ISOTOPE HYDROLOGY AND HYDROCHEMISTRY OF WATER RESOURCES IN THE BANANA PLAIN (MUNGO-DIVISION) OF THE CAMEROON VOLCANIC LINE

The isotope hydrology and hydrochemistry of surface and groundwater of the Banana Plain were studied to trace the origin of groundwaters and evaluate the major ion chemistry and geochemical processes controlling water composition. Water samples from rain, streams, lake, springs, wells and boreholes were collected and analyzed for major ions, stable isotopes, tritium and dissolved silica. (18)O and (2)H data indicate that groundwater has been recharged by meteoric water without significantly being affected by evaporative processes either during or after the recharge process. Evaluation of the groundwater residence time demonstrated that groundwater in the Banana Plain aquifers should be considered as a renewable water resource. In general the waters are Ca/HCO(3) and Ca-Mg-Na/HCO(3) dominated. Weathering of silicate minerals controls the concentration of major ions such as calcium, magnesium, sodium and potassium while NO(3) and CI are of anthropogenic origin. Chemical composition of the groundwater in this area is influenced by rock-water interactions.