环境治理工程对蠡湖水体中磷空间分布的影响

为评估水环境治理工程措施对蠡湖水体营养状态的影响,2012年4月对湖体与环湖河口调查分析,研究了蠡湖磷元素空间分布特征及其影响因素.结果表明:蠡湖水体总磷浓度介于0.03~0.31mg/L之间,平均为0.06mg/L,呈由西向东逐渐递增的趋势,且环湖河口磷含量明显高于湖体;沉积物中总磷空间分布趋势类似于水体,湖体总磷含量在321.77~1062.08mg/kg之间,平均为593.75mg/kg,而环湖河口总磷含量在523.38~1396.39mg/kg之间,平均为784.51mg/kg;结合历年监测数据可以看出,一系列水环境治理工程使得蠡湖水质有了大幅度的改善,水体中总磷的年均值由治理前0.18mg/L下降到0.06mg/L,但仍没有完全从根本上解决水体的富营养化问题.主要原因是沉积物中总磷对水体影响较大,相关性分析表明磷的扩散通量与沉积物总磷和可交换态磷成显著正相关.

Influences of environmental governance project on spatial distribution of phosphorus in Lihu Lake

In order to evaluate the impact of the water environment governance project on the water quality in Lihu Lake, this paper studied on the spatial distribution of phosphorus and its influencing factors by an investigation in the Lihu Lake in April, 2012. The results showed that the TP contents in the water ranged from 0.03 to 0.31mg/L with the mean value of 0.06 mg/L, and increased from the west to the east. At the same time, TP in the estuaries was higher than that in the lake. The spatial distribution of TP in the sediments was similar to that in the water. The TP in the sediments in the lake ranged from 321.77 to 1062.08mg/kg with the mean value of 593.75mg/kg, the TP in the estuaries ranged from 523.38 to 1396.39 mg/kg with the mean value of 784.51mg/kg. The long-term monitoring data of water showed that the water quality had been substantially improved by a series of water treatment projects, the annual average of TP in water fell from 0.18mg/L down to 0.06mg/L after governance project. However, due to the internal loading of phosphorus the eutrophication is still the mean problems we are facing. Furthermore, the correlation analysis indicated that the diffusion flux of phosphorus was positively correlated with the TP and the exchangeable phosphorus in the sediments.