Hydrochemical Characteristics of the Groundwater AQ1 of the Region from Pointe-Noire to Congo Brazzaville

The study is interested in chemical quality of water of the one of the five aquifers, unconfined water AQ1, (other free groundwaters AQ2, AQ3, AQ4 and AQ5 being captive) in the area of Pointe-Noire. A series of physicochemical analysis was carried out on the samples of water of the zone. The results of these analyses were treated starting from a chemical-hydro method which uses the diagrams of Piper, Stabler, Schoeller Berkaloff, Stiff, Wilcox and the statistical methods classic. These chemical-hydro results made it possible to highlight the prevalence of sodic and potassic facies chlorinated in groundwaters of the unconfined water of the area of Pointe-Noire. In this area, the groundwaters of the unconfined water gather in three principal-hydro facies: sodic and potassic chlorinated waters are the most important (66.7%) in the studied water; calcic and magnesian bicarbonated water (16.65%) and bicarbonated sodic and potassic ones (16.65%). This study reveals that the groundwaters of the area of Pointe-Noire undergo an intrusion saltworks. As a whole, these groundwaters require in certain cases, a specific treatment before consumption.