南海湖沉积物重金属形态分布及其对水质影响的研究

Heavy Metals Speciation in Sediments and Effect on Water Quality in Nanhai Lake

通过对包头市南海湖沉积物中Cu、Pb、Zn、Cd的形态、AVS和SEM、上覆水、上覆过滤水及沉积物间隙水重金属的系统分析,结合南海湖为黄河新成牛轭湖的特点,与黄河进行了对比,研究了重金属在固、液两相间的迁移转化规律,结果表明南海湖与黄河沉积物中重金属的残渣态非常接近,反映了沉积的同源性,Pb和Cd次生相则明显在南海湖发生富集,上覆水中重金属81.0%以上均结合在悬浮物上,南海湖水质长期Cu超标的现象是由沉积物的释放造成的,研究证明间隙水为重金属向上覆水迁移起到桥梁通道作用;有机络合物的络合作用超过AVS的沉淀作用,是导致Cu向水相扩散迁移的主导因子。

The speciation of Cu, Pb, Zn and Cd in sediments and the concentrations of Cu, Pb, Zn and Cd in overlying water, filtered water and pore water of the Nanhai Lake , which is an abandoned channel of the Yellow River, are analyzed in this paper accompanied with the data of AVS （ Acid-Volatile Sulfide） and SEM （ Simultaneous Extract Metals） in sediments. The data are compared with those of the Yellow River due to the same origin of sediments between the Nanhai Lake and the Yellow River. The investigation was made for the movement and transformation law of heavy metal in solid-liquid two phase system. The results show that heavy metals concentration in residual fraction in Nanhai Lake is close to which in the Yellow River. Over 81.1% selected heavy metals are in suspended form in overlying water of the Nanhai Lake and the Yellow River. The high concentration of copper in Nanhai Lake＇s overly water is released from the sediments. The pore water functions as a pathway for heavy metal mobilization from sediments to water phase. The AVS is the controlling factor on heavy metal precipitation ; whereas, the organic complexing agent is the key factor on mobilization of Cu from sediments to water.