Hydrochemistry with special reference to fluoride contamination in groundwater of the Bongo district, Upper East Region, Ghana (original) (raw)
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West African Journal of Applied Ecology, 2017
Fluoride contamination of groundwater within the Savelugu-Nanton District was assessed using hydrogeochemical framework and multivariate statistical approach. Eighty-one (No) boreholes were sampled for quality assessment in May and June 2008. The main objective of this study was to assess the fluoride levels in groundwater and delineate areas of low fluoride and high fluoride within the district. The study show that, 41.9% of the boreholes are within the safe limits of 0.5-1.5 mg/L of fluoride for the protection of bones and teeth, 43.2% of the boreholes have fluoride levels below the lower safe limit (< 0.5 mg/L) and therefore vulnerable to dental caries, 10.8% of the boreholes have fluoride levels between 1.5 and 3.0 mg/L and therefore vulnerable to dental fluorosis and 4.1% of the boreholes have fluoride levels between 3.0 and 10 mg/L and therefore vulnerable to skeletal fluorosis. The results further show that, 14.9% of groundwater requires defluoridation, while, 43.2% of groundwater requires fluoride addition to the groundwaters. PCA using Varimax with Kaiser Normalization results in the extraction of three main principal components which delineates the factors that influence the principal components of the physico-chemical parameters. The three principal components have accounted for approximately 83% of the total variance. Component 1 delineates the main natural processes through which groundwater within the basin acquire its chemical characteristics. Component 2 delineates pollution sources principally fluoride and nitrate. Component 3 suggests mineralogical influence of fluoride with some major ions on the chemistry of groundwater. The loadings and score plots of the first two PCs which explains 71.52% of the total variance show grouping pattern which indicates the strength of the mutual relation amongst the hydrochemical variables. Biological defluoridation though not very well understood, is recommended as a best alternative to the conventional methods of defluoridation especially in developing countries due to its cost effectiveness.
Springer policies © Pleiades Publishing, Ltd., 2020
Groundwater is only the primary source for drinking water in the northern Telangana, South India, where a number people suffers from fluorosis. With this concern a 34 groundwater samples were collected and studied to identify the occurrence, hydrochemical distribution of fluoride groundwater, using geo-statistical tool such as principal component analysis (PCA), saturation indices (SI), and correlation analysis were executed in this study. The concentration of fluoride ranges from 0.06 to 4.33 mg/L, with a mean of 1.13 mg/L and 30% of groundwater samples having above the maximum acceptable limit of 1.2 mg/L fluoride for drinking purposes. Fluoride shows a considerable relation with pH, and TDS, while fluoride also demonstrations an insignificant correlation with Ca 2+. Moreover, alkaline nature, elevated HC , Na + and Na +-HC water type were also influenced to enhance the fluoride concentration in the groundwater. The two components from the principal components (PC) analysis reveals that chemical variable accounts for above 67% of the total variance of the groundwater chemistry. The PC-1 and PC-2 have high positive loadings reveals that the dissolution of fluoride bearing minerals like apatite and biotite are the chief source to larger concentration of fluoride in the study region groundwater. Further, groundwater also obviously approves the over-saturated with respect to calcite, fluorite, and dolomite are the major factors to upholds the enrichment of fluoride concentration, while the geogenic activities are also a principal controlling factors to influence the groundwater chemistry in the study region.
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.
Water Science, 2017
High fluoride (F −) groundwater causes fluorosis which might at severe stages lead to deformation of bones, bilateral lameness. The concentration of F − ranged from 0.4 to 4.8 mg/L. This study suggests that high HCO 3 − and Na + in alkaline medium along with water-rock interaction plays important role in enrichment of F − in groundwater. Na-HCO 3 is the dominant water type followed by Ca-HCO 3 suggesting dominance of Na + , Ca 2+ and HCO 3 − ions in groundwater. Factor analysis of water quality parameters suggests that four principal components account for 74.66% of total variance in the dataset. Factor 1 shows higher positive loading for pH, HCO 3 − negative loading for F − , Ca 2+ , SO 4 2− depicting ion-exchange and HCO 3 dominant water type responsible for F enrichment in groundwater. Saturation index for selected minerals suggests that most of the samples are oversaturated with calcite and undersaturated with fluorite. Calcite precipitation leads to the removal of Ca 2+ from solution thus allowing more fluorite to dissolve. These released Ca 2+ ions combine with CO 3 2− ions to further enhance the precipitation of CaCO 3 .
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.
2012
Groundwater plays a pivotal role in the domestic water delivery system in Northern Ghana. The resource has sometimes been rendered unsuitable for use due to contamination from various sources. In this study, a factor model was developed to determine the major hydrochemical processes that control the variations in the concentrations of fluoride and other ions in the groundwater delivered by the Middle Voltaian aquifers in Savelugu and surrounding areas in the Northern Region of Ghana. This study finds that four major processes control the hydrochemistry of groundwater resources in the area: dissolution of soluble salts in the aquifers, the oxidation of organic carbon by nitrate, silicate mineral weathering and the dissolution of sulfate minerals in the aquifers. The present study finds that fluoride enrichment is related to the weathering of silicate minerals. A linear interpolation map, showing the distribution of fluoride concentrations in the groundwater system has been produced. ...
Environmental Monitoring and Assessment, 2017
The present research work is confined to a rural tract located in the northwestern part of Birbhum district, West Bengal, India. Chemical analysis of the groundwater shows the cations is in the order of Na + > Ca 2 + > Mg 2 + while for anions it is HCO 3 ─ > Cl ─ > SO 4 2─ > NO 3 ─. The F ─ concentration was found to vary from 0.01 to 18 mg/L in the premonsoon and 0.023 to 19 mg/L in post-monsoon period. 86% of samples show low F ─ content (<0.60 mg/L) whereas, 8% exhibit elevated concentration of F ─ (>1.2 mg/L) mainly in the central and north-central parts of the study area at a depth of 46 to 98 m. The prime water type is CaHCO 3 succeeded by F ─-rich NaHCO 3 and NaCl waters. The suitability analysis reveals that the water at about 81% of the sampling sites is unsuitable for drinking and at 16% of sites unsuitable for irrigation. The alkaline nature of the water and/or elevated concentration of Fe, Mn and F ─ make the water unsuitable for potable purposes while the high F ─ and Na + contents delimit the groundwater for irrigation uses. Multivariate statistical analysis suggests that chemical weathering along with ion exchange is the key process, responsible for mobilization of fluoride in groundwater of the study area.
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.
Anais da Academia Brasileira de Ciências, 2008
Principal component analysis is applied to 309 groundwater chemical data information from wells in the Serra Geral Aquifer System. Correlations among seven hydrochemical parameters are statistically examined. A four-component model is suggested and explains 81% of total variance. Component 1 represents calcium-magnesium bicarbonated groundwaters with long time of residence. Component 2 represents sulfated and chlorinated calcium and sodium groundwaters; Component 3 represents sodium bicarbonated groundwaters; and Component 4 is characterized by sodium sulfated with high fluoride facies. The components' spatial distribution shows high fluoride concentration along analyzed tectonic fault system and aligned on northeast direction in other areas, suggesting other hydrogeological fault systems. High fluoride concentration increases according to groundwater pumping depth. The Principal Component Analysis reveals features of the groundwater mixture and individualizes water facies. In this scenery, it can be determined hydrogeological blocks associated with tectonic fault system here introduced.