南京栖霞山铅锌矿地区土壤重金属污染评价

Evaluation of Heavy Metal Pollution in Soils from Nanjing Qixiashang Lead-Zinc Mines

针对不同的土地利用类型选用不同的采样方式和评价标准,对南京栖霞山铅锌矿地区土壤重金属污染特性和现状进行调查和评价。研究区主要土地利用类型有露天采矿区、菜地和风景区栖霞寺。露天采矿区和菜地土壤采用梅花布点采样方式,栖霞寺由于属于山地,采用随机布样方式;评价标准参考国家土壤环境质量标准(GB 15618—1995)的要求,对矿区和栖霞寺林区土壤采用土壤环境质量三级标准进行评价,对菜地土壤采用二级标准评价。调查分析结果表明,矿区、菜园和栖霞寺土壤中铅、砷、镉和锌等重金属污染严重,其部分土壤中存在铜的轻度污染,而未受铬污染;内梅罗综合污染指数评价结果均大于3,属于重度污染;污染严重区集中在选矿厂、矿口和坑道排风井口等周围,并且污染程度随着远离矿区而逐渐减小。

The characteristics and status of heavy metal contamination in soils from Nanjing Qixiashang lead-zinc mines were investigated and evaluated. Different sampling methods and evaluation criteria were selected for different soil types mainly from open mining area, vegetable field and scenic spot of Qixia Temple. The quincunx sampling mode was selected for the first two types of soils and the random sampling mode was used for soils at Qixia Temple. The national standards for soil environment quality （ GB 15618--1995 ） was used for the evaluation with the Grade I1 standard for vegetable field soil and the Grade Ⅲ standard for mining area and scenic spot soils. The survey results showed that the soils in the mine area, Qixia Temple and vegetable field were contaminated seriously by Pb, As, Cd and Zn, and the soils in some areas were also polluted by Cu slightly, but no contamination from Cr was found. The Nemerow （multi-factor comprehensive pollution） indexes were all greater than 3, indicating that these three types of soils were suffered from severe contamination, especially in the concentrating mill, mine outlet and tunnel exhaust port, and the pollution level was gradually declined with the distance increase from the mining area.