疏浚及水生植被重建对太湖西五里湖表层沉积物中磷、氮含量及形态分布的影响

Influence of Dredging and Aquatic Macrophytes Reestablishment on the Forms of Phosphorus,Nitrogen in the Sediments of the West Wuli Hu,Taihu Lake

以太湖西五里湖为研究对象,研究了环保疏浚区、环保疏浚并水生植被重建示范区、退渔还湖区及对照区沉积物中磷、氮的含量及其不同形态的分布特征,同时分析了水质状况。结果表明,沉积物中总磷平均含量为486.54mg·kg-1,低于治理工程实施前,其中铁磷和钙磷的含量较高,闭蓄态磷、铝磷次之,不稳定性磷含量最低。总氮平均含量为1018mg·kg-1,铵态氮含量变化趋势与总氮一致,硝态氮含量较低。环保疏浚区总磷、总氮含量相对较高,疏浚的长期效果需要进一步研究,而环保疏浚并水生植被重建示范区沉积物中不同形态磷、氮含量均比环保疏浚区低,水体透明度高,水质恢复较好。在减少外源污染的前提下,对湖区底泥进行环保疏浚并开展水生植被恢复工程有可能是控制湖泊富营养化的有效途径。

Dredging, environmental dredging and aquatic macrophytes reestablishment were carried out in the West Wuli Hu of Taihu Lake. The water quality parameters, total phosphorous and nitrogen, as well as different forms of phosphorus and nitrogen in the sediments of different areas were investigated to examine the effects of different treatment measures. The results showed that, the average content of total phosphorus was 486.54 mg·kg^-1, Fe-P and Ca-P took up the largest proportion in the total phosphorus, followed by Oc-P, Al-P and Lab-P. The average content of total nitrogen was 1 018 mg·kg^-1, the content of NH4^＋-N changed similarly to the total nirtogen, and the content of NO3^--N was low. In the area of environmental dredging plus macrophytes reestablishment, the content of different forms of phosphorus and nitrogen in the sediments were lower than that in the only environmental dredging area, with the better water quality. It was suggested that the effective way to control lake eutrophication may be reestablishing aquatic macrophytes in the environmental dredging area as well as decreasing external source pollution.