渭河沉积物中Cd释放的实验研究

沉积物中Ｃｄ释放浓度与沉积物污染浓度之间存在正相关关系，新污染沉积物较老化沉积物中的Ｃｄ更易于释放，达释放平衡所需时间更短。Ｃｄ释放浓度与悬浮沉积物浓度呈正比，吸附时的悬浮沉积物浓度和吸附平衡时的液相Ｃｄ浓度分别对应着释放时的平衡悬浮沉积物浓度和Ｃｄ的最大平衡释放浓度。重金属释放与沉积物厚度的关系实质上是与间隙水中重金属垂向浓度梯度的关系，一般水体沉积物中重金属释放的有效厚度为５ｃｍ左右，本文实验

Experimental study on Cd release from the sediment of Wei River

The concentration of Cd released from the sediment of Wei River is in direct proportion to that ofthe polluted sediment. Cd is released more easily from newly polluted sediment than from ageing sediment, and the time to reach release equilibrium is much shorter. The concentration of Cd released is alsoproportional to that of suspended sediment. The concentration of the suspended sediment and the adsorption equilibrium concentration of Cd during its adsorbing course are corresponding to the equilibrium concentrations of the suspended sediment and of Cd maximal released respectively during the releasing coures.The relationship between the heavy metal release and the sediment depth is in essince the relationship between the former and the vertical concentration gradient of 'heavy metal in the interstitial water. The effective sediment depth is about 5 cm for heavy metal released from general aquatic sediments, and under theexperimental condition of this paper, the depth is about 4 cm.