四川雷波磷矿区沉积物重金属污染特征研究

Pollution Characteristics of Heavy Metals in Sediments of Leibo Phosphate Mine Area,Sichuan Province

近几十年来,由于矿山开采造成的重金属污染问题日益突出,与之相关的环境案例屡见不鲜。该研究以过河拉达河在四川雷波上田坝磷矿区的水环境为研究对象,采集了矿区水和水系沉积物样品,测定了水化学指标和水系沉积物中砷、镉、钴、铬、汞、铜、锌、铅8种重金属浓度,采用地累积指数法和潜在生态危害指数法评价水系沉积物重金属污染程度和潜在生态风险。水化学分析表明研究区水体属于HCO_(3)^(-)-Mg^(2+)-Ca^(2+)型水,控制因素为岩石风化作用。地累积指数法分析表明As和Cd是研究区2种主要的重金属污染元素。潜在生态危害指数法评价表明As、Cd生态危害达很强级别,Hg生态危害中等,其他重金属生态危害轻微。重金属相关性研究表明As和Hg有较好的相关性。地累积指数和潜在生态危害空间分布均显示污染程度高和生态风险高值区域位于河流上游和中游。

In recent decades,environmental problems caused by mining have become increasingly prominent,and environmental cases of heavy metal pollution were common.In this study,the water environment of Guohelada River in Leibo Shangtianba phosphate mining area,Sichuan Province was studied.The water and water sediment samples were collected.The concentration of arsenic,cadmium,cobalt,chromium,mercury,copper,zinc and lead in water sediments was measured.The degree of heavy metal pollution and potential ecological risk were evaluated by the method of accumulation index and potential ecological hazard index.Hydrochemical analysis indicated that the water body was HCO_(3)^(-)-Mg^(2+)-Ca^(2+)type water,and the controlling factor was rock weathering.The geoaccumulation index indicated that the primary pollution was As and Cd.The evaluation of potential ecological hazard index method shows that As,Cd ecological hazard is very strong,Hg ecological hazard is medium,and other heavy metals ecological hazard is slight.The correlation between As and Hg showed good correlation.Both the geoaccumulation index and the spatial distribution of potential ecological hazards show that the areas with high pollution degree and high ecological risk are located in the upper and middle reaches of the river.