不同生态类型沉积物磷释放特征及影响因素研究

    Study on Phosphorus Release Characteristics and Influencing Factors in Sediments of Different Ecological Types

    • 摘要: 为探究黑臭河道(BO-S)、藻型湖泊(A-S)和草型湖泊(M-S)3种不同生态类型沉积物磷释放特征及其影响因素, 通过物化表征、释放动力学模型等方法分析3种沉积物理化性质方面的差异, 并探究阴离子(CO32-、SO42-、NO3-、HCO3-和Cl-)和溶解性有机质(富里酸和胡敏酸)对3种沉积物磷释放特征的影响及其机理。结果表明, 3种沉积物呈现不同的磷释放特征, BO-S和A-S沉积物主要释放可溶性活性磷(SRP), 其占比分别为56.00%和57.14%, 而M-S沉积物主要释放溶解性有机磷(DOP), 其占比高达81.40%。阴离子和溶解性有机质均能促进沉积物磷的释放, 阴离子主要促进SRP的释放, 其中CO32-的促进能力最强, 与对照组相比, 浓度为10 mmol·L-1时CO32-使3种沉积物SRP最大释放量平均增加39.2倍; 而溶解性有机质主要促进DOP的释放, 其中胡敏酸的促进能力较强, 与对照组相比, 浓度为100 mg·L-1时胡敏酸使3种沉积物DOP最大释放量平均增加56.3倍。此外, 磷释放前后沉积物中金属结合态磷含量的变化显示阴离子和溶解性有机质主要通过竞争沉积物金属氧化物中的磷吸附位点促进磷的释放。

       

      Abstract: To investigate the phosphorus (P) release characteristics and influencing factors of sediments from three different 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 organic P (DOP), which accounted for as much as 81.40% 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 release 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 sediments before and after P release indicated that anions and dissolved organic matter primarily promoted P release by competing for P adsorption sites on metal oxides.

       

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