洪湖沉积物内源污染及其氮磷释放特征

为研究洪湖沉积物污染特征及内源营养盐释放规律，在不同季节对洪湖13个沉积物采样点进行调查，并利用柱状沉积物采样器原位采集沉积物开展静态模拟释放试验. 结果表明:①洪湖沉积物有机质、总氮和总磷含量的平均值分别为19%、4 407.4 mg/kg和1421.0 mg/kg，内源污染严重；②洪湖沉积物污染可能是水体中氮磷营养盐的重要来源之一，在5 d的静态释放模拟试验中，夏季上覆水中总氮和总磷平均浓度分别升高1.467和0.042 mg/L，冬季分别升高0.224和0.036 mg/L；③洪湖沉积物中氮磷的释放表现出显著的时空差异，夏季洪湖沉积物总氮、总磷的平均释放速率分别为133.9和4.0 mg/(m2·d)，冬季分别为32.1和3.4 mg/(m2·d)；④根据试验结果估算，洪湖沉积物氮的释放潜力为3 500~14 000 t/a，磷的释放潜力为350~400 t/a. 研究显示，在控制流域外源污染输入和减少湖区面源污染的同时，应从根本上改善洪湖水质并重塑洪湖湿地生态系统结构与功能，在科学指导下采取远近结合的方式分区域在洪湖开展受污染沉积物的修复工作. 

Sediment Endogenous Pollution and Release Characteristics of Honghu Lake

In order to investigate the sediment pollution characteristics and nutrient release from the sediments in Honghu Lake, 13 sediment samples were investigated in different seasons, and static simulation experiments were carried out using in-situ column sediment samplers. The results showed that the average contents of organic matter, total nitrogen (TN) and total phosphorus (TP) in Honghu sediments were 19%, 4,407.4 mg/kg and 1,421.0 mg/kg, respectively, indicating that the endogenous pollution of Honghu Lake could not be ignored. In the 5-day static release simulation experiment, the average concentrations of TN and TP in the overlying water increased by 1.467 and 0.042 mg/L in summer, and 0.224 and 0.036 mg/L in winter. The average release rates of TN and TP from sediments were 133.9 and 4.0 mg/(m2·d) in summer, and 32.1 and 3.4 mg/(m2·d) in winter, respectively. According to the experimental results, the N release potential from sediments in Honghu Lake was calculated to be 3,500-14,000 t/a, and P release potential was 350-400 t/a. Therefore, while controlling the input of external pollution and reducing the non-point source pollution, the sediments in the highly polluted area should be restored under scientific guidance.