宜兴市横山水库底泥内源污染及释放特征

为弄清宜兴市横山水库底泥内源污染及释放特征，对水库典型断面进行采样分析.结果表明，横山水库表层沉积物中的总氮、总磷和有机质的平均含量分别为2778 mg·kg^-1、899 mg·kg^-1和3.1%，内源污染严重，且水库下游沉积物的污染程度高于水库上游.磷形态分析结果表明，铁结合态磷（Fe-P）和铝结合磷（Al-P）是沉积物中的主要结合态磷，分别占总磷的质量分数为28%和39%.底泥活性磷（弱吸附态磷、有机磷以及铁磷之和）平均含量为255 mg·kg^-1，占总磷的质量分数为38%.底泥氮磷平均释放速率分别为18.0 mg·（m²·d）^-1和0.60 mg·（m²·d）^-1.相关性分析结果表明，沉积物有机质含量与磷酸根、氨氮、二价铁的扩散释放通量相关性显著（P<0.05），说明沉积物中有机质的矿化可能是底泥氮磷释放的主要影响因素.

Endogenous Pollution and Release Characteristics of Bottom Sediments of Hengshan Reservoir in Yixing City

To clarify the endogenous pollution and release characteristics of the bottom sediment of Hengshan Reservoir in Yixing City, a typical section of the reservoir was sampled and analyzed. The research results show that the average concentrations of total nitrogen, total phosphorus, and organic matter in the surface sediments of Hengshan Reservoir are 2778 mg·kg^-1, 899 mg·kg^-1, and 3.1%, respectively. The endogenous pollution is serious, and the downstream sediments are highly polluted upstream of the reservoir. Phosphorus spectroscopic analysis results show that iron-bound phosphorus (Fe-P) and aluminum-bound phosphorus (Al-P) are the main bound phosphorus forms in the sediment, accounting for 28% and 39% of the total phosphorus, respectively. The average concentration of activated phosphorus in the sediment (combination of weakly adsorbed phosphorus, organic phosphorus, and iron phosphorus) is 255 mg·kg^-1, accounting for 38% of the total phosphorus. The average release rates of nitrogen and phosphorus in sediments were 18.0 mg·(m²·d)^-1 and 0.60 mg·(m²·d)^-1. The correlation analysis results show that the organic matter content of the sediment is significantly correlated with the diffusion flux of phosphate, ammonia nitrogen, and ferrous iron (P<0.05), indicating that the mineralization of organic matter in the sediment may be the main release source of nitrogen and phosphorus in the sediment influencing factors.