Fluoride Loading Research Articles

Evaluation of engineered binderless alumina – titania beads for fluoride removal from impaired water resources

Groundwater is often contaminated with various species, with fluoride concentrations being of particular concern. Numerous studies have used adsorbents for fluoride uptake, but most are tested only as powders and not commercially acceptable engineered shapes. Therefore, it was necessary to evaluate the performance of the newly developed Al2O3/TiO2 sorbents in their beaded form to assess their efficacy in comparison to activated alumina granules. Binderless sorbent beads were self-bound with the alumina and titania phases present. The fluoride exchange kinetics of Al2O3/TiO2 beads were comparable to the powdered form. Moreover, the Al2O3/TiO2 beads had higher fluoride loading than commercially available alumina (0.17 meq/g compared to 0.13 meq/g). The Al2O3/TiO2 beads also removed: barium, calcium, lithium, magnesium, manganese, potassium, silica, and strontium from groundwater. In fixed bed column tests, the beads-maintained fluoride within acceptable limits for 42 bed volumes, which substantially outperformed activated alumina (2.5 bed volumes). This study demonstrated that Al2O3/TiO2 beads outperformed commercially available activated alumina materials. Notably, transforming the materials into beaded forms significantly improved their suitability for fluoride removal in industrially relevant fixed-bed column environments. Future studies should focus on enhancing material binding properties to increase crush strength and attrition resistance. A deeper knowledge of regeneration strategies may also facilitate cost reduction.

Improved remediation of fluoride contaminated water using titania-alumina sorbents

Exposure to excessive fluoride levels in drinking water is a common problem to many communities. Activated alumina is the preferred commercial material for fluoride remediation. However, alumina is limited by a small operating pH range and issues with aluminium dissolution. The hypothesis was that if titania was incorporated into an alumina sorbent, the challenges with alumina use may be mitigated. Five synthesis methods were employed (pH swing, co-precipitation, hydrothermal, sol-gel, and sol-gel reflux). Solid products were found to either be crystalline or amorphous in character, with co-precipitation and sol-gel reflux materials possessing the highest surface areas (>250 m2/g). Kinetic studies indicated that the Al2O3/TiO2 materials were loaded within 4 to 6 h after initial contact with fluoride solutions (c.f. 8 h for commercial activated alumina). Equilibrium isotherms revealed that both favourable and unfavourable fluoride ion sorption occurred depending on the synthesis path. Maximum fluoride loading was 0.63 meq/g for co-precipitated Al2O3/TiO2 compared to 0.26 meq/g for commercial activated alumina. Significantly, both sol-gel reflux and co-precipitated oxide materials maintained superior fluoride capacity over the pH range of 4 to 9. However, only the co-precipitated Al2O3/TiO2 material minimized the dissolution of aluminium ions into the treated water. This study confirmed that Al2O3/TiO2 sorbents displayed greater fluoride uptake performance compared to commercial materials. The co-precipitation approach to make Al2O3/TiO2 is worthy of future investigation to not only optimize the synthesis procedure but also gain deeper insight into the nature of the sorption sites.

Use of mining waste as a novel low-cost material for fluoride removal from groundwater in CKDu endemic areas of Sri Lanka

A cost-effective fluoride removal process from groundwater using locally sourced waste materials was postulated for use in remote areas such as northern Sri Lanka. The process is relatively simple to operate, reduces fluoride levels to meet WHO guidelines and uses locally available waste from lime extraction. The “Natural Red Earth” (NRE) waste was a mixture of clays (12.43 wt%) and iron oxides (8.13 wt%) deposited on quartz (64.04 wt%). The smallest mesh size (<63 μm) of NRE was preferred to remove fluoride due to enrichment with aluminium and iron materials. Fluoride exchange kinetics were relatively fast (ca. 5 min) for NRE which was ascribed to sorption sites present in an active coating. Equilibrium studies revealed a low fluoride loading (0.009 meq/g). Thermal modification of the NRE at 350 °C increased the maximum fluoride uptake to 0.014 meq/g. Exposure of NRE to 1 M hydrochloric acid solution was preferred as the fluoride sorption capacity was promoted to 0.02 meq/g. Protonated surface sites on NRE were considered responsible for the enhanced fluoride sorption capacity. Acid activated NRE successfully batch treated simulated groundwater contaminated with fluoride ions to meet WHO guidelines. Practically, NRE may be used in addition to a sand filter and charcoal bed if required to remove organic matter. The economics for constructing and using a new NRE based treatment system is suitable for rural farming communities in Sri Lanka.

Selenomethionine alleviated fluoride-induced toxicity in zebrafish (Danio rerio) embryos by restoring oxidative balance and rebuilding inflammation homeostasis.

Fish are target organisms that are extremely susceptible to fluoride pollution, and an increase in fluoride load will damage multiple systems of fish. Selenomethionine (Se-Met) at low levels has been reported to alleviate oxidative damage and inflammation caused by toxic substances, but whether it can alleviate fluoride-induced toxicity in zebrafish embryos has not been elucidated. In this study, the intervention effects of Se-Met on developmental toxicity, oxidative stress and inflammation in zebrafish embryos exposed to fluoride were determined. Our results showed that fluoride accumulated in larvae and induced developmental toxicity in zebrafish embryos, caused oxidative damage and apoptosis, increased significantly the MPO and LZM activities and the levels of the inflammation-related genes IL-1β, IL-6, TNF-α, IL-10 and TGF-β. Moreover, fluoride significantly increased the levels of ERK2, JNK, p38 and p65 in MAPKs and NF-κB pathways. Se-Met-treatment alleviated the adverse effects induced by fluoride, and all of the above indicators induced by fluoride returned to near control levels with increasing concentrations and time. However, treatment with Se-Met-alone also markedly increased the levels of IL-6, TNF-α, IL-10, TGF-β, ERK2 and JNK. In short, these data demonstrated that Se-Met-could alleviate fluoride-induced toxicity in zebrafish embryos by restoring oxidative balance and rebuilding inflammation homeostasis, although low levels of Se-Met-alone had certain toxic effects on zebrafish embryos. Taken together, Se-Met-plays an important role in preventing toxic damage induced by fluoride in zebrafish embryos, although it has certain toxic effects.

Removal of fluoride from sodium sulfate brine by zirconium pre-loaded chelating resins with amino-methyl phosphonic acid functionality

Fluoride can be removed from brine by loading it onto an aluminum pre-loaded chelating cation exchange resin. In this work, zirconium pre-loaded chelating resin with amino methyl phosphonic acid (AMPA) functional group was investigated and compared with the resin in aluminum pre-loaded form to remove fluoride (<25 mg/L) from sodium sulfate electrodialysis brine solution. With the resin in zirconium pre-loaded form, a series of batch isotherm studies suggested that a change in Na2SO4 brine concentration (6–24 wt%) resulted in a negligible effect on fluoride adsorption. Solution pH in the range of 3–9 was observed to be optimal, and further increase in pH resulted in significant decrease in fluoride loading capacity. Increase in temperature (303−333 K) resulted in lower fluoride loading capacity. Cyclical load-regenerate column studies with zirconium pre-loading solution resin regeneration method showed that a noticeable improvement in the fluoride adsorption was attainable. Notably, for every load-regenerate cycle, fluoride concentration of below 1 mg/L was achieved in effluent. Zirconium concentration in the product solutions were less than 1 mg/L Zr, suggesting that displacement of zirconium from the resin is minimal. This result therefore demonstrated the outstanding stability of zirconium with the AMPA resin.

High-temperature nanoindentation size effect in fluorite material

Micromechanical loading events such as pop-in and indentation size effect (ISE) are well understood at room temperature and have been widely accepted as fundamental factors in the study of material mechanics at the microscale. Experimentally it has been observed that such phenomena can be greatly affected by temperature, but quantitative studies of temperature effects are rarely conducted. This paper presents the effects of high-temperature on the pop-in load and ISE of calcium fluoride (CaF2) single crystal material through in-situ high-temperature nanoindentation experiments and explains the localized dislocation events at the atomic level with molecular dynamic (MD) calculations. Our experimental results show that an increase in temperature leads to a reduction of the pop-in load, the hardness of the material, and the material dependent length scale during plasticity (defined in the Nix-Gao relation). Our computed results show that the differences in dislocation nucleation characteristics of CaF2 at various temperatures are the main reasons for the changes in its material properties. Such an experimental-computational study provides a comprehensive analysis of the relationships between temperature and dislocation mechanisms during nanoindentation.

Isolation of Fluoride Tolerant Bacillus spp (KT201599, KT201600) from the Midgut of Drosophila melanogaster: Their Probable Role in Fluoride Removal

This is for the first time that two fluoride tolerant bacterial strains of Bacillus spp (KT201599 and KT201600) have been isolated from the mid-gut of third instar larvae of Drosophila melanogaster. They are characterized and identified using phenotypic characters and 16S rRNA gene based molecular phylogenetic analysis. Interestingly, KT201599 and KT201600 are able to survive at 2000–2500 µg/mL sodium fluoride (NaF) concentrations. The chronic lethal concentration 50 (LC50) for NaF in Drosophila larvae is 125 µg/mL, whereas, the above-mentioned Bacillus strains isolated from their mid-gut are found to be more tolerant to fluoride (F) in comparison to their host. In search for biological relevance of KT201599 and KT201600, we further deciphered that these strains not only survived at high F concentrations, but also were efficient in removing the fluoride ions from the medium by 16.66 and 24.71% respectively. Thus, the study indicates that resident gut flora of Drosophila having the property of reducing fluoride load from the medium, might be helping the host to thrive in a fluoridated environment.

Study of fluoride content in some commercial phosphate fertilizers

Fluoride levels in seven commercial phosphate fertilizers (four single superphosphate samples, two diammonium phosphate samples, and one ammonium nitrophosphate sample) were analyzed independently at three laboratories employing the techniques of ion chromatography and ion-selective electrode. The results were consistent for aqueous solutions containing 100 mg L−1 (ppm) of fertilizer. The average values of fluoride from four different studies varied from 0.140 ± 0.006–1.33 ± 0.158% (w/w) for the seven fertilizer samples. The [P2O5]/[F] ratios (w/w) were computed for all the seven samples and the values were in the range of 13.79–328.57. By comparing these values with the average [P2O5]/[F] ratio in phosphate rock, it was inferred that 3–75% of fluoride originally present in rock remained in the fertilizers. IR spectral data revealed a small peak at 716 cm−1 – indicative of SiF62− – in the sample containing lowest fluoride which may be on account of fluoride stripping of intermediate phosphoric acid with reactive silica in this case. Considering 15 MMT (million metric tons) of annual consumption of phosphate fertilizers in India, the incremental load of fluoride in agricultural fields was estimated to be 127,650 ± 14,550 MTy−1 based on the grand average fluoride content of 0.851 ± 0.097% (w/w). While a part of this fluoride would likely get discharged into oceans through run-off, the remainder may persist in the soil, some amount may accumulate in vegetation, and a part might find its way into fresh water bodies, thereby aggravating the fluoride problem in the Country. The problem of non-point source pollution can be reduced by eliminating fluoride at source, and utilizing the recovered fluoride as feedstock. This could, in principle, satisfy the entire requirement of the fluorochemicals industry in India. Environmental costs need to be factored in while making an assessment of the viability of fluoride recovery and reuse in this manner compared to production from virgin sources of fluoride.

Removal of fluoride ions from solution by chelating resin with imino-diacetate functionality

We present the first reported study of imino-diacetate ion exchange resins which have been exchanged with aluminium ions which may offer an improved means of selectively removing fluoride ions from solution. Fluoride in water resources remains a significant problem worldwide often preventing or restricting beneficial use. This study undertook kinetics, equilibrium, and column tests to determine the effectiveness of Lanxess TP208 resin for fluoride removal over a range of solution fluoride concentrations and pH. Fluoride uptake was significantly influenced by both solution fluoride ion concentration and pH. Equilibrium studies suggested the maximum loading of fluoride ions was 1.3, 12.4, and 60.7g F/kg resin for fluoride concentrations of ca. 10, 100 and 1000mg/L, respectively at a solution pH of 6–7.5. Decreasing the solution pH to ca. 5.5 by addition of sulphuric acid resulted in a 27% increase in maximum fluoride loading to 15.7g F/kg TP208 resin at a solution fluoride concentration of 100mg/L. Significantly, the sorption process did not release chloride ions or any other detectable anions into solution. Sodium ions were removed from solution stoichiometrically with fluoride. Column studies confirmed the impact of fluoride concentration upon resin performance and suggested that multiple pathways may facilitate fluoride uptake. Future studies should focus on understanding whether imino-diacetate chelating resins exchanged with alternate metal (III) species (e.g. La, Ce, Fe) can effectively remove fluoride ions, the impact of competing ions on resin performance and how to regenerate sodium fluoride loaded resins.

Effects of KF Loading on Mg–Al Mixed Oxides for the Selective Synthesis of Trimethylolpropane Triesters

A series of Mg–Al hydrotalcites (HTCs) calcined at different temperatures were evaluated for their suitability as solid base catalysts for the selective synthesis of trimethylolpropane triesters (TMPTEs) via transesterification of trimethylolpropane (TMP) with a mixture of C8–C10 fatty acid methyl esters (FAMEs). The effect of potassium fluoride (KF) loading of the calcined HTCs on the physicochemical and catalytic properties of the materials attained was ascertained. Using a 5 wt% catalyst loading and a FAME:TMP molar ratio of 3.5:1 at 170°C for 8 h, the Mg–Al mixed oxide obtained by calcining HTC at 500°C (HTC-500) gave the highest TMPTE selectivity and FAME conversion. Impregnating HTC-500 with 10 wt% KF (KF/HTC-500) generated strongly basic KMgF3, KOH, K2O, and coordinatively unsaturated F− sites. The FAME conversion and TMPTE yield obtained over different HTC and KF/HTC-500 catalysts depended on their total basicity, where a basic strength of 15 < H_ < 18.4 was required for optimal TMPTE selectivity. The KF/HTC-500 calcined at 500°C was the most suitable catalyst and showed a superior performance to NaOCH3, a common homogeneous base for the polyol ester production.

Fluoride loaded polymeric nanoparticles for dental delivery

The overall aim of the present paper was to develop fluoride loaded nanoparticles based on the biopolymers chitosan, pectin, and alginate, for use in dental delivery. First, the preparation of nanoparticles in the presence of sodium fluoride (NaF) as the active ingredient by ionic gelation was investigated followed by an evaluation of their drug entrapment and release properties. Chitosan formed stable, spherical, and monodisperse nanoparticles in the presence of NaF and tripolyphoshate as the crosslinker, whereas alginate and pectin were not able to form any definite nanostructures in similar conditions. The fluoride loading capacity was found to be 33–113ppm, and the entrapment efficiency 3.6–6.2% for chitosan nanoparticles prepared in 0.2–0.4% (w/w) NaF, respectively. A steady increase in the fluoride release was observed for chitosan nanoparticles prepared in 0.2% NaF both in pH5 and 7 until it reached a maximum at time point 4h and maintained at this level for at least 24h. Similar profiles were observed for formulations prepared in 0.4% NaF; however the fluoride was released at a higher level at pH5. The low concentration, but continuous delivery of fluoride from the chitosan nanoparticles, with possible expedited release in acidic environment, makes these formulations highly promising as dental delivery systems in the protection against caries development.

Properties of phosphate glass waste forms containing fluorides from a molten salt reactor

Radioactive fluoride wastes are generated during the operation of molten salt reactors (MSRs) and reprocessing of their spent fuel. Immobilization of these wastes in borosilicate glass is not feasible because of the very low solubility of fluorides in this host. Alternative candidates are thus an active topic of research including phosphate-based glasses, crystalline ceramics, and hybrid glass–ceramic systems. In this study, mixed fluorides were employed as simulated MSRs waste and incorporated into sodium aluminophosphate glass to obtain phosphate-based waste form. These waste forms were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Leaching tests were performed in deionized water using the product consistency test A method. This study demonstrates that up to 20 mol% of simulated radioactive waste can be introduced into the NaAlP glass matrix, and the chemical durability is much better than that of borosilicate. The addition of Fe2O3 in the NaAlP glass matrix results in increases of the chemical durability at the expense of fluoride loading (to 6.4 mol%). Phosphate glass vitrification of radioactive waste containing fluorides is a potential method to treat and dispose of MSR wastes.

Fluoride adsorption on a cubical ceria nanoadsorbent: function of surface properties

Development of ceria with high fluoride loading capacity at pH 7.0 within 2 h at 1 g L−1 adsorbent dose.

Defluoridation performance of nano-hydroxyapatite/stilbite composite compared with bone char

Abstract Fluoride contamination of drinking water is a serious problem in the Rift Valley region of Ethiopia. In this work, a nano-hydroxyapatite/stilbite (nHAST) composite was prepared based on locally available stilbite zeolites and its fluoride removal performance was compared with that of Bone Char (BC). The reaction mechanism involving the fluoride adsorption is analyzed based on kinetics and isotherm studies. In both nHAST and BC the kinetic data fitted well to a pseudo-second order kinetic model of similar characteristics. In contrast, the adsorption isotherm on the nHAST composite fitted best with the Freundlich model, whereas on BC, it correlated well with the Langmuir model, suggesting a different mechanism: adsorption of fluoride on BC was homogeneous, whereas on the composite was heterogeneous, possibly related to the higher load of fluoride on the hydroxyapatite component in the composite. At low concentrations, both adsorbents behave similarly; however, the maximum adsorption capacity, measured at high concentrations, is higher in the nHAST composite than in BC. The intrinsic HAp capacity of nHAST, normalized to the amount of HAp on the adsorbent, is significantly higher (9.15 mg F − /gHAp) than that of BC (1.08 mg F − /gHAp) (measured at low F − initial concentrations where the OH/F-exchange mechanism predominates), showing a much higher F − removal efficiency of HAp on the composite. These results foresee a high potential of nHAST composite toward F − removal implementation, specially taking into account the low-cost, ease of production, local availability and social acceptance.

Source apportionment of non-storm water entries into storm drains using marker species: Modeling approach and verification

Inappropriate non-storm water entries into the storm drains and the resulting direct discharge into the natural environment on dry-weather days, is a challenging environmental issue in the cities worldwide. To make a preliminary evaluation of non-storm water entry situations, this study presented an approach for source apportionment of non-storm water entries into storm drains based on marker species and a chemical mass balance (CMB) model using a Monte Carlo statistical simulation. Compared with deterministic approaches, this method is capable of accounting for the measurement errors and the impact of variability of the source marker profiles resulting from heterogeneities and therefore presents the most likely range of estimated source contributions. This method was verified using measured data in a catchment in Shanghai, China, covering 374ha. Here, inappropriate entries of sanitary wastewater, semiconductor wastewater, and groundwater into storm drains can be identified using acesulfame and citric acid, chloride, fluoride and sulfate, and total hardness, respectively, as markers. Using the measured marker profiles, the apportioned source flows were estimated with high precision in comparison to the investigated data, with a relative error less than 11%. Apportioned data revealed strong sanitary source connections to storm drains (i.e., 45.8% of the total sewage output), which were mainly from old residential communities with direct sewer connections to the storm pipes. Additionally, it revealed illicit semiconductor wastewater discharge contributed to 75% of the fluoride load, 52% of the sulfate load, and 32% of the chloride load, despite its low flow component of 9.2%. Therefore, a primary correction strategy of applying end-of-storm pipe control treatment, as well as reconnecting industrial source to the sewer network, was presented. Moreover, the marker library data associated with a variety of source types is expected to provide clear evidence for various non-storm water entry situations in future studies.

Removal of fluoride from spiked water in the batch or static mode and also in the column or dynamic mode

Mature leaves of the neem tree (Azadirachta indica) were converted into fine powder, the neem leaf powder (NLP), which was used for adsorption of fluoride from water. Adsorption was 82.6% at pH 2.1, 97.5% at pH 7.0 and 99.4% at pH 10.0 at a fluoride concentration of 15 mg/L. Adsorption kinetics conformed to pseudo-second-order model with a rate coefficient of 2.04 × 10−2–11.83 × 10−2 min/mg/g for a NLP amount of 1.0–6.0 g/L. The adsorption enthalpy, ∆H, decreased slightly from 26.06 to 24.85 kJ/mol as the fluoride concentration increased (2.50–20 mg/L). In the same concentration range, the adsorption entropy, ∆S, varied from −66.92 to 86.47 J/mol/K. Spontaneity was ensured by Gibbs energy decrease from −5.75 to −0.99 kJ/mol (fluoride 15.0 mg/L) and from −1.79 to −2.65 kJ/mol (fluoride 20.0 mg/L) in the temperature range of 308–318 K. However, at lower concentrations of fluoride, ∆G had values >0 which still decreased with increasing temperature. The influence of competing ions on fluoride adsorption by NLP showed a significant influence of Cl−, HCO3-, SO42-, NO3- and HPO4- ions. Dynamic study on a NLP column showed a breakthrough volume of 2,800 mL for a fluoride loading of 20 mg/L, a flow rate of 0.4 mL/min and a column bed depth of 1.5 cm.

The fin whale, a marine top consumer, exposes strengths and weaknesses of the use of fluoride as ecological tracer

Fluoride is retained in bone tissues of animals and its availability in the environment varies between regions according to natural and anthropogenic sources. These properties suggest this element as a suitable tracer of origin, distribution or movements of animals. In marine environments, krill builds-up fluoride concentrations that are transferred to its predators. In this study we examine the ability of bone fluoride concentrations to discriminate two separate populations of a krill consumer, the fin whale. Background levels of the sampling areas (Western Iceland and North-Western Spain) were determined through the analysis of krill samples. As expected, due to the high load of volcanic-derived fluoride in Icelandic waters, krill from W Iceland showed much higher fluoride concentrations than that from NW Spain. Concentrations in whales’ bone were correlated with sex and age, increasing linearly with age in females and showing significantly lower values and a different age-related pattern of accumulation in males. Fluoride concentrations in whales’ bone were much higher than in krill, indicating accumulation of the element but, rather unexpectedly, the area of origin had no influence on concentrations. This apparent contradiction may be explained either by the integration in bone of food consumed in other areas, or by the activation of homeostatic responses at very high levels of fluoride exposure. It is concluded that fluoride can be a useful tracer only if age and sex data are integrated into the analysis, year-round information on diet is available and/or the investigated population is exposed to mild levels of this element.

Production of biodiesel from microalgae Chlamydomonas polypyrenoideum grown on dairy industry wastewater

This study involves a process of phyco-remediation of dairy industry wastewater by algal strain Chlamydomonas polypyrenoideum. The results of selected algal strain indicated that dairy industry wastewater was good nutrient supplement for algal growth in comparable with BG-11 growth medium. Alga grown on dairy industry wastewater reduced the pollution load of nitrate (90%), nitrite (74%), phosphate (70%), chloride (61%), fluoride (58%), and ammonia (90%) on 10th day of its growth as compared to that of uninoculated wastewater. The lipid content of algal biomass grown on dairy wastewater on 10th day (1.6g) and 15th day (1.2 g) of batch experiment was found to be higher than the lipid content of algal biomass grown in BG-11 growth medium on 10th day (1.27 g) and 15th day (1.0 g) of batch experiment. The results on FTIR analysis of the extracted bio-oil through transesterification reaction was comparable with bio-oil obtained from other sources.

The impact of aluminium smelter shut-down on the concentration of fluoride in vegetation and soils

Although a great deal is known about the deposition of fluoride on vegetation, and the hazards associated with uptake by grazing herbivores, little is known about what happens to the concentration of fluoride in vegetation and soil at polluted sites once deposition ceases. The closure of Anglesey Aluminium Metals Ltd smelter, in September 2009, provided a unique opportunity to study fluoride loading once deposition stopped. Fluoride was monitored in plants and soil within 1 km of the former emission source. Fluoride concentrations in a range of plant material had decreased to background levels of 10 mg F kg−1 after 36 weeks. Concentrations of fluoride in mineral-rich soils decreased steadily demonstrating their limited potential to act as contaminating sources of fluoride for forage uptake. There were significant differences in the rate of decline of fluoride concentrations between plant species.

Iodine Supplementation and Monitoring to Ensure Patient Health and Safety

Iodine deficiency is a leading cause of thyroid disorders. Deficiency can manifest as hypothyroidism, goiter, or impaired mental function. Insufficient levels of iodine increase the risk of thyroid cancer and may be associated with risk of breast, ovarian, endometrial, stomach, and esophageal cancer. In an effort to address iodine deficiency, salt iodization was introduced. Yet, despite these efforts, iodine levels have decreased in recent years. Several tests may be used to determine iodine status including the iodine spot test, iodine loading test, bromide spot test, bromide loading test, fluoride spot test, fluoride loading test and sodium/iodide symporter (NIS) test. Iodine supplements are effective in preventing and treating iodine deficiency and in achieving whole-body iodine sufficiency. In order to avoid adverse effects such as hyperthyroidism, and goiter, iodine supplementation requires proper monitoring of thyroid hormones (TSH, serum total T4, and free T3), with more frequent assessments during the first year of supplementation. Adverse effects are usually avoided when adequate and regular monitoring of thyroid hormone levels and whole-body iodine levels is employed and when dosages are increased/decreased accordingly.