Phosphorus Speciation and Distribution in Sediments and the Relationship with Total Phosphorus in the Overlying Water

Abstract

ABSTRACT:To study phosphorus (P) speciation and distribution in lake water and sediments, and the relationship with total P (TP) in the overlying water, the concentration of different forms of P in lake water and sediments was determined. Samples were collected from Xuanwu and Dong Lakes. The results indicated that the concentration of P in sediments was largely influenced by human processes, vegetation, hydraulic conditions, and geographic settings. The inorganic P (iP) content was much higher than the organic P (oP) content, while naoh-extractable P (naoh-P) was the main inorganic P fraction, accounting for 40-50% of iP. The hcl-extractable P (hcl-P: calcium (ca) bound P) content was low but stable, because ca bound P was not easily adsorbed. The TP content of lake water and sediments were positively correlated, as was naoh-P and apatite P (aP), while there was no obvious correlation between the TP content of lake water and oP and hcl-P. This suggests that labile P accounted for most of the exchange capacity of P at the water-sediment interface. The results indicated that the content of P in lake-bottom sediments was closely related to the concentration in lake water, providing a theoretical basis for the treatment of eutrophic water bodies with regard to the internal P loading.