太湖梅梁湾沉积物中磷吸附／解吸平衡特征的季节性变化

Seasonal changes of P adsorption/desorption characteristics at the water-sediment interface in Meiliang Bay,Taihu Lake,China

室内模拟研究了太湖梅梁湾4个季节沉积物在低磷湖水中的吸附/解吸特征,推测沉积物在各季节的"源"、"汇"转化过程,找出沉积物"源"、"汇"转化过程中最活跃的磷形态;同时通过对冬季沉积物进行不同温度的吸附/解吸热力学实验,探讨了温度对沉积物吸附/解吸磷过程的影响.研究结果表明:梅梁湾4个季节沉积物总磷及各组分磷含量大小关系为春<夏<冬<秋;夏季和秋季沉积物以释放为主,春季和冬季则以吸附为主;铁/铝磷是沉积物"源"、"汇"转化过程中较活跃的磷组分;沉积物对磷的吸附效率和平衡吸附量为春季最小,秋季最大;温度和沉积物磷含量对DIP吸附/解吸平衡浓度都有影响,吸附/解吸平衡浓度随温度的升高而增加,随沉积物磷含量的增加而减小.

Seasonal changes of phosphorus adsorption/desorption were investigated by collecting overlying water and seasonal sediment samples from Meiliang Bay, Taihu Lake, China. The data were analyzed to determine the function change of sediment as “Source” and “Sink” in the different seasons. At the same time, seasonal changes of TP and P fractions＇concentration at the beginning and the end of the adsorption experiment were also carried out to find the most active P fraction in this process. The effects of temperature on the P translocation process were also measured and are discussed. The following conclusions were obtained ： The sequence of concentrations of TP and phosphorus fractions in the different seasons was Cspring 〈 Csummer 〈 CAutuma 〈 Cwintor ; Compared with P concentrations of overlying water in the corresponding season, desorption is the major translocation process for P in summer and autumn, while adsorption is the major translocation process for P in spring and winter. NaOH-P is the most active fraction in the adsorption/desorption process. Adsorption efficiency is lowest in the spring, but highest in the autumn. Temperature and P concentration in sediment have significant effects on the adsorption/desorption equilibrium. The adsorption/desorption equilibrium concentration increased with rising temperature, and decreased as the P concentration of sediment declined.