Fluoride Concentration In Water Research Articles

Fluoride Exposure and Age of Menarche: Potential Differences Among Adolescent Girls and Women in the United States

Fluoride exposure is associated with later pubertal development and decreased testosterone production in adolescent and adult males. However, its effects on female reproductive health and pubertal development are unclear. Therefore, we examined associations of fluoride exposure with reproductive health outcomes among adolescent girls and women in the United States. Participants were from The National Health and Nutrition Examination Surveys (2013 to 2016), aged 16–19 and identified as female. There were 524 and 460 participants with measures of plasma fluoride and household tap water fluoride respectively, who had at least one reproductive health outcome examined, and complete covariate data. We applied covariate adjusted survey-weighted linear or logistic regression to examine associations of fluoride exposure with age of menarche, menstrual cycle regularity, or serum sex steroid hormone levels. Median interquartile range (IQR) water and plasma fluoride concentrations were 0.48 (0.53) mg/L and 0.34 (0.30) µmol/L respectively. An IQR increase in water fluoride was associated with a 3.3 month earlier first menstrual period (B = − 0.28, 95%CI − 0.54, − 0.02, p = 0.05). Additionally, we observed a significant interaction between plasma fluoride and race/ethnicity in association with age of menarche (p = 0.01). Among Non-Hispanic Black adolescents, each IQR increase in plasma fluoride was associated with a 5-month earlier age of menarche (B = − 0.42, 95%CI − 0.61, − 0.23, p < 0.001). Potential impacts of chronic low-level fluoride exposure on reproductive health outcomes are an important area of study. Current study findings, as well as potential health disparities due to disproportionate fluoride exposure should be examined in prospective studies.

Fluoride concentrations in drinking water and health risk assessment in the south of Algeria

Drinking water is the primary source of fluoride intake by humans worldwide. Algeria, Africa's largest country, has been reported to have moderate to high fluoride levels in the water, particularly in the Southern and Saharan regions. In the south of Algeria, dental fluorosis is considered an epidemic that is spreading within the population by health professionals.This study aimed to determine fluoride concentrations in drinking water consumed by Ouargla population (south-east of Algeria) in 2021, assess non-carcinogenic health risk via daily human intake, and calculate the upper acceptable fluoride concentration in drinking water by Galgan and Vermillion formula.Forty-two water samples were collected during the spring season. The fluoride was measured using a validated spectrophotometric method. Hazard quotient of fluoride (HQ) and estimated daily intake (EDI) were calculated.The results reveal a mean fluoride level of 1.07 ± 0.38 mg/L, below WHO recommendation. Fluoride concentrations in water were higher in rural areas than in the central city (p = 0.05). HQ values were less than one for adults but greater than 1 for infants and children, suggesting health risks associated with water consumption for these vulnerable groups (p = 0.007).The main contribution of this study is the establishment of a database concerning fluoride levels and hazard quotient in the south of Algeria. Monitoring drinking water and control fluorosis is essential to avoid potential health risks.

The cholinergic system, intelligence, and dental fluorosis in school-aged children with low-to-moderate fluoride exposure

Disruption of cholinergic neurotransmission can affect cognition, but little is known about whether low-to-moderate fluoride exposure affects cholinergic system and its effect on the prevalence of dental fluorosis (DF) and intelligence quotient (IQ). A cross-sectional study was conducted to explore the associations of moderate fluoride exposure and cholinergic system in relation to children's DF and IQ. We recruited 709 resident children in Tianjin, China. Ion selective electrode method was used to detect fluoride concentrations in water and urine. Cholinergic system was assessed by the detection of choline acetyltransferase (ChAT), acetylcholinesterase (AChE) and acetylcholine (ACh) levels in serum. Compared with children in the first quartile, those in fourth quartile the risk of either developing DF or IQ < 120 increased by 19% and 20% for water and urinary fluoride. The risk of having both increased by 58% and 62% in third and fourth quartile for water fluoride, 52% and 65% for urinary fluoride. Water fluoride concentrations were positively associated with AChE and negatively associated with ChAT and ACh, trends were same for urinary fluoride except for ACh. The risk of either developing DF or having non-high intelligence rose by 22% (95%CI: 1.07%, 1.38%) for the fourth quartile than those in the first quartile of AChE, for having the both, the risk was 1.27 (95%CI: 1.07, 1.50), 1.37 (95%CI: 1.17, 1.62) and 1.44 (95%CI: 1.23, 1.68) in second, third and fourth quartiles. The mediation proportion by AChE between water fluoride and either developing DF or IQ < 120 was 15.7%. For both to exist, the proportion was 6.7% and 7.2% for water and urinary fluoride. Our findings suggest low-to-moderate fluoride exposure was associated with dysfunction of cholinergic system for children. AChE may partly mediate the prevalence of DF and lower probability of having superior and above intelligence.

Maternal fluoride exposure, fertility and birth outcomes: The MIREC cohort

ObjectiveFluoride exposure >1.5 mg/L from water has been associated with adverse pregnancy and birth outcomes. Little is known, however, about the effect of fluoride at levels consistent with water fluoridation (i.e., 0.7 mg/L) on pregnancy and birth outcomes. We examined the relationship between maternal fluoride exposure, fertility, and birth outcomes in a Canadian pregnancy cohort living in areas where municipal drinking water fluoride concentrations ranged from 0.04 to 0.87 mg/L. MethodsUsing data from the Maternal-Infant Research on Environmental Chemicals (MIREC) study, we estimated fluoride exposure during pregnancy using three different metrics: (1) maternal urinary fluoride concentrations standardized for specific gravity (MUFSG) and averaged across all three trimesters (N = 1566), (2) water fluoride concentration (N = 1370), and (3) fluoride intake based on self-reported consumption of water, coffee, and tea, adjusted for body weight (N = 1192). Data on fertility, birth weight, gestational age, preterm birth, and small-for-gestational age (SGA) were assessed. We used multiple linear regression to examine associations between fluoride exposure, birth weight and gestational age, and logistic regression to examine associations with fertility, preterm birth, and SGA, adjusted for relevant covariates. ResultsMedian (IQR) MUFSG was 0.50 (0.33–0.76) mg/L, median water fluoride was 0.52 (0.17–0.64) mg/L, and median fluoride intake was 0.008 (0.003–0.013) mg/kg/day. MUFSG, water fluoride concentrations, and fluoride intake were not significantly associated with fertility, birth weight, gestational age, preterm birth, or SGA. Fetal sex did not modify any of the associations. ConclusionFluoride exposure during pregnancy was not associated with fertility or birth outcomes in this Canadian cohort.

Spatial Distribution Pattern of Fluoride and Nitrate in Groundwater Using Advanced Technical Tool - A GIS Approach

In order to detect the fluoride and nitrate content of the ground water in Koppal city in Karnataka, India and also for its spatial distribution mapping, an experimental work was taken up by selecting 25 bore wells from different stations in and around Koppal city. Ground water samples were collected for both pre-monsoon and post-monsoon seasons and fluoride and nitrate was detected using standard methodology. Locations and altitudes of the selected bore wells were also noted using GPS instrument. Fluoride and Nitrate content, its spatial distribution mapping has been drawn using advanced technical tool (GIS) for the study area. Spatial map has been prepared using an inverse distance weighting technique, which indicates the fluoride and Nitrate content in the study area. The maximum content fluoride was noticed in the Hemareddi Mallamma Nagar, KGW-11 (3.77mg/L) while the minimum was observed in Chikkabaganal, KGW-1(0.97 mg/L). The maximum content of Nitrate was recorded in the Veerapur, KGW-16 (73.98 mg/L) but Dadegal, KGW-13 (13.08 mg/L) showed minimum during the study period.

Assessment of Dental Fluorosis and Dental Caries Among 8–16-year-old Schoolchildren in Kanpur Rural Region, Uttar Pradesh

Context: Dental caries remains a major public health problem, affecting 60-90% of school children. The assessment of dental caries and fluorosis in endemic fluoride areas will facilitate in assessing the relation between fluoride concentrations in water with dental caries, dental fluorosis simultaneously. Aims: The aim of the following study is to assess the dental caries and dental fluorosis prevalence among 8–16-year-old school children in Kanpur rural region, Uttar Pradesh. Settings and Design: This was a cross-sectional study. Materials and Methods: School children, residing in the village since childhood, in the age group of 8–16 years were selected from government schools. School children were categorized in five age groups and were examined for oral examination of available 8–16-year-old children fulfilling the inclusion and exclusion criteria was carried out to assess dental caries and fluorosis. Statistical Analysis Used: The influence of demographic characteristics on caries and fluorosis was tested using Chi square test, independent sample t-test and one-way ANOVA wherever applicable. Spearman rank correlation was applied to analyze the relationship between decayed teeth and dental fluorosis. Results: The caries prevalence was found to be 84.7%. Out of 1565 school children, 53.4% were males and 46.5% were females. The prevalence of dental fluorosis was found to be 87.5%. The fluorosis prevalence increased with increasing fluoride concentration with no difference in gender and age distribution. Conclusions: Children and teenagers are the most typically damaged by dental caries and fluorosis, it is necessary for the management of the prevalence of caries and fluorosis.

Multivariate statistical methods for characterization of waste water quality

The aim of this work is focused on water quality classification of the waste waters and evaluation of pollution by the monitoring measurements during period 2006-2008. Environmental monitoring was performed in the region of Trbovlje, Slovenia, with two sampling sites and 15 chemical and physicochemical water quality parameters (pH, temperature, suspended solids, settling matter, chemical oxygen demand, biochemical oxygen demand, AOX (adsorbable organic halogens), total phosphorus, ammonium, nitrite, sulphate, chloride, fluoride, sulphide and mineral oil content) monitored in monthly periods (total of 60 objects x 15 variables). For handling the results different chemometric methods were employed, such as basic statistical methods for the determination of mean and median values, standard deviations, minimal and maximal values of measured parameters and their mutual correlation coefficients, the principal component analysis (PCA), cluster analysis (CA), and linear discriminant analysis (LDA). Monitoring of general pollution of waste waters and following measuring parameters which are above permitted concentration level can be used for searching of pollution source and for planning prevention measures from pollution, as well. The study allows drawing new information from the data sets such as patterns of similarity between sampling locations, sources of pollution in the environment, seasonal behavior of chemical contents and time trends.

Spatial analysis and probabilistic risk assessment of exposure to fluoride in drinking water using GIS and Monte Carlo simulation.

Prevalence of fluorosis is a worldwide public health problem especially in many states of India. It is necessary to find out the fluoride endemic areas to adopt remedial measures to the people on the risk of fluorosis. The target goals of this research were to assess (a) the exposure of fluoride concentration; (b) probabilistic risk assessment, sensitivity analysis, and uncertainty through intake of groundwater among population of Agra City (infants, children and adults) by Crystal Ball software; and (c) spatial distribution of HQ and fluoride concentration. A total of sixty samples from standing tube wells/hand pumps were gathered from selected and identified fluoride prevalent areas in Agra City. The concentration of fluoride scrutinized was obtained to be ranging from 1.32 to 4.60 mg/L with mean value of 2.36 in Agra City, and more than 91% of samples investigated surpassed the allowable level set for fluoride concentration in potable water 1.5 mg/L, although 9% of the samples were well within the drinking water guidelines (0.5-1.5 mg/L). The hazard quotient (HQ) was obtained to an enormous difference in the exposure dose in infants (1.66-3.91), children (1.87-4.4), and adults (0.92-2.16), correspondingly. The non-carcinogenic HQ values in the group of infants, children, and more than 90% of adults were higher than those of the safety level (i.e., HQ >1). Consequently, the non-carcinogenic risks (HQ level) of fluoride vary from the most to the least: children, infant, and adults, respectively. With 87.41% certainty, the results indicated that the HQ values are between 1 and 3.42. So, infant is the most vulnerable group to fluoride consumption in study area. Uncertainty analysis results indicated that the children group's HQ level was between 1 and 1.90 with 38.48% certainty. To avoid further worsening of the situation as far as health is concerned, remedial actions like alternate sources of water supply and appropriate treatment of water need to be adopted besides required medical attention to affected people.

Ecological Study of Fractures in Paediatric Melanesian Communities with Varying Endemic Environmental Fluoride Exposure

Introduction: Osteoporotic fracture is a major public health burden worldwide, causing significant mortality and morbidity. Studies that have reported bone health in areas of high endemic fluorosis have commonly reported adverse skeletal, as well as dental effects. Vanuatu, sited in the Pacific, and never previously studied with regard to bone health, has six continuous degassing volcanoes on separate islands, resulting in a natural experiment for an ecological study of relationships between naturally occurring fluoride exposure and fracture incidence in paediatric populations. Methods: This ecological study recruited 1026 lifetime residents of the rural Vanuatu islands. A short questionnaire was administered detailing gender, age, and residential history. Participants were asked if they had broken a bone and, if so, were asked to mark its location on a questionnaire manikin. Dental fluorosis was assessed using Dean’s index. Community drinking-water samples were sampled for fluoride concentration. Results: The measured water fluoride concentration and recorded dental fluorosis displayed expected gradients from Aneityum (low) to Ambrym (high) (p &lt; 0.001). The age of participants studied varied from 7.8 (SD 1.2) in Aneityum to 10.6 (3.7) in Lamap/Uliveo. The highest self-reported fracture rates were recorded in the area with medium fluoride levels (Lamap/Uliveo), where 14.9% of boys and 15.6% of girls sampled reported a fracture. In Ambrym, where the mean age of participants was similar, corresponding fracture rates were 4.5% and 2.6%. (p value for differences all &lt; 0.05). Conclusions: Reports of fractures were common in children living in Vanuatu, but demonstrably higher in Lamap, the region with medium fluoride concentrations, rather than Ambrym which had very high rates of naturally occurring fluoride levels. Longer term studies that report validated fracture after peak bone mass acquisition are required.

Dental caries and its association with increasing water fluoride concentration in district Rudraprayag, Uttarakhand

Background: Evidence from scientific literature confirms both beneficial and detrimental effects of fluoride on human health with only a narrow range between intakes associated with these effects. The limits of this range have been controversial among researchers since the 1930s. Considering this, the World Health Organization (WHO) permissible limit of fluoride in India has been reduced from 1.5 to 1.0 mg/l in 1998. This study aimed to evaluate the association between increasing water fluoride levels and dental caries prevention on permanent teeth.Methods: This cross-sectional study involved 1400 children (aged 6–19 years). Caries experience and dental fluorosis were recorded using DMFT/deft and Dean's index respectively. Also, fluoride concentration in drinking water was analyzed. Around 14.4% of children had dental caries with maximum frequency among 9-10 years of age. A significant negative correlation between caries experience and water fluoride level was found (p&lt;0.05), with the lowest DMFT scores at the fluoride level of 0.61–2 mg/l and the highest at 0.0–0.3 mg/l. Whereas, high prevalence of dental fluorosis was observed above 0.7 mg/l.Results: The study revealed that the presence of 0.3-0.7 mg/l fluoride in drinking water reduces dental caries, without an objectionable rise in dental fluorosis.Conclusions: It can be suggested that fluoride has anticaries property but due to a ‘narrow therapeutic window’ of 0.3-0.7 mg/l, in a country like India where endemic fluorosis is prevalent, its topical application should be encouraged which is almost equally effective with less systemic adverse effects.

Assessment of Fluoride in Groundwater and Surface Water in Gorakhpur District, Uttar Pradesh, India

Fluorine is the most electronegative and most reactive halogen. Fluorine is 13th most common element on earth crust found in the form of fluoride. Concentration of fluoride below 1 mg/l are believed beneficial in the prevention of dental carries or tooth decay, but above 1.5mg/l, it increases the severity of the deadly diseases fluorosis, which is incurable in India. The whole study was conducted in Gorakhpur region to know about the concentration of fluoride, mainly in rural areas of the district. We have collected 64 drinking water samples from 9 blocks of the district in which we took 6 number of ground water samples from each block so total 54 number of samples were collected from the groundwater source and 8 number of samples were taken from surface water source. Out of 54 ground water samples, 36 numbers of samples were taken from India Mark-II hand pumps and rest 18 number of samples were taken from shallow depth hand pumps and tested to determine the concentration of fluoride. From our assessment we came to know that in this region the concentration of fluoride in groundwater ranges between 0.004 to 1.42mg/l, minimum value is found in the surface water source and the maximum value is found from the ground water source.The samples collected from both ground water and as well as surface water were taken from potable sources i.e. they are used for drinking purposes in daily routine. After the testing and analyzing the samples it is come to know that surface water has quite lower levels fluoride compare to ground water. The conclusion of this work is to give information about the concentration of fluoride in groundwater and surface water of the district.

Assessment of the drinking water quality for planning endogenic prevention of dental caries

Relevance. Dental caries is a leading dental disease in children. Aim – to study the quality of drinking water in Smolensk and its region to provide evidence for implementing dental caries preventive measures in children.Materials and methods. We took tap water samples from ten water intake points in seven districts of Smolensk and six Smolensk regions. An accredited testing laboratory of the Center for Hygiene and Epidemiology in the Smolensk Region carried out water chemical analysis. The study analyzed standard parameters of drinking water quality: pH 6.5-8.5, fluoride content 0.60-1.2 mg/l; water hardness 7.0-9.0 (Sanitary Regulations and Standards 2.1.4.1116-02). The parameter was considered normal if its 95% confidence interval was within the reference range.Results. In Smolensk, the hydrogen ion concentration in centralized drinking water supply systems is within normal limits and amounts to 7.39 (95% CI: 7.32-7.46; р &lt; 0,05) pH units. The mean fluoride concentration in the Smolensk water is 0.19 (95% CI: 0.14-0.23; р &lt; 0,05) mg/l, which is below the normal range. In most Smolensk districts, water hardness is within normal limits, 8.21 mmol/l (95% CI: 7.03-9.39; р &lt; 0,05). However, the upper limit of the confidence interval of 9.39 mg/l and the maximum of 12.0 mg/l exceed the normal range. In the Smolensk region cities, the hydrogen ion concentration is 7.2 (95% CI: 7.02-7.38; р &lt; 0,05) pH units in the centralized drinking water supply. The fluoride concentration in the Smolensk region water is 0.45 mg/l (95% CI: 0.23-0.68; р &lt; 0,05), which demonstrates the fluoride deficiency in water. In the Smolensk region cities, mean water hardness is 6.66 mmol/l (95% CI: 6.00-7.03; р &lt; 0,05), which is below the normal values. However, the CI upper limit of 7.03 mmol/l and the maximum of 7.05 mmol/l are within normal limits.Conclusions. The water of the centralized drinking water supply system in Smolensk and the Smolensk region is low in fluorides. Urgent community and individual preventive measures should be taken to expose children to fluoride.

Assessment of Fluoride Content in Ground Water and its Impact on Wheat and Vegetables of Dausa District, Rajasthan, India

In the present investigation samples of ground water ( open well, hand pump), wheat and vegetables (spinach, potato and tomato) were collected from different areas of Dausa district of Rajasthan and analyzed to access the adverse effect on human health due to fluoride accumulation. The fluoride concentration varies between 5.1-14.9 mg/l in the collected water samples, where as in wheat samples it was found in the range of 3.42-14.25mg/l and in vegetables from 1.19-22.45mg/l. The fluoride accumulation was found to be much higher in leafy vegetable (spinach) than that of in other vegetables, where seeds or tubers are the main edible part (potato and tomato). Cereal crop ( wheat ) also estimated with more fluoride content then potato and tomato. The maximum concentration of fluoride in water, wheat and vegetables was 14.9mg/l (Bairwa Mohalla/Dausa ), 14.25 µg/g (Seengpura/Dausa) and 22.45 µg/g (Kalyanpura/ Dausa) respectively. It was observed that large number of people from Bairwa Mohalla/Dausa were suffering from Skeletal and Dental fluorosis.

Fluoride levels in deep aquifers of Makurdi, North-central, Nigeria: an appraisal based on multivariate statistics and human health risk analysis

Fluoride enrichment of groundwater has been adjudged to be a global environmental challenge in the past decade as most humans depend on groundwater for their domestic needs. This study was conducted to investigate the ionic and fluoride concentrations in borehole water and its associated health risk potentials to residents of Makurdi town and its environs, Benue state, Nigeria. Multivariate statistical techniques were for the first time used to explain the mechanisms of fluoride occurrence in groundwater in the study area. An aggregate of sixty-three (63) groundwater samples were retrieved from boreholes in twenty-one (21) diverse points within the study area and assessed for its physico-chemical composition with emphasis on fluoride content and health risk potentials following standard field and laboratory procedures. It was observed that fluoride content in the sampled water exceeded the stipulated safe limit of 1.5mg/L in about 33.33% of the total samples and ranged from 0.34 to 2.06mg/L with an average of 1.26 ± 0.41mg/L. Moderate affirmative relationships were observed to exist between F- and TDS, F- and EC, F- and Cl-, and F- and NO3- in the water samples indicative of a common source pollution. Principal component analysis (PCA) revealed that high fluoride content in the water samples was associated with the dissolutions from quartzite and shale into the underlying deep aquifers as well as from contributions from anthropogenic activities including fertilizer and pesticide uses. Fluoride risk assessment indicated that the hazard quotient (HQ) for ingestion of fluoride laden water exceeded the threshold value in 66.7, 71.4, 52.4, and 9.5% of the samples for infants, children, teenagers, and adults respectively. It was found that multivariate statistical procedures such as PCA and correlation analysis (CA) are capable of establishing the relationship among groundwater pollutants, while hierarchical cluster analysis (HCA) was found suitable for explaining the likely sources/processes of pollutant enrichment in the groundwater. It is recommended that the findings of this study would serve as a basis for policy makers and regulatory bodies towards ameliorating the menace of groundwater contamination within the study area.

Monitoring of Fluoride Content in Drinking Water by Ion Chromatography: A Case Study in the Suzhou Urban Area, China.

Both deficient and excessive intake of fluoride can lead to adverse health problems. The aim of this study is to investigate the fluoride content in three types of drinking water in Suzhou urban area. Ion chromatography was employed to conduct the validation of analysis of fluoride ion in water and the method was applied to analyze the concentration of fluoride in 22 drinking water samples, including tap water, purified water, and commercially available bottled water, collected from five municipal districts of Suzhou urban area. The method was validated in the range of 0.05-2.00 mg/L with good repeatability and accuracy. Results of water analysis indicated that fluoride content in tap water ranged from 0.267 to 0.336 mg/L (average 0.304 mg/L), and the levels of fluoride in purified water and bottled water were 0.068-0.317 mg/L (average 0.134 mg/L) and 0-0.120 mg/L (average 0.080 mg/L), respectively. The amount of fluoride in all samples analyzed were lower than the limit set for fluoride in drinking water according to the China standard (1.0 mg/L). Low fluoride exposure for the population in the studied area was observed, and the replacement of tap water with purified and bottled water could further aggravate the deficiency of fluoride intake for local residents. The present study is the first to characterize the fluoride content in these three types of drinking water in Suzhou urban area by ion chromatography.

Neuro-medical manifestations of fluorosis in populations living in the Main Ethiopian Rift Valley.

Prolonged exposure to higher concentrations of fluoride (> 1.5mg/L) is associated with dental and skeletal fluorosis. The effects of fluoride on dental and skeletal system have been studied extensively; however, the neurological consequences of fluoride in population-based studies are limited. The study aims to assess the epidemiology of neurological and other manifestations of fluorosis among rural populations living in the Main Ethiopian Rift valley. In this cross-sectional study, we enrolled 316 individuals from 23 rural communities in the Main Ethiopian Rift valley. Fluoride concentration was measured in drinking water samples collected from 23 community wells. Association between fluoride concentrations and clinical features of fluorosis was assessed using student t test, chi square, multivariable regression using adjusted odds ratio (OR). The mean fluoride concentration in the drinking water was 6.8 ± 4.3mg/L (range: 0.3-15.5mg/L). At least one clinical sign of skeletal fluorosis was observed in 54.4% (n = 175) of the study participants. Headache and joint pain reported by 67.1% and 56.3% of the participants as the most common neurological manifestation, and skeletal fluorosis symptom, respectively. The mean fluoride level was higher for those individuals who reported paresthesia compared to those with no-paresthesia. Loss of appetite, constipation, and fatigue were reported by 48.0%, 45.6%, and 56.6% of the participants, respectively. Signs of crippling fluorosis were observed in small proportion (1.6%) of the participants. Individuals who reported headache are most likely exposed to higher fluoride concentrations in drinking water compared to those reported no-headache (p < 0.001). The study demonstrates high prevalence of neuro-medical manifestations of fluorosis in population living in the Main Ethiopian Rift valley. Fluoride concentration in drinking water and joint pain were independent predictors of fluorosis.

A novel alum impregnated CaO/ carbon composite for de-fluoridation of water

Excessive fluoride concentration (>1.5 mg/L) in water adversely affects human teeth and bones. The present study focuses on the development of a fluoride adsorbentvia wet chemical method, by treating activated carbon and CaO (derived from rice straw and egg shell respectively) with alum. The prepared adsorbents were characterized for various physico-chemical parameters and fluoride adsorption test. The optimized composite with highest fluoride adsorption capacity was further subjected to batch adsorption study. The adsorbent followed second order kinetic model with intra-particle diffusion revealing that the adsorption was controlled by pore diffusion along with the other process, i.e. electrostatic interaction between opposite charges. This has been explained by a mechanism which in turn is supported by XPS data. Langmuir isotherm fitted well with experimental data suggesting homogenous and monolayer adsorption of fluoride. The adsorption capacity obtained from Langmuir isotherm model is 48.78 mg/g. Thus the adsorbent is highly effective in removing fluoride from the initial concentration of 10 ppm to less than 0.2 ppm which is safe for drinking purpose.

Associations of low level of fluoride exposure with dental fluorosis among U.S. children and adolescents, NHANES 2015–2016

Drinking water fluoridation was a mid-twentieth century innovation based on the medical hypothesis that consuming low doses of fluoride at the teeth forming years provided protection against dental decays. Numerous studies showed that high level exposure to fluoride could cause dental and skeleton fluorosis. However, there was limited study focusing on the fluorosis effect of low levels of exposure to fluoride. Therefore, our study aimed to examine whether the low level of fluoride exposure (measured in blood plasma and household tap water) was associated with the risk of dental fluorosis based on data of the National Health and Nutrition Examination Survey (NHANES) 2015–2016. We analyzed data in 2098 children and adolescents who had Dean's Index scores, and water and plasma fluoride measures. The Dean's Index score was measured by calibrated dental examiners using the modified Dean's fluorosis classification system. Fluoride was measured in plasma and household tap water. In this study, we found that the rate of fluoride concentration in water above the recommended level of 0.7 mg/L was 25%, but the prevalence of dental fluorosis was 70%. Binary logistic regression adjusted for covariates showed that higher water fluoride concentrations (0.31–0.50, 0.51–0.70, > 0.70 compared 0.00–0.30) were associated with higher odds of dental fluorosis (OR = 1.48, 95% CI: 1.13–1.96, p = 0.005; OR = 1.92, 95% CI: 1.44–2.58, p < 0.001, and OR = 2.30, 95% CI: 1.75–3.07, p < 0.001, respectively). The pattern of regression between plasma fluoride and dental fluorosis was similar. Inclusion, our study showed that even low level of water or plasma fluoride exposure was associated with increased the risk of dental fluorosis. The safety of public health approach of drinking water fluoridation for global dental caries reduction are urgently needed further research.

Fluoride exposure and children’s intelligence: Gene-environment interaction based on SNP-set, gene and pathway analysis, using a case-control design based on a cross-sectional study

BackgroundExcessive fluoride exposure has been associated with intelligence loss, but little is known about gene-fluoride interactions on intelligence at SNP-set, gene and pathway level. ObjectivesHere we conducted a population-based study in Chinese school-aged children to estimate the associations of fluoride from internal and external exposures with intelligence as well as to explore the gene-fluoride interactions on intelligence at SNP-set, gene and neurodevelopmental pathway level. MethodsA total of 952 resident children aged 7 to 13 were included in the current study. The fluoride contents in drinking water, urine, hair and nail were measured using the ion-selective electrode method. LASSO Binomial regression was conducted to screen the intelligence-related SNP-set. The gene-fluoride interactions at gene and pathway levels were detected by the Adaptive Rank Truncated Product method. ResultsThe probability of high intelligence was inversely correlated with fluoride contents in water, urine, hair and nail (all P < 0.001). The SNP-set based on rs3788319, rs1879417, rs57377675, rs11556505 and rs7187776 was related to high intelligence (P = 0.001) alone and by interaction with water, urinary and hair fluoride (P = 0.030, 0.040, 0.010), separately. In gene level, CLU and TOMM40 interacted with hair fluoride (both P = 0.017) on intelligence. In pathway level, Alzheimer disease pathway, metabolic pathway, signal transduction pathway, sphingolipid signaling pathway and PI3K-AKT signaling pathway interacted with fluoride on intelligence in men. ConclusionsOur study suggests that fluoride is inversely associated with intelligence. Moreover, the interactions of fluoride with mitochondrial function-related SNP-set, genes and pathways may also be involved in high intelligence loss.

Distributing and assessing fluoride health risk in urban drinking water resources in Fars Province, Iran, using the geographical information system.

Excessive fluoride intake has been reported in many studies, which can lead to diseases such as autism, mental retardation, low birth weight, reproductive disorder, as well as dental and bone fluorosis. The potential risk assessment of fluoride intake for the health of people living in Fars Province, Iran, is investigated. Hence, 1700 drinking water samples were taken from April 2018 to March 2020 in four seasons in 29 cities of Fars Province and were analyzed. Non-carcinogenic health risks of exposure to fluoride through drinking water were evaluated. Moreover, the spatial distribution maps of fluoride and hazard quotient (HQ) risk index were prepared using GIS software. The results showed that the concentration of fluoride in the drinking water of the studied area was in the range of 0.086 to 2.61mg/L. Accordingly, in 48.27% of the cities, fluoride was in the range below the national and international standards, 34.48% of the cities were in the permissible range of 0.5 to 1.5mg/L, and 17.24% of the urban areas of the province had fluoride contents above the permissible range. Hazard quotient index had the health risk of HQ > 1 in 27.58% of children, 17.24% of teenagers, and 10.34% of adults in the urban areas of Fars Province. In the cities with HQ > 1, there was risk of diseases associated with excessive fluoride intake. Therefore, it is necessary to replace water supply sources in these cities.