Assessment of heavy metal contamination in drinking water sources at Tapa Abotoase community in the Oti Region of Ghana

Abstract

Access to safe drinking water is critical to human health and sustainable development. This study aimed to identify heavy metals present in the drinking water sources at Tapa Abotoase Community in the Oti Region of Ghana. The Abotoase Community relies primarily on the Volta River and boreholes for domestic water supply. The study employed an experimental research design using a quantitative analytical approach to identify heavy metals, to examine their concentration levels and to evaluate their potential health risks to consumers. The water samples were collected from eight sampling points, comprising five boreholes and three points along the Volta River (upstream, midstream, and downstream). Sampling was conducted twice during the dry season and twice during the wet season, making a total of 32 samples. The samples were analyzed in the laboratory following the Standard Methods for the Examination of Water and Wastewater (APHA, 2017). Heavy metals such as iron (Fe), lead (Pb), copper (Cu), cadmium (Cd), mercury (Hg), and arsenic (As) were identified. The results were compared with the World Health Organization (WHO, 2022) and Ghana Water Quality Standards to determine compliance levels. The findings revealed that concentrations of some heavy metals, such as iron and lead, exceeded the WHO permissible limits in certain sampling locations, indicating localized contamination likely associated with anthropogenic activities such as waste disposal, small-scale mining, and agricultural runoff. Seasonal analysis also revealed that concentrations of most heavy metals were higher during the wet season compared to the dry season. However, only mercury (Hg) exhibited a statistically significant variation (p = 0.016; Cohen’s d = 0.903), suggesting that its mobilization was strongly influenced by rainfall and runoff. Health risk assessment showed potential non-carcinogenic risks for children due to prolonged exposure. The study concluded that while most water sources in the area remain suitable for domestic use, periodic monitoring and proper management are required to prevent health hazards. It was recommended that local authorities strengthen water quality surveillance, promote safe waste disposal practices, and educate residents on household water treatment methods. Further studies should also investigate other potential contaminants such as microbial pathogens, organic pollutants, and emerging contaminants that may affect drinking water quality in the area.