有机质对大型富营养化浅水湖泊沉积物磷吸附特征的影响

Effects of Organic Matter on Phosphorus Sorption Characteristics in Sediments of Large Eutrophic Shallow Lakes

以大型浅水湖泊(太湖和巢湖)为研究对象,系统分析了沉积物有机质(OM)含量和组成、磷吸附参数、磷形态及间隙水溶解反应性磷(SRP)浓度在水平方向上的分布。吸附解吸平衡浓度(EPC0)与SRP浓度的比较结果表明,在太湖北部与巢湖南淝河入湖口等污染较严重的区域,沉积物仍表现出吸附磷的功能;OM与土壤有效磷(Olsen-P)、磷吸附指数和碱性磷酸酶活性均显著正相关,有机质分解所产生的小分子物质可增加磷的吸附容量;添加小分子有机质的室内模拟试验进一步证实了上述假设,糖类主要影响磷的吸附能,而氨基酸主要增加最大吸附量。有机质自身及其降解产物以不同方式影响沉积物对磷的吸附能力,并据此调节湖泊富营养化过程。

Content and composition of sediment organic matter （OM）, phosphorus sorption parameters, phosphorus forms and the horizontal distribution of interstitial soluble reactive phosphorus （SRP） concentration were addressed systematically, targeting large shallow lakes（Lake Taihu and Lake Chaohu）. Comparison of equilibrium phosphorus concentration （EPC0） with SRP concentration results showed that comparatively seriously-polluted area including northern Lake Taihu and inlet of the Nanfei River to southern Lake Chaohu, sediments still had phosphorus-absorbing function. In addition, OM and Olsen-P, P adsorption index, alkaline phosphatase activity （APA） were significant positive correlation, so the small molecular substance produced by the decomposition of organic matter increased phosphorus adsorption capacity. The indoor simulation experiments of adding small molecular substance furtherly confirmed the above hypothesis. Carbohydrate mainly affected the phosphorus sorption energy, while amino acid mainly increased the maximum phosphorus sorption. In short, the organic matter itself and its degradation products affected the sediment phosphorus adsorption capacity in different ways, and accordingly adjusted the process of lake eutrophication.