Occurrence of phenolic derivatives in Buffalo River of Eastern Cape South Africa: Exposure risk evaluation

Phenolic derivatives are compounds used in the production of pesticides, pharmaceutical products and several other industrial applications. These compounds are discharged into freshwater from industrial effluents, domestic sewage, urban and agricultural run-offs which leads to pollution. Water at six sampling locations along the course of Buffalo River; namely Buffalo river estuary (BRE), Mdantsane (MSN), Zwelitsha (ZW), King William's Town (KWT), Izele Town (IZ) and Maden dam (MD) in the Eastern Cape Province, South Africa, were evaluated for phenolic contamination using eleven phenolic derivatives of United State Environmental Protection Agency (USEPA) priority pollutants. Samples were extracted using liquid-liquid extraction technique, derivatized with acetic anhydride and analyzed with gas chromatography mass spectrometry (GC-MS). The levels of the individual pollutants in the river water were higher in summer (< LOD to 12246 ng/L) than in autumn (< LOD to 713 ng/L). Their concentrations were found higher than the USEPA recommended limit (500 ng/L) in most of the sampling sites. The most prominent pollutant was 2-NP. However, the cancer risk assessment values and hazard quotient were below USEPA maximum limits of 10(-6) and 1, respectively. Conclusively, the concentrations of these organic pollutants could be a threat to public health and should be managed to be below the recommended limit though the present levels are unlikely to cause cancer to both human and wildlife.