平原河网地区农田土壤重金属污染特征及来源解析OA北大核心CSTPCD

The purpose of this study is to achieve accurate control of heavy metals in farmland soil from the plain river network area,so as to ensure the quality and safety of agricultural products.In this study,we selected Jiaxing City,a typical plain river network area,as a study area.The concentration and distribution of heavy metals in soil were examined by collecting surface soil samples(0-20 cm,n=40);then,two methods[the geo-accumulation index(Igeo)and the potential ecological risk index]were used to evaluate the risks posed by heavy metals.Moreover,absolute principal component score-multiple linear regression and positive matrix factorization were combined to quantitatively analyze the sources of heavy metals.The content of copper(Cu),nickel(Ni),chromium(Cr),zinc(Zn),lead(Pb),cadmium(Cd),arsenic(As),and mercury(Hg)in soil were(28.8±3.73),(36.5±5.98),(60.7±5.38),(70.5±8.04),(33.2±6.25),(0.08±0.04),(7.30±1.52)mg·kg-1,and(0.31±0.15)mg·kg-1,respectively.Among these,the Hg content exceeded the screening value of soil pollution risk for agricultural land(the over-standard rate was 12.5%).The dominant element was Hg[Igeo=(0.20±0.77)],showing slight to mild pollution(67.5%).Moreover,the comprehensive potential ecological risk[RI=(122±39.8)]was found to be moderate,and Hg was established to be the main risk factor(64.4%).The sources of heavy metals in farmland soil were industrial sources with a contribution of 32.0%,followed by natural(28.2%),agricultural(25.8%),and transportation(14.0%)sources.Among these,Hg was mainly derived from agricultural(62.9%)and industrial(37.1%)sources.In the future,the control of agricultural inputs and industrial waste can be strengthened to reduce the input of Hg into farmland soil,ensuring the safe utilization of farmland soil and the quality and safety of agricultural products.