The present study is based on the evolution of the physico-chemical and microbiological quality of surface and groundwater used for the daily needs of populations in the northern part of the Brazzaville region. The physico-chemical study of groundwater and surface water revealed that these waters are soft, weakly mineralized and that the alkalinity of these waters would be essentially dominated by bicarbonate ions (HCO3-). These waters are also characterized by two (2) chemical families (chemical family of chloride and sulfate calcium and magnesium waters and chemical family of calcium and magnesium bicarbonate waters).
On the qualitative side, the good potability of water is called into question by the presence of certain minor chemical elements such as total iron (FeTot), hexavalent chromium (Cr6+), lead (Pb2+) and aluminum (Al3+) whose contents sometimes would exceed the values of the maximum admissible concentrations for drinking water defined by the WHO.
On the microbiological level, surface and groundwater in the northern part of Brazzaville would indicate fecal contamination. These surface and groundwater indicate a fecal contamination and a deterioration of the bacterial quality. This study would show that the water resources in the northern part of Brazzaville would be subject to significant anthropogenic pollution. The consumption of this type of water without any treatement would expose populations who consume it to health risk.
