大宝山矿区污染水体中重金属的形态分布及迁移转化

Speciation Distribution and Transfer of Heavy Metals in Contaminated Stream Waters around Dabaoshan Mine

对受广东大宝山矿区矿山废水排放污染的横石河水体中的过滤水、悬浮物和沉积物中重金属的污染分布特征及其迁移转化进行了系统地研究。结果表明:该水体的环境污染是以Cu,Zn,Cd和Pb则为主的多金属复合污染,综合污染指数(PI)为2 23～18 11,重金属Cu,Zn,Cd和Pb的溶解态质量浓度分别达13 82,50 83,0 103和2 91mg L;Cu,Zn,Cd和Pb的溶解态、悬浮态及总量沿河流断面呈相似的空间分布规律,而As则略有不同,但都是沿水流方向逐渐降低的;由于受低pH的影响,水体中As主要以细微颗粒物悬浮态为迁移载体,而Cu,Zn,Cd和Pb则以水溶态为主要迁移方式;沉积物中5种重金属元素都以残渣态为主要存在形态,Cd和Pb的可交换态及Cu和Zn的有机态含量很高,说明这4种元素对环境都有一定的潜在威胁性。

The chemical speciation and transfer of heavy metals in water, suspensate and sediments of the Hengshi River with acid mine drainage from Dabaoshan Mine, Guangdong province, were characterized systemically. The results showed that the environmental problem in the water system was Cu, Zn, Cd and Pb related multi-metal pollution. The pollution index (PI) of heavy metals was 2.23～18.11. The levels of water soluble Cu, Zn, Cd and Pb were found as high as 13.82, 50.83, 0.103 and 2.91 mg/L, respectively. Water-soluble, suspensate and total concentrations of Cu, Zn, Cd and Pb, which decreased gradually along the river, have the similar spatial distribution, while As has a little difference. Because of low pH value, fine-grained particles were major fractions for transportation of As, while water-soluble forms were for Cu, Zn, Cd and Pb. Through chemical speciation analysis, the residual speciation was the major species for those five metals in sediments. And the exchangeable speciation of Cd and Pb and organic speciation of Cu and Zn were also relatively high which indicated that they all have potential risk to environment.