The Application of Sequential Extraction in Phosphorus Fractionation in Environmental Samples

Background: Maintaining the balance of phosphorus in ecosystems is a priority activity in environmental protection. To achieve this successfully, it is necessary to know the physicochemical properties of phosphorus forms. Objective: Speciation analysis is used for this purpose. This process helps to assess the concentration of various physical and chemical forms of phosphorus. When there are very unstable chemical forms of the analyte hindering the determination in the environmental test, fractionation is performed, i.e., the process of classifying the analyte or a group of analytes from a given sample according to physical properties. Methods and Results: The paper discusses the phosphorus fractionation methods in environmental samples. The authors critically analyzed over a dozen phosphorus fractionation procedures using sequential extraction of this element. Particular attention was paid to the possibility of sequential extraction when determining the phosphorus pool available to plants (bioavailable fraction) and labile phosphorus able to migrate in the environment. The paper discusses examples of phosphorus fractionation in various environmental matrices, such as river and lake sediments, sewage sludge, composts, and soils. The selection of an appropriate method for the studied environment was made. Conclusions: Adapting the proposed methodology to the environmental matrix being tested determines the most accurate results of the experiment. Attention was also paid to the possibilities of practical applications of fractionation results, particularly the possibility of isolating phosphorus available for plants from various environmental matrices.