Low Fluoride Concentrations Research Articles

Hydrogeochemical and isotopic controls on the source of fluoride in groundwater within the Vea catchment, northeastern Ghana

Groundwater consumption is considered as a major exposure route to fluoride in humans. Therefore, this study unraveled the sources and sinks of groundwater fluoride in the Vea catchment of northeastern Ghana using an integration of litho-petrography, hydrogeochemical analysis, multivariate statistical analysis, and stable isotope analysis. In this regard, 70 groundwater samples were collected from boreholes and analyzed for major ions and stable isotopes using standard procedures whilst 10 rock samples were collected from the crystalline basement rocks of the Birimian Supergroup and used for the petrographic studies. The petrographic results revealed the dominance of quartz, microcline, plagioclase (albite), biotite, muscovite and hornblende in the lithological units. The order of dominance of fluoride in the various lithologies is K-feldspar-rich granitoid > hornblende-biotite granitoid > basaltic flow > hornblende-biotite tonalite > hornblende biotite granodiorite > biotite granitoid. The groundwater fluoride concentrations varied from 0.35 to 3.95 mg/L with a mean concentration of 1.68 mg/L. Almost 61% of the samples have fluoride concentrations above the World Health Organization's maximum permissible limit of 1.5 mg/L. Groundwater is supersaturated with respect to albite due to silicate weathering and undersaturated with respect to fluorite and calcite. This enhanced ion exchange and fluoride mobilization in the groundwater from progressive calcite precipitation. The fluoride concentrations show positive correlations with Na+, Mg2+, HCO3−, and SO42−, confirming that fluoride enrichment is due to silicate weathering and ion exchange reactions. The δ18O and δ2H values with respect to V-SMOW vary between −4.15 and −2.75‰ and −22.49 and −13.74‰, respectively suggesting considerable isotopic variation of the groundwater. Enriched isotopic composition is observed with low fluoride concentration whilst depleted isotopic composition is observed with a higher concentration of fluoride in groundwater. The stable isotopic compositions of the groundwater also indicated meteoric origin with an evaporative effect, which partly influences the groundwater chemistry.

Engineered fluoride sensitivity enables biocontainment and selection of genetically-modified yeasts

Biocontainment systems are needed to neutralize genetically modified organisms (GMOs) that pose ecological threats outside of controlled environments. In contrast, benign selection markers complement GMOs with reduced fitness. Benign selection agents serve as alternatives to antibiotics, which are costly and risk spread of antibiotic resistance. Here, we present a yeast biocontainment strategy leveraging engineered fluoride sensitivity and DNA vectors enabling use of fluoride as a selection agent. The biocontainment system addresses the scarcity of platforms available for yeast despite their prevalent use in industry and academia. In the absence of fluoride, the biocontainment strain exhibits phenotypes nearly identical to those of the wildtype strain. Low fluoride concentrations severely inhibit biocontainment strain growth, which is restored upon introduction of fluoride-based vectors. The biocontainment strategy is stringent, easily implemented, and applicable to several eukaryotes. Further, the DNA vectors enable genetic engineering at reduced costs and eliminate risks of propagating antibiotic resistance.

Erosion protection of low‐concentration fluoride on human tooth enamel: results from surface morphology and nanomechanical and anti‐wear properties

Dental erosion results in excessive tooth wear. The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood. In this study, the effects of fluoride (225 ppm F−) on the surface morphology and nano-mechanical and anti-wear properties of human tooth enamel were investigated to explore whether low-concentration NaF solution could help protect tooth enamel from erosion. In total, 40 enamel samples were divided into 5 groups, viz. group O: original surface with no treatment, group F: fluoride treatment (NaF, 225 ppm F−, pH 6.3), group E: erosion treatment (0.001 M citric acid, pH 3.2, 3 min), group EF: erosion treatment and then fluorination and group FE: fluoride treatment and then erosion. The mechanical and anti-wear properties of enamel samples were examined using a nano-indentation/scratch technique. Both surface morphology and scratch morphology of enamel samples were observed with scanning electron microscopy. The results showed that, from the perspectives of surface morphology and anti-wear properties, fluorination with low-concentration fluoride (225 ppm F−) before erosion has a certain potential for protection against dental erosion. Fluoride treatment after erosion has no obvious impact on the remineralisation of eroded enamel.

Hydrological and geochemical evaluation of fluoride-safe groundwater from Rampurhat-II block in fluoride-laden Birbhum district, West Bengal, India: a multivariate statistical approach

ABSTRACT It has been reported earlier that Birbhum district is often contaminated with groundwater fluoride and many studies have been conducted to decipher that. Our present study area (Rampurhat-II block) is fluoride-safe (<1.5 mg/L) and located in fluoride-laden Birbhum district. The present investigation mainly focused on the reason behind the occurrence of a low concentration of fluoride (0.24–0.37 mg/L) in groundwater fluoride contaminated Birbhum district. It is very interesting to know that groundwater from the study area contains fluoride in groundwater below the permissible limit (1.5 mg/L) though the aquifer sediments contain fluoride bearing minerals (mainly fluorite). To understand the anomaly, multivariate statistical analysis (Pearson correlation matrix, factor analysis and Agglomerative Hierarchical Clustering) has been performed for the physiochemical data of the collected groundwater samples. Moreover, the mineral phase’s equilibrium studies have been done to recognise the actual scenario of water-rock interaction in the aquifers of the present study area. The dissolution of carbonate minerals (mainly calcite) in saturated to super-saturated conditions hinders the dissolution of the fluoride bearing minerals resulting in fluoride-safe groundwater. Again, ion-exchange (between Ca2+/Mg2+ and Na+/K+) is one of the principal mechanistic pathways in the aquifers which maintain the lower content of fluoride in the groundwater.

New Design Strategy Toward NIR I Xanthene-Based Dyes.

An effective design strategy with an efficient synthetic route to xanthene-based far-red to near-infrared dyes is reported. The dyes were prepared by the Suzuki cross-coupling of the electron-poor fluorescein ditriflate with the electron-rich boronic acid/ester-functionalized pyrrole (2C/3C) and indole (2D/3D) moieties. Upon treatment with trifluoroacetic acid, the closed nonfluorescent forms of the dyes (2C and 2D) ring-opened to their fluorescent forms (3C and 3D). The absorption maxima were 665 and 704 nm, while the emission maxima were 717 and 719 nm for 3C and 3D, respectively. The closed forms of the dyes were soluble in chloroform and acetonitrile. To test the efficacy of the dyes as probes, a turn-off fluoride ion probe was prepared from 3C, which consisted of a silyl ester receptor. The probe responded strongly to low concentrations of fluoride, carbonate, and acetate ions, weakly to phosphate ions, but not to the other halogens. Moreover, the probe can detect the minimum concentration of F- in water.

Yttrium speciation in subduction-zone fluids from ab initio molecular dynamics simulations

Abstract. The rare Earth elements (REEs) are important geochemical tracers for geological processes such as high-grade metamorphism. Aqueous fluids are considered important carriers for the REEs in a variety of geological environments including settings associated with subduction zones. The capacity of a fluid to mobilize REEs strongly depends on its chemical composition and on the presence of suitable ligands such as fluoride and chloride. In this study, we present structural and thermodynamic properties of aqueous yttrium–chloride and yttrium–fluoride species at a temperature of 800 ∘C in a pressure range between 1.3 and 4.5 GPa derived from ab initio molecular dynamics simulations. The total yttrium coordination by H2O and halide ions changes from seven to eight within the pressure range. For the yttrium–chloride species, a maximum number of three chloride ligands was observed. The derived thermodynamic data show that aqueous yttrium–fluoride complexes are more stable than their yttrium–chloride counterparts in chloride- and fluoride-rich environments at conditions relevant to slab dehydration. Mixed Y(Cl,F) complexes are found to be unstable even on the molecular dynamics timescale. Furthermore, in contrast to field observations, thermodynamic modeling indicates that yttrium should be mobilized at rather low fluoride concentrations in high-grade metasomatic systems. These results suggest a rather low fluoride activity in the majority of subduction-zone fluids because yttrium is one of the least-mobile REEs. Additionally, the simulations indicate that yttrium drives the self-ionization of hydration water molecules as it was observed for other high-field-strength elements. This might be a general property for highly charged cations in aqueous solutions under high-temperature and high-pressure conditions.

Spatiotemporal distribution of fluoride in drinking water and associated probabilistic human health risk appraisal in the coastal region, Bangladesh

Spatiotemporal distribution of fluoride in drinking water has been posing serious health concerns worldwide. However, in Bangladesh, to date, there is a very limited study reported the probabilistic health risks from fluoride content in drinking water. Therefore, we investigate the spatiotemporal distribution of fluoride concentration in drinking water and associated health risks in the coastal districts of Bangladesh based on randomly collected 840 groundwater samples (Dry-season = 302 and Wet-season = 538). Probabilistic health risk appraisal from fluoride was performed using the Monte-Carlo simulation and sensitivity analysis. Fluoride concentration in 11.89% (Wet-season) and 24.50% (Dry-season) of the samples exceeded the acceptable level of 1.0 mg/L, while 3.90% (Wet-season) and 7.28% (Dry-season) samples surpassed the maximum permissible limit (fluoride: 1.5 mg/L. The deficiency of fluoride content in groundwater (<0.50 mg/L) in Wet-season (60.41%) and in Dry-season (55.63%) was identified from the study area. The seasonality to the spatial change of fluoride concentration in drinking water has been explored. The mean non-carcinogenic risks e.g., hazard quotient (HQ) from the consumption of high fluoride-containing water for infants and children were mostly exceeded the threshold value 1 (HQ > 1) in both seasons. However, the risk of children and infants at the 95th percentile crossed the safe level (SL: 1) in the wet season and the risk of infants, children, teens and adults at the 95th percentile surpassed 1 in the dry season, indicating the potential adverse health effects. Apart from the high exposure, fluoride deficiency might be a severe problem in this region due to the very low concentration of fluoride (<0.50 mg/L) in drinking water. Sensitivity analyses indicate high fluoride-containing drinking water was the most contributing variables affecting the model outcome. Finally, the case-control study should be performed to examine further the health effects from the ingestion of high/low fluoride-bearing groundwater in the study area.

Principles of fluoride toxicity and the cellular response: a review.

Fluoride is ubiquitously present throughout the world. It is released from minerals, magmatic gas, and industrial processing, and travels in the atmosphere and water. Exposure to low concentrations of fluoride increases overall oral health. Consequently, many countries add fluoride to their public water supply at 0.7-1.5ppm. Exposure to high concentrations of fluoride, such as in a laboratory setting often exceeding 100ppm, results in a wide array of toxicity phenotypes. This includes oxidative stress, organelle damage, and apoptosis in single cells, and skeletal and soft tissue damage in multicellular organisms. The mechanism of fluoride toxicity can be broadly attributed to four mechanisms: inhibition of proteins, organelle disruption, altered pH, and electrolyte imbalance. Recently, there has been renewed concern in the public sector as to whether fluoride is safe at the current exposure levels. In this review, we will focus on the impact of fluoride at the chemical, cellular, and multisystem level, as well as how organisms defend against fluoride. We also address public concerns about fluoride toxicity, including whether fluoride has a significant effect on neurodegeneration, diabetes, and the endocrine system.

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

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

Prevention of dental caries by regular overnight application of a low-concentration fluoride gel loaded in a custom tray in patients undergoing radiotherapy for head and neck cancer: A preliminary study.

Some studies have reported topical application of 1.0%-2.0% fluoride gel in a custom tray for 4-5 minutes every day for the prevention of radiation-related dental caries. However, in Japan, the concentration of fluoride used by patients is limited to less than 0.15%. The efficacy of a low-concentration fluoride gel in a custom tray for the prevention of radiation-related dental caries has not been investigated. Methods and Material: In this preliminary study, we enrolled 13 patients with head and neck cancer who underwent radiotherapy. They wore a custom tray containing 0.145% sodium fluoride gel during sleep every night and were examined for newly developed dental caries 1 year later. Results: No new dental caries were found in the 13 patients 1 year after radiotherapy, and no adverse events were observed. We conclude that low-concentration fluoride gel in a custom tray during sleep could prevent radiation-related dental caries, and we plan to conduct a multi-center phase III randomized controlled trial to examine the efficacy of this method for the prevention of radiation-related dental caries.

Molecular and cellular toxicity of fluoride in mystery, tubulointerstitial chronic kidney disease: a systematic review

Chronic kidney disease of multifactorial origin (CKDmfo), also known as CKD of uncertain origin (CKDu), is a tubulointerstitial disease. CKDmfo is an environmentally induced, preventable occupational disease that predominantly affects male farmers in tropical countries. Several causative factors have been proposed, including agrochemicals, heavy metals, medications, microbial/cyanobacterial toxins, illicit alcohol, microbes, dehydration, and fluoride. Properly conducted scientific data collections and analyses are lacking in relation to any of the postulated nephrotoxins, dehydration, genetics, or malnutrition as the genesis of CKDmfo. However, the disease can be experimentally induced in animals with chronic exposure to high-dose hard water containing fluoride or in combination with other nephrotoxins. Water fluoride levels in CKDmfo-affected regions vary, from less than 0.4 mg/L (0.4 ppm) in shallow wells to more than 1.5 mg/L in most tube wells, which are the two most-common sources of drinking water in the regions. Surface water from natural springs, reservoirs, and canals contains much lower concentrations of fluoride and hardness and those drinking such water have a significantly lower incidence of CKDmfo. Several animal studies reported that fluoride exacerbates the renal tubular oxidative stress that contributes to cell damage. This systematic review covers the mechanisms of fluoride-induced renal tubular cell damage, chemical interactions, and oxidative stress in persons with CKDmfo/CKDu. Although the disease is initiated by nanomineral formation in renal tubules together with chronic renal ischemia, fluoride can augment the nephrotoxicity. Renal tubular toxicity caused by CaPO4 nanocrystals and nanotubes is exacerbated by fluoride and other nephrotoxins, malnutrition, micronutrients and antioxidant deficiency, and conditions that increase oxidative stress. These data indicate key targets and modes of action that could be used to prevent this deadly disease. Although fluoride likely contributes, it is unlikely to be the sole cause of the tubulointerstitial renal damage of CKDmfo.

Fluoride Inhibits Longitudinal Bone Growth by Acting Directly at the Growth Plate in Cultured Neonatal Rat Metatarsal Bones.

Excessive intake of fluoride inhibits bone growth in both humans and animals. It is unknown whether fluoride acts directly on the growth plate to inhibit longitudinal bone growth, and its mechanism of action has not been elucidated. In this study, we used an organ culture system and SW1353 cells to evaluate the effects of fluoride on endochondral ossification. Neonatal rat metatarsal bones were dissected and cultured with or without fluoride for 7days. The total length and width of the metatarsal rudiments and the length of the calcification zone were measured. Chondrocyte proliferation, differentiation, and apoptosis were analyzed by immunohistochemistry and TUNEL assay in sectioned bones. The apoptosis was detected by flow cytometry, and the expression of apoptosis-related proteins Bax, Bcl-2, and Caspase-3 were detected by western blotting in SW1353 cells. Linear measurements demonstrated that fluoride induced a biphasic effect on longitudinal bone growth in organ culture, with a significant growth inhibition at a high concentration (10-4M) and a stimulatory action at low concentration (10-6M) of fluoride. Histomorphometrical analysis of growth plate from fluoride-exposed metatarsal rudiments showed a significant reduction in the height of the proliferative and hypertrophic chondrocyte zones. Analysis of the Col2α1 and Col10α1 expression by immunohistochemistry revealed fluoride-suppressed metatarsal growth plate chondrocyte proliferation and differentiation. In addition, fluoride increased the number of apoptotic chondrocytes in the metatarsal growth plate. Western blotting showed an up-regulated expression of Caspase-3 and Bax and down-regulated expression of anti-apoptotic protein Bcl-2 after treatment with 5 × 10-4M fluoride in SW1353 cells. Our findings indicated that fluoride inhibited longitudinal bone growth by acting directly at the growth plate in cultured neonatal rat metatarsal bones. Such growth inhibition was mediated by suppressing proliferation and differentiation, increasing apoptosis of resting chondrocytes and causing premature cell senescence in the growth plate.

Geochemical evaluation of fluoride contamination in groundwater from Shanmuganadhi River basin, South India: implication on human health.

In order to assess the geochemical mechanism liable for fluoride contamination in groundwater and its health effects on the people of the Shanmuganadhi River basin, Tamil Nadu, India, 61 groundwater samples were collected during post- and pre-monsoon seasons from the wells used for drinking purposes. Collected samples were analysed for various physico-chemical parameters. The parameters estimated in the present study are hydrogen ion concentration (pH), total dissolved solids, electrical conductivity, calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), bicarbonate (HCO3-), chloride (Cl-), sulphate (SO42-), nitrate (NO3-), phosphate (PO43-) and fluoride (F-). The fluoride ion concentration in the groundwater samples of this region varied from 0.01 to 2.50mg/l and 0.01 to 3.30mg/l during post- and pre-monsoon seasons, respectively. Out of 61 groundwater samples, 14 samples of post-monsoon season and 16 samples of pre-monsoon season represented high, very high and extremely high classes of fluoride, which cause dental fluorosis in this region. The fluoride-bearing minerals in the granitic and gneissic rocks such as apatite, hornblende, muscovite, biotite and amphiboles are the major sources for fluoride contamination in this area. In addition to the geogenic sources, applications of synthetic fertilizers in the agricultural fields also contribute significant amount of fluoride ions to groundwater. The spatial distribution of fluoride in different geological formations clearly indicate that the wells located in charnockite terrain were possessing very low fluoride concentration when compare with the wells located in the hornblende-biotite gneiss formation. Therefore, dental fluorosis risks are mostly associated with rock types in this region. People living over the basement rock comprising of hornblende-biotite gneiss are prone for fluorosis. Fluoride exhibited good positive correlation with bicarbonate in groundwater. As fluoridated endemic regions normally acquire lot of bicarbonate in groundwater samples, Shanmuganadhi basin falls under fluoride endemic category. The present study identified 26 villages in Shanmuganadhi basin as probable fluorosis risk areas where attention should be given to treat the fluoride-rich groundwater before drinking water supply. The groundwater level fluctuation study also designates that rise in water level reduces the concentration of fluoride due to dilution mechanism. Therefore, recharge of groundwater by artificial methods will definitely improve the present scenario.

A simple method for detection of low concentrations of fluoride in drinking water

Naturally occurring elevated levels of fluoride in drinking water pose a health hazard throughout the developing world, with over 200 million people potentially impacted. In some cases, treatment methods or safer alternative sources are available, but robust, simple, affordable technologies for measuring fluoride in drinking water are absent. In this work, a simple method for fluoride detection is presented comprising a 35 nm aluminum coating on the distal tip of a length of single mode optical fiber. Broadband light is launched into the proximal end of the optical fiber and a portion of this light is reflected by the distal tip of the fiber, which is immersed in water containing an unknown concentration of dissolved fluoride. The intensity of the reflected light is detected by a photodiode connected to the proximal end of the fiber. The aluminum coating is removed from the distal tip by reaction with the dissolved fluoride at a rate that depends on the fluoride concentration and the intensity of the light reflected from the distal tip depends upon the thickness of this coating. Therefore, the rate at which the intensity of light detected by the photodiode decreases is correlated with the concentration of fluoride. The fabricated sensor measures fluoride concentration within the range of 0–5 mg L−1.

How do toothpastes of different high- and low-fluoride concentrations compare for preventing dental caries in children and adolescents?

How do toothpastes of different high- and low-fluoride concentrations compare for preventing dental caries in children and adolescents?

How do different high- and low-concentration fluoride toothpastes compare for preventing dental caries in young children?

How do different high- and low-concentration fluoride toothpastes compare for preventing dental caries in young children?

Experimental evaluation of sorptive removal of fluoride from drinking water using natural and brewery waste diatomite

This paper focuses on introducing low-cost water treatment options by using waste products from the beer industry, thereby contributing to cleaner production. To this purpose, sorptive removal of fluoride from drinking water using locally available natural grade diatomite (NGD) and brewery waste diatomite (BWD) was studied in a batch adsorption system. The equilibrium was achieved within an adsorption time of 60 min for NGD and 30 min for BWD at the optimum pH of 5 and adsorbent dose of 60 g/L. The equilibrium data were best fitted to the Freundlich isotherm (R2 = 0.979 and 0.995) for NGD and BWD, respectively. The adsorption capacity (qmax) calculated from the Langmuir isotherm value obtained for NGD and BWD was 0.917 mg/g and 0.617 mg/g, respectively. The adsorption kinetics data for both adsorbents followed the pseudo-second-order model (R2 = 0.734 and 0.947 for NGD and BWD, respectively). The influence of other anions on fluoride removal process has a slight influence, following the order PO43− > HCO3− > CO32− > SO42− > NO3− > Cl- for both adsorbents. The materials can be used on a system level for real water sample of low fluoride concentration (≤ 5 mg/L) and could be regenerated. Though BWD is considered as a waste for the brewery, it is used as a useful material for removal of fluoride. This application can be a stepping stone for providing a solution for safe management of industrial waste while providing a resource for water treatment on a system level.

Surface modified exfoliated graphite as a novel adsorbent for de-fluoridation of drinking water

Excessive fluoride concentration (>1 mg l−1) is responsible for dental and skeletal fluorosis. Out of the several fluoride removal methodologies available for de-fluoridation of drinking water, the present studies focused on the adsorption technique. The surface modification of exfoliated graphite was achieved by impregnating it with alumina by wet-chemical method. It was further subjected to physico-chemical characterizations such as Raman spectroscopy, SEM, TGA, XRD, point of zero charge etc. The batch adsorption studies of the adsorbent were conducted while varying the pH, adsorbent doses, contact time and initial fluoride concentrations. It followed the second order kinetics model and Langmuir model fitted well during the adsorption process shows the monolayer adsorption at lower fluoride concentration. However, the D-R model reveals that the adsorption of fluoride is due to the physical adsorption at higher fluoride concentration. The alumina impregnated exfoliated graphite could effectively remove fluoride to less than 0.01 ppm when the initial fluoride concentration in water was 10 ppm. Moreover the equilibrium pH achieved with the present adsorbent is favorable for drinking purpose.

Comparative Transcriptomics Reveals the Role of the Toll-Like Receptor Signaling Pathway in Fluoride-Induced Cardiotoxicity.

Many studies have shown that fluorosis due to long-term fluoride intake has damaging effects on the heart. However, the mechanisms underlying cardiac fluorosis have not been illuminated in detail. We performed high-throughput transcriptome sequencing (RNA-Seq) on rat cardiac tissue to explore the molecular effects of NaF exposure. In total, 372 and 254 differentially expressed genes (DEGs) were identified between a group given 30 mg/L NaF and control and between a group given 90 mg/L NaF and control, respectively. The transcript levels of most of these genes were significantly down-regulated and many were distributed in the Toll-like receptor signaling pathway. Transcriptome analysis revealed that herpes simplex infection, ECM-receptor interaction, influenza A, cytokine-cytokine receptor interaction, apoptosis, and Toll-like receptor signaling pathway were significantly affected. IL-6 and IL-10 may play a crucial role in the cardiac damage caused by NaF as external stimuli according to protein-protein interaction (PPI) network analysis. The results of qRT-PCR and Western blotting showed a marked decreased mRNA and protein levels of IL-1, IL-6, and IL-10 in the low concentration fluoride (LF) and high concentration fluoride (HF) groups, which was in agreement with RNA-Seq results. This is the first study to investigate NaF-induced cardiotoxicity at a transcriptome level.

Monitoring of fluoride content in bottled mineral and spring waters by ion chromatography

Water and mineral components dissolved in it play an important role in nutrition. Fluoride in drinking water, besides arsenic and nitrate, is reported as chemical causing widespread health effects in humans as a consequence of exposure when present in excessive quantities. Due to significant impact of fluoride on human health and differentiation concentration in water depending on many chemical and geological factors, we decided to establish the fluoride content in Polish bottled waters. In this study, forty commercially available mineral and spring bottled waters, sold under various brand names in Poland have been analysed. The used ion chromatographic method was validated in the range 0.04–2.0 mg L−1 and verified with certified reference material. The obtained results were compared with contents declared by producer, some world standards and results reported by other investigators.Validation of the method showed a good within run repeatability, stability and accuracy. The limit of detection (LOD) in our research was found to be 0.016 mg L−1, while the limit of quantification amounts to 0.049 mg L−1.Content of fluoride in 40 studied bottled waters was higher in mineral (24 samples, 0.302 ± 0.291 mg L−1) than in spring waters (16 samples, 0.159 ± 0.072 mg L−1), but only in one tested mineral water (No 39, Java, with pH 9.16) slightly exceeded the permission level for infant consumption (1.5 mg L−1) and amounted to 1.566 ± 0.0188 mg L−1. No bottled water exceeded the permitted norm. The measured fluoride concentration was in line with these declared on product label, it means difference in less than ±20%, only in 47% of tested waters. The concentration of fluoride was negatively correlated with pH values of waters. In comparison to other countries, the Polish bottled waters characterized low content of fluoride (mean 0.240 ± 0.237 mg F− L−1).