粤北某废弃矿区排土场土壤重金属污染评价

Evaluation of Heavy Metals Pollution in Soil of Dump in a Abandoned Mining Area,Northern Guangdong

研究矿区废弃排土场土壤重金属分布及污染状况可为矿区污染整治和生态恢复提供科学依据。通过测定粤北某废弃矿区排土场土壤中Cr、Cd、Pb、Hg、As共5种重金属元素的含量,应用地质累积指数法和潜在生态危险指数法对排土场风化土壤污染状况进行分析与评价。结果表明,As-Cr、As-Cd呈正相关关系,有机质与Hg、As、Cr、Pb呈正相关关系,具有统计学差异。Cd污染地质累积指数达到了偏中度污染水平,Hg为无污染水平,Cr、Pb为极重污染水平,重金属污染程度由高到低排序为Cr>Pb>As>Cd>Hg;就潜在生态危险单项指数而言,各研究区Pb均达到极重度潜在生态危险水平,Hg、Cr、As达到轻度潜在生态危险水平,Cd达到偏重潜在生态危险水平,潜在生态危险强弱顺序为Pb>Cd>As>Hg>Cr,两种方法的污染分析与评价结果基本一致。该研究区主要污染物为Pb,对环境的污染最为严重,应加强对Pb污染的预防与治理。

Studying the distribution and pollution of heavy metals in the soil of dump in abandoned mining areas can provide scientific basis for pollution control and ecological restoration. Via measuring 5 heavy mental elements, such as Cr, Cd, Pb, Hg and As in abandoned mining areas of Northern Guang- dong, the pollution condition of dump weathering soil were analyzed and evaluated by geoaccumulation in- dex and potential ecological risk index. Results show that the relationships between As-Cr and As-Cd were positive correlation, and the positive correlation relationships were found among the organic matter and Hg, As, Cr, Pb with significant difference in statistics. In terms of geo-accumulation index, Cd reached moderate pollution level, Hg appeared no pollution, Cr and Pb were heavy pollution level. The order of pollution level among the elements was Cr 〉 Pb 〉 As 〉 Cd 〉 Hg. In terms of potential ecological risk in- dex, Pb reached most severe potential ecological risk level, Cd appeared the more serious level, Hg, Cr and As were in lower ecological risk level in every research area. The potential ecological risk index fol- lowed the order of Pb 〉 Cd 〉 As 〉 Hg 〉 Cr. The analysis and evaluation results of the soil pollution were consistent using two indexes. The main heavy metal pollutant in the research areas was Pb, which made the most severe pollution on environment. Therefore, the prevention and control of Pb pollution should be strengthened in the mining area.