Abstract: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 sugg… Show more
“…Occurrence of high fluoride levels in shallow wells may be attributed to weathering of fluoride bearing material from granite, granite-gneiss, amphibolite and mica-schist and deposition of same over the host rock as a weathered mantle might be the prominent reason for higher fluoride concentration in the area 39,47 . Upward movement of fluoride-concentrated water from deep aquifer may be another dominant factor for enrichment of fluoride concentration in shallow wells 48–50 .Figure 3Fluoride distribution in paired deep and shallow wells of same location.…”
Section: Resultsmentioning
confidence: 99%
“…Say for an instance, if the hydrogen ion concentration of less than 7 prevails in the groundwater, F − remains adhered with clay due to the low solubility of F − . The reverse is the situation in alkaline medium, where, OH − group replaces the exchangeable F − of clay minerals (biotite/muscovite) resulting in the enhanced F − concentration in aquifer 48,57 .…”
Section: Resultsmentioning
confidence: 99%
“…4–10 mg/L) 3,4,66 . This happens mainly because of the F − being highly electronegative and having similar ionic radius (133 pm) with that of hydroxyl ion (140 pm) that leads to the formation of hydrogen fluoride 48,55–57 . Particularly, this compound in human body freely diffuses across the intestine, dissolves in the blood, and accumulation in calcified tissues 7,21 .…”
As drinking water is considered as a major pathway of exposure to fluoride in the human body, an endeavor has been made for the assessment of the non-carcinogenic health risk by using hazard quotient (HQ) of fluoride for males, females, and children separately in fluoride affected ground water areas of Indo-Gangetic Alluvial Plains. The study suggests that children groups are more prone to the non-carcinogenic risk of fluoride in the area as HQ for fluoride is more than unitary in 44% (Pre-monsoon) and 38% (Post-monsoon) samples respectively. Field survey conducted in fluoride-affected villagers of the study area portrays cases of mottling of teeth and bone deformities depending on the duration and dosage of fluoride consumption. Petrographic observations of host rocks coupled with molar ratios of chemical species studies exemplify that weathered material developed over the granite-gneiss, mica-schist, amphibolite, granitic intrusive and pegmatite veins due to weathering and extensive water-rock interaction resulting higher concentration of fluoride in groundwater. Likewise, the base exchange index (r1) and meteoric genesis index (r2) advocates that most of the samples belong to Na+-HCO3− type and meteoric origin respectively, and substantiate longer residence time of water along with solute acquisition processes are responsible for elevated fluoride in groundwater. It is, therefore, solar energy-driven electrolytic de-fluoridation technology ought to be provided on a priority basis to the affected inhabitants besides the implementation of rainwater harvesting schemes for mitigation/ dilution of elevated fluoride concentration.
“…Occurrence of high fluoride levels in shallow wells may be attributed to weathering of fluoride bearing material from granite, granite-gneiss, amphibolite and mica-schist and deposition of same over the host rock as a weathered mantle might be the prominent reason for higher fluoride concentration in the area 39,47 . Upward movement of fluoride-concentrated water from deep aquifer may be another dominant factor for enrichment of fluoride concentration in shallow wells 48–50 .Figure 3Fluoride distribution in paired deep and shallow wells of same location.…”
Section: Resultsmentioning
confidence: 99%
“…Say for an instance, if the hydrogen ion concentration of less than 7 prevails in the groundwater, F − remains adhered with clay due to the low solubility of F − . The reverse is the situation in alkaline medium, where, OH − group replaces the exchangeable F − of clay minerals (biotite/muscovite) resulting in the enhanced F − concentration in aquifer 48,57 .…”
Section: Resultsmentioning
confidence: 99%
“…4–10 mg/L) 3,4,66 . This happens mainly because of the F − being highly electronegative and having similar ionic radius (133 pm) with that of hydroxyl ion (140 pm) that leads to the formation of hydrogen fluoride 48,55–57 . Particularly, this compound in human body freely diffuses across the intestine, dissolves in the blood, and accumulation in calcified tissues 7,21 .…”
As drinking water is considered as a major pathway of exposure to fluoride in the human body, an endeavor has been made for the assessment of the non-carcinogenic health risk by using hazard quotient (HQ) of fluoride for males, females, and children separately in fluoride affected ground water areas of Indo-Gangetic Alluvial Plains. The study suggests that children groups are more prone to the non-carcinogenic risk of fluoride in the area as HQ for fluoride is more than unitary in 44% (Pre-monsoon) and 38% (Post-monsoon) samples respectively. Field survey conducted in fluoride-affected villagers of the study area portrays cases of mottling of teeth and bone deformities depending on the duration and dosage of fluoride consumption. Petrographic observations of host rocks coupled with molar ratios of chemical species studies exemplify that weathered material developed over the granite-gneiss, mica-schist, amphibolite, granitic intrusive and pegmatite veins due to weathering and extensive water-rock interaction resulting higher concentration of fluoride in groundwater. Likewise, the base exchange index (r1) and meteoric genesis index (r2) advocates that most of the samples belong to Na+-HCO3− type and meteoric origin respectively, and substantiate longer residence time of water along with solute acquisition processes are responsible for elevated fluoride in groundwater. It is, therefore, solar energy-driven electrolytic de-fluoridation technology ought to be provided on a priority basis to the affected inhabitants besides the implementation of rainwater harvesting schemes for mitigation/ dilution of elevated fluoride concentration.
“…This indicates that the hydro-chemical facies of the high-fluoride drinking groundwater are more complex and diverse. Generally, the high-fluoride groundwater belonged to the Na-HCO 3 type, as dissolved Na + and Mg + promote elevated Fconcentrations in water [15,16,39,40].…”
There has been substantial research on the sources and geochemical processes associated with fluoride (F -) in agricultural groundwater. However, the spatial distribution, geochemical behaviours, and enrichment mechanisms of fluoride in the groundwater from a coal-mining district used for drinking water supply have not been fully understood. In this study, 42 drinking water samples of the groundwater were collected in May 2019 and March 2020 from the Sulin coal-mining district, Anhui, China. Samples were analysed to investigate the distribution, geochemical behaviour, and formation mechanisms of fluoride. The Fconcentrations in the groundwater samples ranged from 0.55 to 2.06 mg/L, with a mean value of 1.16 mg/L. The Fconcentrations in 54.76% of the water samples exceeded China's national standards (1.00 mg/L). The results show that the Fin the water was enriched in an environment with high pH and HCO 3 content. The weathering of Fbearing minerals was the main source of Fin the drinking water supply. Evaporation, cation exchange, competitive effect, and anthropogenic activities were considered to have promoted elevated Fconcentrations in the groundwater resource. This research will aid policy development for properly managing drinking water to eliminate health problems in coal-mining districts due to excessive fluoride intake.
“…As discussed later in Section 4.3.1, saturation index for selected minerals suggests that most of the thermal water samples are oversaturated with calcite and undersaturated with fluorite. Calcite precipitation leads to the removal of Ca 2+ from thermal waters, thus allowing more fluorite to dissolve [46].…”
Two separate groups of geothermal waters have been identified in the coastal region of Guangdong, China. One is Xinzhou thermal water of regional groundwater flow system in a granite batholith and the other is thermal water derived from shallow coastal aquifers in Shenzao geothermal field, characterized by high salinity. The hydrochemical characteristics of the thermal waters were examined and characterized as Na-Cl and Ca-Na-Cl types, which are very similar to that of seawater. The hydrochemical evolution is revealed by analyzing the correlations of components versus Cl and their relative changes for different water samples, reflecting different extents of water-rock interactions and clear mixing trends with seawaters. Nevertheless, isotopic data indicate that thermal waters are all of the meteoric origins. Isotopic data also allowed determination of different recharge elevations and presentation of different mixing proportions of seawater with thermal waters. The reservoir temperatures were estimated by chemical geothermometries and validated by fluid-mineral equilibrium calculations. The most reliable estimates of reservoir temperature lie in the range of 148-162 ∘ C for Xinzhou and the range of 135-144 ∘ C for Shenzao thermal waters, based on the retrograde and prograde solubilities of anhydrite and chalcedony. Finally, a schematic cross-sectional fault-hydrology conceptual model was proposed.
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