北方污灌区土壤重金属污染特征分析

Pollution characteristics of heavy metals in sewage irrigated soil of Northern China

【目的】研究我国北方污灌区农田土壤Cu、Pb、Zn、Cr、Cd、Ni、As、Hg等8种重金属元素的污染特征,为污灌区土壤环境质量评价、土壤重金属污染修复提供参考。【方法】以我国北方30个污灌区土壤重金属污染数据为基础,采用统计分析方法、内梅罗综合污染指数法及地质累积指数法,对北方污灌区土壤重金属的污染特征进行分析。【结果】结果表明,北方污灌区农田土壤中8种重金属元素含量均未超过土壤环境质量二级标准,但除Cr外,其余7种重金属的平均含量均显著高于全国背景值;8种重金属含量变异系数从大到小依次为Cd>Hg>Pb>As>Zn>Cu>Cr>Ni,其中Cu、Cr、Ni在不同灌区差异性相对较小,Cd、Hg、Pb在不同灌区差异较大;Cu与Zn、Cr、Cd、As、Hg,Zn与Ni,Cr与Pb、Ni、As、Hg,Cd与As呈显著相关的概率较大,Pb与Cu、Zn、Ni、Hg,Hg与Zn、Cd、Ni、As呈高度相关的概率较大;各种重金属内梅罗综合指数和地质累积指数由大至小依次为Cd>Hg>Cu>As>Zn>Pb>Ni>Cr。【结论】我国北方污灌区农田土壤中Cu、Pb、Zn、Cr、Cd、Ni、As、Hg等8种重金属元素明显积累,应该引起有关部门的足够重视。

【Objective】This research aimed to investigate the pollution characteristics of heavy metals Cu,Pb,Zn,Cr,Cd,Ni,As and Hg in the surface soil of farmland in sewage irrigation area,which will provide a reference for the quality evaluation of soil environment and remediation of heavy mental pollution in sewage irrigated area.【Method】Based on the statistical data of 30 sewage irrigation regions in Northern China,this article analyzed the heavy mental pollution in sewage irrigation area with statistical analysis methods,Nemerow index method and geoaccumulation index method.【Result】Contents of tested heavy metals in the surface soil in sewage irrigation area in Northern China were all lower than the secondary standards regulated in Soil Environment Standards.However,the average contents of all the heavy metals except Cr were higher than their national background values.Their variation coefficients were in a decreasing order of Cd＞Hg＞Pb＞As＞Zn＞Cu＞Cr＞Ni,among which Cu,Cr,and Ni had very small differences and Cd,Hg,and Pb had large differences.Significant relationships were found between Cu with Zn,Cr,Cd,As,and Hg, Zn with Ni,Cr with Pb,Ni,As,and Hg,and Cd with As,while extremely significant relationships were found between Pb with Cu,Zn,Ni and Hg,and Hg with Zn,Cd,Ni and As.The Nemerow indexes and geoaccumulation indexes of studied heavy metals were in a decreasing order of Cd＞Hg＞Cu＞As＞Zn＞Pb＞Ni＞Cr.【Conclusion】Heavy metals Cu,Pb,Zn,Cr,Cd,Ni,As and Hg were accumulated in soil of Northern China due to human activities.