.Comprehensive Pollution Index from high to low was Cd,Hg,As,Zn,Cu,Pb.The Pollution Index of Hg element was 3.74,the most serious pollution degree.Potential ecological risk assessment showed that the Potential Ecological Harm Index RI was 734.91,belonging to the very strong ecological harm V.ERL/ERM evalution results showed that the content of Cu and Hg element in wetland sediments was higher than the value of ERM,which has a strong toxicity to the water ecological system.The content of As and Zn element was between the ERL and ERM,which may produce certain toxicity to water organisms.