Pollution Characterization And Risk Assessment Of Heavy Metal At An Antimony Smelting Site

China is the first country with a large reserve of antimony(Sb),accounting for more than 50% of the total in the world.Long-term of antimony smelting activities have led to soil antimony-arsenic compound pollution.Based on the special hydrogeological conditions of smelting sites,rapid identification of soil heavy metal contamination levels and accurate characterization of heavy metal contamination are prerequisites for effective soil heavy metal pollution prevention and control.This paper takes a typical antimony smelting site in Hunan as the research object.Portable X-ray fluorescence(rapid measurement technology)and inductively coupled plasma mass spectrometry method were used to analyze the heavy metals content in the soils at the smelting site.The applicability of portable X-ray fluorescence(PXRF)in the rapid detection of heavy metal content at the smelting site has been performed.The spatial distribution characteristics of heavy metal pollution at the antimony smelting site have been assessed.The ecological and human health risks of heavy metals contaminating the soil were evaluated to provide a scientific basis for the remediation and risk control of soil heavy metal pollution at the antimony smelting site.The research results were presented as following:(1)PXRF is applicable to the rapid detection of heavy metals in soils in an antimony smelting sites.By comparing the heavy metal content based on PXRF and ICP-OES analysis,there were certain correlations between Sb,As,Pb,Zn,Cu,and Ni.Soil moisture and particle size significantly influenced the results of PXRF analysis of heavy metals,and the airdrying/sieving treatment was more favorable to the accuracy of PXRF analysis of heavy metals content in the soil.In addition,the organic matter content also had some influence on the analysis of heavy metals content in the soils.(2)Heavy metal contamination at an antimony smelting site was dominated by antimony and arsenic,with high ecological health risks.The heavy metal content in soil was decreasing following the order: Sb > As >Pb > Zn > Cu > Ni.The pollution level decreased with increasing soil depth.Applying the enrichment factor(EF),geo-accumulation index(Igeo),and contamination factor(CF)assessment revealed that the degree of soil heavy metal contamination was in the following order: As > Sb > Pb > Zn >Ni > Cu.The potential ecological risk index(RI)results indicated that Sb was a serious ecological risk,As was a medium ecological risk,and Cu,Ni Pb,and Zn were classified as low ecological risk.In addition,noncarcinogenic risk revealed that As,Pb,and Sb posed health risks for children;for carcinogenic risk,the risk values for As and Ni were higher than the limit values for both children and adults,implying a high carcinogenic risk in the study.(3)Soil heterogeneity at antimony smelting sites is high,and Sb and As mainly originate from human activities.From Pearson analysis,As,Cu,Ni,Pb,Sb,and Zn have strong correlation coefficients(p≤0.01);there is a slight correlation between Cu-Zn and Ni-Sb(p≤0.05).The PCA and PMF analysis results show that Sb,As,and Pb pollution are influenced by human activities and high background value soils.High geological background soils mainly influenced Cu,Ni,and Zn.18 Figures,21 Tables,and 212 References...