Range Of Fluoride Concentrations Research Articles

Assessment of groundwater fluoride and human health effects in a hard rock province of south India: Implications from Pollution Index Model (PIM) and GeographicalInformationSystem (GIS) techniques.

This research examines whetherthe groundwater in the Sivakasi Region of South India is suitable for consumption, and assesses the possible health hazards for various age demographics including infants, children, teenagers, and adults. A totalof 77 groundwater samples were gathered, covering a total area of 580km2 and analyzed for major and minor ions. The hydrogen ion concentration (pH) of the samples indicates neutral to marginally alkaline. The total dissolved solids (TDS) fluctuate from 255 to 2701mg/l and electrical conductivity varies from 364 to 3540µS/cm. A wide range of fluoride concentration was detected (0.1 to 3.2mg/l) with nearly 38% groundwater samples surpassing the proposed limit (1.5 mg/l) suggestedby the World Health Organization in 2017. Gibbs plot analysis suggested that most of thesamples were influenced by geogenic factors, primarily rock weathering in this region. Correlation analysis showed that most of the samples were impacted by both natural and human sources. The pollution index of groundwater (PIG) fluctuated from 0.67 to 2.60 with approximately 30% and 53% of samples falling into insignificant and low pollution categories, respectively. Furthermore, 10% and 5% of total samples were characterized as moderate and high pollution levels, and 2% asvery high pollution category. Spatial analysis using GIS revealed that 440.63km2 were within safe fluoride levels according to theWHO standards, while 139.32km2 were identified as risk zone. The principal component analysis (PCA1) showedstrong positive loadings on EC (0.994), TDS (0.905), Mg2+ (0.910), Cl- (0.903) and HCO3- (0.923) indicating rock water interaction. PCA2 accounts the high positive factor loading on HCO3- (0.864) indicating ion exchange and mineral leaching. The PCA1 and PCA2 indicated that variables such as mineral leaching and rock water interaction are themajor mechanisms contributing to the chemical signatures in groundwater, which may support for theelevated fluoride levels in certain areas. Risk assessments, including Hazard Quotient results showed that 71%, 61% 38%, and 34% of groundwater samples exceededthe permissible THI limit (THI > 1) for infants, children, teenagers, and adults, respectively. The study recommends implementing measures such as denitrification, defluorination, rainwater harvesting, and improved sanitation infrastructure to enhance the health conditions in the study region. Additionally, it suggests introducing educational programs in rural areas to create awarenessabout the health dangers due to consumptionof water with high fluoride levels.

Should we be concerned about the use of non-fluoride toothpaste? A survey study in two European countries.

Toothpastes available in Europe contain a range of fluoride concentrations, with some meeting the recommended level for caries prevention (>1000 ppm fluoride (ppm)) and others containing low or no fluoride. This study evaluated toothpaste fluoride concentrations in Latvia and Lithuania to inform targeted public health strategies in regions with a high prevalence of dental caries. This cross-sectional study was conducted from May 2019 to May 2020, using a validated questionnaire in Latvia and Lithuania. Nationally representative samples (1309 families and 5436 members) provided data through a mixed-mode survey (paper and online) on sociodemographic information, toothpaste type, brand, and type. Descriptive statistics and chi-square tests (p < 0.05) were used for analysis. Fifteen percent of families used non-fluoridated toothpaste and 12% used <1000 part per million (ppm) fluoride. In Latvia, 56.8% of preschoolers and 28.7% of schoolchildren used <1000 ppm or non-fluoride toothpaste, whereas in Lithuania, 47.2% of preschoolers and 29.1% of schoolchildren used <1000 ppm or non-fluoride toothpaste; 63% of adolescents and 73% of adults used toothpaste with optimal fluoride content (≥1000 ppm). Of the 228 registered toothpaste types, 62% contained more than 1000 ppm, which is optimal for caries prevention; 29% of Latvian and 24% of Lithuanian families used at least one non-fluoridated toothpaste. This study revealed significant gaps in the use of fluoride toothpaste among families in Latvia and Lithuania, especially among children. To effectively prevent dental caries, targeted interventions, and education must promote optimal fluoride toothpaste use, particularly among vulnerable populations.

Taguchi’s optimization technique for water deflouridation through electrocoagulation

Excess fluoride in drinking water is posing serious health concern to humankind. Electrocoagulation is an emerging technique for water defluoridation, and recent research is focused on the optimization of process variables for achieving maximum fluoride removal. As such, the Taguchi optimization technique is adopted to arrive at optimum values process parameters which can provide maximum fluoride removal with more accuracy and fewer experimental runs. In the present research a laboratory-scale batch EC reactor with four aluminum electrodes (98% pure) connected to a DC supply for a wide range of fluoride concentrations which were not studied in earlier researches. Taguchi’s L 16 orthogonal array was applied for optimization of the process variable It revealed maximum efficiency of 86.67% for defluoridation at optimum conditions of process variables with pH: 6 ± 0.1, initial adsorbate concentration: 5 mg/L, EC time: 45 min, voltage: 25 V, and IED: 2 cm. The percentage contribution of process variables was obtained by ANOVA in descending order as initial adsorbate concentration (45.31%) > pH (33.83%) > voltage (13.68%) > EC time (4.2%) > IED (2.98%). Freundlich isotherm and second-order kinetic models were found to be the best suitable for water defluoridation using the EC process. FTIR and XRD analysis for EC sludge also confirmed the fluoride sorption onto A l ( O H ) 3 flocs. The electrode consumption of 0.263 kg/ m 3 , and total operational cost of USD 0.6004/ m 3 were estimated for water defluoridation using the EC process.

Evaluation of Fluoride Concentration in Drinking Water of Some Cities within Anbar Province, Iraq

A fluoride atom (F) has a negatively-charged ion called a fluoride ion. The element fluoride can also be found in a compound called fluoride. Many countries with high rates of dental fluorosis naturally contain high levels of fluoride in their minerals and water supplies. The fluoride ion concentrations were determined by collecting drinking water samples twice a month from (July/2020 - to June/2021) from 4 main cities in Anbar Province in Iraq, during the rainy and dry seasons. The fluoride concentrations were then analyzed and compared with standard guides of the United States Environmental Protection Agency (USEPA) and the World Health Organization (WHO). The objective of this study is to evaluate the fluoride concentrations in Ramadi, Fallujah, Khalidiyah, and Heet cities. The results showed small variations ranging from (0.041 mg/l) to (0.051 mg/l) when these results are compared with Environmental Protection Agency (EPA) and World Health Organization (WHO) standard limitations. the recommended standard limitations of (EPA) and (WHO) for fluoride concentration range from (0.4 - to 1.5) mg/l, therefore the drinking water of these cities is comfortable to drink, but it may cause some problems, such as dental caries, dental fluorosis, colorless teeth yellowish, and blackish teeth. The results are also less than the typical concentration limitations, which, is (0.7 mg/l). To avoid the danger of poisoning, adding fluoride to water is not recommended unless it has been recommended by a professional in the food system or a dentist. However, humans can also get fluoride from sources other than water, and the quantity of fluoride they consume is different from one person to another.

Synchrotron radiation analysis of root dentin: the roles of fluoride and calcium ions in hydroxyapatite remineralization.

Although the use of fluoride for root caries control is reported to be effective, the mechanism of maintaining hydroxyapatite is still unclear. This study elucidates the roles of fluoride in the recrystallization of hydroxyapatite, and the impact of calcium to maintain the abundance of hydroxyapatite on acid-challenged root dentin with a novel approach - using synchrotron radiation. Root dentin samples obtained from 40 extracted human premolars were subjected to pH challenge in combination with fluoride treatment. The effect of fluoride on hydroxyapatite regeneration on the root was investigated by using a range of fluoride concentrations (1000-5000 p.p.m.) and the EDTA-chelation technique in vitro. Synchrotron radiation X-ray micro-computed tomography and X-ray absorption spectroscopy were utilized to characterize the chemical composition of calcium species on the surface of prepared samples. The percentage of hydroxyapatite and the relative abundance of calcium species were subsequently compared between groups. The absence of calcium or fluoride prevented the complete remineralization of hydroxyapatite on the surface of early root caries. Different concentrations of fluoride exposure did not affect the relative abundance of hydroxyapatite. Sufficient potency of 1000 p.p.m. fluoride solution in promoting hydroxyapatite structural recrystallization on the root was demonstrated. Both calcium and fluoride ions are prerequisites in a caries-prone environment. Orchestration of F- and Ca2+ is required for structural homeostasis of root dentin during acid attack. Sustainable levels of F- and Ca2+ might thus be a strict requirement in the saliva of the population prone to root caries. Fluoride and calcium contribute to structural homeostasis of tooth root, highlighting that routine fluoride use in combination with calcium replenishment is recommended for maintaining dental health. This study also demonstrates that utilization of synchrotron radiation could provide a promising experimental platform for laboratory investigation especially in the dental material research field.

Formulation and fluoride content of dentifrices: a review of current patterns.

Introduction Consumer oral hygiene products play a key role in improving and maintaining population oral health. The oral personal care market is rapidly diversifying; a growing number of dentifrices marketed a 'natural' and fluoride-free are entering mainstream retailers, which may have implications for the oral health of the population 'with regards to caries risk.Aims To investigate the range of fluoride concentrations, flavour formulations and delivery mechanisms of dentifrices available on the UK market.Methods A cross-sectional survey was used to catalogue dentifrices sold in a range of supermarkets, high-street pharmacy and health chains, and specialist online retailers. In addition, a standard search engine was used to examine dentifrice brands being sold in the UK. The fluoride content was recorded as parts per million (ppm) and the product name data were analysed for key terms using Microsoft Excel. Excluded from the survey were mouthwashes, rinses and non-dentifrice whitening products.Results Five hundred different toothpaste, tooth powder and tablet products from 95 different brands were recorded. Sixty percent of these contained a fluoride concentration of 1,000 ppm or above. Forty-five percent of all products had the recommended adult concentration of at least 1,350 ppm. Almost one-third (31%) contained no fluoride and 4% of products did not specify the absence, presence or concentration of fluoride.Conclusions This study has quantified and confirmed the increasingly diverse range of dentifrices for sale in the UK. A large number of fluoride-free products exist within a growing 'natural' and 'organic market'. The study also gives oral health professionals an insight into the diverse types of products available to consumers in order to appropriately advise patients on caries prevention.

سنتز و بکارگیری نانوکامپوزیت منیزیوم فریت – کیتوسان برای حذف فلوراید از محلول آبی با استفاده از بهینه سازی سطح – پاسخ

Background and objectives: Excess fluoride ions in drinking water cause several diseases so the defluoridation of drinking water with excess fluoride is necessary for human health. Hence this work describes fluoride removal from water using MgFe 2 O 4 – chitosan nanocomposite. Material and methods: In this work a nitrate salt of Mg and Fe were used to synthesis MgFe 2 O 4 through a combustion route. Then MgFe 2 O 4 - chitosan nanocomposite was synthesized using epichlorohydrin as a linker. Characterization of the sorbent was performed with FESEM, TEM, VSM, EDX and XRD techniques. Effective parameters on the adsorption process such as pH, contact time, adsorbent dosage and fluoride concentration was optimized by response surface methodology (RSM) using Box – Behnken design (BBD). Isotherm study was studied at the fluoride concentration range of 10 – 100 mg/L. Results: The optimum value of pH, contact time, adsorbent dosage and fluoride concentration were 2.8, 4.5 min, 19.0 mg and 28.87 mg/L, respectively. At the optimum condition maximum removal efficiency was 98.1%. Results showed that adsorption process followed Langmuir model with capacity of 181.1 mg/g. Conclusion: The result of the present work showed that the nanohybrid has good potential as a cheap magnetic sorbent for environmental remediation purpose as can be used for effective removal of fluoride from water solution.

Development of the New Fluoride Ion-Selective Electrode Modified with FexOy Nanoparticles.

A new modified ion-selective electrode with membranes of LaF3 single crystals with different internal contacts (solid steel or electrolyte) and with FexOy nanoparticles as loading was developed. The best response characteristic with linear potential change was found in the fluoride concentration range from 10−1 to 3.98 × 10−7 M. The detection limit for the electrolyte contact was determined at 7.41 × 10−8 M with a regression coefficient of 0.9932, while the regression coefficient for the solid contact was 0.9969. The potential change per concentration decade ranged from 50.3 to 62.4 mV, depending on whether the contact was solid or electrolytic. The prepared modified electrode has a long lifetime, as well as the possibility of application in different positions (solid contact), and it can also be used for the determination of iron ions. The electrode characterization was performed with scanning electron microscopy and elemental analysis with the technique of electron-dispersive X-ray spectroscopy.

Synthesis and characterization of magnetized ETS‐4 modified with lanthanum and iron for fluoride adsorption

AbstractIn this work, two adsorbents were synthesized by loading lanthanum and iron ions on magnetized ETS‐4 titanosilicate. The sorbents were identified by Fourier‐transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), thermogravimetry, differential thermogravimetry (TG‐DTG), X‐ray diffraction (XRD), and Brunauer‐Emmette‐Teller techniques, and their adsorption performance for the sorption of fluoride was evaluated in a wide fluoride concentration range. The influence of various variables, including shaking time, fluoride concentration, pH, and temperature, on the uptake of fluoride was investigated. The maximal capacity of ETS‐4 impregnated with La and with Fe was 260.69 and 231.43 mg/g, respectively. The used sorbent was readily removed from the solution by using a magnet bar. The regenerated sorbent retained most of its capability after regeneration. The results of the kinetic study were described by a pseudosecond‐order model, indicating that the process was chemisorption in nature. The Freundlich isotherm well described the sorption data, which implied that the adsorption was multilayered and heterogeneous.

Hidden dangers? Investigating the impact of volcanic eruptions and skeletal fluorosis in medieval Iceland

Volcanic emissions are known to be a serious source of pollution to humans and animals. This study aimed to examine the possible health burden of fluoride (F) exposure from volcanic eruptions in the past. Osteological analyses were performed on 186 skeletons from seven sites across Iceland with the aim of identifying skeletal changes potentially associated with osteofluorosis. Additionally, ion selective electrode (ISE) was used to investigate possible correlations between skeletal lesions and bone fluoride concentrations in a subset of skeletons (n = 50) from two of these sites, Skriðuklaustur in Fljótsdalur and Skeljastaðir in Þjórsárdalur. The results showed that pathological markers or skeletal changes increased according to age across all investigated time periods and geographical regions but likely not due to significant fluoride exposure. The fluoride concentration range was 223–4370 ppm (mean = 2324 ± 1067 ppm) at Skriðuklaustur (n = 36) while at Skeljastaðir (n = 14), the range was 223–3030 ppm (mean = 1366 ± 937 ppm). The pathological changes noted in this study are thus more likely to relate to the environment, population dynamics, culturally mediated behaviours and increasing urbanisation than serious fluoride contamination. Therefore, volcanic emissions appear to have only substantially affected those living within the closest vicinity of actual eruption events. It may be vital to not only consider the severity of the immediate effects of volcanic pollution but also to reinforce socioeconomic circumstances and disaster preparation in regions with environmental hazards.

Determination of Fluoride in Various Samples Using a Fluoride Selective Electrode

Fluoride is widespread in the environment, water, air, vegetation and Earth’s crust which can entre ground and surface water by natural process. Fluoride in minute quantities is essential component for human health and help in normal mineralization of bone and formation of dental enamel. The determination of fluoride in some species was performed by using fluoride ion-selective electrode by direct measurement and standard addition method. The concentration of fluoride ion was determined in drinking water (from different place at Kathmandu), toothpaste, various brand of tea and coffees. The range of fluoride concentration in water sample was 0.16 to 0.39 mg/l, tea and coffee samples were 0.011 to 0.084 mg/l and its value of toothpaste was 0.026 to 0.75 mg/l. The concentration of fluoride ion obtain from different sample was compared with the legitimate value given by the world health organization.

Evaluation of groundwater quality, Peddavagu in Central Telangana (PCT), South India: an insight of controlling factors of fluoride enrichment

Groundwater is one of the most valuable natural resources in Peddavagu in Central Telangana (PCT). Most of the PCT region population rely on groundwater for especially drinking purposes. For this reason a thirty-five groundwater samples were collected, analysed various physico-chemical parameters including F−. The range of fluoride concentration 0.6–3.6 mg/L in Zone-I and 1–3.5 mg/L in Zone-II. pH of groundwater is from 7.1 to 8.4 and 7.3 to 8.3 in Zone-I and Zone-II respectively. Fluoride shows a significant correlation with pH, HCO3−, and Na+, which may leads to enhance the fluoride content in groundwater. Insignificant relationship between F− and NO3− suggests no influence of anthropogenic sources for F− content in groundwater. The results of the relationship between Na++K+ versus total cations (TZ+), Ca2++Mg2+ versus HCO3−+SO42− describes silicate weathering is prevails in the groundwater chemistry. The dominance of the water types Na+-HCO3−> Ca2+-Mg2+-HCO3−> Ca2+-Mg2+-SO42−Cl−>Na+-Cl−. Gibbs plot employed to differentiate the controlling mechanisms of hydrochemistry, which showed that rock water interaction is the governing process. Na+-HCO3−, alkaline nature water and rock water interaction can leads to elevate fluoride content into groundwater in the study region. Thereby, most of the region people suffer with fluorosis problem, due to intake of higher fluoride content of drinking water. Therefore, the study region population may avoid such untreated water for drinking and adopt a suitable method to reduce the fluorosis problem in future.

Investigation and mapping of fluoride-endemic areas and associated health risk—A case study of Agra, Uttar Pradesh, India

ABSTRACTThe present study aimed at identifying the fluoride-endemic areas in five different blocks in Agra district, Uttar Pradesh, India. A total of 365 groundwater samples from 73 villages were analyzed for establishing the concentration range of fluoride in drinking water. The fluoride level in the study area varied from 0.14 to 4.88 mg/L. Out of 73, the fluoride levels in 45 villages did not meet the permissible Word Health Organization standards. The Baroli Ahir block was found the highly fluoride-endemic area followed by Saiyan, Bichpuri, Achnera and Etmadpur. Chronic daily intake of fluoride in adults was 1.25 and 1.5 times higher than those in children and infants, respectively. The probability of dental fluorosis in infants was higher (42%) while adults were more prone to bone and skeletal fluorosis (60%). The hazard quotient analysis revealed that children were found to be at maximum risk followed by infants and adults. Sensitivity analysis revealed that the fluoride concentration is the major influencing parameter responsible for different types of fluorosis in various age groups.

Spatial distribution mapping of drinking water fluoride levels in Karnataka, India: fluoride-related health effects.

(1) To estimate the concentrations of fluoride in drinking water throughout different zones and districts of the state of Karnataka. (2) To investigate the variation of fluoride concentration in drinking water from different sources, and its relationships to daily temperature and rainfall status in the regional districts. (3) To develop an updated fluoride concentration intensity map of the state of Karnataka, and to evaluate these data in the context of fluoride-related health effects such as fluorosis and their prevalence. Aqueous standard solutions of 10, 100 and 1,000 ppm fluoride (F-) were prepared with analytical grade Na+/F- and a buffer; TISAB II was incorporated in both calibration standard and analysis solutions in order to remove the potentially interfering effects of trace metal ions. This analysis was performed using an ion-selective electrode (ISE), and mean determination readings for n = 5 samples collected at each Karnataka water source were recorded. The F- concentration in drinking water in Karnataka state was found to vary substantially, with the highest mean values recorded being in the north-eastern zone (1.61 ppm), and the lowest in the south-western one (only 0.41 ppm). Analysis of variance (ANOVA) demonstrated that there were very highly significant 'between-zone' and 'between-districts-within-zones' sources of variation (p < 10-5-10-9), results consistent with a substantial spatial variance of water source F- levels within this state. The southern part of Karnataka has low levels of F- in its drinking water, and may require fluoridation treatment in order to mitigate for dental caries and further ailments related to fluoride deficiency. However, districts within the north-eastern region have contrastingly high levels of fluoride, an observation which has been linked to dental and skeletal fluorosis. This highlights a major requirement for interventional actions in order to ensure maintenance of the recommended range of fluoride concentrations (0.8-1.5 ppm) in Karnataka's drinking water sources.

High fluoride drinking water in Gokwe, northwest Zimbabwe

More than 200 million people worldwide are exposed to excessive fluoride in drinking water. According to the World Health Organization, the optimal concentration range of fluoride in drinking water is 0.5 to 1.5 mg/L. Above this range, populations may contract dental fluorosis or, in severe cases, crippling skeletal fluorosis. In the Gokwe area in NW Zimbabwe, where drinking water contains up to 11 mg/L fluoride, fluorosis prevalence has previously been estimated at 62%. This paper investigates the water quality of 126 water sources in Gokwe (58 pumped boreholes, 15 flowing artesian boreholes, 46 wells and 7 streams). The water chemistry, determined from high performance ion chromatography and field measurements, showed that the water source types exhibit significantly different (P &amp;lt; 0.05) concentrations of F−, Cl−, Na+, K+, Ca2+, Mg2+, temperatures, pH and conductivity values. Thirty-five (28%) of the 126 water sources (18 pumped boreholes, 15 artesian boreholes, one well and one stream) contained F− &amp;gt; 1.5 mg/L, indicating that fluoride contamination in the area is a characteristic of deeper groundwater, possibly due to its interactions with the potentially fluoridic coaly and carbonaceous materials of the Lower Karoo Aquifer at depth. The plausibility of providing alternative low fluoride water, and defluoridation, should be investigated.

Dose–response effect of fluoride dentifrice on remineralisation and further demineralisation of erosive lesions: A randomised in situ clinical study

ObjectiveThe objective was to evaluate the ability of fluoride in a conventional, non-specialised sodium fluoride–silica dentifrice to promote tooth remineralisation and enamel fluoride uptake (EFU), and assess the resistance of the newly formed mineral to attack by dietary acid, across the concentration range used in mass-market dentifrices. MethodsSubjects wore a palatal appliance containing eight polished bovine enamel specimens, each including an early erosive lesion. In a randomised full-crossover sequence, 62 healthy subjects were treated with dentifrices containing four different fluoride concentrations: no fluoride; 250ppm, 1150ppm and 1426ppm fluoride. At each treatment visit, under supervision, subjects brushed with 1.5g dentifrice and rinsed once while wearing the appliance; the appliance was removed after a 4-h remineralisation period and effects on the enamel specimens determined. The primary efficacy variable was surface microhardness recovery (SMHR); others included EFU, relative erosion resistance (RER) and comparative erosion resistance. ResultsHighly significant linear and, with the exception of SMHR, quadratic dose–response relationships were observed between all efficacy variables and fluoride concentration. For SMHR, EFU and RER, values for the different fluoride concentrations were statistically resolved from one another, with the exception of the two highest fluoride concentrations. The degree of remineralisation and the acid resistance of enamel after treatment were closely related to EFU. ConclusionAfter a single brushing, conventional non-specialised sodium fluoride–silica dentifrices promoted remineralisation of early enamel lesions, and imparted increased acid-resistance to the enamel surface, in a dose-dependent manner at least up to 1500ppm fluoride. Clinical significanceEnamel erosive tissue loss is an increasing concern, associated with modern diets. This study demonstrated that sodium fluoride, in a conventional non-specialised dentifrice formulation, can promote repair of the earliest stages of enamel erosion after a single application, in a dose-dependent fashion across the fluoride concentration range used in mass-market dentifrices.This study is registered in the GlaxoSmithKline Study Register (ID RH01299), available at: www.gsk-clinicalstudyregister.com/study/RH01299.

A rapid method for the removal of fluoride in contaminated groundwater using natural crystalline apatite: a laboratory and field study

Natural apatite from Eppawala located in the north central province of Sri Lanka was investigated for its ability to adsorb fluoride from aqueous solutions under laboratory conditions to develop an inexpensive and environmentally friendly adsorbent material. The adsorption of fluoride was evaluated as a function of pH, adsorbent dosage, contact time and initial fluoride concentrations. The solid materials were characterized using FTIR and XRD methods and their geochemical composition was obtained from XRF analyses. The adsorption studies were carried out under controlled conditions in which the fluoride activities of the solution were measured using an ion-selective electrode. The fluoride adsorption onto apatite is strongly pH dependent and the highest fluoride removal was observed at pH 6.0, while adsorption decreases both at low and high pH levels. The percentage fluoride removal increases with the absorbent dosage mainly due to increasing the number of adsorption sites, but the optimum adsorption can be obtained using small initial amounts of apatite in the suspension. The sorption process was very rapid and the maximum adsorption was achieved within the first 10 min in a solution containing 15.0 mg/L fluoride at pH 6.0. The kinetic studies showed that the fluoride removal process follows pseudo-second-order kinetics. The Langmuir isotherm best fitted (R2 = 0.9537) with the adsorption over a range of fluoride concentrations from 5.0 to 25.0 mg/L. The monolayer coverage of fluoride on apatite was estimated as 0.212 mg/g. The simulated experimental conditions were tested for natural water with high fluoride levels with promising results and hence the results obtained from this study can be used to design an inexpensive, easy to use and environmentally friendly method for removal of fluoride in water supplies at village level.

Performance evaluation of Fenton process removing fluoride from aqueous solution

Aims: This study was conducted to determine the Fenton performance on the fluoride removal efficiency from aqueous solutions. Materials and Methods: The removal efficiency of fluoride from aqueous solutions by the Fenton was carried out by preparation of the water solutions. The studied concentrations of fluoride were in the range of 1.5-3.5 mg/L, pH 2-11, contact times 1-17 min, and the Fenton ratios in the range of 1:1-1:10. The SPADNS method was used for fluoride determinations. Results: The optimum obtained values of the studied parameters to maximum 67% removal of the fluoride from the solutions were, the fluoride concentration 2.5 mg/L, pH = 3, Fenton ratio (H 2 O 2 :Fe) = 1:2 and the contact time of 15 min. Conclusion: The proposed material has successfully been applied to the removal of fluoride in different aqueous solutions having a broad concentration range of fluoride. The simplicity of the proposed fluoride removal material, high removal efficiency, a short time and the use of safe chemicals demonstrate the high potential of the proposed method for routine fluoride removal from water samples. The obtained results showed that Fenton process in the removal of fluoride concentration could be an effective method for the removal of fluoride.

A microchip based fluoride sensor based on the use of CdO doped ferric oxide nanocubes

CdO-doped Fe2O3 nanocubes (NCs) were prepared by a hydrothermal method using reducing precursors in alkaline medium, and characterized by UV/vis, FT-IR, Raman, and X-ray photoelectron spectroscopy, by X-ray powder diffraction, energy-dispersive X-ray spectroscopy, and field-emission scanning electron microscopy. The NCs were then deposited on a μ-chip with a surface area (~0.0222 cm2) to fabricate a sensor for detecting fluoride. Compared to sensor performance using gold-electrodes, the new sensor with microchip exhibits better sensitivity, a wider dynamic range, and a better long-term stability. The calibration plot is linear (r2 = 0.9764) over the 10.0 nmolL−1 to 1.0 mmolL−1 fluoride concentration range. The sensitivity is ~2.170 μA cm−2 mmolL−2, and the detection limit (DL, at an SNR of 3) is ~1.8 ± 0.02 nmolL−1. The sensor is fairly simple, works reliably, requires a sample volume of 70.0 μL only, and can be easily integrated into a μ-chip.

Assessment of relationship on excess fluoride intake from drinking water and carotid atherosclerosis development in adults in fluoride endemic areas, China

Cross-sectional analysis was conducted to access the relationships between developing carotid artery atherosclerosis through consuming high fluoride in drinking water and its possible mechanism, using the baseline data collected from 585 study subjects. In the cross sectional analysis, subjects were divided into four groups based on the concentrations of fluoride in their drinking water. The range of fluoride concentrations was: normal group (less than 1.20 mg/L), mild group (1.21-2.00 mg/L), moderate group (2.01-3.00 mg/L), and high concentration group (more than 3.01 mg/L). The prevalence rate of carotid artery atherosclerosis in the subjects in each group was found to be 16.13%, 27.22%, 27.10%, and 29.69%, respectively. Significant difference between the prevalence of carotid artery atherosclerosis in the mild, moderate and high fluoride exposure group and in the normal group was observed (P<0.05). In addition, it was found that elevated intercellular cell adhesion molecule-1 (ICAM-1) and reduced glutathione peroxidases (GPx) was associated with carotid artery atherosclerosis in fluoride endemic areas. The findings of the research study revealed a significant positive relationship between excess fluoride exposure from drinking water and prevalence of carotid artery atherosclerosis in adults living in fluoride endemic areas. The possible mechanism was the excess fluoride induced the decreasing level of GPx causing the systemic inflammation and endothelial activation by oxidative stress.