渔溪河流域重金属采选污染调查与来源初步分析

Investigation and preliminary source tracing analyses for a small contaminated river basin caused by non-ferrous metal mining activities

有色金属采选矿区污染往往呈现历时长、污染重、污染面积大、环境介质复杂等特征。为了解某小流域重金属污染的状况和成因，对该区域重金属污染的潜在来源进行了初步调查分析。结果表明，流域内有色金属采选活动造成河道、农田、地表水、地下水重金属污染，其中As、Pb、Sb、Zn是重点防控的元素。流域潜在污染源有13个，其中长城岭矿及周边区域、废弃冶炼厂及周边地下泉水、下涟选场尾矿及周边区域是最主要的显性污染源。流域重金属污染来源复杂，包括尾矿砂释放、矿石淋溶、矿坑水、矿井水、地下泉水等点源和面源，其中青头江、下涟两个区域对流域下游河水Sb浓度的贡献分别达到约60％～75％和15％～20％。区域历史遗留面源污染问题突出，河流底泥、沿岸尾矿砂冲积物等污染贡献度很难定量，针对河流水体采取的应急工程措施难以完全解决流域Sb浓度升高问题。

Non-ferrous metal mining areas were often seriously contaminated in a long history,large areas,and multi-environmental media. To understand the current status of heavy metal contamination and sources,we investiga ted the small river basin where mining activities kept for a long time. The results showed that the mining activities had caused metal contaminations in rivers, farmlands, surface water and groundwater, within which As, Pb, Sb and Zn were the dominant pollutants. There were thirteen potential metal pollution sources,among which the Changchengling mine,groundwater and spring around the junction of Qingtoujiang River and Yuxi River,and the tailings and the surrounding area of Xialian were the most important explicit sources. Sources of heavy metal pollution in the river basin were complex,including many point and non-point sources, such as tailings, abandoned ores, mining water,groundwater and spring. The areas of Qingtoujiang and Xialian contributed about 60% -75% and 15%- 20% to the Sb concentration in the downstream water,respectively. Since the historical non-point pollution was serious in the region and it was difficult to quantify the Sh contributions of sediments and tailings,the emergency responding measures focusing on the surface water may not be able to solve the problem of increasing Sb concentration thoroughly.