小兴凯湖表层沉积物的理化特征和磷吸附效率研究

Physical and Chemical Characteristic and Phosphorus Adsorption Efficiency of Surface Sediment in Xiaoxingkai Lake

在小兴凯湖设置了12个采样点,2018年9月11~13日,在各采样点,采集表层(0~5 cm深度)沉积物样品;2018年5月12日、7月13日、9月11日和10月11日,在各采样点,采集湖水样品;测定表层沉积物样品和湖水样品的理化指标,计算出表层沉积物的磷吸附效率;分析水体理化指标对表层沉积物理化特征和磷吸附效率的影响。研究结果表明,小兴凯湖水体中的总磷和总氮含量符合地表水Ⅳ类水域标准,水体中的化学需氧量含量符合地表水Ⅴ类水域标准;水体中总铁离子含量较大,是地表可饮用水铁含量的2.87倍;各采样点表层沉积物中全磷和全氮含量都较大,东北泡子采样点表层沉积物中的全氮和全磷含量尤其偏大;表层沉积物中铁离子和铝离子含量较大,表层沉积物粒径组成主要以粉粒为主;冗余分析结果表明,表层沉积物的磷吸附效率分别与表层沉积物中黏粒所占比例、粉粒所占比例、有机质含量、铁离子含量、铝离子含量正相关,与砂粒所占比例负相关;大量富铁地下水排入小兴凯湖中,促进了其表层沉积物的磷吸附作用。

12 sampling sites were set in Xiaoxingkai Lake.Surface sediment samples(0-5 cm depth)were collected on September 11-13,2018.Water samples were collected during May 12,July 13,September 11 and October 11,2018,respectively.The physical and chemical indexes of surface sediment and water samples were determined,and the phosphorus adsorption efficiencies of surface sediment were calculated.The results showed that the contents of total phosphorus and total nitrogen in the water of Xiaoxingkai Lake conformed to the surface water standard of IV,and the content of chemical oxygen demand conformed to the surface water standard of V.The total iron content in the water of Xiaoxingkai Lake was larger,which was 2.87 times the iron concentration of surface drinking water.The contents of total phosphorus and total nitrogen in the surface sediments at each sampling site were larger,especially in the site of Dongbeipaozi.The contents of ferric ion and aluminium ion in the sediment were larger,and the particle size composition was mainly powder particles.Redundant analysis results showed that the phosphorus adsorption efficiency of surface sediments was positively correlated with the proportion of clay and powder particles,the content of organic matter,the content of ferric ion and aluminium ion,and negatively correlated with the proportion of sand.The discharge of a large amount of iron rich groundwater promoted the phosphorus adsorption of the surface sediments in Xiaoxingkai Lake,formed co-precipitation with organic matter and phosphate,and accumulated on the surface of the sediments.