[Dynamic Material Flow Analysis of Perfluorooctane Sulfonate in China: 1985-2019]

Perfluorooctane sulfonates (PFOS) are regarded as a category of chemicals with persistence, bioaccumulation, and toxicity. Understanding dynamic flows, stocks, and emissions of PFOS on a macro spatial and temporal scale can help provide a scientific basis for their sound management. In this work, a dynamic material flow analysis (d-MFA) model was built to characterize and analyze the cycles of PFOS in mainland China over the period 1985-2019. Flows, stocks, and environmental emissions were calculated and the sensitivity and uncertainty of the results were then analyzed. Results show that domestic production was the primary source of PFOS in China, most of which was flowed to the domestic market in the form of final products, with the remainder exported to international markets; soil and water were the main sinks of PFOS in China, with emissions from the usage stage contributing the largest portion (103 tons in 2019). The number of inflows and outflows were relatively low before 2000, but gradually increased until 2009 when the relevant convention was issued. Since 2005, in-use stocks and emissions of PFOS have grown yearly. In addition, stocks in landfill have been climbing since 1985. End-of-life management was still dominated by traditional methods, such as landfill and incineration, while there was a trend towards green treatments. This study can provide basic data and theoretical support for the sound management of PFOS in China.