污染水体沉积物营养盐释放过程

RELEASE PROCESSES OF NUTRIENTS FROM THE SEDIMENT UNDER CONTAMINATED WATER BODIES

通过实验室模拟试验,以富营养化湖泊-乌梁素海沉积物为试验材料,模拟了在零外源污染状态下沉积物中营养盐的释放特征,揭示了沉积物中TN、TP的释放规律和过程,量化了营养盐的释放速率.试验结果显示,在无扰动的静态水力条件下,沉积物中营养盐在向上覆水体的释放过程中,伴随着解吸-平衡的动态过程,其中TP的释放量是调控水体富营养化程度的主要因素.通过各种途径淡化污染水体,可以在短时间内降低污染水体中TN和TP的浓度,但沉积物中污染物在短时间内难以得到迅速的消减,且逐渐向上覆水体释放,会在一定程度上较长时间地影响上覆水体的水质.

A laboratory test was carried out on modelling the release processes of nutrients from the sediment of contaminated water bodies.The sediment was sampled from Lake Wuliangsuhai,which had been highly eutrophicated.The work revealed the release processes and characteristic nutrients from the sediment,and quantified the release rates.The results showed that at static state of water bodies the release processes were accompanied by dynamic transport processes.TP was the key element in controlling the eutrophication level of the water bodies.As a result,although dilution could decrease the concentrations of TN and TP in the water bodies within a short period of time,the comtamintants in the sediment would be difficult to eliminate quickly.They would be gradually released into the water bodies and affect the water quality for quite a long time.