山东省沂南县东部土壤重金属地球化学特征及源解析

Geochemical Characteristics and Source Analysis of Heavy Metals in Soils of Eastern Yinan,Shandong Province

为查明山东省沂南县东部地区土壤重金属污染现状和污染源,系统采集了4 779件表层土壤样品,测试分析Cd、Hg、Pb、As、Cr、Ni、Cu、Zn元素含量及pH值,用地统计学、多元统计、空间分析等方法,探讨土壤重金属元素地球化学特征及其可能来源。结果表明,研究区土壤Hg含量均值略高于临沂市表层土壤背景值,另外7种元素含量均值与临沂市土壤背景值相当。与GB 15618-2018土壤环境质量农用地土壤污染风险管控标准筛选值相比,研究区土壤8种重金属元素浓度超标率低,但极大值的超标倍数较大,反映局部点式和小片污染较重。研究区8种元素含量水平总体表现出由西到东三级台阶下降的特征。研究区土壤中Cd、Pb、Zn、As高含量主要受控于自然源母岩,叠加了程度不同的工矿交通和农业活动因素;Cr、Ni几乎完全受控于成土母岩;Hg、Cu主要受控于沂南金场、铜井金矿采冶活动,其次受工业和交通排放以及农业粪肥、农药施用影响。

In order to present the status of soil heavy metal pollution in Yinan County, Shandong Province, 4,779 surface soil samples were collected systematically in this area, and the concentration of Cd, Hg, Pb, As, Cr, Ni, Cu, Zn and pH value were analyzed. The geochemical characteristics of heavy metals and possible sources have been discussed by geostatistics, multivariate statistics, spatial analysis and other analysis methods. The results show that the Hg mean value in soil is slightly higher than the background value of surface soil in Linyi city, and the respective mean values of the other seven elements are equivalent to that of Linyi. Compared with the screening value of GB 15618-2018(soil environmental quality risk control standard for soil contamination of agricultural land), the concentration over-standard rate of eight heavy metal elements in the research area is low. But the exceeding standard multiple of the maximum value is large, that shows local point and small pieces are seriously polluted. The concentration of 8 kinds of elements in the research area shows a three-step decline from west to east. The high concentration of Cd, Pb, Zn and As in the soil are mainly controlled by natu-ral source, parent rocks, superimposed different degrees of industrial and mining transportation and agricultural activities. Cr and Ni are almost completely controlled by parent rocks. Hg and Cu are controlled mainly by the mining and smelting activities of Yinan Jinchang and Tongjing gold mine, followed by industrial and traffic emissions, agricultural manure and pesticide application.