title: [Mechanism of phosphorus adsorption and immobility by sediments in innercity heavily polluted canal].
abstract: The mechanisms of phosphorus (P) adsorption and immobility were investigated in laboratory experiments. The sediments and waters used were taken from an inner-city heavily polluted canal. Addition of KH2PO4 into the operated experimental units, with and without (i.e., static) intermittent sediment resuspension, were made similar to the external P input and carried out periodically. The results show that the amount of the accumulative P adsorption onto the sediments was up to 363.4 mg x kg(-1) under the conditions of sediment disturbance over a 39-day period, and it was evidently higher than that (213.2 mg x kg(-1)) under static conditions. Sequential fractionation indicated that most of the incorporated P was accounted for in the Fe/Al-P. There were over 61% in the case of intermittent sediment disturbance and up to 83% in the case of static conditions. Based on the bioavailability of Fe/Al-P, 40.6% of the incorporated P was accounted for in non-occluded Fe/Al-P of the sediments under intermittent sediment disturbance conditions. This value increased to 59.5% under static conditions. In addition, more than 23% of the incorporated P was accounted for in HCl-P of the sediments under intermittent sediment disturbance conditions, on the other hand, the concentration of HCl-P kept relatively constant under static conditions. After 39 d of P adsorption by the both sediments, the values of the maximum sorption capacity (S(max)) decreased,while zero equilibrium P concentration (EPC0) and P saturation P(%) increased. However, the extent of EPC0 and P% under intermittent sediment disturbance conditions was obviously lower than that under static conditions. It was hopefully suggested that intermittent sediment disturbance can not only accelerate the P adsorption but also enhance the P retention by sediments.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Da-Peng
authors.initials: DP
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Yan
authors.initials: Y
authors.lastname: Yuan
authors.forename: Cheng-Xin
authors.initials: CX
authors.lastname: Fan
mesh_terms: D000327:Adsorption; D002681:China; D002947:Cities; D019015:Geologic Sediments / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus