Simulation of Multimedia Transfer and Fate of Perfluorooctane Sulfonate (PFOS) in Shenzhen Region

Abstract

To study the transfer and fate of perfluorooctane sulfonate (PFOS) in Shenzhen region, a level Ⅲ fugacity model was used to simulate and calculate the concentrations of PFOS in local air, water, soil and sediment. Physical and chemical parameters of PFOS and environmental parameters of Shenzhen were entered into the model. The simulated concentrations were compared with actual measurements to validate the model, and then analyzed based on the transfer flux of PFOS between media to identify the main transfer route. The input parameters and output results of the model underwent sensitivity analysis and uncertainty analysis, respectively. The simulated concentrations of PFOS in air, water, soil and sediment were 1.4 pg·m-3, 7.0 ng·L-1, 0.39 μg·kg-1 and 0.11 μg·kg-1, in good agreement with the actual measurements. The transfer from air to soil, soil to water and air to water were the main PFOS transfer routes between media, accounting for 32%, 32%, 5.8% of total transfer, respectively. The transfer through water was the major PFOS outlet from a region. The advective input of air and water, temperature, PFOS solubility, precipitation and density of soil and sediment were the key parameters affecting the model output. Uncertainty analysis showed that the coefficient of variation of PFOS concentrations reached the minimum in water and the maximum in soil, which may be caused by the highly changeable content of organic carbon in soil.