Phosphorus Sorption Capacity of the Surfical Sediment in the Dongping Lake and Risk Assessment of Potential Phosphorus Release

Phosphorus sorption capacity of the surface sediments are estimated by the phosphorus sorption index(PSI)and the degree of phosphorus saturation(DPS)of the sediments in the Dongping Lake,China.And the risk of potential phosphorus release was also investigated.The results showed that the phosphorus sorption index ranged from 30.3 to 45.2(mgP·(100g)-1)·(μmol·L-1)-1,increasing gradually from the mid-lake and the east to the north and the south of the lake.However,the variation tendency of the degree of phosphorus saturation (DPS)was exactly opposite,ranging from 6.9% to 24.7%.The phosphorus sorption index was very significantly and positively correlated to iron(FeOX)and summation of iron and aluminum extracted from sediment by ammonium oxalate.The degree of phosphorus saturation was significantly and positively correlated to phosphorus(POX)extracted from sediment by ammonium oxalate.And iron extracted from sediment by ammonium oxalate might be played a major role in adsorbing phosphorus.Additionally,the results showed that the phosphorus release risk index(ERI)ranged from 15.9% to 69.3%.The results of the phosphorus release risk index indicated that the Dongping Lake might be in high potential eutrophication risk due to the release of phosphorus from the surfacial sediments.