Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in seafood from Thailand: Levels, geographic distribution, and risk from dietary exposure

Abstract

This study investigated the contamination of perfluorooctane sulfonate (PFOS), its isomers, and perfluorooctanoic acid (PFOA) in seafood from Thailand to assess public health risks. A total of 144 samples from eight marine species were collected from three provinces—Rayong, Samut Sakhon, and Bangkok—between 2022 and 2023. Samples were analysed using a validated ultra–high performance liquid chromatography with tandem mass spectrometry (UHPLC–MS/MS) technique. PFOS and PFOA were detected in all samples, with concentrations ranging from < 24 to 623 ng/kg wet weight (ww) and < 48 to 419 ng/kg ww, respectively. PFOS was detected at a higher concentration than PFOA, and both compounds were found predominantly in cockles. Geographically, seafood from Rayong province revealed higher PFOS contamination, likely due to industrial activities. Linear PFOS was the most prevalent isomer, accounting for 84% of the total PFOS. The maximum levels of PFOS and PFOA in fish and molluscs complied with the European Union limits, and the estimated PFOS exposure assessment from seafood consumption was below the European Food Safety Authority (EFSA) guideline. However, for children (3–12.9 years) in the high-seafood-consuming group, the estimated exposure was two-fold higher than the guideline of 4.4 ng/kg body weight/week. These findings highlight the need for continued PFAS monitoring and for implementing strategies to mitigate risks for vulnerable populations.