Distribution pattern, source apportionment, and health risk assessment of per- and polyfluoroalkyl substances in drinking water treatment plants in South Africa

Abstract

Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals and have been found to be ubiquitous in various environmental compartments. These compounds have been detected in various water bodies such as surface waters and drinking and wastewater treatment plants across the globe. In this study, water samples were collected from five provinces in South Africa in wet and dry seasons, extracted, and analyzed using solid phase extraction and liquid chromatography-tandem mass spectrometry, respectively. The mean PFAS concentrations in drinking water treatment plants in Eastern Cape, Free State, Mpumalanga, Northern Cape, and North West provinces ranged from limit of detection (LOD)-109 ng/L, LOD-307 ng/L, LOD-490 ng/L, LOD-740 ng/L, and LOD-230 ng/L, respectively, for dry and wet seasons. Perfluorobutanoic acid, 8:2 fluorotelomer sulfonate anion, perfluorononanoic acid, and perfluoropentanoic acid had the highest percentage contribution in wet and dry seasons. The hazard index (HI) value was higher in the Northern Cape drinking water treatment plant with estimated HI of 9.95 ng/Kg∗per body weight, which was above the daily recommended intake of 4.4 ng/Kg∗ per body weight. Therefore, the presence of these compounds in drinking water treatment plants is a concern due to their bio-accumulative and health implications. Principal component analysis revealed a PFAS contamination profile that can aid in identifying the source and evaluating risks posed by these chemicals. The findings of the study will aid in chemical-specific management that will necessitate the development of stringent environmental legislation of PFAS in South Africa.