广东大宝山矿区横石河沿岸水土重金属分布规律及其累积风险

The distribution regularity and accumulation risk of heavy metals in water and soil along the Hengshi River in the Dabaoshan mining area, Guangdong Province

研究矿业活动重金属的释放、迁移及累积特征对于控制和治理矿区水土环境污染具有重要的意义。本文通过广东大宝山矿区水土污染源调查及横石河流域沿岸水土样品采集,以研究区土壤对照值及国家环境质量为标准,试图探讨了大宝山矿区重金属迁移及累积特征。研究结果表明,横石河沿岸土壤重金属元素主要来自采矿活动的酸性废水的排放,土壤中Cd、Pb、Cu和Zn的含量均超过对照值,呈现出明显的累积特征,且Cd、Cu含量超过了国家土壤环境质量标准;土壤中重金属累积程度及其风险等级呈现出从源头向下游递减的特点,其中凉桥、水楼下地段农田重金属处于高风险区,阳河—莲心村虽有累积,但无风险;上坝村地处土壤重金属累积的中风险区,下坝村处于低风险区。研究结果为矿区重金属污染防治提供了重要依据。

The study of the release,migration and accumulation characteristics of heavy metals by mining activities is of important sig-nificance for the prevention and control of environmental pollution of soil and water in the mining area. In this paper, through collec-tion of soil and water samples along the Hengshi River during the survey of Dabaoshan mining pollution and with the soil control val-ues of the study area and the national environment quality as the evaluation standard, the authors studied migration and accumulation characteristics of heavy metals in the Dabaoshan mining area. The result shows that the soil heavy metal elements along the Hengshi River mainly come from mining activities of acid waste water emissions, the concentrations of soil Cd, Pb, Cu and Zn are higher than the local control values, showing obvious accumulation characteristics, with Cd, Cu content exceeding the national standard of soil environmental quality. Heavy metal accumulation in soil and its level of risk degree show decreasing characteristics from the source to the downstream area. Liangqiao Village and Shuilouxia Village are areas of high risk in soil heavy metals;Yanghe River-Li-anxin Village area has no risk in spite of some accumulation of heavy metals;Shangba Village is located in medium risk zone of the ac-cumulation of soil heavy metals;Xiaba Village is located in low risk zone. The research results provide an important basis for the pre-vention and control of heavy metal pollution in mining areas.