天鹅湖潟湖表层沉积物磷的吸附容量及潜在释磷风险

Phosphorus Adsorption Capacity of Surface Sediments in Swan Lagoon and the Potential Risk of Phosphorus Release

研究了天鹅湖潟湖表层沉积物对磷的吸附容量,分析了沉积物磷吸附指数（PSI）、磷吸附饱和度（DPS）及由这两个指标构成的磷释放风险指数（ERI）,预测了不同区域沉积物磷的潜在释放风险。结果表明,沉积物的PSI变化范围为7.44~28.53 mg L/100 gμmol,湖北部和中部沉积物的PSI值较高;DPS与PSI的变化趋势相反,变幅为0.85%~4.99%,表现为湖南部和中部沉积物的DPS高于北部。沉积物的PSI与磷的理论吸附容量（Qmax）呈极显著正相关（P〈0.01）,而DPS与沉积物各理化参数间的相关性较差。有机质（OM）、活性铝（Alox）和粘粒是表层沉积物对磷持留的主要影响因素。此外,天鹅湖潟湖表层沉积物的ERI变化范围为2.93%~44.70%,磷释放诱发富营养化的风险处于中度范围,其中东南部发生富营养化的风险较高，

Phosphorus sorption capacity（Qmax）, phosphorus sorption index（PSI） and the degree of phosphorus saturation（DPS） of surface sediments in Swan Lagoon were determined in laboratory. In addition, phosphorus release risk index（ERI） of the sediments in different areas was investigated. The results showed that the PSI of the sediments ranged from 7.44 to 28.92 mg L/100 g μmol, which were relatively high in the northern and center sediments. However, DPS varied at the range of 0.85%-4.99% and higher in the southern and center than in the northern sediments. PSI had a significant positive correlation with Qmax（P〈0.01）, while DPS showed a poor correlation with physical-chemical properties of the sediments. Organic matter, clay and active aluminum extracted by ammonium oxalate（Alox） were the main effect factors of phosphate adsorption. ERI ranged from 2.93% to 44.70%. The results indicated that Swan Lagoon, especially in the Southeast region, might be in a moderate potential eutrophication risk due to phosphorus release from surface sediments.