巢湖及其入湖河流表层沉积物营养盐和粒度的分布及其关系研究

Distribution and Correlation of Nutrients and Particle Size in Surface Sediments of Lake Chaohu and Its Inflow Rivers

为识别巢湖及其入湖河流的主要污染特征及其来源,测定了巢湖及其入湖河流34个采样点表层沉积物总氮(TN)、总磷(TP)、无机磷(IP)、有机磷(OP)及有机质(OM)浓度,分析了TN、TP、IP、OP、OM浓度及粒度分布间的相关性。结果表明,巢湖西半湖区沉积物营养盐浓度明显高于东半湖区,巢湖中部沉积物营养盐浓度明显偏低。南淝河沉积物营养盐浓度明显高于其他入湖河流,并在流经合肥市的下游处达到最高值。相关性研究表明,沉积物中TOC与TN,TN与OM,TP与IP表现出显著相关性,表明沉积物中氮主要以有机氮的形态存在,与有机氮相比,沉积物中无机氮浓度相对恒定,沉积物中磷主要以无机磷的形态存在;TN与TP、IP也表现出显著相关性,表明沉积物中氮磷来源具有同源性。随着沉积物粒径的增大,沉积物粒径与TOC、TN、TP、IP的相关性变差。

In order to identify the main pollution sources and characteristics of Lake Chaohu and its inflow rivers, contents of total nitrogen （TN）, total phosphorus （TP）, inorganic phosphorus （IP）, organic phosphorus （OP） and organic matter （OM） of 34 surface sediments samples were determined, and the correlation of TN, TP, IP, OP, OM and particle size distribution also analyzed separately. The results showed that the nutrients content of sediments in the west part of Lake Chaohu was significantly higher than that of the east part, and the nutrients content of sediments in the middle part was strikingly low. The nutrients content of Nanfei River sediments was much higher than that of other inflow rivers, and reached its peak down the river which flowed through the Hefei City. Furthermore, it was founded that the contents between TOC and TN, TN and OM, TP and IP of sediments were significantly correlated, which indicated that organic nitrogen and inorganic phosphorus were the main fractions of TN and TP respectively, and content of inorganic nitrogen remained relatively constant comparing with organic nitrogen. However, TN was significantly correlated with TP and IP, indicating the homology betweennitrogen and phosphorus of sediments. The results of sediment particle size analysis also showed that the correlation between sediment particle size and TOC, TN, TP, IP became less significant with the increase of the particle size.