Laboratory simulation study on the influence of resuspension on the release of mercury from Yangtze Estuarine tidal flat

Using a Particle Environment Simulator, laboratory simulation experiment on the influence of resuspension on the release of mercury from sediments collected from medium tidal flat and low tidal flat in Chongming Dongtan was conducted. Results indicated that the conditions of overlying water changed significantly during resuspension. The concentrations of HgD and HgP were mainly in the rang of 0.152-2.657 μg · L^-1, 0.080-2.722 μg · L^-1 separately. In the resuspension processes, mercury was released from the medium intertidal sediments under the salinity condition of 4.1‰, 8.0‰, 10.0‰, 13.0‰, and from the low intertidal sediments under the salinity condition of 13.0‰. However, the release of mercury from the medium intertidal sediments is not significant under the salinity condition of 4.1‰, 8.0‰, 10.0‰. The salinity of overlying water had an important effect on resuspension. In different salinity condition, the release of mercury was different. And the release of mercury from medium tidal flat and low tidal flat was different during the resuspension periods, the release of mercury from the medium intertidal sediment was significantly higher than the release from the low intertidal sediment. When the rotate speed was(210 ±5) r · min^-1, the desorption of mercury significantly increased, thereby the rotate speed had an effect on the release of mercury.