宁夏中部干旱带土壤重金属污染及生态风险评价

Pollution characteristics and ecological risk assessment of soil heavy metals in arid area of central Ningxia

土壤质量作为生态安全及资源可持续利用的重要指标,对可持续发展有着重要意义,为了解宁夏中部干旱带土壤重金属污染及生态风险现状,本文采集5个县域共40个土壤样品,参照宁夏土壤背景值诊断土壤中Cu、Zn、Pb、Cr、Mn和Ni等6种重金属污染现状,采用单因子污染指数法及潜在生态风险指数法进行污染程度分析。结果表明:研究区域土壤重金属元素变异系数范围为:26.10%~59.72%,其中Zn、Pb、Mn含量高于宁夏土壤背景值;土壤重金属含量插值空间分布差异性明显,呈现斑块状;单因子污染指数的平均值由大到小为:Pb=Zn>Mn>Cr>Cu>Ni,土壤重金属处于轻度污染水平;研究区除Pb外,其他重金属元素生态风险程度均为轻微级别,处于低风险,Pb是最主要的潜在生态风险因子;综合计算6种重金属的RI值为78.70,研究区域生态风险程度为轻微等级。本文对宁夏中部干旱带重金属污染及生态风险状况的研究,促进发展绿色与可持续经济,为区域土壤质量优化提供决策参考。

As an important indicator of ecological security and sustainable utilization of resources,soil quality is of great significance for sustainable development.In order to understand the status of soil heavy metal pollution and ecological risk in the arid zone of central Ningxia,40 soil samples were collected from 5 counties,according to the background value of Ningxia soil,the pollution status of six heavy metals(Cu,Zn,Pb,Cr,Mn and Ni)in soil was diagnosed,and the pollution degree was analyzed by single factor pollution index method and potential ecological risk index method.The results showed that the coefficient of variation of heavy metal elements in the soil ranged from 26.10% to 59.72%,among which the contents of Zn,Pb and Mn were higher than the background value of Ningxia soil;the spatial distribution of heavy metal content in soil is different,showing patchy;the average value of single factor pollution index from large to small was Pb=Zn>Mn>Cr>Cu>Ni,and the soil heavy metals were in mild pollution In addition to Pb,the ecological risk of other heavy metals in the study area is low,and Pb is the main potential ecological risk factor;the RI value of the six heavy metals was 78.70,and the degree of ecological risk in the study area is slight.In order to promote the development of green and sustainable economy and provide decision-making reference for regional soil quality optimization,heavy metal pollution and ecological risk in the central arid zone of Ningxia were studied.