江西省南丰蜜桔土壤重金属特征评价及源解析

为了了解江西南丰蜜桔土壤环境条件,通过Excel、Arcgis软件、单因子污染、Nemerow综合污染和潜在生态风险分别对南丰蜜桔表层土壤中Cd、Cr、Hg、Pb、As、Cu、Zn、Ni等重金属的含量统计、空间分布、污染特征及来源进行了评价和分析.结果表明,表层土壤重金属Cd、Hg、Pb、Cu和Zn均值含量高于江西省土壤背景值.所有重金属元素的平均值均未超过国家农用地土壤污染风险控制标准的筛选值.频率直方图显示Cd、Cu和Hg的分布呈右偏,而Cr、As、Hg、Pb、Zn和Ni的分布接近正态分布.土壤污染特征评价结果表明,Cr和Ni的单因子污染评价为安全范围;Cd、Hg、Pb、As、Cu和Zn均有不同程度的单因子污染,但总体污染程度较低.Nemerow综合污染指数显示,重度重金属污染主要集中在城区工业园区附近以及研究区的东北部和中南部.Cr、Pb、As、Cu、Zn和Ni的潜在生态风险评价属于轻微生态风险,而Cd和Hg存在不同程度的潜在风险.综合潜在生态风险评价强风险和极强风险主要分布在城区工业园附近和中南部.Cd、Hg、As和Cu的空间分布相似,含量高值出现在城区工业园区附近;Pb、Zn和Ni的空间分布相似,含量高值出现在东南部,Cr的含量高值出现在东北部和东南部.根据Pearson相关矩阵、主成分分析和主成分-绝对主成分得分受体模型分析表明,Cr和Ni主要来自自然源,Cd、Hg、As和Cu主要来自工业活动,Pb和Zn主要来自农业活动,部分Pb来自交通源,南丰蜜桔表层土壤环境质量总体良好.

Evaluation and source analysis of heavy metals in the soil of orange in Nanfeng, Jiangxi Province

In order to understand the soil environmental conditions of Nanfeng orange, Excel, Arcgis, single factor pollution, Nemerow comprehensive pollution and potential ecological risk were used to evaluate and analyze the content statistics, spatial distribution, pollution characteristics and sources of heavy metals such As Cd, Cr, Hg, Pb, As, Cu, Zn and Ni in the surface soil of Nanfeng orange. The results showed that the surface soil quality of Nanfeng orange was generally good. The mean values of Cd, Cr, Hg, Pb, As, Cu, Zn and Ni in the surface soil were 0.131mg·kg-1, 30.062mg·kg-1, 0.141 mg·kg-1, 37.380 mg·kg-1, 5.148 mg·kg-1 27.880 mg·kg-1, 85.642 mg·kg-1 and 14.605 mg·kg-1. The mean contents of Cd, Hg, Pb, Cu and Zn were higher than the background values of jiangxi province. The average value of all heavy metal elements did not exceed the screening value of national soil pollution risk control standard for agricultural land. The frequency histogram shows that the distribution of Cd, Cu and Hg is skewed to the right, while the distribution of Cr, As, Hg, Pb, Zn and Ni is close to normal distribution. The evaluation results of soil pollution characteristics show that the single-factor pollution evaluation of Cr and Ni is the safe range. Cd, Hg, Pb, As, Cu and Zn all have different degrees of single-factor pollution, but the overall pollution degree is low. According to the Nemerow Composite pollution Index, heavy metal pollution is mainly concentrated in the vicinity of urban industrial zones and the northeast and south central of the study area. The potential ecological risk assessment (Ei) of Cr, Pb, As, Cu, Zn and Ni is a slight ecological risk, while Cd and Hg have different degrees of potential risk. The comprehensive potential ecological risk assessment RI strong risks and very strong risks are mainly distributed in the vicinity of industrial parks in urban areas and in the central and southern area. The spatial distribution of Cd, Hg, As and Cu is similar, and the high content value appears near the urban industrial park. The spatial distribution of Pb, Zn and Ni was similar, and the high content of Cr appeared in the northeast and southeast. According to Pearson correlation matrix, principal component analysis and multivariate linear regression analysis showed that the absolute principal component source 1 is a natural source, Cr and Ni mainly from natural source, the source 2 is the source of industrial activity, Cd, Hg, As and Cu come mainly from industrial activity, source 3 is the source of agricultural activities, Pb and zinc mainly from agricultural activities, other source mainly traffic source, part of the Pb from traffic source.