水生植被恢复对城市景观水体磷浓度及沉积物磷形态的影响

以上海市两个水生植被恢复时间为5—10年的城市景观水体为研究对象,通过分析水体理化性质以及水和沉积物磷的含量和形态,研究水生植被恢复对富营养化水体修复的长期生态效应.结果表明,水生植被恢复能有效降低水体氮、磷浓度,对水体富营养化有明显的改善作用.在外源磷的污染源得到控制后,水体磷浓度会随着修复时间的增加而逐渐降低并相对稳定.沉积物磷形态以钙磷为主,随着水生植被恢复时间的增加,生物活性较强的可交换态磷、铝磷和铁磷的含量下降,而相对稳定的钙磷所占的比例增加.研究结果还表明,即使不进行底泥疏浚,长期的水生植被恢复也可以使城市河流沉积物中内源磷释放及水体磷浓度得到有效控制.

Effects of aquatic vegetation rehabilitation on phosphorus in water and sediments of urban landscape waters

The paper was conducted to investigate the long term effects of aquatic vegetation rehabilitation on phosphorus in eutrophicated urban landscape waters. The results indicated that aquatic vegetation rehabilitation could effectively reduce the level of nitrogen and phosphorus in water and the eutrophication. With the control of external source, phosphorus concentration in water decreased till it reached a relatively stable state. By analysis of P fraction, Ca-P was found to be the main fraction in sediment and increased while the ratios of Ex-P, Al-P and Fe-P, which are considered more bioavailable than Ca-P, decreased with vegetation rehabilitation time. It's also indicated that long term aquatic vegetation rehabilitation was possible to effectively immobilize internal sediment P and reduce its release to water in Caoyang River, even without dredging activity.