亚热带深水库沉积物-水界面磷释放受控因子的研究

A Study on the Limiting Factors for the Release of Phosphorus at the Sediment-Water Interface in the Shanzi Reservoir in Fujian Province

山仔水库是福建省福州市160万人口的第二饮用水源地,沉积物磷的释放影响着水库的水质。采用SMT法分析了山仔水库表层沉积物总磷含量在641.5～982.7kg·kg-1之间,铁/铝结合态磷和有机磷是沉积物磷的主要赋存形态,占总磷含量的70%～85%左右。采用正交实验,探讨了山仔水库3个不同断面沉积物-水界面磷释放的受控因素。结果表明,pH值对磷释放速率的影响最大,其次是溶解氧多少和温度的高低。碱性条件下沉积物释放磷强度大,厌氧条件下有利于沉积物中磷的释放,随着温度的升高,沉积物中磷的释放强度随之增大。从空间上看,各断面磷释放速率的差异不明显。本研究可为该水库内源污染的防治提供参考。

The Shanzi reservoir is one of the drinking water sources to provide 1.6 million people living in Fuzhou City, Fujian Province, China. Since phosphorus release from the sediments could be impact on water quality, the exchange potentials of phosphates at the water-sediment interface were investigated by the sediment sampling from three sections area. The analysis of total phosphorus, the form of the phosphorus and releasing rates under different conditions to the water column found that the content of total phosphorus in the surface sediment was in range of 641.5-982.7 kg ·kg^-1, while the aluminium/lron bounded phosphorus and the organic phosphorus were the preponderant forms in the surface sediment, which was about 70%-85% of the total phosphorus. The limiting factors for the release of phosphorus at the sediment-water interface were also examined using optimized synthesis method, and it shows that the pH value was the most important factor. In addition, the DO concentration and the temperature also affect on phosphorus releasing from the sediment to overlay water obviously. More phosphorus was released from the sediment to overlay water under the alkaline, anaerobic and higher temperature condition. However, the releasing rate of phosphorus from the sediment to overlay water at each section did not show a significant difference.