Assessing Microbial Contamination and Water Safety Risks in the Black Volta River Basin of Northern Ghana

Abstract

Microbial contamination of surface water remains a critical public health concern, particularly in low-resource settings with limited access to safely managed drinking water. This study evaluates the microbial quality of the Black Volta River, a key water source for Wa Municipality in Northern Ghana, and examines the implications for water safety and public health. Water samples were collected from raw, treated, and distributed sources during both dry and rainy seasons in 2021 and 2022. Microbial analyses assessed total viable count (TVC), Escherichia coli, and total coliforms, benchmarked against World Health Organization (WHO) standards. Results revealed that raw water consistently exceeded WHO limits, with TVC levels reaching 580 CFU/ml and 1000 CFU/ml in the dry and rainy seasons, respectively. Similarly, E. coli concentrations peaked at 250 CFU/ml (dry season) and 480 CFU/ml (rainy season). Treated and distributed water samples, however, consistently met WHO microbial quality guidelines, indicating effective disinfection by Ghana Water Limited. Seasonal dynamics significantly influenced contamination levels, with elevated microbial loads during the rainy season. Qualitative data from key informant interviews identified anthropogenic pressures, including open defecation, livestock grazing, and agricultural runoff along riverbanks, as major contributors to microbial pollution. Although the treatment system ensures compliance at the point of distribution, elevated raw water contamination levels increase operational burdens and treatment costs. The study underscores the need for integrated watershed protection, public sanitation education, and adaptive management strategies to safeguard water quality and public health in Ghana's rural and peri-urban communities.