Effects Of Fe And Al On Phosphorus Fractions,Transformation In The Sediments Of Lakes

A sequential extraction method was used to study the occurrence characteristics of lake sedimental phosphorus and discuss the influence of iron and aluminum on phosphorus content and occurrence characteristics in the sediments of lakes, which was in-depth analysed in different Lakes region (the Yunnan-Guizhou Plateau and the eastern plains of Lakes), different types of lakes (urban lakes, aquaculture lakes etc), especially in lakes of different eutrophication level. The results showed that the level of lake eutrophication were related to the content of phosphorus in lake sediments, the relationship between the phosphorus fractions and its content percentage and the level of lake eutrophication was more close. The higher eutrophication level of lakes was, the higher content percentage of readily releasable phosphorus was, and the lower content percentage of calcium phosphorus and residue phosphorus in the lake sediment was, while the lake sediments in low eutrophication level were the opposite. The average of total phosphorus content in the lake sediments of Yunnan-Guizhou Plateau Lakes (647.12～2102.68mg/kg) was more than the average of total phosphorus content in the lake sediments of eastern plains lakes (421.76-1432.80mg/kg), and the average of iron and aluminum content in the lake sediments of Yunnan-Guizhou Plateau Lakes was more than the lake sediments of eastern plains lakes. In the more severe eutrophic lakes, the content of total P was higher, also the content of iron and aluminum.Effects of the content of iron and aluminum on the content and distribution of different phosphorus fractions were not identical, in which Fe and Al had less effect on ion-exchangeable species, and the influence on the content and distribution of Fe-P and Al-P was greater. If Fe-P、 Al-P and BD-Fe had significant correlation was closely related with the degree of lake eutrophication, mainly because the release of phosphorus fraction sediments were partly adsorbed by iron and aluminum; however there was more influence of Fe、Al on the content and distribution of refractory phosphorus, refractory phosphorus had significant correlation with NaOH85-Fe and NaOH85-Al (P<0.01), which may be related to the formation mechanism of refractory phosphorus. TFe/TP, TA1/TP, Fe/P and Al/P may have regional characteristics, and the ratio range of Yunnan-Guizhou Plateau Lakes and the eastern lake area is different, the reasons may be lake sediments of different Lakes have greater difference in nature. But TFe/TP, TA1/P, Fe/P and Al/P of the lake sediments in different Lakes have similar regularity. TFe/TP、TA1/TP、Fe/P and Al/P may be associated with the level of eutrophication in the lakes, the smaller the ratios were, the higher the eutrophication level were.In addition, the higher content of iron and aluminum was, the stronger adsorption of phosphorus in lake sediments was, and then higher TFe/TP, TAl/TP, Fe/P and Al/P in lake sediments may indicate that phosphorus retention capacity of the lake was stronger.