环境条件变化对瓦埠湖沉积物磷释放的影响

Effects of Environmental Factor on Phosphorus Release from Sediments in Wabuhu Lake

拟议中的“引江济淮”调水工程涉及到长江、淮河两大河流,瓦埠湖为其中的一个重要湖泊,其水质是否受到调水的影响为该工程关注的环境问题之一。分析了外界环境因子变化对瓦埠湖底泥在不同环境条件下以及干、湿沉积物样品磷释放的差异,环境因子分别选取了不同磷浓度的上覆水、光照、pH、温度、DO、微生物、水体扰动等。结果表明:湿样释磷能力明显高于风干样品;上覆水体磷的浓度对底泥释磷能力有较强的调节作用;光照对底泥释磷影响不明显,但温度对底泥的释磷有较明显的影响,磷的最大释放量与之呈正相关;水动力条件的改变可在短期内使底泥达到最高的释放量,而DO、pH的改变也可不同程度地增加底泥的释磷能力。综合瓦埠湖底泥的释磷特征与湖泊水文状况,认为调水工程使得底泥释磷的地球化学行为较易实现。

The recommended project of diversion of water from Changjiang River to Huaihe River is a water allocation programe which involve both Changjiang River and Huaihe River. Water quality of Wabuhu Lake is one of the attentive environment problem of the project. The paper analyze the difference of phosphorus release between dried and fresh sediment from Wahuhu Lake, discusses the effects of environmental conditions（P concentration of overlaying water,illumination, pH, temperature, DO, microorganism and disturbance） on the experiment of P release. The results are showed that：the capability of P release in fresh sediment was obvious than of dried sediments;the P concentration of overlaying water has stronger function to adjust the P release of sediments;the effect of illumination to P release of sediments is not obvious;high temperature profits sediment P released to water,and the maximum is concerned with the increase of temperature; the amount of sediment P released can get the maximum rapidly under the stirring condition ;the changes of DO and pH increase the capability of P released in various degree. The character of sediment P released and the hydrology of the Wabuhu Lake make the geochemistric behavior of P release realize easily for the project of diversion of water.