High Fluoride Water Research Articles

Utilization of organic waste from Chinar leaves as sustainable and eco-friendly adsorbent for fluoride removal.

Due to concerns about high water fluoride concentrations and their detrimental consequences on health, particularly dental and skeletal fluorosis, dependable and cost-effective defluoridation techniques are needed. Chinar leaves (Platanus orientalis), a common waste, might be utilized for the production of activated carbon. For Chinar leaf activated carbon (CLAC) manufacturing, two pre-pyrolysis chemical modification procedures were used: acidic HCl (H-activation) and alkaline NaOH (OH-activation). The success of fluoride removal suggests further research and implementation in locations with fluoride-related water quality issues. This study examines how CLAC dosage, fluoride concentration, temperature, pH, and contact exposure effect defluoridation efficiency. The pseudo-second-order non-linear kinetic model and Freundlich non-linear isotherm model with R2 = 0.99 fit the data, resulting in a peak adsorption capacity of 30.3mg/g for 0.3g CLAC. In the present work, the adsorption mechanism was regulated by more than intraparticle diffusion. Adsorption occurred spontaneously as exothermic monolayer chemisorption, according to thermodynamic studies. Adsorbent activated with HCl (H-activated) showed promising results, with 73% F- removal efficiency for OH-activated and 91% for H-activated CLAC.

Effect of Groundwater Fluoride Concentration on Human Health: A Systematic Review

In studies conducted by various researchers it was observed that the groundwater is polluted by fluoride in most of the parts of World. Due to reported health related issues some workers carried out carcinogenic risk assessments and meta-analysis of fluoride exposure to humans. In this context, fluoride concentration data in groundwater across India by systematic searches conducted in various international search engines databases was collected. In some tests High water and urine fluoride levels in children indicated the chronic exposure to fluoride and suggested that the population is at high risk of developing chronic fluorosis in some regions of World. This paper highlighted the research work of various workers wherein Fluoride concentration risk factors related to human health are pointed and also discussed the steps to reduce fluoride in ground water. Keywords: Fluoride, Carcinogenic risk assessment, meta-analysis, ground water, chronic fluorosis.

Association of Dental Fluorosis and Urinary Fluoride with Intelligence among Schoolchildren.

Fluoride is present naturally in water and has been used worldwide for the prevention of caries. Several studies conducted in high water fluoride or endemic fluorosis areas reported that fluoride adversely affected children's cognitive function, but some studies had negative findings. This study aimed to assess the relationship between urinary fluoride, dental fluorosis, and intelligence among schoolchildren living in communities with non-fluoridated drinking water. This cross-sectional study was conducted on 562 children aged 6-12 years in Taichung, Taiwan. Each child's urinary fluoride level was determined by a fluoride-ion-selective electrode, and the dental fluorosis condition was evaluated according to the criteria of Dean's Index. The Raven's Colored Progressive Matrices-Parallel and Standard Progressive Matrices-Parallel were used to assess children's intelligence. The results showed that the mean (±standard deviation) urinary fluoride concentrations were 0.40 ± 0.27 mg/L (0.43 ± 0.23 mg/g creatinine) among participants. The prevalence of dental fluorosis was 23.67%. After extensive evaluation of potential confounders, dental fluorosis and urinary fluoride were not associated with intelligence quotient (IQ) scores or grades in the regression models. In conclusion, dental fluorosis and urinary fluoride levels were not significantly related to the IQ of schoolchildren living in areas with low drinking water fluoride.

A community-based study of dental fluorosis in rural children (6-12 years) from an aspirational district in Karnataka, India.

The present study was planned to estimate the prevalence of dental fluorosis in 6-12 years of children and its association with various drinking water sources, water, and urine fluoride levels among the subset of children under the umbrella of a larger study to address iodine deficiency disorders and iron deficiency anemia in 17 villages of Manvi and Devadurga talukas of Raichur district of Karnataka. Analysis of subset of data and urine samples of children under the umbrella of a larger cross-sectional community-based study was conducted in 17 villages of Manvi and Devadurga taluks of Raichur district. House to house survey was carried out to collect data using a semi-structured questionnaire in ODK software. Demographic details, source of drinking water, clinical assessment of dental fluorosis, and height and weight measurements were performed by trained staff. Urine and water samples were collected for fluoride level estimation. The overall prevalence of dental fluorosis and its severity-wise prevalence were estimated. Association between dental fluorosis and age, gender, type of diet, source of drinking water, height for age, BMI for age, water fluoride level, and urine fluoride level were carried out using logistic regression analysis. The prevalence of dental fluorosis was 46.0%. Mild, moderate, and severe dental fluorosis was found in 37.9, 7.8, and 0.3% of children. With the increasing age of participants, the odds of dental fluorosis were found to increase by 2-4 folds. The odds of having dental fluorosis were significantly increased with increasing water fluoride levels of 3 to 5 ppm [AOR = 3.147 (1.585-6.248); P = 0.001] in comparison with water fluoride levels of < 1 ppm. The similar trend was found with urine fluoride level > 4 ppm [AOR = 3.607 (1.861-6.990); P < 0.001]. As compared to river water, other sources of drinking water were significantly associated with higher odds of dental fluorosis. Prevalence of dental fluorosis was high in 6 to 12 years due to overexposure of fluoride from drinking water. High water and urine fluoride levels in children indicate the chronic exposure to fluoride and suggest that the population is at high risk of developing chronic fluorosis.

Fluorine in shallow groundwater in China: A review of distribution, occurrence and environmental effects

With rapid economic development and the increasing demand for drinking water, a large amount of groundwater is exploited, resulting in a high F− content in groundwater, which is harmful to the environment and human body. In this study, 5,464 data points of fluoride in shallow groundwater were collected, and the F− content distribution, occurrence form and environmental impact of shallow groundwater were discussed. The results showed that 1) the F− content in shallow groundwater in China ranged from 0 to 60 mg/L, with a mean content of 0.90 mg/L; the lowest average F− content in shallow groundwater in Southwest China was 0.36 mg/L; South China (1.20 mg/L), Northeast China (1.25 mg/L) and Northwest China (1.25 mg/L) were considered high-fluoride areas, and North China (0.93 mg/L), East China (0.67 mg/L) and Central China (0.80 mg/L) were considered low-fluoride areas. The mean F− content in groundwater differed between provinces and cities. 2) The F− in shallow groundwater mainly occurred in ionic, complex ionic and organic fluoride molecular states. 3) The influence of a high F− content in shallow groundwater on the environment was mainly manifested in the increase in water F− concentration and soil F− and vegetable F− content. The influence of a high F− content on the human body was mainly manifested in an increase in urinary F− content in children, a high prevalence of dental fluorosis in children, an increase in skeletal fluorosis rate in adults with age, and an influence on cognitive function of older adults. These results provide a basis for F− pollution control and high-fluoride water treatment.

The effect of mining development in karst areas on water acidification and fluorine enrichment in surface watersheds

High fluoride water is a crucial driving factor for endemic fluorosis. As an important research content of hydrogeochemistry, the enrichment of fluorine in alkaline water has received a fair amount of scholarly attention, but the understanding of the migration and enrichment of fluorine in acid mine drainage (AMD) in karst area remains very limited. An analysis of 13 consecutive periods of hydrochemical samples (312 samples in total) revealed that the weathering of carbonates and sulfide-rich coal measures induced a pH as low as 2.29 in the Chetian River in Jinsha, Southwest China. The highest content of fluorine in AMD was 23.8 mg/L, and the average content in the basin was 1.4 mg/L. In terms of the seasonal variation in the whole basin, the fluorine content were higher in the rainy season than in the dry season. The mineral saturation index shows that the dissolution of fluorapatite and fluorite is an important source of fluorine. The chloro-alkaline indices displayed a strong ion exchange process in the basin, promoting the release of fluorine in silicate minerals. In comparison, the contribution of external inputs, such as atmospheric deposition, was less. Additionally, evaporation was shown to have a limited influence on fluorine enrichment. Meanwhile, pH was an essential factor driving the dynamic transformation of the mode of occurrence of fluorine in water. In the upstream alkaline water, the main occurrence form of fluorine was free F−, while the F/Al ratio for most of the acidic samples was ≤ 1.0, indicating the main occurrence form of fluorine was likely AlF2+. The conclusion of this study provides a new understanding for deepening the geochemical characteristics of fluorine in karst surface water.

Hydro-geochemical control of high arsenic and fluoride groundwater in arid and semi-arid areas: A case study of Tumochuan Plain, China

Globally, groundwater with high fluoride and arsenic receives extensive concern because of its wide distribution and great harm to human health caused by drinking water. In this paper, taking Tumochuan Plain in China as an example, based on hydrogeological investigation, groundwater flow system theory and hydro-chemical analysis methods were applied to reveal the mechanism of high fluoride and high arsenic in arid and semi-arid regions. In unconfined and confined groundwater of Tumochuan Plain, the highest concentration of fluoride is 7.2 and 11.2 mg/L respectively, and the highest concentration of total arsenic is 200.3 and 162.3 μg/L respectively. Fluoride in groundwater is mainly derived from the soluble fluoride in soil and aquifer medium. Because of the water-rock interaction, the alkaline environment caused by the hydrolysis of feldspar minerals in the central part of the plain has an important influence on the accumulation of F and As in this area. High fluoride water is formed in the alkaline environment (high pH values) of high concentration of Na+ and low concentration of Ca2+. The high arsenic groundwater is distributed in the alkaline reducing environment that the content of soluble salt in aquifer media is high (>200 mg/100 g dry soil). The reductive dissolution of iron and manganese oxides and competitive adsorption of HCO3− all contribute to a high level of arsenic in both unconfined and confined aquifers. The research results have important guiding significance for water supply safety and water quality improvement in arid-semiarid areas in the world with high fluoride and high arsenic groundwater distribution.

Preparation of 2D carbon ribbon/Al2O3 and nitrogen-doped carbon ribbon/Al2O3 by using MOFs as precursors for removing high-fluoride water

2D carbon ribbon/Al2O3 was synthesized with two-dimensional metal organic frameworks 2D-MOFs as precursors using the solvothermal and calcination methods. Batch experiments of adsorption parameters such as pH, liquid/solid ratio, adsorption kinetics, adsorption thermodynamics, and anions competitions were investigated to understand the adsorptive behavior of fluoride on carbon ribbon/Al2O3 and nitrogen-doped carbon ribbon/Al2O3. The adsorption of fluoride on carbon ribbon/Al2O3 could be described as the chemical and multilayer adsorption, while the adsorption of fluoride on nitrogen-doped carbon ribbon/Al2O3 followed the chemical and monolayer adsorption phenomenon. The fluoride on nitrogen-doped carbon ribbon/Al2O3 had a much faster adsorption rate of 3.1×10−7 m/s than carbon ribbon/Al2O3, which was 1.2×10−7 m/s. The nitrogen-doping on carbon ribbon enhances structural defects and improves the adsorption performance of fluoride. Also, the diacetylene linkages (—C≡C—) and pyridinic-N were studied to understand their influences on removing fluoride. The result indicates that carbon ribbon and nitrogen-doped ribbon could serve as good adsorbents for removing fluoride.

Effect of drinking high fluoride water on liver enzymes a comparitive cross-sectional study

ABSTRACT Objective: The aim of this study is to determine the effects of drinking water with high fluoride level on liver functions. Method: This is a descriptive comparative cross-sectional study conducted at Sammu rind village where the drinking water has increase fluoride content. The comparative area was Gadap town where the drinking water has normal fluoride level. Sampling was done randomly and sample size was calculated by WHO calculator and found to be 121 each for exposed and unexposed population. Blood samples taken for liver functions included bilirubin, AST, ALT, Alkaline phosphate, Gamma GT, total protein, albumin and globulin. SPSS version 16 was used for analysis. Mean and SD calculated for quantitative variable and the two comparative groups were cross-tabulated. To check the statistical significance t-test was applied. Results: There was no statistically significant difference with consideration to serum bilirubin, ALT, and AST. However, statistically significant difference was established with respect to alkaline phosphatase, Gamma GT total proteins and A/G ratio between two groups. Conclusion: In our study, there was no evidence of impaired liver function tests in subjects drinking water with high fluoride content.

Study on Environmental Factors of Fluorine in Chagan Lake Catchment, Northeast China

The Chagan Lake Catchment is located in the midwest of Songnen Plain, which is a typical high fluoride groundwater area. High fluoride water has an important impact on the economic development and ecosystem stability of Chagan Lake. In this study, the spatial distribution characteristics and influencing factors of fluorine in Chagan Lake Catchment are discussed by using hydrochemistry and mathematical statistical analysis. The groundwater in the study area was characterized as Na+-rich and Ca2+-poor, with a high pH value and high HCO3– content. The average concentration of F– was 3.02 mg/L, which was the highest in Qian’an County. The dissolution of fluorine-containing minerals and the desorption of F– in soil provided the source of F– in groundwater, while calcite and dolomite precipitation, cation exchange, and evaporation concentration provided favorable conditions for F– dissolving, migration, and enrichment in water. In addition, the concentration of F– in surface water was 4.56 mg/L, and the highest concentration was found in Hongzi Pool and Hua’ao Pool. The elevated concentrations of F– in both surface water and groundwater in the study were affected by human factors, such as rice planting and water conservancy project construction.

Dental Fluorosis and Periodontium: an Original Research Report of In Vitro and In Vivo Institutional Studies.

Fluorosis is one of the global problems that have persisted for a very long time now without any specific treatment and cure. Fluoride is known for its influence on the tooth structures like enamel and dentin, but little information exists on its effect on the surrounding periodontal structures and bone. With this background, we conducted multiple studies assessing etiological, diagnostic, therapeutic and clinical criteria in subjects with and without dental fluorosis in a single group of the population residing in high fluoride water areas (1.5-3.0ppm) of Davangere District, Karnataka, India. These preliminary studies conducted are hereby elaborately presented and discussed in this comprehensive review article along with their important conclusions.

Lactobacillus johnsonii BS15 improves intestinal environment against fluoride-induced memory impairment in mice-a study based on the gut-brain axis hypothesis.

BackgroundExcessive fluoride can lead to chronic neurodegeneration characterized by neuron and myelin loss and memory dysfunction. The gut–brain axis hypothesis suggests that gut microbiota plays a crucial role in regulating brain function. Thus, using probiotics to adjust the gut microenvironment may be a potential therapy for mental diseases.MethodsMice in the prob group were administrated with Lactobacillus johnsonii BS15 for 28 days prior to and throughout a 70-day exposure to sodium fluoride. The drinking water of all groups (F and prob groups) except the control group were replaced by high-fluoride water (100 mg NaF/L) on day 28. Animals in each group were divided into two subsets: one underwent behavioral test, and the other was sacrificed for sampling. The mRNA expression level and protein content related to inflammatory reaction in the ileum and hippocampus were respectively detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of proteins related to myelin structure, apoptosis, and memory in the hippocampus and tight junction proteins in the ileum were determined by RT-qPCR and/or immunohistochemistry. Gut permeability markers (D-lactate and diamine oxidase (DAO)) in the serum were also examined by ELISA.ResultsThe results showed that fluoride exposure induced a lower spontaneous exploration (P < 0.05) in T-maze test, which indicated an impairment of memory. Spontaneous exploration of BS15-treated mice was significantly higher (P < 0.05) than that in F group. Fluoride reduced (P < 0.05) levels of myelin structural protein (proteolipid protein) and neurogenesis-associated proteins (brain-derived neurotrophic factor and cAMP/Ca2+ responsive element-binding protein), induced disordered inflammatory cytokines (TNF-α, IFN-γ, and IL-6; P < 0.05), increased pro-apoptotic genes (caspase-3; P < 0.05), and decreased anti-apoptotic genes (Bcl-2; P < 0.05) in the hippocampus, of which the influences were reversed by BS15. BS15 treatment exerted significant preventive effects on reversing the gut inflammation induced by excessive fluoride intake by reducing (P < 0.05) the levels of pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ)) and remarkably increasing (P < 0.05) the level of anti-inflammatory cytokines (IL-10). Moreover, the serum DAO activity and D-lactate concentration significantly increased by fluoride were also reduced (P < 0.05) by BS15. This result indicated the profitable effect of BS15 on gut permeability.ConclusionL. johnsonii BS15 intake could benefit the neuroinflammation and demyelination in the hippocampus by improving the gut environment and ameliorating fluorine-induced memory dysfunction.

Challenges of Groundwater Development for Towns and Big Cities Water Supply in Rift Valley Areas

The experiences of the last 30 years developed an understanding in the Addis Ababa Water Utility that groundwater sources are not fully dependable for such a big city. Notwithstanding this, additional wells and well-fields are being developed especially in the last 10 years to meet the ever increasing demand. The Akaki well-field was initially designed for an abstraction rate of up to 35,000 m3/day for 20 years until 2020 though the current abstraction rate is nearly ten-fold. The current developments are only demand driven irrespective of safe and sustainable utilization. What is making things worse is the rise of other water competing demands for irrigation projects in adjacent well-fields. The present water supply coverage of the Addis Ababa city is not more than 50%. The situation in other urban centers in the Upper Awash basin is not different. Conceptual modelling, time series well water level measurements and operational assessments showed that the aquifer systems are not uniform and dotted with many volcanic flow barriers; there is sharp decline of water table (up to 70 meters since 2000) in some well-fields and the decline is propagating upstream of the Akaki well-field. Moreover, the excessive and uncontrolled pumping is impacting regional groundwater table. Topographic and technical issues are hampering upstream water distribution, and the once exemplary hundreds of wells are now abandoned. The frequent tapping of thermal and high fluoride water is another complication. Unless proper intervention is devised, grave environmental problems are likely to come in the near future.

Revealing drinking water quality issues and possible health risks based on water quality index (WQI) method in the Shanmuganadhi River basin of South India.

The aim of the study is to address the issues and associated health risks due to consumption of high-fluoride water supplied for drinking in a rural part of Shanmuganadhi River basin, Tamil Nadu, India. In this study, 61 groundwater samples were gathered from various tube and open wells and analysed for fluoride and other physicochemical parameters. The abundance of cations is Na+ > Ca2+ > Mg2+ > K+, and that of anions is HCO3- > SO42- > Cl- > F-. The fluoride concentration in drinking groundwater varied from 0.10 to 3.3mg/l. According to the WHO standards, about 26% of the samples were unfit for drinking requirements (16 out of 61 samples) Water quality index (WQI) method was adopted to categorize the water into different classes to understand its suitability for drinking requirements. WQI signified that nearly 52% of the samples denoted poor, very poor and not suitable categories, whereas 48% of samples denoted good and excellent categories for consumption. Health risks associated with high-fluoride drinking water were assessed for various age groups of inhabitants such as children, teens and adults. The hazard quotient estimated based on the oral intake ranged from 0.00E+00 to 5.50E+00, from 0.00E+00 to 4.22E+00 and from 0.00E+00 to 3.45E+00 for children, teens and adults, respectively. It suggested that the health risks are associated with 75%, 59% and 43% of samples, respectively, among children, teens and adults. Therefore, children are more inclined towards risk than teens and adults in this region based on the intake of fluoride-rich drinking water. To improve the present scenario, groundwater should be either treated before drinking water supply or must be artificially recharged to lower the concentration of ions.

Mechanism of fluoride removal by AlCl3 and Al13: The role of aluminum speciation

Coagulation is an important defluorination process. However, because of the poor sedimentation properties, conventional coagulants often result in limited defluorination performance and excessive residual aluminum. In this study, AlCl3 and the highly-positively-charged molecule [AlO4Al12(OH)24(H2O)12]7+ (Al13) was utilized to treat fluoride-containing water. By comparison, the role of aluminum speciation in fluoride removal was elucidated. Under initial pH of 6.0, 7.0 and 8.0, the highest defluorination efficiencies of high-fluoride water ([F−]0 = 8.0 mg/L) were 78.2%, 71.6% and 83.2% at Al13 dosage of 20 mg/L, 40 mg/L and 50 mg/L. Combined with detailed investigations of the chemical compositions of flocs, along with electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) analysis of residual aluminum, the defluorination mechanisms of both coagulants were discussed. In acidic conditions, both coagulants hydrolyzed and formed various Al clusters, among which transient Al (Alts) was the intermediate of the other clusters. The coprecipitation of high-polymerized Al and F− contributed most of the defluorination rate. While under neutral and alkaline conditions, hydrogen bonding and ion exchange together with coprecipitation were the main roles for Al13. The effects of AlCl3 were merely physical actions, and were affected by the decreased pH. This work provides new insights into the coagulation and defluorination process.

Experimental rat model for acute tubular injury induced by high water hardness and high water fluoride: efficacy of primary preventive intervention by distilled water administration

BackgroundHigh water hardness associated with high water fluoride and the geographical distribution of Chronic Kidney Disease of unknown etiology (CKDu) in Sri Lanka are well correlated. We undertook this study to observe the effects of high water hardness with high fluoride on kidney and liver in rats and efficacy of distilled water in reducing the effects.MethodsTest water sample with high water hardness and high fluoride was collected from Mihinthale region and normal water samples were collected from Kandy region. Twenty-four rats were randomly divided into 8 groups and water samples were introduced as follows as daily water supply. Four groups received normal water for 60 (N1) and 90 (N2) days and test water for 60 (T1) and 90 (T2) days. Other four groups received normal (N3) and test (T3) water for 60 days and followed by distilled water for additional 60 days and normal (N4) and test (T4) water for 90 days followed by distilled water for another 90 days. The rats were sacrificed following treatment. Serum samples were subjected to biochemical tests; serum creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and elemental analysis. Histopathological examinations were carried out using kidney and liver samples.ResultsTest water treated groups were associated with acute tubular injury with loss of brush border and test water followed with distilled water treated groups maintained a better morphology with minimal loss of brush border. Serum creatinine levels in T1 and T2 groups and urea level in T2 group were significantly (p < 0.05) increased compared to control groups. After administration of distilled water, both parameters were significantly reduced in T4 group (p < 0.05) compared to T2. Serum AST activity was increased in T4 group (p < 0.05) compared to control group with no histopathological changes in liver tissues. The serum sodium levels were found to be much higher compared to the other electrolytes in test groups.ConclusionHard water with high fluoride content resulted in acute tubular injury with a significant increase in serum levels of creatinine, urea and AST activity. These alterations were minimized by administering distilled water.

Appraisal of groundwater quality for drinking and irrigation purposes in Central Telangana, India

Groundwater is only an important water resources for drinking and irrigation in the central Telangana, India. Rapid growth in the population and intensive irrigation practises has become stress on groundwater, the available groundwater are being depleted and its quality has also deteriorated. For this reason, a total of 105 groundwater samples collected from semi-arid region of central Telangana, were executed in order to evaluate its suitability for drinking and irrigation purposes. Results highlighted that most of the groundwater is suitable for drinking purposes based on pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH) as CaCO3, calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl−), and sulphate (SO42−). About, 51% and 71% of groundwater samples were exceeded the maximum permissible limits of fluoride and nitrate, respectively. Therefore, it is suggested that groundwater with high fluoride and nitrate concentration water should be avoided for drinking purposes. Spatial distribution maps are generated using GIS platform and the dissimilar distribution pattern was noticed for nitrate and fluoride in the study region. Gibbs plots authenticate that the groundwater chemistry is controlled by rock-water interaction and geochemical scatter plots suggested that the silicate mineral dissolution play dominant role in the chemistry of groundwater. According to the water quality index (WQI) values, 60% and 36% of groundwater samples fall under excellent and good category for drinking purposes. The groundwater is Na+ - SO42−, deep meteoric percolation type, but most of it belong to Ca2+–Mg2+–HCO3−, Na+–HCO3− facies and few are Ca2+–Mg2+–Cl− and Na+-Cl- facies. Majority of groundwater samples exhibit that the alkaline earths (Ca2+ + Mg2+) exceed alkali cation (Na+ + K+) and strong acids (SO42− + Cl−) dominate over weak acid (HCO3−). Irrigational suitability of groundwater in the study area was also estimated through sodium adsorption ratio (SAR), sodium percentage (%Na), and residual sodium carbonate (RSC), magnesium hazard ratio (MHR), and Kelly ratio (KR) results shown that the majority of the groundwater samples were suitable for irrigation uses.

Relationship between dental fluorosis and I.Q of school going children aged 10-12 years in and around Nalgonda district-A cross-sectional study.

The fluoride ion toxicity has been associated with both dental fluorosis and neurotoxicity; dental fluorosis has tended to be considered with respect to tooth appearance and function rather than as a marker for neurotoxicity. This study assessed the intelligence quotient (IQ) of school-going children aged 10-12 years in villages of Nalgonda district with different fluoride levels. A cross-sectional study was conducted among the permanent residents of Nalgonda district of Telangana state, India. A total of 480 government schoolchildren aged 10-12 years were selected by stratified random sampling from three different areas with different levels of naturally occurring fluoride in drinking water. Intelligence levels were assessed by conducting the Ravens standard progressive matrices test (1991 edition). The data were subjected to analysis of variance (ANOVA), Student's t-test, and Krustal-Wallis ANOVA. A logistic regression model was performed (SPSS version; 21(IBM corporation, Chicago,IL, USA)). The mean IQ levels were more in the villages with low fluoride concentration in drinking water (15.26) compared to villages with medium fluoride content (12.91) and high fluoride content (9.1). A significant statistical association was found (P < 0.001). The overall IQ levels in children exposed to high fluoride level significantly lower than the low fluoride areas. Thus, children intelligence can be affected by high water fluoride levels.

Geochemical assessment of fluoride enriched groundwater and health implications from a part of Yavtmal District, India

A comprehensive study was conducted from a semi-arid part of Yavtmal District, Maharashtra, India through combination approaches of geochemical modeling and its health consequences. The groundwater quality assessment shows that 55% of groundwater samples have the concentration of fluoride above the desirable limit. The high Na+/Ca+ ratio (>1.0) suggest the occurrence of cation exchange, which is further supported by Scholler’ chloro-alkaline indices. The geochemical modeling reveals that the existence of CaCO3 precipitation and CaF2 in groundwater. Simulation analysis indicates the dissolution of calcite, gypsum, and albite and precipitation of dolomite, fluorite, halite, and K-feldspar along with cation exchange as the main water–rock interactions influencing the groundwater chemistry. This is further significantly supported by pollution index of groundwater (PIG). PIG indicates about 18% of total samples fall in very high pollution zone, 3% in high pollution zone, 8% in moderate pollution zone, 24% in low pollution zone, and remaining (47%) express insignificant pollution. The 28% of subject studied have skeletal fluorosis varying from mild to severe type. In different pollution zones, the affected persons by dental fluorosis are varying from 15% to 41%. A proper monitoring and treatment are required for high fluoride water before its use for drinking and cooking.

Facile defluoridation of drinking water by forming shell@fluorapatite nanoarray during boiling egg shell

High fluoride water is one of the major problems against drinking water and are affecting millions of people all over the world. Refined adsorbents and water treatment plants aim at massive water supply but can't meet scattered household requirements, especially in the developing areas. Here, we developed a facile defluoridation method in which F- can be removed by boiling eggs or shell assisted by phosphate. 0.4 L of high fluoride water (10 mg/L) can be transformed to safe drinking water with F- concentration lower than 1.5 mg/L by boiling one egg at 80 °C for 10 min with the addition of 0.3 g/L of NaH2PO4 and 0.05 v% acetic acid. The mechanism study shows that F- is adsorbed onto the egg shell outer surface forming nanorod arrays of fluorapatite and/or F- substituted hydroxyapatite. Higher F- adsorption capacity can be obtained (Langmuir adsorption capacity, 47.9 mg/g) if using egg shell powder instead of whole eggs. Pilot scale defluoridation (2.5 L, 10 times) was successfully realized by boiling egg shell in the presence of phosphate and acetic acid. The boiling shell defluoridation technology has potential household applications by common people with little professional backgrounds.