Speciation and presence of fluorine in the groundwater in the Maradi region (central Niger)

The present study aims to study the impact of seasonal variations on the different forms of fluoride in groundwater in the Maradi region. The methodology consisted in carrying out three (3) water sampling campaigns at different periods, rainy season, hot season and cold season; respectively in December 2019; May 2020 and November 2020. The results obtained show that the levels of fluoride ions exist at variable levels ranging from traces to 2.84 mg/L. These results also show that, in well water, fluorine is mainly present in the F-, NaF and HF forms whatever the season; whereas, in borehole waters, the F-, NaF and MgF⁺ forms are those which predominate during all the seasons.