Spatial and Temporal Dynamics of Chemical Parameters in Surface Waters of Bandama Catershed, Ivory Coast

The heavy pressures on Bandama watershed surface waters could expose them to pollution. This study aimed to determine spatial and seasonal variation of chemical parameters of these waters and to identify the origin of their mineralization. Thirteen (13) surface waters were collected in the northern and southern zones of Bandama watershed and analyzed for selected chemical parameters during different seasons. In-situ and laboratory analyses were carried out using standard procedures. No-parametric tests of Kruskal-Wallis and Mann-Whitney and the analysis of variance were used to compare chemical parameters values for all different sampling sites and seasons. Principal component analysis was used to identify water mineralization origin. During these seasons, water chemical quality was good according to World Health Organization (WHO) guidelines for most of the parameters. Spatial variation revealed that high loads of nitrogenous nutrients and suspended solids are recorded in the northern zone with a decrease in transparency. In contrast, the southern zone waters are more oxygenated and transparent. Results, based on temporal variation indicate that highest values of these parameters were recorded during the rainy season. Mineralization by soil leaching, anthropogenic pollution, long time of water-rock contact and acid hydrolysis of silicate minerals have been identified for Bandama surface waters.