基于PMF模型的山区农用地土壤重金属来源分析

Source Analysis of Soil Heavy Metals in Agricultural Land in Mountainous Areas Based on PMF Model

为了解山区农用地土壤重金属的污染情况及查明8种重金属的污染来源,在研究区内采集土壤表层(0~20cm)样品1311个,分析化验了pH值、砷(As)、镉(Cd)、铬(Cr)、铜(Cu)、汞(Hg)、镍(Ni)、铅(Pb)和锌(Zn)指标。采用了内梅罗综合指数法、地统计学法、相关分析、单因素方差分析及正定矩阵(PMF)模型等方法,研究山区农用地土壤重金属污染特征及可能的污染来源。结果表明,研究区土壤中8种重金属含量均明显高于重庆市土壤背景值;除局部区域呈现重度污染之外,研究区土壤整体上呈清洁或轻度污染,主要污染元素为Cd;PMF模型结果显示,研究区土壤重金属污染来源主要有3类,分别为自然母质源(Cd、Cr、Cu、Ni、Pb、Zn)、采矿活动源(As、Cr、Hg、Pb、Zn)和农业活动源(As、Cd、Cr、Hg)。

In order to understand pollution of soil heavy metals in agricultural land in mountainous areas and identify pollution sources of eight kinds of heavy metals,1311 samples of soil surface(0-20 cm)were collected in the study area,and pH,As,Cd,Cr,Cu,Hg,Ni,Pb,Zn were tested and analyzed.Nemerow comprehensive index method,geostatistics method,correlation analysis,one-way analysis of variance and positive definite matrix(PMF)model were used to study characteristics and possible pollution sources of heavy metal pollution in agricultural land in mountainous areas.Results showed that contents of eight heavy metals in the soil of study area were significantly higher than background value of soil in Chongqing.Except for heavy pollution in some areas,soil in the study area was generally clean or slightly polluted,and main polluting element was Cd.PMF model results showed that there were three main sources of soil heavy metal pollution in the study area,namely natural parent material source(Cd,Cr,Cu,Ni,Pb,Zn),mining activity source(As,Cr,Hg,Pb,Zn),source of agricultural activities(As,Cd,Cr,Hg).