阳山金矿安坝矿段农用地土壤重金属污染评价及来源分析

Pollution assessment and source analysis of heavy metals in agricultural soils of Anba ore section in Yangshan gold deposit

目的:以安坝矿段为例,调查阳山金矿开采前周边农用地土壤重金属As、Cd、Hg、Pb污染情况。方法:采集表层土样80件,垂向土样15件,研究重金属含量变化趋势。运用多种分析方法对表层土壤重金属污染情况进行评价;结合相关性分析及前人地球化学研究成果,分析重金属的来源;结果:As、Cd、Hg、Pb元素平均值分别为陇南市平均值的3.80、1.13、1.12、1.87倍,As分布受人为活动影响最大,属轻度污染;As表现为偏中度累积,Hg和Pb也出现一定的富集,研究区为中等潜在生态危害等级。结论:地表为重金属最集中区,重金属污染可能出现了垂向扩散。As、Hg和Pb主要来源于金矿盗采和平硐建设,也受交通运输的影响,Cd主要来自土壤母质。意义:为后期矿山建设开发提供依据。

Purpose:The pollution caused by heavy metals including As、Cd、Hg and Pb in the agricultural soils around the Yangshan gold deposit has been investigated,and the Anba ore section was taken as an example in this paper.Method:We have collected 80 topsoil and 15 vertical soil samples,combined using multiple methods to make the pollution assessment.Based on correlation analyses and previous geochemical results,the heavy metals sources and their vertical variations have been determined.Result:The average of As,Cd,Hg,and Pb concentrations is larger than that in the Longnan city.The As distributions are mainly influenced by human activities and belong to low-degree pollution.The As shows moderate accumulation.The Hg and Pb also display a certain degree of enrichment.The potential ecological hazard grade in the study area is medium.Conclusion:The shallow surface contains highly heavy metals,and their pollution may have diffused to the deeper depth.The As,Hg,and Pb were mainly derived from illegal gold mining and Pingdong construction,which were also influenced by transportation,whereas the Cd was mainly came from the soil materials.Significance:That can provide the basis for later mine construction and development.