Evaluating the geologic controls on Fluoride concentrations in Groundwater from Northern and Southern Ghana: A case study of Bongo and Afigya Sekyere Districts (original) (raw)
Related papers
Hydrogeochemical appraisal of fluoride in groundwater of Langtang area, Plateau State, Nigeria
Global Journal of Geological Sciences, 2016
Consumption of high fluoride in groundwater of Langtang area, manifest in the inhabitants of the area in form of dental fluorosis and skeletal fluorosis in older group. The aim of this study was to appraise the hydrogeochemistry of fluoride in the groundwaters of Langtang area. Thirty seven surface and groundwater samples and nine rock samples were collected in Langtang area for geochemical analysis. The Inductively Coupled Plasma Emission Spectrometry (ICPOES) was used to detect cations. The anions (Cl-, SO 4 = and Br-) were determine by Ion Chromatography method. Fluoride was determined by the Specific Ion Electrode and bicarbonate was determined by titration. Major oxides, trace elements and rare earth elements for the rock samples were determined by the XRF method and fluorine by the Fusion method. Polished thin sections for rocks were prepared and studied. Geochemical results from analysis of the samples (rock and water) show that four major rock units make up the geology of the area; coarse porphyritic biotite granite, migmatite, rhyolite and riebeckite granites, the minor ones are pegmatite, trachyte, aplite and fine to medium grained biotite granites. The rhyolite, the riebeckite granites and trachyte have the highest level of fluorine content in the area (1,470, 1000, 900 and 800 ppm) respectively. The fluorine mineral (Fluorite) crystallized in the late stage of the magma as replacement of Fe/Mg mineral probably hornblende or biotite. Fluorine is leached into the groundwater from the rhyolite under the slightly alkaline (Ca-Mg-HCO 3 evolving Na-HCO 3) water in the area. The two major groundwater types (Ca-Mg-HCO 3 and Na-HCO 3) in the area have good relationship with content of fluoride in water. Although, the riebeckite granites have high fluorine content, contribution of fluoride from them is towards the southern portion of the map, owing to the groundwater flow direction. The different water sources in the area do not show variation in content of fluoride in water. However, groundwater barriers (dykes) may be responsible for some area having low fluoride (<1.5 mg/l) content. The consumption of high content of fluoride in the area has resulted in severe dental fluorosis in both children and youths and bowing of legs (Genu Valgum) in children with no discrimination between the sexes.
Fluoride content in water has received a world-wide attention due to its importance to health. This study attempts to trace the factors responsible for low fluoride levels in the aquifers of the Jos Younger Granites despite the high fluorine content in the rocks. A total of 41groundwater samples (1 mining pond, 2 hand pumps and 38 hand dug wells), 7 rock samples from the various lithological units, and 13 soil sections from two exposed locations were collected and analyzed for their fluorine content. Analysis of major cations was carried out using ICP-OES; the anions were analyzed using the UV multi-ion parameter and bicarbonates by titration method. Fluoride in underground water was determined by multi-ion parameter. Fluorine in rocks and soil were analyzed by the fusion method. The rock samples show variations in their fluorine content (Jos – Bukuru Biotite Granite 6,231, aplo-pegmatic granite-gneiss (basement rock) 4,864, Quartz-pyroxenes-fayalite porphyry 1,280, Dilimi-Biotite Granite 258 and Ngeil Biotite Granite-162 ppm). The soil sections from different locations also show variations of fluorine with depth of sampling. Cumulatively, the fluorine content in the sections and fluoride content in water do not correlate with fluorine in rock in the rock units. The low content in the two media, indicate that: 1. bulk fluorine have not been released from minerals in the host rocks and those retained in soils have not been mobilized to the groundwater. 2. Fluorine have formed complexes with other ions and occurring in compound form rather than ionic form. Apart from low fluoride in about 70% of the water samples all other parameters are within the WHO recommended limit for house hold uses. Although there are no records on the effect of low consumption of fluoride in water, inferences from the data show that most areas with low fluoride level should have dental caries.
Sustainable Water Resources and Management
This study was conducted to understand the hydrochemistry of groundwater in the Bongo district and unravel the source of fluoride in the groundwater using an integrated hydrochemical analysis and multivariate geostatistical analysis. A total of thirty (30) borehole water samples were collected in various communities in the district during the dry season. The district is dominated by Upper Birimian (Paleoproterozoic) metavolcanics and granitoids known as the Bongo granitoids. Hydrochemical facies identified in the area include Ca–Na–HCO3 (70%) and Ca–Mg–HCO3 (30%) water types. The Ca–Na–HCO3 water types are hosted in fractured bedrocks of the Upper Birimian metavolcanics and the K-feldspar rich Bongo granitoids, whereas the Ca–Mg–HCO3 water types are within the Upper Birimian volcanic/metavolcanic sequences. All the hydrochemical parameters show acceptable concentrations for drinking purposes except fluoride (1.71–4.0 mg/L). The high fluoride concentrations in the groundwater are largely due to intense dissolution of the Bongo granitoids, which contain biotite and muscovite as the dominant fluoride-bearing minerals. The pH, Ca²⁺, SO4²⁻, HCO3⁻ and CO3²⁻ concentrations have weak positive correlations with F⁻ concentrations of the groundwater implying some dependent relationship and different source for the fluoride. Principal component analysis performed on the hydrochemical data resulted in three principal components (PCs), which explain 76.251% of the total variance. The three PCs represent the dominant processes influencing the groundwater chemistry, which include water–rock interaction, mineral dissolution, and ion exchange reactions, respectively, with water–rock interaction as the most dominant process. However, anthropogenic sources such as the use of phosphate fertilizers cannot be precluded from contributing to the groundwater fluoride contamination.
Environmental Earth Sciences, 2017
A total of 194 groundwater samples were collected from wells in hard rock aquifers of the Medak district, South India, to assess the distribution of fluoride in groundwater and to determine whether this chemical constituent was likely to be causing adverse health effects on groundwater user in the region. The study revealed that the fluoride concentration in groundwater ranged between 0.2 and 7.4 mg/L with an average concentration of 2.7 mg/L. About 57% of groundwater tested has fluoride concentrations more than the maximum permissible limit of 1.5 mg/ L. The highest concentrations of fluoride were measured in groundwater in the north-eastern part of the Medak region especially in the Siddipeta, Chinnakodur, Nanganoor and Dubhaka regions. The areas are underlain by granites which contain fluoride-bearing minerals like apatite and biotite. Due to water–rock interactions, the fluoride has become enriched in groundwater due to the weathering and leaching of fluoride-bearing minerals. The pH and bicarbonate concentrations of the groundwater are varied from 6.6 to 8.8 and 18 to 527 mg/L, respectively. High fluoride concentration in the groundwater of the study area is observed when pH and the bicarbonate concentration are high. Data plotted in Gibbs diagram show that all groundwater samples fall under rock weathering dominance group with a trend towards the evaporation dominance category. An assessment of the chemical composition of groundwater reveals that most of the groundwater samples have compositions of Ca2?–Mg2?–Cl-[Ca2?–Na?– HCO3-[Ca2?–HCO3 -[Na?–HCO3 -. This suggests that the characteristics of the groundwater flow regime, long residence time and the extent of groundwater interaction with rocks are the major factors that influence the concentration of fluoride. It is advised not to utilize the groundwater for drinking purpose in the areas delineated, and they should depend on alternate safe source.
Environmental …, 2010
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.
Occurrence of Fluoride in the Groundwater of Kaltungo Area and Environs, North Eastern Nigeria
Journal of Geoscience and Environment Protection, 2019
The aim of the study is to assess the occurrence of fluoride in the groundwater of Kaltungo area and environs. Consumption of high fluoride waters clearly manifests in the majority inhabitant of the area in form of dental fluorosis especially in the majority of the populace. Thirty groundwater samples were collected from hand-dug wells and boreholes using standard method and were analyzed to determine the fluoride level. The results revealed that the Fluoride in the waters ranges from 0.8 to 1.94 mg/l with a mean value of 1.65 mg/l. No clear variations in fluoride content have been observed in both the borehole samples and those from the hand-dug wells. Ca-Mg-HCO 3 and Ca-Mg-Cl are the two major water types obtained in the area, which have a good association with fluoride. Negative correlation is observed between fluoride and temperature, fluoride and magnesium, fluoride and potassium and poor correlation is observed between fluoride and chloride, fluoride and nitrate, fluoride and phosphates which rules out the possibility of anthropogenic source of the fluoride in the waters. Positive correlation between fluoride and iron, indicates that the presence of fluoride in the water is as a result of dissolution of biotite within the host rock (Basalt).
Distribution of fluoride in groundwater of Maku area, northwest of Iran
Environmental Earth Sciences, 2008
High fluoride groundwater occurs in Maku area, in the north of West Azarbaijan province, northwest of Iran. Groundwater is the main source of drinking water for the area residents. Groundwater samples were collected from 72 selected points including 40 basaltic and 32 nonbasaltic springs and wells, in two stages, during June and August 2006. The areas with high fluoride concentrations have been identified, and the possible causes for its variation have been investigated. Regional hydrogeochemical investigation indicates that water-rock interaction is probably the main reason for the high concentration of ions in groundwater. The concentration of F− in groundwater is positively correlated with that of HCO3− and Na+, indicating that groundwater with high HCO3− and Na+ concentrations help to dissolve some fluoride-rich minerals. All of the water samples, collected from the basaltic areas do not meet the water quality standards for fluoride concentration and some other parameters. Hence, it is not suitable for consumption without any prior treatment. Inhabitants of the area that obtain their drinking water supplies from basaltic springs and wells are suffering from dental fluorosis. The population of the study area is at a high risk due to excessive fluoride intake especially when they are unaware of the amount of fluoride being ingested due to lack of awareness.
Environmental Geochemistry and Health, 2010
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 3 signatures, while those with fluoride >1.5 mg/l show a tendency towards Na-HCO3 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.
DESALINATION AND WATER TREATMENT
Fluoride contamination in groundwater in the Bongo District of Ghana was investigated using samples from 323 boreholes covering three geologic zones; granite, greenstones, and igneous/ metamorphic. The relationship between fluoride concentrations and the geologic zones, ground water depth, pH, and conductivity were determined to assess the risk of fluorosis from the inges tion of groundwater in these zones and to potentially guide future borehole locations. Data clearly showed that the problem of groundwater fluoride contamination exists mainly in the area underlain by granite and the risk of fluorosis and other fluoride ingestion related diseases exist for about 39% of the population of the District living in the granite zone. No clear correlation was found between fluoride concentration and pH, conductivity or depth of the boreholes, which rules out alternative borehole locations as a solution to the problem. An option for fluoride removal is a hybrid pre adsorption/ultrafiltration treatment system powered by solar panels in offgrid communities in the District. Under nonoptimized field conditions, the performance was affected by the adsorption capacity of the unmodified, natural laterite and membrane type. Improvement on laterite capacity or use of other adsorbents, and membrane type selection and optimization of such a system would be required for the field application.
Applied Water Science , 2017
Hydrogeochemical investigation has been carried out in the granitic terrain of Siddipet area, Medak district, Telangana State, India with an aim to understand the distribution of fluoride in the groundwater and to understand the relationship of fluoride with other major ions, and also to identify the high fluoride-bearing groundwater zones. 104 groundwater samples were analyzed in the study area for fluoride and other major ions like calcium, magnesium, chloride, carbonate, bicarbonate, sodium, potassium, sulfate, and nitrate in addition to pH and electrical conductivity. The studies revealed that the concentration of fluoride in groundwater is ranging from 0.2 to 2.2 mg L-1 with a mean of 1.1 mg L-1. Nearly 22 % of groundwater has more than the permissible limit of fluoride (1.5 mg L-1), which is responsible for the endemic dental fluorosis in the area concerned. Geo-chemical classification of groundwater shows that Na– HCO 3 , Ca–Cl, and Ca–HCO 3 –Na are the dominant hydrochemical facies. Gibbs diagram shows rock–water interaction dominance and evaporation dominance, which are responsible for the change in the quality of water in the hard rock aquifer of the study area. The groundwater in villages and its environs are affected by fluoride contamination , and consequently majority of the population living in these villages suffer from dental fluorosis. Hence, they are advised to consume drinking water which has less than 1.5 mg L-1 fluoride to avoid further fluorosis risks.