工矿企业周边土壤重金属含量预测研究

Prediction Study of Heavy Metal Content in the Soil around Industrial and Mining Enterprises

为了明确工矿企业周边土壤重金属污染程度及其含量变化,配合土壤监测与有效治理,降低其对人体健康的威胁,本文以宁夏某工矿企业周边土壤为研究对象,采用土壤淋溶试验和土壤环境容量模型,对土壤中5种重金属(Pb、Hg、Cd、Cr和As)的纵向迁移特征及含量变化趋势展开研究。结果表明,该企业周边土壤的重金属纵向迁移能力排序为Cr>Cd>Hg>As>Pb,Cr具有强溶性形态和较强的迁移能力;企业开始运营后,周边土壤中重金属含量明显增加,超过该区域土壤本底值。Hg和Cd含量增长较快,而Cr的残留率较低;2020年前,厂区周边Hg、Cd、Cr和As的点位超标率从未达到100%,但现在已经达到这一水平;厂区周边土壤中Pb含量的增长率不高,但Pb在表层土壤中富集,97%的点位Pb含量已超过宁夏背景值。因此,企业生产对厂区周边的污染影响较大。未来,该企业要推进清洁生产,强化环境监测和治理,完善厂区绿化,以减少周边土壤重金属污染。

In order to clarify the pollution degree and content changes of heavy metals in the soil around industrial and mining enterprises,cooperate with soil monitoring and effective treatment,and reduce its threat to human health,this paper takes the soil around a certain industrial and mining enterprise in Ningxia as the research object,uses soil leaching experiments and soil environmental capacity models to study the vertical migration characteristics and content change trends of five heavy metals(Pb,Hg,Cd,Cr,and As)in the soil.The results show that the vertical migration ability of heavy metals in the surrounding soil of the enterprise is ranked as Cr>Cd>Hg>As>Pb,and Cr has a strongly soluble form and strong migration ability;after the enterprise starts operating,the heavy metal content in the surrounding soil significantly increases,exceeding the background value of the soil in the region.The content of Hg and Cd increases rapidly,while the residual rate of Cr is relatively low;before 2020,the point exceeding rate of Hg,Cd,Cr,and As around the factory area never reached 100%,but now it has reached this level;the growth rate of Pb content in the soil around the factory area is not high,but Pb is enriched in the surface soil,and the Pb content in 97%of the points has exceeded the background value of Ningxia.Therefore,the production of enterprises has a significant impact on the pollution around the factory area.In the future,the enterprise will promote clean production,strengthen environmental monitoring and treatment,improve greening in the factory area,and reduce heavy metal pollution in the surrounding soil.