Surface water quality and safety for human and livestock use: a comparative case study of two tropical lakes

Abstract

This study assesses the suitability of surface water from Lakes Fallai and Wullum, located in the Benue Valley, Adamawa State, Nigeria, for human and livestock consumption by analysing selected physicochemical and bacteriological parameters. Water samples were collected from disturbed and relatively undisturbed littoral zones in both lakes and analysed using standard laboratory methods. Concentrations of heavy metals (cobalt and manganese), pH, biochemical oxygen demand (BOD), and faecal coliform counts were determined and compared with guideline values established by the World Health Organization (WHO), the National Agency for Food and Drug Administration and Control (NAFDAC), and the Nigerian Academy of Science (NAS). The results show that manganese concentrations were within acceptable limits in Lake Fallai (mean 0.15 mg/L) but exceeded WHO guideline values in Lake Wullum (mean 0.30 mg/L). Cobalt concentrations were relatively low in both lakes and did not individually exceed guideline thresholds. pH values (mean 6.0) and BOD levels (4.0 mg O₂/L) were similar across both lakes, indicating comparable acid–base conditions and organic matter loads. In contrast, bacteriological analysis revealed faecal coliform contamination in both lakes, with higher counts in Lake Fallai (25.5 CFU/mL) than in Lake Wullum (8.5 CFU/mL). Although several physicochemical parameters complied with guideline ranges, the combined presence of elevated manganese concentrations in Lake Wullum and microbial contamination in both lakes renders the water unsuitable for direct human consumption without treatment. These findings underline the influence of local environmental conditions and anthropogenic activities on surface water quality and emphasise the need for regular monitoring and appropriate water treatment strategies in the Benue Valley region.