Assessment of the mineralogy of granitoids and associated granitic gneisses responsible for groundwater fluoride mobilization in the Vea catchment, Upper East Region, Ghana (original) (raw)
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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.
ABSTRACT Groundwater is the most appropriate portable and widely used source of drinking water for many rural communities in Ghana and its quality has special health significance and needs great attention of all concerned since it is the major alternate source of domestic, industrial and drinking water supply in Ghanaian communities. Fluoride is a common constituent of groundwater and its sources are connected to various types of rocks and to volcanic activity, Agricultural (use of phosphate fertilizers) and industrial activities. Fluoride contamination in drinking water is a public health problem in many areas around the world. Chronic ingestion of high doses has been linked to the development of dental fluorosis, abnormal thyroid function and other hormonal disturbances and in extreme cases, skeletal fluorosis. High doses have also been linked to cancer (Marshall, 1990) and (Ilamiiton, 1992). The study was carried out to evaluate the geologic controls on fluoride concentrations in groundwater from northern and southern Ghana on the West African Craton. Groundwater from active pumping wells and rock samples from outcrops were collected from various communities from northern and southern Ghana for fluoride and petrological (thin section) analysis. The fluoride concentration in groundwater in some communities of northern Ghana was recorded up to 4.0 mg/l and the overall water quality found was unsatisfactory with respect to fluoride for drinking purposes without any treatment and 0.8mg/l for the south which is considered to be good for drinking. The petro logical analysis indicates that the geological source of fluoride in groundwater is related to leaching of minerals from rocks thus metamorphic (gneissic) rocks and granitoids (Bongo granites) which are rich in mica, quartz and sericite as well as microcline. Among the fluoride-bearing minerals, only biotite was abundant in rock samples. There was a Positive correlation between fluoride concentration in the groundwater and the percentage of biotite composition in rock samples. Therefore, the high fluoride concentrations in the groundwater are more likely to result from the dissolution of biotite (K (Mg,Fe)3AlSi3O10(F,OH)2) which contain fluorine at the OH− sites of the octahedral sheet.
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.
Journal of Hydrology, 2019
Fluorosis is an endemic disease that is now a global challenge. In this review paper we have classified and described the global fluoride belts (GFB) geologically and geographically connecting different countries. A proper map of the global fluoride belts showing the inland connections between each belt is presented. Several natural factors like the rock type, soil, tectonics, hydrogeology and climate of a terrain which are majorly responsible for engrafting higher fluoride in drinking water are described. A detailed uniform description of each belts with respect to geology, geochemistry are discussed. The minor factors like altitude, phosphate mining etc. on fluorosis are also discussed including countries like Canada, Norway etc. which are potentially affected by fluorosis. The correlation of different ions like Cl-, Ca 2+ , etc; pH, electrical conductivity, TDS etc are compared and reviewed in detailed with respect to different GFB. The genesis and sources of fluoride contamination are also supported by different isotopic evidences. In this article, the insitu methods involving natural minerals and materials which can adsorb fluoride effectively and are being used globally are exhaustively assessed. The methods 2 which are highly sustainable with minimum waste generation and cost effective are also evaluated.
The aim of the present study is to identify the geochemical processes responsible for higher fluoride (F –) content in the groundwater of the Yellareddigudem watershed located in Nalgonda district, Andhra Pradesh. The basement rocks in the study area comprise mainly of granites (pink and grey varieties), which contain F-bearing minerals (fluorite, biotite and hornblende). The results of the study area suggest that the groundwater is characterized by Na + : HCO facies. The F – content varies from 0.42 to 7.50 mg/L. In about 68% of the collected groundwater samples, the concentration of F – exceeds the national drinking water quality limit of 1.5 mg/L. The weathering of the granitic rocks causes the release of Na + and HCO ions, which increase the solubility of ions. Ion exchange between Na + and Ca 2+ , and precipitation of CaCO 3 reduce the activity of Ca 2+. This favours dissolution of CaF 2 from the F-bearing minerals present in the host rocks, leading to a higher concentration of F – in the groundwater. The study further suggests that the spatial variation in the F – content appears to be caused by difference in the relative occurrence of F-bearing minerals, the degree of rock-weathering and fracturing, the residence time of water in the aquifer materials and the associated geochemical processes. The study emphasizes the need for appropriate management measures to mitigate the effect of higher F groundwater on human health.
The aim of this paper was to explore new factors that might be reasons for the occurrence of fluoride-rich groundwater in the area around a construction site. During the construction of two deep shafts of the Mizunami Underground Research Laboratory (MIU) in Mizunami city, central Japan, a large quantity of groundwater with high fluoride concentration was charged into the shafts. Chemical investigation carried out during the excavation revealed that fluoride concentrations in the area around the MIU site greatly exceeded those prescribed by Japanese standards. Therefore, the origin of fluoride ion was experimentally investigated. Samples were collected from the core of a deep borehole drilled in the study area. The weathering -and alteration levels of the collected granites varied greatly. Granitic powders were used to measure fluoride content in the granitic rock mass. The fluoride content ranged between 200 and 1300 mg/kg. The powders were reacted with purified water for 80 days. The results of water-rock interaction showed granitic rock to be one of the main sources of fluoride-rich groundwater in Mizunami area. Fluoride concentrations in these solutions that were shaken for 80 days varied between 2 and 7 mg/l. This change may have occurred as a result of the spatial distribution of fluoride ions in the granite mass as evidenced by mineralogical analysis of fluoride content in several specimens. X-ray powder diffraction analysis of the rock before-and after the water-rock interaction tests manifested that the presence of fluorite mineral was relatively small compared to other minerals. The degree of weathering and alteration might be an additional factor causing dissolution of fluoride-rich minerals. However, it was difficult to interpret the change in fluorite composition by X-ray diffraction analysis.
Applied Water Science, 2014
Fluoride is a chemical element that has been shown to cause significant effects on human health through drinking water. Different forms of fluoride exposure are of importance and have shown to affect the body's fluoride content and thus increasing the risks of fluoride-prone diseases. Fluoride has beneficial effects on teeth; however, low concentrations of fluoride intensify the risk of tooth decay. Fluoride can also be quite detrimental at higher concentrations at skeletal fluorosis. The Thoothukudi District is a hard rock and alluvial plain marked as one of the Fluoride-increase area in Tamilnadu due to occurrence of various rock types including fluoride-bearing minerals. The Fcontent of groundwater can thus originate from the dissolution of Fluoride-bearing minerals in the bed rock. Hundred representative groundwater samples from Thoothukudi District were collected during two different seasons. Samples were analysed for F-, other major cations and anions. The study area is chiefly composed of hornblende biotite gneiss, charnockite, alluvio marine, fluvial marine and granite with small patches of quartzite and sandstone. Higher concentration of fluoride is observed during pre-monsoon (3.3 mg l-1) compared to the postmonsoon (2.4 mg l-1) due to the dilution effect. Spatial distribution and factor score show that higher concentrations of Fare noted in the north and central part of the study area owing to lithology. Bicarbonate is well correlated with Fwhich explains that both ions were derived from the weathering. While Fhas a very weak correlation with pH which may be due to the increase of alkalinity resulting from the increase of carbonate and bicarbonate ions.
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.
Geological Source of Fluoride in Fluoride Endemic Region of Gaya District, Bihar, India
Biochemical and Biophysical Research Communications, 2019
The present study reports about the fluoride containing minerals present in the rock and soil samples collected from the fluoride endemic region of Gaya district of Bihar. Fluoride was measured in 77 water samples collected from fluoride endemic villages and 69 samples contained fluoride > 1.5 mg/L. A positive correlation was found between pH and fluoride (r=0.24), suggesting geogenic contamination of fluoride into groundwater. X-ray diffraction (XRD) analyses of rocks and soil samples were done. Results showed the presence of biotite in the rock and soil samples, suggesting that F might be leaching from biotite into the groundwater.
Fluoride in groundwater: a case study in Precambrian terranes of Ambaji region, North Gujarat, India
Fluoride is one of the critical ions that influence the groundwater quality. World Health Organization (WHO, 1970) and Bureau of Indian Standards (BIS, 1991) set an upper limit of 1.5 mg L −1 in F − concentration for drinking water purpose and above affects teeth and bones of humans. The presence of fluoride in groundwater is due to an interaction of groundwater and fluoride bearing rocks. Fluoride rich groundwater is well known in granitic aquifers in India and elsewhere. Generally, the concentration of F − in groundwater is controlled by local geological setting; leaching and weathering of bedrock and climatic condition of an area. The main objective of the present study is to assess the hydrogeochemistry of groundwater and to understand the abundance of F − in groundwater in hard rock terranes of Ambaji region, North Gujarat. A total of forty-three representative groundwater samples were collected and analyzed for major cations and anions using ICP-AES, Ion Chromatograph (Metrohm 883 Basic IC Plus) and titration methods. The F − concentration in groundwater of this study area ranges from 0.17 to 2.7 mg L −1. Among, twenty groundwater samples have fluoride exceeding the maximum permissible limit as per the BIS (1.5 mg L −1). It is also noticed that residents of this region are affected by dental fluorosis. The general order of the dominance of major cations and anions are Ca 2+ > Mg 2+ > Na + > K + and HCO − 3 > Cl − > F − respectively. Geochemical classification of groundwater shows most of the samples are the alkaline earth-bicarbonate type. The semi-arid climatic conditions of the region, the dominance of granitoid-granulite suite rocks and the fracture network in the disturbed and brittle zone has facilitated the development of potential aquifers and enrichment in F − concentration in this area. The concentration of fluoride is due to high evaporation rate, longer residence time in the aquifer zone, intensive and long term pumping for irrigation.