ANALYSES PHYSICO-CHIMIQUES ET BACTERIOLOGIQUES DES EAUX DE TROIS AQUIFERES DE LA REGION DE TILLABERY : APPLICATION DES METHODES D’ANALYSES STATISTIQUES MULTI VARIEES

Abstract

Groundwaters constitute one of the main sources of supply in drinking water of the population of the region of Tillabery. The present study is interested in the quality of waters of three aquifers (continental terminal 2, the broken base and the alluviums of the dallol Bosso) of the region of Tillabery. The aim of this study is to improve the knowledge on ground-water sheets and to determine the origin of the mineralization of these waters. This work was led from a combination of the physico-chemical analyses and bacteriological parameters, on samples of waters of wells and drillings of certain localities of the region, and the multi-statistical varied analysis (Analyze in Standardized Main Components (ACPN) and Ascending Hierarchical Classification (CHA)). The hydro analysis chemical showed important values of an electrical conductivity in waters of certain localities such as Diagorou (794 µS.cm-1), Sawani (736 µS.cm-1), Bonkoukou (716 µS.cm-1). Significant Iron values, in the locality of Abala (0,43mg / L), nitrites and nitrates values in other localities were found well as contamination of all the wells by germs of faecal contamination. The combination of both methods of static analysis allowed to identify two important phenomena in the acquisition of the mineralization of waters. The main phenomenon is the dissolution of the rock by the contact water rock (mineralization residence time). The second phenomenon is superficial contributions bound to water inputs through superficial infiltrations in the aquifer. The analysis in Ascending Hierarchical Classification (CHA) allowed to identify three groups of water of different chemical composition. The groundwater resources in the region of Tillabery have a good physico-chemical quality but require in certain cases (waters of the well and the water of the river) a specific treatment before supply.