Fluoride Variations in Rivers on the Slopes of Mount Meru in Tanzania

Abstract

This study reports the variations of fluoride ions in rivers on the slopes of Mount Meru in the northern part of Tanzania. More than 318 water samples were collected from Temi, Nduruma, Tengeru, and Maji ya Chai Rivers in both wet (mid-March and April) and dry (August) seasons. The samples were analyzed for fluoride levels using Ion Selective Electrode (ISE). The minimum and maximum average fluoride levels in the wet season were 0.24 ± 0.03 mg/l and 65.20 ± 0.03 mg/l, respectively, whereas the average lowest and highest levels in the dry season were 1.02 ± 0.02 mg/l and 69.01 ± 0.03 mg/l, respectively. Tengeru River had the lowest fluoride levels in both seasons, whereas Maji ya Chai recorded the highest fluoride levels in both seasons. The headwater of all rivers with the exception of Maji ya Chai met the World Health Organization's (WHO) maximum acceptable fluoride levels of 1.50 mg/l and the downstream environment qualified for Tanzania Bureau of Standards (TBS) maximum permissible fluoride concentration in drinking water of 4.00 mg/l. Also, the laboratory experiments showed that fluoride containing rocks exposed to pH above 7.6 display high leaching of F − in solution which gradually increased with the increase in pH, indicating that dissolution of fluoride in water is a function of pH.

Assessing the influence of horticultural farming on selected water quality parameters in Maumau stream, a tributary of Nairobi River, Kenya

“…Fluoride dissolution and availability seems to have correlated with the high pH of the water, indicating that the dissolution of fluoride influenced the pH. This finding is consistent with the observations Kitalika et al. (2018) , who observed a linear correlation when comparing fluoride and pH trends in rivers of Mount Meru, Tanzania.…”

Identification of low fluoride areas using conceptual groundwater flow model and hydrogeochemical system analysis in the aquifer system on the flanks of an active volcano: Mount Meru, Northern Tanzania

“…In the Arusha volcanic region in northern Tanzania, around Mount Meru, several studies with focus on F⁻ concentration in surface water (Kilham and Hecky, 1973;Nanyaro et al, 1984;Kitalika et al 2018) and groundwater (Ghiglieri et al, 2012;Chacha et al, 2018;Makoba and Muzuka, 2019;Bennett et al, 2021) have been conducted. The studies found that the general groundwater chemistry is F⁻-rich NaHCO3 alkaline water.…”

Land-Use and Land Cover Changes on the Slopes of Mount Meru-Tanzania

“…The study area involved the foothills of the eastern and south west parts of Mount Meru which is part of the entire Pangani basin sub catchment located in the Nothern part of Tanzania sub catchment (Figure 1). 41 The natural vegetation in this area is typically tropical forest to savannah and topography is dominated by the Mount Meru volcanic cone of Pleistocene to recent origin. The local climate of the area is temperate Afro-Alpine with minimum and maximum daily temperature of 20.6 °C and 28.5 °C, respectively.…”