基于文献计量的关中地区农田土壤重金属污染特征及源解析

Characteristics of heavy metal pollution and source analysis in farmland soil of Guanzhong area based on bibliometric analysis

掌握关中地区农田土壤重金属污染特征和来源,对推进区域土壤环境风险管控、提升土壤环境管理水平具有重要意义。利用大量的文献检索数据,借助地累积指数法、潜在生态风险指数法和PMF源解析模型探究了关中地区农田土壤重金属的分布特征、污染程度、生态风险和可能来源。结果表明,关中地区农田土壤中8种重金属元素超过农用地土壤污染风险筛选值的比率,从高到低依次为Cd(43.3%)、Zn(13.7%)、Cu(10.9%)、Ni(8.1%)、Pb(7.2%)、As(6.1%)、Hg(5.4%)、Cr(4.0%)。Cd污染最重,部分地区达到重污染程度,Pb、Cu、Zn的污染程度次之,同时,Cd、Hg的生态风险最大,中风险以上的点位中Cd占76.51%,Hg占90.18%。PMF源解析模型计算结果表明,土壤中Cd污染主要来源于工业排放及农业活动,Hg污染主要来源于采金提炼和化石燃料燃烧,矿产资源开采和冶炼对土壤中Pb、Zn的富集影响较大,As、Cr在土壤中的累积与污水灌溉、化肥农药使用等农业活动有关,土壤中的Ni来源于成土母质。

To understand the characteristics and sources of heavy metal pollution in farmland soil in Guanzhong area is of great significance for promoting regional soil environmental risk control and improving the level of soil environmental management.After collected massive documents data,were explored the distribution characteristics,pollution degree,ecological risk and possible sources of heavy metals in the study area farmland soil by means of land accumulation index method,potential ecological risk index method and PMF source analysis model.The results showed that:From high to low,the proportion of soil samples exceeding the risk screening values of agricultural land was Cd(43.3%),Zn(13.7%),Cu(10.9%),Ni(8.1%),Pb(7.2%),As(6.1%),Hg(5.4%),Cr(4.0%).Among the heavy metal elements,The areas with Cd pollution was the most serious,and some areas reach the level of heavy pollution,followed by Pb,Cu and Zn.At the same time,with Cd accounted for 76.51%and Hg accounted for 90.18%,at the point above medium risk.The calculation results of PMF source analysis model showed that,in the soil,Cd pollution mainly comes from industrial emissions and agricultural activities,while Hg pollution mainly comes from gold extraction and fossil fuel combustion,the mining and smelting of mineral resources had a great impact on the enrichment of Pb and Zn in soil.The accumulation of As and Cr in soil was related to agricultural activities such as sewage irrigation,fertilizer and pesticide use,Ni in soil were derived from soil forming parent materials.