黄河三角洲北部湿地沉积物重金属污染风险评价及来源分析

Risk assessment and source analysis of heavy metal pollution in wetland sediments in the northern Yellow River Delta

以黄河三角洲北部湿地39个表层沉积物样品为研究对象,测定Cu、Pb、Zn、Cr、Ni、Cd、As、Hg的含量,对其进行重金属污染风险评价及来源分析。结果表明:8种重金属元素在表层沉积物中平均含量由高到低顺序为:Cr>Zn>Ni>Pb>Cu>As>Cd>Hg,除As外其含量均低于山东省土壤背景值;沉积物以砂质粉砂为主,重金属元素的空间分布特征相似,可能受到“粒度效应”的影响;基于地累积指数法和潜在生态危害指数法,揭示了Cd、Hg为研究区主要污染物和重要的潜在生态危害因子;相关分析和因子分析表明,Cu、Pb、Zn、Cr、As、Hg可能来源于成土母质、工业活动以及油田开采,Ni、Cd可能来源于农业活动、水产养殖以及油田开采;聚类分析表明,可进一步把Cr单独分为一类;通过因子探测分析发现,黏土含量、TOC和含水率对潜在生态危害指数(RI值)解释力较大,表明其对RI值的影响较大;通过交互作用探测分析可知,任意两个影响因子交互作用后结果为双因子增强或非线性增强,表明复杂的环境加剧了湿地的潜在生态危害。

The contents of Cu,Pb,Zn,Cr,Ni,Cd,As and Hg in 39 surface sediment samples collected in June 2021 from the northern wetland of the Yellow River Delta were determined,and the risk assessment and source analysis of heavy metal pollution in the sediments of the northern wetland of the Yellow River Delta were carried out.Results show that the average contents of eight heavy metal elements in the surface sediments of the wetland in the northern Yellow River Delta were in the order of Cr>Zn>Ni>Pb>Cu>As>Cd>Hg,which were lower than the soil background values of Shandong Province except for As.The sediments were mainly sandy silt,and the spatial distribution characteristics of heavy metal elements are similar,which may be affected by the“grain size effect”.The cumulative index and potential ecological hazard index(RI)revealed that Cd and Hg were the main pollutants and important potential ecological risk factors in the study area.Correlation analysis and factor analysis showed that the sources of Cu,Pb,Zn,Cr,As,and Hg might be soil parent materials,industrial activities,and oilfield exploitation,and the sources of Ni and Cd might be from agricultural activities,aquaculture and oilfield exploitation.Cluster analysis showed that Cr could be placed into separate category.Through factor detection analysis,it was found that clay content,TOC and water content had a greater explanatory power on the RI,indicating that they had a greater impact on the RI value.The interaction detection analysis showed that the interaction of any two influencing factors resulted in two-factor enhancement or nonlinear enhancement,indicating that the complex environment aggravated the potential ecological hazards of wetlands.This study provided a scientific support for the control of heavy metal pollution in wetlands in the northern Yellow River Delta.