The Development Of Phosphorus Speciation Reference Materials In Lake Sediments And Study Of Environmental Geochemical Behavior Of Phosphorus

Eutrophication is the important environmental problem on the world, it considers that eutrophication have close relationship with the concentration of phosphorus and nitrogen and their concentration ratio in water. As phosphorus is one restrictive factor, accurately determination for phosphorus is the key problem, Reference materials are to guarantee the accuracy of the results, and developed high-level phosphorus speciation reference materials of lake sediments are significative for control eutrophication. Because if we control the phosphorus input from outside source, the phosphorus in sediments are mainly source, but there are not phosphorus speciation reference materials of lake sediments in domestic.This paper is mainly studied phosphorus in sediments from three aspects:1. Discussing the classification of phosphorus in sediments, there are divided into five ones:Easy exchange state or weak sorption state phosphorus, Fe-P, Al-P, Ca-P, occluded phosphate, organic phosphorus. Easy exchange state or weak sorption state phosphorus are totally absorbed by organism, Fe-P, Al-P and partial organic phosphorus are potential absorbed by organism, Ca-P and occluded phosphate are not absorbed by organism;2. Developing two reference materials candidate refer to BCR684which was developed by SMT, the collection points are Tai lake and Dong ting lake, broken samples in order to99.90%samples pass200mesh. According to JJG1006-1994and ISO GUIDE35we did the homogeneity and stability test, several laboratories collaboration and uncertainty calculation. Certified values parameters are total phosphorus, inorganic phosphorus, organic phosphorus, apatite phosphorus, non-apatite phosphorus, determined methods used colorimetry and ICP-OES, and moreover we used BCR684as the quality control. The results indicated homogeneity and stability well, certified values reliable, uncertainty reasonable. These reference materials are the first phosphorus speciation reference materials of lake sediments in China and filled the gaps at home.3. Study on phosphorus release, adsorption kinetic and isothermal adsorption in sediments of Dongting lake and Tai lake were made. The results indicated sediments release phosphorus quickly in a few hours before, within24h could level off. Dongting lake is higher than the sediment of Tai lake, because there are more Fe-P and Org-P in sediment of Dongting lake. Phosphate adsorption kinetic results were fitted to Elovich equation, and basically reach the state of dynamic balance after12h. adsorption isotherms curves were fitted to Langmuir equation, the values of Qm and MBC of Dongting lake are higher than the Tai lake, but the values of K is lower than the Tai lake sediment.