铅和镉在实验室水环境模拟体系中的分布特征研究

选取长春市南湖作为采样地点,通过建立实验室水环境模拟体系(包括人工培养生物膜、沉积物和水)模拟自然条件下铅和镉的分布特征。研究结果显示:重金属进入到水环境之后,其浓度持续下降,Langmu ir动力学方程可以很好地描述其在水相中的变化规律。重金属在沉积物和生物膜中富集。生物膜对外界金属浓度变化的灵敏度高于沉积物。当水相中的重金属浓度降低到一个较小值时,生物膜中富集的重金属会被部分释放出来,通过水相,最终转移到沉积物中。沉积物对重金属的富集作用持续时间较长,富集速率较慢。水相、生物膜、沉积物三者共同作用,影响着重金属在自然水体中的分布规律。不同金属的分布过程变化趋势相似,但也存在一定差异。

Distribution of Pb and Cd in a Simulated Aquatic System

Nanhu Lake was selected as the sampling point. Lab systems were built to simulate the distribution and fate of Pb and Cd in natural water system. Results indicated that: after certain amounts of Pb and Cd were added in to the systems, the concentrations of Pb and Cd were decreased and could be described via Langmuir kinetic equation. Pb and Cd were enriched in solid materials. When the concentration of Pb and Cd in water dropped to a low value, Pb and Cd enriched in biofilms would be release to water. Pb and Cd would be finally enriched in sediment. The fate of heavy metals in natural system was affected by interactions among water, biofilms and sediment. The fate of different heavy metals was similar and had certain diversity.