模拟水体pH控制条件下太湖梅梁湾沉积物中磷的释放特征  

Characteristic of phosphorus release with the control of pH of sediments from Meiliang Bay, Lake Taihu

作　　者：袁和忠[1,2] 沈吉[1] 刘恩峰[1] 孟祥华[3] 王建军[1] 

机构地区：[1]中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008 [2]中国科学院研究生院,北京100049 [3]济南大学城市发展学院,济南250022

出　　处：《湖泊科学》2009年第5期663-668,共6页Journal of Lake Sciences

基　　金：中国科学院知识创新工程重大项目(KZCX1-YW-14-5);国家重点基础研究发展计划(973)(2008CB418104);江苏省自然科学基金项目(BK2008055)联合资助

摘　　要：采用缓冲溶液控制水体pH值,模拟研究了太湖梅梁湾沉积物扰动悬浮状态下水体磷的释放规律(48h),分析了实验前后沉积物中磷的赋存形态组成及变化特征.结果表明,pH条件对沉积物磷释放具有显著影响,强酸性(pH=2.0)及碱性(pH=9.5,11.8)条件下皆利于磷的释放,但强酸性水体磷含量随时间逐渐降低,而碱性水体磷呈持续释放状态;中性条件(pH=7.2)磷的释放释放作用不明显.磷释放达到稳定状态(14h)后,碱性条件下(pH=9.5,11.8)磷释放量为酸性(pH=2.0,4.6)及中性(pH=7.2)条件下的4倍以上.通过对比释放前、后沉积物中磷的形态组成可知,酸性条件主要为钙结合态磷的释放;碱性条件主要是铁结合态磷释放,部分可发生再沉淀,转化为钙结合态磷.研究表明,梅梁湾沉积物中铁结合态磷的解析是沉积物磷的主要释放源,是水体内源磷增加的重要贡献者.The phosphorus stored in the sediments can be released into the overlying water, acting as internal source for lakes, pH is one of the important factors influencing phosphorus release. In this paper, phosphorus fractions and the effect ofpH on P release （48h） were investigated for the sediment from Meiliang Bay, Lake Taihu. The pH of the system was controlled with different buffer solutions. The release characteristics of phosphorus were influenced markedly by the pH condition. Specifically, acidity （pH=2.0） and alkalinity （pH=9.5, 11.8） conditions were more beneficial for phosphorus release than the neutral pH（pH=7.2） condition. The amount of phosphorus released from the sediments under alkalinity conditions （pH=9.5, 11.8） was about 4 folds than that in the acidity （pH=2.0, 4.6） and neutral condition when the release of phosphorus tended to be stable（14h）. There had been distinct difference for the phosphorus speciation in the sediments of different simulation system. With the analysis to the phosphorus speciation of sediments after release experiment, it can be concluded that acidic condition can enhance Ca-bound phosphorus release, whereas alkaline condition can promote the release of Fe-bound phosphorus significantly. Fe-bound phosphorus is the key form of phosphorus release in Meiliang Bay of Lake Taihu. pH value is an important mechanism of influencing phosphorus content and eutrophication.

关 键 词：沉积物 磷释放 磷形态 PH 太湖 

分 类 号：X524[环境科学与工程—环境工程]