锁磷剂对杭州西湖底泥磷释放的控制效果

Efficacy of Phoslock~ on the Reduction of Sediment Phosphorus Release in West Lake,Hangzhou,China

为探索杭州西湖高有机质底泥内源磷释放的控制技术,分别于春、夏、冬这3个季节采集西湖8个湖区的原状泥柱,进行室内磷释放过程连续培养,研究锁磷剂Phoslock对底泥磷释放通量的控制效果.结果发现,西湖底泥冬、春季磷释放通量较小,全湖平均分别为0.13 mg·(m^2·d)^(-1)和0.29 mg·(m^2·d)^(-1),而夏季则大幅度增高,全湖平均释放通量为3.29mg·(m^2·d)^(-1),每日全湖释放磷可达23.7 kg(以P计);空间上,磷释放通量受底泥有机质含量控制,底泥有机质污染重的湖区总体上磷释放通量大,而与底泥磷含量及有效态磷含量关系不大;投加630 g·m^(-2)的锁磷剂能够有效控制西湖底泥磷释放,在3个季节所有点位,均能将上覆水磷含量控制在0.010 mg·L^(-1)以下,夏季磷释放通量大的时期,锁磷剂的控磷效果达98%.本研究结果表明,即便对于高有机质含量、"香灰土"特征的西湖沉积物,锁磷剂的控磷效果也比较好.在西湖富营养化治理工程中,可以考虑在局部湖湾投放应用.

Famous as the world cultural heritage,West Lake in Hangzhou city has plenty of soft sediments with high organic matter content.To search the countermeasures for internal phosphorus release reduction from the sediment,the sediment core incubation was conducted to understand the efficacy of Phoslock~ on internal phosphorus release in spring,summer and winter,respectively.The results showed that the internal phosphorus release fluxes in winter and spring were relatively low,with averaged values in the entire lake of 0.13 mg·（m^2·d）^-1and 0.29 mg·（m^2·d）^-1,respectively,while the release flux was 3.29 mg·（m^2·d）^-1in summer,more than ten times higher than those in spring and winter.It was estimated that 23.7 kg of phosphorus could be released from sediment in the entire lake every day in summer.Spatially,the phosphorus release flux was related to organic matter contents in sediments,but not the phosphorus or bioavailable phosphorus contents in sediments in West Lake.With Phoslock~ added at the rate of 630 g·m^（-2）,sediment phosphorus release was successfully controlled,which reduced the phosphorus concentration in the lake water to less than0.010 mg·L^-1.Especially during summer time,the sediment phosphorus release was reduced by 98% after Phoslock~ application.The research suggested that Phoslock~ is powerful for phosphorus control even for sediments with high organic matter content,which could be considered in ecological restoration of WEst Lake.