High Fluoride Concentrations Research Articles

Evaluation of the Effect of Different Types of Fluoride on Tensile Properties and Surface Roughness of Different Titanium-Based Archwires: An In vivo Study.

Objectives:The purpose of the study was to evaluate the effect of different types of fluoride on tensile properties and surface roughness of titanium based archwires clinically.Materials and methods:Three groups of archwires, namely nickel–titanium (NiTi), heat activated NiTi, and TMA was evaluated clinically. Each group comprised four subgroups, namely as received group, nonfluoride control group, APF gel group (received one application of 1.23% APF gel), and sodium fluoride mouthwash group (patients rinsed twice daily with 0.2% sodium fluoride mouthwash). All the archwires were removed after 3 weeks of clinical use and evaluated for surface roughness with three dimensional optical profiler. Tensile strength and elongation rate was determined with Instron universal testing machine.Results:NiTi, heat activated NiTi, and TMA archwires with APF gel application showed the highest reduction in tensile strength and elongation rate and highest value for surface roughness, followed by sodium fluoride mouthwash group and finally wires without fluoride application. NiTi wires had the highest reduction in tensile strength with APF gel followed by heat activated NiTi and TMA.Conclusion:APF gel with highest concentration of fluoride caused most degradation in the tensile properties and surface roughness of titanium based arch wires.

Groundwater fluoride across the Punjab plains of Pakistan and India: Distribution and underlying mechanisms

Chronic exposure from drinking well-water with naturally high concentrations of fluoride (F−) has serious health consequences in several regions across the world including South Asia, where the rural population is particularly dependent on untreated groundwater pumped from private wells. An extensive campaign to test 28,648 wells was conducted across the Punjab plains of Pakistan and India by relying primarily on field kits to document the scale of the problem and shed light on the underlying mechanisms. Groundwater samples were collected from a subset of 712 wells for laboratory analysis of F− and other constituents. A handful of sites showing contrasting levels of F− in groundwater were also drilled to determine if the composition of aquifer sediment differed between these sites. The laboratory data show that the field kits correctly classified 91% of the samples relative to the World Health Organization guideline for drinking water of 1.5 mg/L F−. The kit data indicate that 9% of wells across a region extending from the Indus to the Sutlej rivers were elevated in F− relative to this guideline. Field data indicate an association between the proportion of well-water samples with F− > 1.5 mg/L and electric conductivity (EC) > 1.5 mS/cm across six floodplains and six intervening doabs. Low Ca2+ concentrations and elevated bicarbonate (HCO3− > 500 mg/L) and sodium (Na+ > 200 mg/L) in high F− groundwater suggest regulation by fluorite. This could be through either the lack of precipitation or the dissolution of fluorite regulated by the loss of Ca2+ from groundwater due to precipitation of calcite and/or ion exchange with clay minerals. Widespread salinization of Punjab aquifers attributed to irrigation may have contributed to higher F− levels in groundwater of the region. Historical conductivity data suggest salinization has yet to be reversed in spite of changes in water resources management.

Molecular Mechanism of Changes in Gene Expression of Cytosolic Cu/Zn SOD, Lipid Peroxidation and Hepatic Function Impairments during Experimental Fluorosis

Background: Long term intake of high amount of fluoride leads to fluorosis causing metabolic, functional and structural damages affecting many tissues and organs including dental and skeletal manifestations. The liver is the most susceptible organ to fluoride toxicity because of its active and major role in digestion and detoxification.
 Aim: The present study aims to elucidate the effects of sodium fluoride on hepatic function biomarkers, lipid peroxidation and gene expression of Cu/Zn SOD in albino rats.
 Materials and Methods: Wistar albino rats were randomly assigned to three groups. The control rats were given 1 ml deionized water orally for 40 days. Groups II and III were administered 300 and 600 mg NaF/kg b.w. /day for the same period. Animals were sacrificed under anaesthesia, liver tissue was excised and used for biochemical and molecular analysis. The level of fluoride and lipid peroxidation (MDA) as well as reduced glutathione (GSH) content was determined. The activities of cytosolic copper/zinc superoxide dismutase (Cu/Zn SOD), aminotransferases (ALT and AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) in the hepatic tissue were determined. The analysis of gene expression of Cu/Zn SOD in the liver was determined using Real-time PCR.
 Results: The results revealed significantly (P<0.0001) higher concentration of fluoride and MDA in the liver of rats exposed to fluoride when compared to control. The GSH content reduced significantly (P<0.0001) in fluorotic rats. The activities of hepatic function biomarkers viz; ALT, AST, LDH and ALP elevated significantly (P<0.0001) compared to the control. An elevation of 108.60% (ALP), 121.45% (AST), 33.77% (LDH) and least 24.40% (ALT) was found in rats treated with 300 mg/L fluoride and maximum elevation of 226.20% (ALP), 211.52% (AST), 57.75% (LDH) and least 56.79% (ALT) was registered in rats exposed to 600 mg/L fluoride in drinking water. The activity of cytosolic Cu/Zn SOD decreased significantly (P<0.0001) in fluorotic rats. Pearson’s bivariate correlation and simple linear regression analysis exhibited strong positive correlation between level of hepatic tissue fluoride and activities of ALT (Pearson r= 0.85), AST (Pearson r= 0.94), LDH (Pearson r= 0.89), ALP (Pearson r= 0.86) and in MDA (Pearson r=0.984) while negative correlations existed between levels of fluoride and GSH (Pearson r=-0.93) as well as activity of Cu/Zn SOD (Pearson r= -0.99). The gene expression of cytosolic Cu/Zn SOD was significantly (P<0.0001) reduced in fluorotic rats.
 Conclusion: The present study revealed that fluoride declined the antioxidant activity of hepatic Cu/Zn SOD at biochemical as well as molecular level which leads to oxidative stress and tissue damage. This further affirms by increased activities of hepatic function biomarkers in correlation with high fluoride level during experimental fluorosis.

Fluoride removal by hybrid cation exchanger impregnated with hydrated Al(III) oxide nanoparticles (HCIX-Al) with novel closed-loop recyclable regeneration system

A high concentrations of fluoride (F-) in groundwater limits drinking water supplies and results in fluorosis for hundreds of millions of people globally. A novel F- selective adsorbent (HCIX-Al) with a closed-loop regeneration system was developed, characterized, and assessed for its effectiveness in F- removal using both synthetic and natural groundwater. The system used an inexpensive polymeric macroporous cation exchanger doped with hydrous aluminum oxide (HAlO) nanoparticles. The HAlO nanoparticles were loaded into the matrix of the polymer phase by ion-exchange reactions between Al3+ and Ca2+ ions that bind with sulfonic acid functional groups of the cation exchangers. Hydrogen ions were generated in-situ during the HAlO formation process, creating acidic conditions inside the polymeric phase, which significantly increased F- sorption capacity (maximum sorption capacity = 5.75 mg/g at pH 7.5). While most other aluminum oxide-based F- selective sorbents suffer from low F- removal capacity at neutral to alkaline pH of typical groundwater, the HCIX-Al exhibited high F- sorption capacity even using alkaline (pH 8.5) groundwater. The treated water had a pH greater than 6.5 and non-detectable levels of aluminum (detection limit 0.002 mg/L), which complies with drinking water regulations. The HCIX-Al material can be reused by conditioning the exhausted material with a closed-loop regeneration chemical containing a recyclable 12% AlCl3 solution. The F- was precipitated from the regeneration system as CaF2 using lime at pH 11. This material, including a novel regeneration scheme, offered high F- removal capacity, cost-effectiveness, and provided a sustainable defluoridation process.

A Treatment Design and Operation Effect of Membrane Material Production Wastewater Treatment Project

Classification treatment was applied for the fluorine-containing membrane material production wastewater, which was low biodegradability with high concentration of fluoride and salinity. Salinity wastewater was collected and pretreated by three-effect evaporation and ozone oxidation for desalting and improving the biodegradability, then mixed with other production wastewater with low concentration. Mixed wastewater was treated by hydrolysis acidification, AO biological treatment and modified Fenton treatment process. The operation results of stable operation showed that when the influent concentrations of COD, NH3-N, fluoride, TN and TP were 5000mg/L, 50mg/L, 5000mg/L, 60mg/and 1mg/L, the effluent mean concentrations were 32mg/L, 1.2mg/L, 1.1mg/L, 13.5mg/L and 0.12mg/L, which could meet the discharge standards.

Voriconazole-associated periostitis: Pathophysiology, risk factors, clinical manifestations, diagnosis, and management.

Voriconazole use has been associated with osteoarticular pain and periostitis, likely due to high fluoride content in the drug formulation. This phenomenon has been described primarily with high dosage or prolonged course of voriconazole therapy in immunocompromised and transplant patient populations. Patients typically present with diffuse bony pains associated with elevated serum alkaline phosphatase and plasma fluoride levels in conjunction with radiographic findings suggestive of periostitis. We provide a comprehensive review of the literature to highlight salient characteristics commonly associated with voriconazole-induced periostitis.

Concentration, distribution and probabilistic health risk assessment of exposure to fluoride in drinking water of Hormozgan province, Iran

Herein, the health risk assessment of exposure to fluoride in drinking water of southern province of Iran was performed with a definite and probabilistic approach. The Monte-Carlo simulation and sensitivity analysis were used to explain the impact of risk and uncertainty upon estimations. The results indicated that fluoride concentration was in the range of 0.1–0.9 mg/L with an average of 0.454 ± 0.205 mg/L, and distribution function followed the normality. Moreover, the highest fluoride concentration was observed in the central and northern regions of the province. In the definitive method, hazard quotient (HQ) associated with fluoride in drinking water were lower than 1 (HQ < 1). Conducting Monte-Carlo simulation illustrated that the potential non-carcinogenic risk for children in the 95th percentile exceeded the safe limit of 1, indicating a potential non-carcinogenic in this age group. Sensitivity analysis showed that fluoride concentration and water consumption rate had the most effect in the model. Therefore, consumption of water and foods containing fluoride along with excessive consumption of tea could increase the risk for human health. The results suggested that a continuous monitoring of fluoride in water resources besides proper dietary regime for inhabitants of this province should be taken into consideration.

Geospatial Variability Analysis of Fluoride Quantification in Underground Aquifers of Central Parts of Haryana State, India

The elevated levels of fluoride in underground water enhance the prevalence of the fluorosis epidemic in Haryana state. To assess the groundwater geospatial variability of fluoride at different depths in central parts of Haryana, the present study has been explored. The samples at eight sites were collected in triplicate at 3 depth levels viz. a) &lt; 10 m below ground level (bgl), b) 10-40 m bgl, and c) &gt; 40 m bgl. Fluoride levels have been determined by the SPADANS-zirconyl oxychloride method using UV-VIS spectrophotometer (Systronics-118). The fluoride concentration varies from 0.19 mg/L to 2.87 mg/L. More than 38 percent of samples exceed the standard prescribed limit of 1.0 mg/L fluoride in drinking water. Fluoride contamination increases in post-monsoon samples with maximum concentration at 40 bgl depth. Due to geological factors (fluoride-bearing minerals in basement rocks) and human-induced (brick-kiln industries, phosphatic fertilizers) factors, a high concentration of fluoride in groundwater is observed. Sustainable defluoridation techniques and a good diet (calcium &amp; vitamin c enriched) can control the adverse effects of fluorosis.

Dietary fluoride intake during pregnancy and neurodevelopment in toddlers: A prospective study in the progress cohort

Foods and beverages provide a source of fluoride exposure in Mexico. While high fluoride concentrations are neurotoxic, recent research suggests that exposures within the optimal range may also pose a risk to the developing brain. This prospective study examined whether dietary fluoride intake during pregnancy is associated with toddlers' neurodevelopment in 103 mother-child pairs from the PROGRESS cohort in Mexico City. Food and beverage fluoride intake was assessed in trimesters 2 and 3 using a food frequency questionnaire and Mexican tables of fluoride content. We used the Bayley-III to evaluate cognitive, motor, and language outcomes at 12 and 24 months of age. Adjusted linear regression models were generated for each neurodevelopment assessment time point (12 and 24 months). Mixed-effects models were used to consider a repeated measurement approach. Interactions between maternal fluoride intake and child sex on neurodevelopmental outcomes were tested. Median (IQR) dietary fluoride intake during pregnancy was 1.01 mg/d (0.73, 1.32). Maternal fluoride intake was not associated with cognitive, language, or motor outcomes collapsing across boys and girls. However, child sex modified the association between maternal fluoride intake and cognitive outcome (p interaction term = 0.06). A 0.5 mg/day increase in overall dietary fluoride intake was associated with a 3.50-point lower cognitive outcome in 24-month old boys (95 % CI: -6.58, -0.42); there was no statistical association with girls (β = 0.07, 95 % CI: -2.37, 2.51), nor on the cognitive outcome at 12-months of age. Averaging across the 12- and 24-month cognitive outcomes using mixed-effects models revealed a similar association: a 0.5 mg/day increase in overall dietary fluoride intake was associated with a 3.46-point lower cognitive outcome in boys (95 % CI: -6.23, -0.70). These findings suggest that the development of nonverbal abilities in males may be more vulnerable to prenatal fluoride exposure than language or motor abilities, even at levels within the recommended intake range.

Predicting geogenic groundwater fluoride contamination throughout China

Endemic fluorosis exists in almost all provinces of China. The long-term ingestion of groundwater containing high concentrations of fluoride is one of the main causes of fluorosis. We used artificial neural network to model the relationship between groundwater fluoride concentrations from throughout China and environmental variables such as climatic, geological. and soil parameters as proxy predictors. The results show that the accuracy and area under the receiver operating characteristic curve of the model in the test dataset are 80.5% and 0.86%, respectively, and climatic variables are the most effective predictors. Based on the artificial neural network model, a nationwide prediction risk map of fluoride concentrations exceeding 1.5 mg/L with a 0.5 × 0.5 arc minutes resolution was generated. The high risk areas are mainly located in western provinces of Xinjiang, Tibet, Qinghai, and Sichuan, and the northern provinces of Inner Mongolia, Hebei and Shandong. The total number of people estimated to be potentially at risk of fluorosis due to the use of untreated high fluoride groundwater as drinking water is about 89 million, or 6% of the population. The high fluoride groundwater risk map helps the authorities to prioritize areas requiring mitigation measures and thus facilitates the implementation of water improvement and defluoridation projects.

Biosorption of fluoride from aqueous solutions by Rhizopus oryzae: Isotherm and kinetic evaluation

AbstractRemoval of high fluoride contents from aqueous solutions by inexpensive, and biocompatible biosorbent is a main concern for human health. In the present study the efficacy of Rhizopus oryzae fungal biomass in removal of fluoride from aqueous solutions considering the effects of different parameters such as contact time (10–180 min), initial fluoride concentration (2–10 mg/L), and biosorbent dose (0.25–2 g/L) was studied in a batch system. The optimum condition for the maximum fluoride biosorption (90.5%) was obtained at 2 g/L biosorbent dose, 30 min contact time and 2 mg/L initial fluoride concentration. The Langmuir model (R2 = 0.9844) fitted better than the other models and showed a homogeneous biosorption surface with the possibility of a monolayer biosorption of fluoride by biosorbent. The Langmuir maximum biosorption capacity of fluoride for R. oryzae was obtained at 1.16 mg/g. The biosorption kinetic was controlled by the pseudo‐second‐order (R2 = 0.9999) model and based on the intra‐particle diffusion model; the fluoride biosorption rate was not controlled only by the mechanisms of intra‐particle diffusion. Consequently, the results showed that fungal biomass can be used as a suitable biosorbent for fluoride removal from aqueous solutions.

Assessment of shallow aquifer vulnerability to fluoride contamination using modified AHP-DRASTICH model as a tool for effective groundwater management, a case study in Yuncheng Basin, China

Vulnerability assessment is an effective tool for the precaution of groundwater quality to specific pollutants. Groundwater fluoride pollution is severe and universal in the world, however, the method of groundwater risk assessment to fluorine is never built. The objective of this study was to establish an effective method to assess the potential level of groundwater vulnerability to fluoride by a modification of the typical DRASTIC model. The hydrogeochemical (H) factor (pH and TDS) was designed as a complementary parameter in the DRASTICH model. The weights of the parameters were revised by Analytical Hierarchy Process (AHP) method. The built AHP-DRASTICH model was applied to evaluate the groundwater vulnerability to fluoride contamination in Yuncheng basin, northern China, where groundwater with high fluoride concentration occurred extensively. The assessment result indicates that about 40 percent of the area belonged to relatively high and high vulnerability zones, which mainly distributed at the central part of the basin with strong evaporation and longer water-rock interaction time. The AHP-DRASTICH model shows a stronger positive correlation between risk scores and F concentration, giving better vulnerability assessment to F pollution compared with DARSTIC and DRASTICH models. The AHP-DRASTICH model is reliable and useful for guiding government and policy maker to take effective actions protecting groundwater from specific pollution.

Effects of desensitizer containing fluoroaluminocalciumsilicate glass nanoparticles on remineralization of root dentin subsurface lesions in vitro.

We investigated the remineralization effects of Nanoseal (NS) dentin desensitizer on demineralized root dentin. Baseline lesion specimens prepared from bovine root dentin were immersed in artificial saliva (AS) or deionized water (DW) after treatment with NS or fluoride-free Nanoseal (NS(-)). Treatment and control groups comprised: 1, AS; 2, NS/AS; 3, NS(-)/AS; 4,NS/DW; 5, NS(-)/DW; and 6, baseline demineralization. Integrated mineral loss (IML) and lesion depth (LD) were determined by transverse microradiography. Fluoride concentrations in the immersion solutions were measured. AS, NS/AS and NS(-)/AS showed higher mineral volume % at the surface and lesion body than did other groups. NS/AS showed significantly lower IML than did AS. There was no significant difference in IML between NS/AS and NS(-)/AS. The highest concentration of fluoride was in the NS/AS immersion solution. The findings suggest Nanoseal facilitated remineralization of demineralized root dentin, and fluoride and other ions included may have contributed to this effect.

Spatial Distribution of Fluoride in Drinking Water in Dhamar City, Yemen

The fact that groundwater is the only source of drinking water in Yemen mandates strict monitoring of its quality. The aim of this study was to measure the levels of fluoride in the groundwater resources of Dhamar city. Dhamar city is the capital of Dhamar governorate located in the central plateau of Yemen. For this purpose, fluoride content in the groundwater from 16 wells located around Dhamar city was measured. The results showed that 75% of the investigated wells contain fluoride at or below the permissible level set by the World Health Organization (0.5 – 1.5 mg/L), whereas 25% of the wells have relatively higher fluoride concentrations (1.59 – 184 mg/L). The high levels of fluoride have been attributed to the anthropogenic activities in the residential areas near the contaminated wells. Interestingly, some wells contain very low fluoride concentrations (0.30 – 0.50 mg/L). Data were statistically treated using the principal component analysis (PCA) method to investigate any possible correlations between various factors. PCA shows a high correlation between well depth and its content of fluoride. On the other hand, health problems dominating in the study area necessitate further studies to investigate any correlation with imbalanced fluoride intake.

Analysis of Fluoride Contamination in Sheep Serum and in Water in the North East of Tunisia Ore Deposits.

The north east of Tunisia ore deposits (Hammam Zriba) contain a large amount of fluorides constituting a risk of environmental pollution as well as risks to human and animal health. The aim of our work was to assess the levels of fluorides in the water and blood of sheep in the east of Tunisia region. This analysis study included 78 water samples and 60 blood samples taken during 3 days in the year 2019, from a sheep herd at Hammam Zriba delegation. The determination of fluorine concentration in the samples was carried out by potentiometry with a selective electrode type ISE combined Fluoride perfectION™. High Fluoride concentrations were found at a mean of 1.62 ± 1.18, 1.45 ± 0.98, and 2.65 ± 1.61 mg/l, respectively, in running, deep, and stagnant waters. In addition, 83.3% of the animals reared within 400 m of the study area had elevated fluoride levels in the blood exceeding the usual values (fluoremia> 0.15 mg/l). The concentration of fluoride in the blood of the animals decreases with increasing distance from the mine.

Geochemical evaluation of volcanic rocks and soils around Meru volcanic complex, northern Tanzania: Implications for fluorine source, mobility and contamination of groundwater systems

Much of the water sources along the East Africa Rift System (EARS) are characterized by high fluoride. Geochemical evaluation of volcanic materials was undertaken to assess the possible source of high fluoride concentration, its mobility and eventual contamination of groundwater systems. In addition to rocks, this assessment involved evaluation of soils and water samples to elucidate the fluoride concentration in a rock-soil-water system. Results indicated that volcanic rocks are weakly to moderately fractionated with variable compositions that span from foidite to andesite. Petrographic examination indicated the presence of at least four minerals that are known to incorporate fluorine (F) in their lattice structures. In order of decreasing abundance, these minerals include: sphene or titanite, hornblende, apatite and biotite. These results indicated that fluorine occurs in all rock types in varying amount that ranges from 251 to 19,122 mg/kg (mean = 3921 mg/kg, n = 68) and that andesitic rocks contain the highest amount than the other rock types (mean = 7133 mg/kg, n = 13). This may suggest that F is largely incorporated during late crystallization process. Based on rocks and equivalent soils, fluorine was higher in rocks than equivalent soils at the ratio of 3:1. In general, distribution of F is largely controlled by parent material, the texture of the parent material and geomorphology. Furthermore, it is revealed that the amount of fluoride in well waters correlated well with fluorine in the rocks and/or soils proximal to the wells.

Epidemiological Study of Fluorosis on Different Age Groups in Tirunelveli District, Tamil Nadu, India

The component fluorine has long been documented to have benefits for dental well-being. High doses have been linked to the development of dental fluorosis, skeletal fluorosis, and deformation of bones in children and adults. High fluoride concentrations are most often associated with groundwater as these accumulate fluoride from minerals sources. The use of this study was to determine the fluoride level of drinking water interrelated to different age groups of people nearby Radhapuram block, Tirunelveli district, Tamil Nadu, India. In the present study, 2500 samples were collected, analyzed, and performed to ascertain the prevalence of epidemiological fluorosis. Information on the total population 2500 in different age groups are recorded, among the normal people, 1273 (51.1%) were male and 1227 (48.9%) were female affected in Radhapuram block. Information on the total sample of 1183, 48.9% were male and 51.1% of females normal. Among the total number samples 328, 57.0% were male and 43.0% of females were questionable, 427 samples, 44.7% were male and 55.3% of females very mild, 228 samples, 45.2% were male and 54.8% of females mild, 262 samples, 47.3% were male and 52.7% of females moderate, and 72 samples, 59.7% were male and 40.3% of females were found severely affected. The persons belong to 11–20 years, 21–30 years, 31–40 years, 41–50 years, 51–60 years, and 60 above were normal (39, 52, 58, 50, 63, and 70%), questionable (18, 11, 9, 9, 5, and 0%), very mild (20, 18, 11, 17, 8, and 11%), mild (9, 8, 10, 9, 7, and 4%), moderate (10, 10, 9, 12, 13, and 15%), and severe (3, 2, 3, 3, 4, and 0%), respectively. The selected 2500 total population 2109 persons used tap water, 161 persons used mineral water, 147 persons used borewell water, and only 83 persons used municipal water for their drinking purpose.

The Comparison of Biofilm Formation, Mechanical and Chemical Properties between Glass Ionomer Cement and Giomer

Aims: The aim of this study was to compare compressive strength and its correlation with the surface morphology and chemical elements of GIC and Giomer, as well as to determine the fluoride amount effect on the bacterial biofilm formation of GIC and Giomer. Background: The liability of Glass Ionomer Cement (GIC) mechanical properties is overcome with better antibacterial properties among restorative materials. Another fluoride-releasing restorative material, such as Giomer, has been discovered and is expected to overcome the issues with GIC’s mechanical properties; however, no research has been conducted related to antibacterial properties in Giomer. Objective: To compare compressive strength and its correlation with the surface morphology and chemical elements, then determine the fluoride amount effect on the bacterial biofilm formation of GIC and Giomer. Methods: Sixteen specimens of GIC and Giomer were prepared for a compressive strength measurement with the Universal Testing Machine. Sixteen specimens of GIC and Giomer were incubated for three days with the Streptococcus mutans culture at 37°C. The bacterial colonization was calculated using the Colony Forming Unit (CFU) and bacterial adhesion was calculated using a Scanning Electron Microscope (SEM). The mechanical properties’ compressive strength measurement, surface morphology, and chemical elements analyses were performed using SEM-EDX. Results: The compressive strength of Giomer was higher than GIC (P=0.001). The higher compressive strength of Giomer was reflected by a predominant regular surface, fewer voids, smaller and denser particles, and a higher content of silica and carbon. The bacterial biofilm on the surface of Giomer was higher than GIC, although there was no significant difference. GIC and Giomer have identical chemical elements: C, O, F, Na, Al, Si, P, and Ca. Conclusion: The compressive strength of Giomer is better than GIC; however, the biofilm formation of Giomer is higher than GIC, whereas GIC has a higher fluoride content but inferior in surfaces morphology characteristic

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.

ASSESSMENT OF FLUORIDE CONTENT IN THE RIVER WATER UZH AND LATORITSIA

The fluoride content in the waters of the Uzh and Latorytsia rivers was assessed (2020, all seasons). The basins of the studied rivers have complex tectonics and geology. It was found that the total content of fluorides in the water of the Uzh River is low (23.7-61.5 μg×L-1) and relatively stable over time. There are no natural and anthropogenic sources of fluoride pollution of river water. Variation of the total content of fluorides in water downstream occurs due to the geochemical characteristics of the river basin. The highest fluoride content is observed near the Uzhhorod city. It is shown that the content of biologically available forms (not chemically bonded) of fluorides in the water of the Uzh River is extremely low (2.2-4.8 μg×L-1). This can lead to fluoride deficiency in the region's residents, who use the Uzh River water as a source of drinking water.&#x0D; The total content of fluorides in the water of the Latorytsia River varies between 31.4-67.6 μg×L-1, which is to some extent comparable to the content in the Uzh River. Variation of fluoride content along the river is due to the geochemical characteristics of the river basin, the highest fluoride content in the water of the Latorytsia River is observed near Mukachevo city. It was also found that the content of biologically available forms of fluorides in the water of the Latorytsia River is extremely low (2.9-5.6 μg×L-1). Therefore, if the residents of the region use the water of the Latorytsia River as a source of drinking water, fluoride deficiency is possible. In general, the content of fluorides in the river waters of the Transcarpathian region is relatively low. The results of the research will be used for the planning the diet of residents of these regions of Transcarpathia.