Distribution and release characteristics of phosphorus in water-sediment interface of Lake Dianchi

The distribution status and release characteristics of phosphorus were investigated by studying the lease kinetics characteristics and phosphorus forms from thirty-five sediment samples collected in Lake Dianchi. Results indicated that: The rank order of phosphorus contents in the surface sediment of Lake Dianchi was organic P( OP)( 1482. 49 ± 1156. 82 mg / kg) calcium-bound P( Ca-P)( 865. 54 ± 558. 40 mg / kg) metal oxide-bound P( Al-P)( 463. 77 ± 662. 18 mg / kg) residual P( Res-P)( 218. 52 ±83. 11 mg / kg) Fe-bound P( Fe-P)( 128. 13 ± 101. 56 mg / kg) weakly absorded P( NH4Cl-P)( 2. 26 ± 3. 05 mg / kg); The amount of total phosphorus in overlying water exceed V class in Caohai and between Class Ⅳ and Class Ⅴ in other sections. The amount of particulate P( PP) is the highest among total phosphorus( TP); The process of phosphate release from the surface sediment to the water in Lake Dianchi mainly occurred in the first 8 h and the kinetics were divided into the rapid-stage and the slowstage. The rank order of mean values of maximal phosphorus adsorption rate( Vmax),maximal phosphours adsorption capacities( Qmax),the release potential of sedimentary phosphorus( IDE-P) were Caohai northern coast southern coast lake center;From the correlation parameters,phosphorus release can be inferred to obtain the contribution degree of different forms of phosphorus on release potential of phosphorus in the sediments of Lake Dianchi. Therefore,the evaluation of sediment phosphorus releaserisk should not be only limited to the analyse of the basic physical and chemical properties. Great attention should be paid to the contents of different forms of phosphorus content and their proportions of total phosphorus.