Industrial source identification and emission estimation of perfluorooctane sulfonate in China.

Perfluorooctane sulfonate (PFOS) and related chemicals (collectively "PFOS equivalents") are currently manufactured and used in a wide variety of industrial processes in China. Since 2003, the national annual production has increased dramatically to accommodate both domestic demands and ongoing overseas needs for metal plating, fire-fighting foams, photographic, semiconductor and aviation industries. Accordingly, PFOS-related industries are significant sources of PFOS to the environment in China, though little information is available. In the present study, industrial sources of PFOS in China were identified and emissions from major related industries, including PFOS manufacture, textile treatment, metal plating, fire-fighting and semiconductor industries, were evaluated. Contribution by various industrial sources and spatial distribution of the PFOS emission were discussed. It was estimated that the total emission of PFOS equivalents in China was 70t in 2010. Industrial use of PFOS in metal plating was identified as the largest source of PFOS pollution at the national level, followed by textile treatment, fire-fighting, PFOS manufacture and semiconductor industry. At the regional level, greater contributions were made by metal plating and textile treatment in most provinces of eastern China, while in the western part of China and several northeastern provinces fire-fighting was the predominant source. The contribution by PFOS manufacture was considerable in Hubei and Fujian provinces. Total emission, emission density and emission intensity showed geographical variations. In general, the eastern coastal provinces, as the most intensively industrialized regions of China, were characterized by significantly higher emission rates, emission density and emission intensity than those in western and northern China. Available monitoring data of PFOS concentrations in surface water of China reflected a similar distribution pattern, confirming that manufacture and industrial uses were crucial sources of PFOS pollution which would cause significant risks in the environment.