喀斯特山地废弃矿区土壤重金属污染评价

Study on heavy metals pollution assessment method of soil around a wasted mining in Karst mountain area

为探究喀斯特山地废弃矿区土壤重金属污染情况及不同评价方法之间的差异,以贵州某废弃矿区周边土壤为研究对象,采用原子荧光光度计及电感耦合等离子体-原子发射光谱仪分别检测土样中As、Cd、Cr、Cu、Pb和Zn的含量。运用潜在生态风险指数法、模糊数学评价法和污染负荷指数法对研究区土壤重金属的污染情况进行评价。结果显示,研究区土壤中6种重金属元素均存在不同程度的污染,不同评价方法皆指出Cd的污染等级较高,表明Cd是研究区土壤污染的主要贡献因子。运用潜在生态风险指数及模糊数学归一化运算法进行评价,研究区土壤受多种重金属元素污染,且达到强等级综合污染水平,运用综合负荷指数法评价为无污染。不同方法之间的评价结果存在较大差异,潜在生态风险评价具有较高的灵敏性,更适于生态环境高度异质的喀斯特山地废弃矿区土壤重金属污染评价。

In order to compare the discrepancy of different evaluation methods on heavy metals pollution in Karst mountainous area,soil samples were taken around a waste mining area in the west of Guizhou province.The contents of heavy metals in soil were tested by using atomic fluorescence spectrometer(AFS)and inductively coupled plasma(ICP).The pollution of heavy metals in soils were evaluated by using potential ecological risk index method(RI),Fuzzy mathematics(FM)and pollution load index(PLI).The results showed that the soils in the study area have been polluted by concerned six heavy metals to certain degrees.All evaluation methods indicated that Cd presented a high pollution level and it was the main contributor to the soil pollution in the study area.According to potential ecological risk index and fuzzy mathematics normalization algorithm evaluation,the soil in the study area was polluted by multiple heavy metals,reaching a strong comprehensive pollution level.However,results from the comprehensive load and index method suggested that the study area was pollution-free.Clearly,the evaluation results of different methods are quite different.The potential ecological risk index is more sensible and it can be better used to assess the soil heavy metals pollution in Karst areas.