Distribution of legacy, precursor and emerging per-and polyfluoroalkyl substances in environmental waters in South Africa and their potential health risk to the population

We present a study of per-and polyfluoroalkyl substances (PFASs) in water samples from 48 sites in 8 South African provinces. Twenty-six targeted PFASs were analysed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), after solid phase extraction (SPE). Of the different PFAS classes detected, the PFAS precursor 8:2 Fluorotelomer alcohol (8:2 FTOH) was among the prominent PFAS detected, with the sum concentration (∑8:2 FTOH, all sites) of 1042.1 ng L -1 (mean = 4.9 ng L -1 , median = 1.1 ng L -1 ). In comparison, the most dominant legacy PFAS was PFBA, with the sum concentration (∑PFBA, all sites) of 8174.8 ng L -1 (mean = 146.7 ng L -1 , median = 25.7 ng L -1 ). Out of the groups of PFASs, perfluorocarboxylic acids (PFCAs) were the most detected PFASs, though the average concentrations were not statistically significant (p>0.05) between all the provinces assessed. Seasonally, the individual concentrations varied in each province, but generally, the concentrations were higher during the wet season than the dry season. Moreover, detection frequency (DF%) amongst the PFASs varied with only detections during the dry season achieving >70%. Since PFASs were never manufactured in South Africa, the potential sources of PFAS contamination were linked to the use of PFAS containing products that may be used in the surroundings of the sampling sites. The potential sources identified were domestic and industrial discharges, agricultural activities, wastewater effluents and other anthropogenic activities. The non-dominance of the long-chain legacy PFASs may indicate a shift on the use of fluorinated alternatives. The trend could also be due to long chain PFAS adsorption on to solids such as sediments in the aquatic environment. In addition, the health assessment risk to humans from contaminated surface water was low to moderate for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), and no significant risk was observed for the rest of the compounds at the detected concentrations.