沉积物团聚体稳定性和总磷释放特征

沉积物内源磷释放会对水体造成二次污染，研究表明沉积物团聚体的稳定性与水体污染关系密切。以秦淮河石头城的沉积物为研究对象，探究沉积物总磷释放与团聚体稳定性的关系以及影响总磷释放和团聚度的因素。结果表明，不同pH值的上覆水，沉积物总磷释放浓度最大可达0.91 mg·L-1，一定时间内团聚度下降最大幅度为27.27%；沉积物有机质含量越高（1.0%），总磷释放浓度和团聚度最大下降幅度越小（分别为1.48 mg·L-1和62.84%），；扰动强度越大（200 r·min-1），总磷释放浓度和团聚度下降最大幅度越大（分别为2.32 mg·L-1和65.23%）。颗粒内扩散模型和Boxlucasl模型的拟合结果表明沉积物释放总磷过程中，总磷释放量越大，团聚度越小；颗粒物理吸附-解吸作用比沉积物颗粒的扩散作用强；有机质在沉积物释放总磷过程中起着重要作用，且对沉积物团聚度有着重大影响。

The stability of sediment aggregates and the release characteristics of total phosphorus

The release of endogenous phosphorus from sediments will cause secondary pollution to water bodies. Studies show that the stability of sediment aggregates is closely related to water pollution.Taking sediments from Shitoucheng of Qinhuai River as the research object, the relationship between the release of total phosphorus and the stability of sediment aggregates as well as the factors affecting the release of total phosphorus and aggregation degree are investigated. The results show that the maximum release concentration of total phosphorus in overlying water of different pH values is 0.91 mg·L-1, and the maximum decrease of aggregation degree is 27.27% in a certain period of time. The higher the organic matter content is (1.0%), the smaller the maximum decrease of total phosphorus release concentration and aggregation degree is (1.48 mg·L-1 and 62.84%, respectively). With the increase of disturbance intensity (200 r·min-1), the maximum decrease of total phosphorus release concentration and aggregation degree is 2.32 mg·L-1 and 65.23%, respectively. The fitting results of the intra-particle diffusion model and Boxlucasl model show that in the process of releasing total phosphorus from sediments, the greater the amount of total phosphorus releases, the smaller the degree of aggregates. The physical sorption and desorption of sediment particles are stronger than the diffusion of sediment particles in the process of total phosphorus release. Organic matter plays an important role in the release of total phosphorus from sediments and has a significant impact on the degree of sediment aggregation.