Study on Phosphorus Release Characteristics and Influencing Factors in Sediments of Different Ecological Types
To investigate the phosphorus(P)release characteristics and influencing factors of sediments from three differ-ent ecological types,black-odor river(BO-S),algal lakes(A-S)and macrophytic lakes(M-S),physical and chemical characterization,as well as release kinetics model were employed.In addition,the effects and mechanisms of anions(CO32-,SO42-,NO3-,HCO3-and Cl-)and dissolved organic matter(fulvic acid and humic acid)on the P release characteristics of the three types of sediments were explored.The results show that the three types of sediments exhibited distinct different P release patterns.BO-S and A-S sediments primarily released soluble reactive P(SRP),accounting for 56.00%and 57.14%of the total release contents,respectively,while M-S sediments predominantly released dissolved or-ganic P(DOP),which accounted for as much as81.40%of the total release contents.Both anions and dissolved organic matter facilitated the release of P from sediments.Anions,particularly CO32-,were the most effective in promoting the re-lease of SRP.Compared to the control group,a concentration of 10 mmol·L-1 of CO32-led to an average increase of 39.2 times in the maximum release of SRP.Dissolved organic matter,particularly humic acid,mainly promoted the release of DOP.At a concentration of 100 mg·L-1,humic acid caused an average increase of 56.3 times in the maximum release of DOP from sediments compared with the control group.Furthermore,the changes in the content of metal-bound P in sedi-ments before and after P release indicated that anions and dissolved organic matter primarily promoted P release by compe-ting for P adsorption sites on metal oxides.
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