Distribution, release and removal behaviors of tetrabromobisphenol A in water-sediment systems under prolonged hydrodynamic disturbances.

Since tetrabromobisphenol A (TBBPA) has been increasingly used and found widely in the aquatic environment, it has attracted much attention due to its high toxicity to aquatic organisms. However, less work has been carried out for the TBBPA environmental fate in water-sediment systems. In this paper, the distribution, release and removal of TBBPA in different forms of the water-sediment system were investigated under three typical hydrodynamic conditions using a specialized racetrack-style flume. Three water-sediment systems which are water, suspended particulate matter (SPM) and sediment were taken into account in this study. The results of 34 days experiments showed that the equilibrium of physicochemical parameters was reached under different disturbance conditions within a relatively short period. The distribution ratio of TBBPA in three water-sediment systems will also reach a relatively equilibrium state over time under different disturbance conditions. The fluctuation range in each form was <1.26%. The TBBPA released to the water and SPM, increased remarkably with hydrodynamic enhancement due to adsorption and resuspension processes. Removal efficiency of TBBPA in each form was found to be observably accelerated with hydrodynamic disturbances. The half-lives (T1/2) in water, SPM and sediment ranged from 10.1 to 12.6 days in strong hydrodynamic condition, comparing to the static control, it ranges from 34.7 to 37.1 days. This phenomenon may result from the increase of dissolved oxygen (DO) and nutrient concentrations in overlying water affected by hydrodynamic force. The results of the experiment demonstrate that hydrodynamic disturbance may be an important driving factor which will influence the TBBPA environmental fate in aquatic environment.