Evaluation of per-/polyfluoroalkyl substances (PFAS) contamination in Binh Duong surface water and correlation with physico-chemical indicators.

In recent years, rapid growth of the fluorinated chemical industry in Binh Duong (Vietnam) has led to notable per-/polyfluoroalkyl substances (PFAS) emissions into the local environment. These compounds are very stable, hard to biodegrade and pose risks to ecosystem and human health, especially when exposed to polluted water sources for a long time. This study focused on assessing the presence of eight main PFAS groups in twenty-eight surface water samples, using liquid chromatography tandem mass spectrometry (LC-MS/MS) equipped with an Acquity BEH C18 column. Seasonal variations and correlations with available physicochemical parameters were also performed via R language. The results showed that two dominant PFAS groups, perfluoroalkanesulfonates (PFSAs) and perfluoroalkylcarboxylic acids (PFCAs) recorded the highest concentrations (27.42 and 22.77 ng/L in the dry season, respectively). Within the PFSAs group, the most frequently detected compounds were perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), and perfluorooctanesulfonic acid (PFOS) with maximum concentrations recorded in individual samples of 26.74, 13.69, and 12.70 ng/L, respectively. In contrast, the remaining groups showed much lower levels: perfluoroalkanesulfonamides (FASAs) at 4.08 ng/L, telomer sulfonates (FTSs) at 4.20 ng/L, 9-chlorohexadecafluoro-3-oxanonane sulfonate (F-53B) at 2.75 ng/L, and perfluorooctansulfonamidoacetic acids (FOSAAs) 0.29 ng/L; hexafluoropropylene oxide dimer acid (HFPO-DA, also known as GenX), and sodium dodecafluoro-3H-4,8-dioxanonanoate (DONA) were not detected (<0.20 and <0.13 ng/L, respectively). Seasonal differences of these groups were also observed with PFAS concentrations varying significantly between the dry season (DS) and rainy season (RS), except for F-53B remained relatively stable. Furthermore, the correlation analysis results indicated a moderate correlation between PFCAs and chemical oxygen demand (COD) (r = 0.56; p < 0.05), weak correlations between FTSs and FASAs with iron (Fe) (r = 0.40 and 0.23, respectively; p < 0.01). In conclusion, these findings highlight the seasonal fluctuations and associations with water quality factors of PFAS in the study area, providing a useful reference for developing future pollution control and management plans.