Mechanism of pollutant release due to sediment re-suspension

During the process of pollutants release due to sediment re-suspension, particles and pore water alternately affect the release flux to the overlying water. Conservative tracer (NaCl) and reactive tracer (Phosphorus) were respectively used as the contaminants to characterize the different ways of particles and pore water under hydrodynamic conditions in a laboratory flume. Studies have shown that reactive tracer responded more slowly to the bed shear stress than the conservative tracer did. Pollutants release process under constant flow can be divided into two significant stages: The suspended particles were in the desorption state during the first two hours, the ratio of water-soluble pollutants contribution between particles and pore water got a maximum values of 3:1. After two hours, the particles begun to adsorb contaminants instead, and the contribution rate of the particles was always negative while pore water’s contribution rate peak reached 60:1. The partition coefficient of pollutants first increased and then stays low, and the reactive pollutants mainly made an impact on water quality in the form of particular. Comparing derived formulas with the experimental dates, the theoretical result increased linearly while the increasing trend of experimental one is slow after the first rapid increment.