Hydrochemical and geothermometric study of thermal waters of Kaswa/Mahagi in Ituri Province, Democratic Republic of the Congo

Abstract

The thermal waters of Kaswa/Mahagi, located in the Albertine Rift (North-East of the Democratic Republic of the Congo) constitute a hydrogeochemical and geothermal potential that the country needs for its development. This study aimed to determine the lithological nature and the temperature of the reservoir of these waters. The combination of Hydrogeochemical and statistical methods made it possible to achieve these objectives. The thermal waters of Kaswa/Mahagi, volcanic waters of origin are essentially evaporitic in its lithological nature, the bedrock calcium chloride sulfate. The identified metallic trace elements and their distribution in the thermal waters of Kaswa/Mahagi were: Fe²⁺(4.36mg/L) > Pb²⁺(3.84mg/L) > Zn²⁺(1.03mg/L) > Cu²⁺(0.48mg/L) > Mn²⁺(0.18mg/L) > Cr³⁺ (0.09mg/L). The concentrations of Cd²⁺, Ni²⁺, Hg²⁺, Bi³⁺ and Sn2+ were less than 0.02 mg/L. Certain metallic trace elements were in significant concentrations, thus reflecting their circulation in depths. The application of SiO2 geothermometers showed that their temperature in the deep reservoir oscillates between 70 and 75°C, while the geothermometers of Na-K-Ca displayed an average temperature of 89°C; the thermal loss being important considering the temperature measured at emergence and attributed to many factors. These results are useful for integrated management of water resources and the exploitation of geothermal potential for the benefit of the population.