Evaluation of groundwater and surface water quality in selected villages from four local municipalities in the Eastern Cape Province, South Africa

Surface water and groundwater are crucial sources of drinking water in most rural areas of the Eastern Cape Province, South Africa, particularly in villages within the OR Tambo and Alfred Nzo District Municipalities. This highlights the importance of water quality monitoring in these regions to gain insights into the status of drinking water quality and water security, as these differ significantly across South Africa. This study assessed the key physicochemical parameters influencing the suitability of surface water and groundwater as drinking water sources in selected villages in the Eastern Cape Province. A total of 33 water samples were collected in May and September 2023 and analysed for fourteen physicochemical parameters. Assessment of water samples revealed that various parameters indicate that the water is chemically suitable for drinking. However, most water samples were unsuitable due to their turbidity levels (>1-217 NTU), and some samples had nitrate (>11-165 mg/L) and ammonia (>1.5-2.24 mg/L) levels exceeding the national permissible limits. Based on the concentrations of the investigated physicochemical indicators, the water quality index (WQI), Principal Component Analysis (PCA), and a Pearson correlation matrix were employed to identify the sources of surface water and groundwater pollution and to assess their suitability for consumption. The WQI values indicated that most water samples had poor to unsuitable quality, whereas borehole water samples ranged from excellent to good. The PCA and Pearson correlation results revealed that the physicochemical parameters responsible for water quality changes in the study area were mainly associated with anthropogenic activities and geogenic sources.