庐江废弃明矾石矿土壤重金属形态特征及生态危害评价

Morphological characteristics and ecological risk assessment of soil heavy metals in Lujiang alumite mine

对庐江明矾石矿区选择排土场废石和冶炼废渣堆废渣中重金属(Cu、Zn、As、Cd)总量和形态分布进行探究,并用Hakanson潜在生态危害指数法评价其对环境的影响。结果表明,冶炼废渣堆土壤中的各重金属总量均高于排土场,并且As的含量是国家二级标准值的5.8倍;基于总量的Hakanson潜在生态风险评价结果表明,废石废渣重金属的潜在生态危害指数(RI)分别为1579.05和2022.25,均属于很强生态危害程度,另外,Cd对RI的贡献率均最大,分别占总量的97%和84%,其次为As。排土场和冶炼废渣堆土壤重金属的形态分布特征既有相似性又有差异性。各重金属均以残余态为主,含量在50%以上;废石中Cu的可交换态和碳酸盐结合态的比例占整体的11.11%,对矿区危害性较高,其余重金属对矿区存在低风险性危害。

The contents and distribution of heavy metals(Cu,Zn,As,Cd)in the waste rock of waste soil and smelting waste residue in Lujiang alunite mining area were studied.The Hakanson potential ecological hazard index method was used to evaluate the environmental impact.The results showed that the total amount of heavy metals in smelting slag heap was higher than that in refuse dump,and the content of As was the national secondary standard value of 5.8 times.The Hakanson potential ecological risk assessment results showed that the potential ecological hazard index(RI)of heavy metals in waste rock and the smelting slag was 1579.05 and 2022.25 respectively,belonging to the strong ecological hazard degree.In addition,the contribution rate of Cd to RI was the highest,accounting for 97%and 84%of the total,and it was followed by As.The distribution characteristics of heavy metals in soils of refuse dump and smelting slag heap were similar and different.The heavy metals mainly existed with residual form,content in more than 50%,and the proportion of Cu exchangeable and carbonate-bound in the waste rock accounted for 11.11%of the whole,which was highly harmful to the mining area.The rest of heavy metals had low risk.