滇池沉积物中磷的释放行为研究

滇池分为草海和外海两个水体,且草海污染较外海严重,但是外海的藻类爆发的频率和强度都高于草海。通过实验室模拟,研究了滇池草海与外海沉积物中磷的释放行为及其藻类爆发程度不同的原因。结果表明,两个沉积物中磷的释放动力学都表现了非单一的扩散过程,拟二级动力学模型可以较好描述释放过程。草海比外海总磷高7倍,但是在水中的释放只高2倍。对两个沉积物而言,由于与表面附着的磷有竞争作用,溶解胡敏酸的加入都显著增大了磷的释放。与草海相比,外海的水交换速率慢、水深浅、沉积物有机质含量低、内源磷释放强以及对外源磷缓冲能力弱,这些特征都是有利于藻类爆发的条件。研究表明抑制滇池藻类爆发要同时考虑对外源磷和内源磷的控制。

Release Behavior of Phosphate in Dianchi Sediment

Dianchi Lake,Yunnan Province is divided into Caohai and Waihai,and Caohai pollution is more serious while algae bloom occurs more frequent in Waihai. Results of simulation indicated that phosphate release kinetics could be better described by pseudo-second order kinetic model. TP concentration in Caohai sediment is 7 times higher than Waihai,but phosphate release in water is only 2 times higher. Because of the competition between phosphate and dissolved humic acid, the presence of DHA significantly increased phosphate release for both sediments. Slower water exchange rate,shallower water body,lower organic content,higher release of phosphate and lower buffering ability of Waihai are primary reasons for its frequent algae blooming. The study indicated that both inner and outer sources of phosphate should be controlled in order to control algae bloom in Dianchi Lake.