Investigation of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) in Freshwater and Seawater in Thailand

Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) as persistence organic pollutants (POPs) have been detected in environmental waters around the world. However, only few information on PFOA and PFOS in the Thai environment has been obtained. In order to clarify the pollutions of PFOA and PFOS in waters of lakes and seaside areas in Thailand, we analyzed PFOS and PFOA with SPE-LC/MS in water samples in Kasetsert University in Bangkok, Thailand. However, commercial methanol and RO water for LC/MS analysis purchased from chemical companies in Bangkok were contaminated with PFOS and PFOA before use. The contaminants in the solvent and the commercial pure water were removed using a mix-mode anion exchange solid-phase extraction cartridge (OASIS MAX, Waters). PFOS and PFOA were detected from all samples at the ranges between 0.8 and 61.7 ng/L and between 10.0 and 29.0 ng/L, respectively. It should be noted that the molar ratios of PFOS and PFOA in the East-side and the West-side of the Thai Gulf were different. The finding suggests that the pollutants in the both sides might be drained from different sources.