Christophoridis Christophoros, Fytianos Konstantinos
Environmental Pollution Control Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece.
J Environ Qual. 2006 May 31;35(4):1181-92. doi: 10.2134/jeq2005.0213. Print 2006 Jul-Aug.
Laboratory studies were conducted to determine the effect of pH and redox conditions, as well as the effect of Fe, Mn, Ca, Al, and organic matter, on the release of ortho-phosphates in lake sediments taken from Lakes Koronia and Volvi (Northern Greece). Results were evaluated in combination with experiments to determine P fractionation in the sediment. The study revealed the major effect of redox potential and pH on the release of P from lake sediments. Both lakes showed increased release rates under reductive conditions and high pH values. The fractionation experiments revealed increased mobility of the reductive P fraction as well as of the NaOH-P fraction, indicating participation of both fractions in the overall release of sediment-bound P, depending on the prevailing environmental conditions. The results were assessed in combination with the release patterns of Fe, Mn, Ca, Al, and organic matter, enabling the identification of more specific processes of P release for each lake. The basic release patterns included the redox induced reductive dissolution of P-bearing metal oxides and the competitive exchange of phosphate anions with OH- at high pH values. The formation of an oxidized surface microlayer under oxic conditions acted as a protective film, preventing further P release from the sediments of Lake Volvi, while sediments from Lake Koronia exhibited a continuous and increased tendency to release P under various physicochemical conditions, acting as a constant source of internal P loading.
开展了实验室研究，以确定pH值和氧化还原条件以及铁、锰、钙、铝和有机物对取自希腊北部科罗尼亚湖和沃尔维湖的湖泊沉积物中正磷酸盐释放的影响。结合沉积物中磷分级实验对结果进行了评估。该研究揭示了氧化还原电位和pH值对湖泊沉积物中磷释放的主要影响。在还原条件和高pH值下，两个湖泊的磷释放速率均有所增加。分级实验表明，还原性磷组分和氢氧化钠磷组分的迁移率增加，这表明这两个组分在沉积物结合磷的总体释放中均有参与，具体取决于当时的环境条件。结合铁、锰、钙、铝和有机物的释放模式对结果进行了评估，从而能够确定每个湖泊更具体的磷释放过程。基本释放模式包括氧化还原诱导的含磷金属氧化物的还原溶解以及在高pH值下磷酸根阴离子与氢氧根离子的竞争性交换。在有氧条件下形成的氧化表面微层起到了保护膜的作用，阻止了沃尔维湖沉积物中磷的进一步释放，而科罗尼亚湖的沉积物在各种物理化学条件下都表现出持续且增加的磷释放趋势，成为内部磷负荷的持续来源。
