Investigation of PFOS and PFOA pollution in snow in Shenyang, China

The purpose of this study was to investigate the atmospheric perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) pollution in Shenyang by analyzing the concentration of the two compounds in snow. Snow samples were collected from both urban and suburban areas on Feb.6 (n=36) and Feb.25 (n=5) in 2006 in Shenyang, China. PFOS and PFOA were extracted from the snowmelt by solid phase extraction and then were analyzed by LC-MS-SIM. PFOS and PFOA were discernable in all the samples. In the snow samples collected on Feb.6, 2006, the geometric average concentrations of PFOS and PFOA were 2.0 ng·L-1 (range: 0.4-46.2 ng·L-1) and 3.6 ng·L-1 (range: 1.6-22.4 ng·L-1), respectively. The 95% confidence intervals of PFOS and PFOA were 1.5-2.8 ng·L-1 and 3.1-4.2 ng·L-1, respectively. The concentration of PFOS and PFOA showed significant correlation at the center of Shenyang City (n=9), while the highest concentrations of PFOS and PFOA were detected at the same site located in the rural area. Geometric average concentrations of PFOS and PFOA were both 2.2 ng·L-1 in the Feb.25 snow samples. Concentrations of PFOS in two snow events did not show significant difference. Whereas PFOA concentration in Feb. 25 snow was higher than that in Feb.6 snow. Results suggested the widespread PFOS and PFOA pollution in snow in Shenyang. There may be similar resources for the two compounds in regional area. Moreover, there may be continual import of PFOS to the atmosphere in Shenyang from specific resources, while PFOS and PFOA may exhibit different environmental behavior.