Geochemical provenance and spatial distribution of fluoride in groundwater of Mayo Tsanaga River Basin, Far North Region, Cameroon: implications for incidence of fluorosis and optimal consumption dose.
The 500,000 inhabitants of Mayo Tsanaga River Basin are vulnerable to a "silent" fluorosis from groundwater consumption. For the first time, the groundwater is investigated for the purpose of identifying the provenance of fluoride and estimating an optimal dose of fluoride in the study area. Based on the fluoride content of groundwater, fluorine and major oxides abundances in rocks from the study area, mean annual atmospheric temperature, and on-site diagnosis of fluorosis in children, the following results and conclusions are obtained: Fluoride concentration in groundwater ranges from 0.19 to 15.2 mg/l. Samples with fluoride content of <1.5 mg/l show Ca-HCO(3) signatures, while those with fluoride >1.5 mg/l show a tendency towards Na-HCO(3) type. Fluor-apatite and micas in the granites were identified as the main provenance of fluoride in the groundwater through water-rock interactions in an alkaline medium. The optimal fluoride dose in drinking water of the study area should be 0.7 mg/l, and could be adjusted downward to a level of 0.6 mg/l due to the high consumption rate of groundwater, especially during drier periods.
Fantong
Wilson Y
WY
Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan. fyetoh@yahoo.com
Satake
Hiroshi
H
Ayonghe
Samuel N
SN
Suh
Emmanuel C
EC
Adelana
Segun M A
SM
Fantong
Emilia Bi S
EB
Banseka
Hycinth S
HS
Gwanfogbe
Cletus D
CD
Woincham
Leonard N
LN
Uehara
Yoshitoshi
Y
Zhang
Jing
J
D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005459:Fluorides / Q000032:analysis* / Q000737:chemistry; D009050:Fluorosis, Dental / Q000453:epidemiology*; D005618:Fresh Water / Q000737:chemistry*; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry; D055593:Geological Phenomena; D006801:Humans; D015994:Incidence; D012822:Silicon Dioxide / Q000737:chemistry; D014881:Water Supply / Q000032:analysis
C007886:granite; D012822:Silicon Dioxide; D005459:Fluorides