Seasonal Variation of Drinking Water Quality and Human Health Risk Assessment: A Case Study in Rural Village of the Eastern Cape, South Africa

Abstract

Contamination of drinking water by metals remains a global threat to living organisms. Therefore, the current study describes variations of metal occurrence, water quality and human health risk assessment between the dry and wet seasons of a rural village located in the Eastern Cape Province, South Africa. The concentrations of major and trace metals were determined in drinking water samples using inductively coupled plasma-optical emission spectrometry (ICP-OES). The physicochemical parameters, water quality index (WQI), total water hardness (TWH) and health risk assessment (hazard quotient: HQ and chronic daily intake: CDI) were evaluated seasonally. The TWH results showed that the water was very hard with water hardness values ranging between 415 and 442. The water also contained several metals and metalloids such as Al (2.18–3.36 mg L−1), As (0.17–0. 53 mg L−1), Cd (0.0068–0.0134 mg L−1), Cr (0.2481–0.2601 mg L−1), Mn (0.387–1.582 mg L−1), Pb (0.064–0.0802 mg L−1), Sb (0.0496–0.1391 mg L−1) and Se (0.075–0.148 mg L−1) that exceeded the SANS and WHO permissible limits in drinking water. The health risk assessment revealed that the water may cause noncarcinogenic and carcinogenic health effects due to the presence of As, Cr, Sb, Tl and V in water samples, while the water quality index revealed that the water was of very poor quality.

Keywords

• heavy metals
• trace metals
• groundwater
• health risk assessment
• total water hardness
• water quality index