环境因子对杭州西湖沉积物各形态磷释放的影响

对西湖沉积物的磷形态、粒径组成、化学组成进行了分析, 模拟研究了上覆水磷含量、光照、pH、温度、水动力条件等不同环境因子对西湖沉积物各形态磷释放的影响。结果表明, 上覆水为蒸馏水时的最大释磷量约为底泥-湖水系统的1.15倍, 且释放形态均以IP中的Fe/Al-P为主。在蔽光条件下的最大TP释放量约为光照条件下最大TP释放量的1.35倍。pH 是影响磷释放的重要因素, 在碱性条件下, 促进Fe/Al-P的释放; 在酸性条件下, 促进Ca-P 的释放。在高温条件下沉积物的释磷量会高于低温条件下的释磷量。沉积物各形态磷的释放量在15h后逐渐趋于平衡扰动状态达到平衡时TP释放量是静态释放平衡状态的1.61倍。研究结果旨在探讨不同环境因子对湖泊沉积物磷迁移转化的生态环境效应, 预测西湖内源磷释放的发展趋势, 为控制沉积物内源污染提供理论基础。

EFFECTS OF VARYING ENVIRONMENTAL CONDITIONS ON RELEASE OF SEDIMENT PHOSPHORUS IN WEST LAKE,HANG ZHOU,CHINA

To understand the eco-environment effects of varying environmental factors on the transportation and transformation of sediments P and the development of West Lake sediments P release, we analyzed phosphorus (P) fractions, grain size and chemical composition of sediments in West Lake, and investigated the influence of varying environmental conditions including P concentration in overlying water, light, pH, temperature and disturbing on the release of sediment P. The results indicated that the largest release quantity of sediment total phosphorus (TP) in the distilled water was 1.15 times compared with that in sediment-water system, and the main P form were P bound to Al, Fe, and Mn oxides and oxyhydroxides (Fe/Al-P) of inorganic phosphorus (IP). The greatest release quantity of TP under no light was almost 1.35 times larger than that under illumination condition. The pH value was an important factor for the release of P from sediments, and alkaline condition promoted the Fe/Al-P release and acid condition promoted the Calcium bound phosphorus (Ca-P) release. High temperature promoted sediment P release. Various P fractions content in the sediment gradually gained equilibrium in the condition of disturbing intensity after 15h. Sediment P release amount under equilibrium disturbing condition was about 1.61 times compared with that under static equilibrium. This study provides theoretical basis for the control of internal pollution caused by sediment P release.