Physico-Chemical and Microbial Characterisation of Water from the Abengourou dam in Eastern Côte d’Ivoire

The water from the Abengourou dam is used for the production of drinking water. This study aims to characterise this resource in order to assess the quality of the water for monitoring and sustainability of the operation. Six sampling points were identified, four of which were at the main entrances, one inside the water body and another at the dam. Samples were taken at three different depths and during the two main seasons. In total, some forty physical, chemical and microbiological parameters were monitored for the thirty-six samples taken in one year. The results obtained show an inter-seasonal variation in the parameters monitored. The waters of the dam are very weakly mineralised and not very turbid. The highest turbidity during the wet and dry seasons are respectively 6.5 NTU and 11.1 NTU. The electrical conductivity of the water is between 173 and 190 µS/cm in the dry season and between 149 and 163 μS/cm in the wet season. This is mainly due to rising water levels during the wet season and evaporation during the dry season. Concentrations of iron, pesticide residues, manganese and ortho-phosphate above the WHO guidelines for drinking water were recorded. Average iron levels in the wet and dry seasons are 0.84 and 0.53 mg/L respectively. Manganese levels reached 2.02 in some samples in the dry season. Organohologenes were found at levels up to 0.04 µg/L in the high-water period. A greater presence of germs indicating faecal contamination was found during the high-water period. This contamination is of human or mixed human-animal origin depending on the sampling point. The highest levels are recorded at point P2, which represents the urbanised part of the catchment area for several of the parameters analysed.