Speciation and Release Mechanism of Phosphorus in Sediments and Analysis Methods for Sequential Extraction

This article introduces the concept of chemical speciation analysis, the current status about eutrophication in China and the relationship between nitrogen and phosphorus in eutrophication. It considers that eutrophication has a close relationship with the concentration of phosphorus and nitrogen and their concentration ratio in water. If eutrophication occurs in one lake, the concentration of nitrogen and phosphorus are very high, but are not a fixed value, but rather in a relatively broad range. Moreover, the ratio of phosphorus and nitrogen is almost between 10-20. As the important accumulation reservoir of phosphorus in lakes, phosphorus in sediments is the main source of endogenous phosphorus, a small amount of stable phosphorus changed into reactive phosphorus could cause lake eutrophication .Therefore, the article discusses the classification and relationship between various speciations of phosphorus and the mechanism of phosphorus on eutrophication in sediments. It analyzes the four phosphorus extractale methods used by the European Commission when they developed the phosphorus reference materials in sediments: namely, the Williams method, Hieltjes-Lijklema method, Ruttenberg method and Golterman method. It summarizes the domestic and foreign scholars applied extractable method and determination method about phosphorus in sediments. The domestic scholars application methods are based on the foreign scholars used methods, expounding the geochemical significance of sequential extraction methods. Also reviewed are the release mechanism of phosphorus in sediments. Establishing sediments-phosphorus in water migration, circulation and transformation model which have great significance has been proposed because it could solve the problem of eutrophication fundamentally.