Fluoride Concentrations Within the Shallow Aquifers in Iree, Southwest Nigeria

Abstract

Assessing the toxic fluoride concentration in groundwater is critical and vital, since its occurrence in the water has been linked to the natural deposition of parent rocks during weathering. Consumption of fluoride in water can cause serious health problems, such as skeletal fluorosis, dental fluorosis, fertility reduction, urinary tract infection and disorder, nervous system damage and so on. The aim of this study is to determine the fluoride contamination level in the shallow aquifers of a crystalline basement system in Iree community, south-west Nigeria. Fifteen near-surface wells were tested for fluoride constituents and the determination of some physical parameters (such as pH and water temperature). Samples were analyzed by colorimetry in order to determine fluoride concentrations. The normality of the data was tested using the Kolmogorov–Smirnov test, while the fluoride constituents in the water samples were compared to the World Health Organization (WHO) threshold. The obtained fluoride contents varied from 0.75 to 1.5 mg.l−1 , the pH varied from 6.89 to 8.07, and the water temperature varied from 26.8 to 30.5 °C. It was revealed that some near-surface wells exceeded the WHO permissible standard of 1.0 mg. l −1 for fluoride constituents in potable water. Based on these results, it could be concluded that a crucial and periodic assessment of the near-surface wells is recommended to keep track of the fluctuations in the fluoride concentrations within the study area. The outcome of this study will serve as baseline guidance for policy-makers as well as the concerned authorities to know the degree of fluoride constituents in their shallow wells and to proffer possible solutions in mitigating these pollution risks as soon as possible.