Total Iodine Content Research Articles

Experimental observations of marine iodide oxidation using a novel sparge-interface MC-ICP-MS technique

Iodine speciation is used as a redox indicator and water mass tracer. However, the kinetics and mechanisms of oxidation of the reduced iodine species, iodide (I−), in seawater remain largely unresolved. Here, we provide constraints on I− oxidation rates from seawater incubation experiments using a sensitive radiotracer–incubation approach with high-precision mass spectrometry. Samples are inoculated with iodine-129 as I−, incubated under controlled conditions, then oxidized and reduced iodine species are isolated using liquid chromatographic separation. Samples are subsequently aspirated using a novel sparging interface, and the 129I/127I ratio of both iodine species is determined via multi-collector inductively-coupled plasma mass spectrometry. This highly-sensitive analytical approach is optimized for estimating the predicted slow rates of iodine redox transformations in small volume seawater samples at marine-relevant total iodine concentrations. Application of this method to coastal samples from Martha's Vineyard Sound, USA, evidences the heretofore-elusive oxidation of I− under marine-analogue conditions. Our results demonstrate an increase in the 129I/127I of aqueous oxidized iodine species in unamended seawater, most likely due to formation of hypoiodous acid and then dissolved organic iodine, at rates of 118–189 nM/ yr. These rates are comparable to those inferred from previous open ocean mass balance approaches but have the benefit of directly linking iodine speciation changes to in situ I− oxidation. Though our treatment experiments do not definitively isolate the oxidation mechanism, they provide preliminary insight into important roles for both abiotic and biotic factors as well as iodine transformations between dissolved, particulate, and gaseous forms. Ultimately, the derived rates and novel experimental technique have potential to improve marine iodine cycling models and provide constraints on the importance of in situ processes in setting patterns of iodine speciation.

Effect of different cooking methods on the content and bioaccessibility of iodine components in abalone (Haliotis discus hannai)

The present study aimed to evaluate the changes in total iodine and iodine species (iodide, iodate, 3-iodo-l-tyrosine, and 3,5-diiodo-l-tyrosine) content in abalone after different treatments (raw, semi-drying, steaming, grilling, and boiling) and in-vitro digestion using high-performance liquid chromatography-inductively coupled plasma-mass spectroscopy (HPLC-ICP-MS). The highest reduction in iodine content was found in boiled abalone (64.95%), followed by steamed (32.40%) and grilled (32.11%) abalones. There is no significant difference between iodine content of raw and semi-dried abalone. Absorption efficiency was determined by an in vitro digestion procedure using simulated gastro/intestinal solutions. Unlike total iodine content after cooking, absorption efficiency increased after cooking. Absorption efficiency of semi-dried abalone is the highest (28.53%), followed by boiled (23.85%), grilled (22.62%), steamed (21.51%), and raw (12.20%) abalones. Iodide was the major form of iodine present in the abalone after cooking and in vitro digestion. No iodate was observed, and the organic iodine content was very low.

Investigating the use of microdialysis and SEC-UV-ICP-MS to assess iodine interactions in soil solution

Element cycling in the terrestrial environment is heavily reliant upon processes that occur in soil solution. Here we present the first application of microdialysis to sample iodine from soil solution. In comparison to conventional soil solution extraction methods such as Rhizon™ samplers, centrifugation, and high-pressure squeezing, microdialysis can passively sample dissolved compounds from soil solution without altering the in-situ speciation of trace elements at realistic soil moisture conditions. In order to assess the suitability of microdialysis for sampling iodine, the permeability factors and effect of perfusion flowrate on I− and IO3− recovery was examined in stirred solutions. Furthermore, microdialysis was used to sample native soluble iodine at a range of water contents and iodine-enriched soils to investigate iodine soil dynamics. Total iodine concentrations were measured using ICP-MS. Inorganic species and the molecular weight distribution of organically bound iodine were determined by anion exchange and size exclusion chromatography (SEC) coupled to an ICP-MS, respectively. The most effective recovery rates in stirred solution were observed with the slowest perfusion flowrate yielding 66.2 ± 7.1 and 70.5 ± 7.1% for I− and IO3−, respectively. Microdialysis was proven to be capable of sampling dissolved iodine from the soil solution, which accounted for <2.5% of the total soil iodine and speciation followed the sequence: organic-I > I− > IO3−. The use of SEC coupled to (i) UV and (ii) ICP-MS analysis provided detail regarding the molecular weight distribution of dissolved org-I compounds. Dissolved org-I was detected with approximate molecular weights between 0.1 and 4.5 kDa. The results in this study show that microdialysis is a suitable technique for sampling dissolved iodine species from soils maintained at realistic moisture contents. In addition, inorganic iodine added to soils was predominately bound with relatively low molecular weight (<4.5 kDa) soluble organic matter.

Ultra-low dose one-step CT angiography for coronary, carotid and cerebral arteries using 128-slice dual-source CT: A feasibility study.

Atherosclerotic diseases are systemic and patient outcomes depend on comprehensive imaging evaluation. Computed tomography angiography (CTA) is a powerful tool used to assess atherosclerosis. However, the scanning protocol is designed for cardiovascular and cerebrovascular imaging, which require considerations into the radiation dose, contrast agent and image quality. The purpose of the present study was to evaluate ultra-low dose one-step CTA for coronary, carotid and cerebral arteries with a low concentration contrast agent. A total of 78 patients were enrolled and randomly divided into two groups: Group A (n=38) and B (n=40). High-pitch CTA for coronary, carotid and cerebral arteries with a tube voltage of 70 or 80 kVp and 40 ml contrast agent (270 mgI/ml) was performed by a 128-slice dual-source CT scanner for group A. Standard high-pitch CTA with a tube voltage of 100 kVp and 60 ml contrast agent (370 mgI/ml) was conducted for group B. The image quality, radiation dose and amount of contrast agent in group A were evaluated and compared with group B. The dose length product for groups A and B was 62.95±21.54 vs. 160.15±15.13 mGy cm, respectively (t=−23.157, P<0.001). The mean total iodine content was 10.8±0 mg for group A and 22.2±0 mg for group B. In total, 99.4% of the arterial segments could be assessed for the two groups (χ2=0.267, P=0.606). The results revealed that ultra-low dose one-step high-pitch CTA can provide assessable image quality, and minimize the radiation dose and contrast agent.

Spot and Diffuse Signs: Quantitative Markers of Intracranial Hematoma Expansion at Dual-Energy CT.

Purpose To compare dual-energy CT with iodine quantification to single-energy CT for evaluation of the spot sign for intracranial hematoma expansion. Materials and Methods In this retrospective study, 42 patients (mean age, 66 years ± 15 [standard deviation]; 19 women) were referred for dual-energy CT assessment of intracranial hemorrhage from October 2014 to January 2017. A machine learning approach (naive Bayes classifier) was used to identify iodine markers of extravasation for risk of hematoma expansion. Specificity and sensitivity of these markers were then independently validated in 65 new patients from February 2017 to February 2018. Results Analysis of dual-energy CT images identified two features of iodine extravasation: total iodine concentration within the hematoma (Ih) and focal iodine concentration in the brightest spot in the hematoma (Ibs) as predictors of expansion. The I2 score derived from these features provided a measure of expansion probability. Optimal classification threshold was an I2 score of 20 (95% confidence interval [CI]: 18, 23), leading to correct identification of 39 of 46 (85%; 95% CI: 71%, 94%) of the hematomas on the training set (sensitivity of 79% [11 of 14; 95% CI: 57%, 100%] and specificity of 88% [28 of 32; 95% CI: 76%, 99%]), and 62 of 70 (89%; 95% CI: 79%, 95%) of the hematomas on the validation set (sensitivity of 71% [10 of 14; 95% CI: 48%, 95%] and specificity of 93% [52 of 56; 95% CI: 86%, 100%]). Sensitivity, specificity, and accuracy of conventional spot sign were, respectively, 57% (eight of 14), 90% (29 of 32), and 80% (37 of 46) on the training set and 57% (eight of 14), 83% (47 of 56), and 75% (53 of 70) on the validation set. Conclusion This study identified two quantitative markers of intracranial hemorrhage expansion at dual-energy CT of the brain. The I2 score derived from these markers highlights the utility of dual-energy CT measurements of iodine content for high sensitivity risk assessment. © RSNA, 2018 Online supplemental material is available for this article.

Spectrophotometric Determination of the Total Iodine Content in Drinking and Mineral Waters Using the Microextraction Preconcentration

Optimal conditions for the microextraction concentration and spectrophotometric determination of iodine (I, V, VII) forms as ionic associates of triiodide anions with the cation of astrazone brilliant red 4G dye have been found. A new procedure for the spectrophotometric determination of the total iodine content in drinking and mineral waters with the detection limit of 8.9 μg/dm3 was developed and tested. This procedure is combined with microextraction concentration and meets the requirements of “green” chemistry.

Heat-treated rapeseed expeller press cake with extremely low glucosinolate content reduce transfer of iodine to cow milk

The main objective of this study was to investigate the effect of increasing dietary levels of heat treated low glucosinolate rapeseed expeller press cake (RSC) on the transfer of iodine from feed to cow milk. Eight cows of the Norwegian red cattle breed were split in two 4 × 4 Latin squares, using 4 treatments and 4 periods of 14 days each. The 4 different treatments were 1) Control, 0.0 kg RSC/day, 2) RSC-Low, 0.6 kg RSC/day, 3) RSC-Medium, 1.4 kg RSC/day and 4) RSC-High, 2.0 kg RSC/day. Irrespective of a planned constant dietary iodine content, the analysed concentration of iodine ranged from 1.4 mg/kg DM in the RSC-High diet to 1.9 mg/kg DM in the Control diet. From day 11–14 in each period, samples were collected and the total iodine concentrations in feed, milk and plasma were determined by inductively coupled plasma mass spectrometry. The iodohormones, triiodothyronine (T3) and thyroxin (T4) in plasma were determined by fluoroimmunoassay. No differences (P > 0.05) in total iodine as well as the T3 and T4 plasma concentrations were observed between the four treatments, even though the plasma iodine reflected the somewhat varying dietary iodine. Feed intake, milk production and milk composition was not affected by the different treatments (P > 0.05). Although the levels of glucosinolates were low and no glucosinolate metabolites (e.g., goitrin and indole acetonitrile) were found in the RSC, an increasing offer decreased the milk iodine concentration from 0.35 mg/kg in the Control to 0.25 mg/kg with RSC-Low, to 0.15 mg/kg with RSC-Medium and to 0.10 mg/kg with RSC-High treatments. The iodine transfer, i.e. the output of iodine via milk related to the iodine intake, amounted to 25, 19, 13 and 10% in the Control and the 3 groups with increasing dietary RSC level. This study indicates that milk iodine transfer is severely inhibited at considerably lower levels of glucosinolates in RSC than previously anticipated.

The influence of precursors and treatment process on the formation of Iodo-THMs in Canadian drinking water

The National Survey of Disinfection By-Products and Selected Emerging Contaminants investigated the formation of various disinfection by-products and contaminants in 65 water treatment systems (WTSs) across Canada. Results for six iodo-trihalomethanes (iodo-THMs) are reported in this paper. The participating water treatment systems included large, medium and small systems using water sources and treatment processes which were representative of Canadian drinking water. Five water samples (source water, treated water and three water samples along the distribution system) were collected from each treatment system, both under winter and summer conditions. Samples were stabilized, shipped cold and analysed for six iodo-THMs (dichloroiodomethane–DCIM; dibromoiodomethane–DBIM; bromochloroiodomethane–BCIM; chlorodiiodomethane–CDIM; bromodiiodomethane–BDIM and triiodomethane or iodoform–TIM), using a SPME-GC-ECD method developed in our laboratory (MDLs from 0.02 μg/L for iodoform to 0.06 μg/L for bromodiiodomethane). Concentrations of relevant precursors like dissolved organic carbon (DOC), bromide, iodide and total iodine, as well as other water quality parameters, were also determined. Detailed information about the treatment process used at each location was recorded using a questionnaire. The survey showed that one or more iodo-THMs were detected at 31 out of 64 water treatment systems (WTSs) under winter conditions and in 46 out of 64 WTSs under summer conditions (analytical results from one site were excluded due to sampling challenges). Total iodo-THM concentrations measured during this survey ranged from 0.02 μg/L to 21.66 μg/L. The highest total iodo-THM concentration was measured in WTS 63 where all six iodo-THMs were detected and iodoform was present in the highest concentration. The highest iodo-THM formation was found to occur in treatment systems where water sources had naturally occurring ammonium as well as high bromide, high iodide and/or total iodine concentrations. In two such water systems the total concentration of iodo-THMs exceeded the concentration of regulated THMs.

Ultra-low-dose CT coronary angiography using 128-slice dual source CT with low concentration contrast agent: initial experience.

To optimize and evaluate an ultra-low-dose (ULD) technique for CT coronary angiography (CTCA). Eighty-two patients were randomly divided into two groups. ULD and routine CTCA were performed in groups A and B. Image quality, radiation dose and contrast agent were evaluated. The effective dose (ED) was 0.20±0.01mSv for the ULD technique, a decrease of 87% (t=-21.182, P<0.001) compared with the control group. The total iodine content was 8.10±0g, a decrease of 62% (t=-73.458, P<0.001) compared with 21.10±1.15g for the control group. The assessment rates for both groups were the same (99.26 vs 99.64%, χ 2 =0.727, P=0.394). The contrast-to-noise ratio was 19.31±7.95 for group A and 20.73±5.07 for group B: the difference was not statistically significant (t=-1.678, P=0.095). Using an ultra-low radiation dose and contrast agent technique, while maintaining an assessable image and improving the safety of the medical examination, was a feasible and reliable method for CTCA.

In vivo uptake of iodine from a Fucus serratus Linnaeus seaweed bath: does volatile iodine contribute?

Seaweed baths containing Fucus serratus Linnaeus are a rich source of iodine which has the potential to increase the urinary iodide concentration (UIC) of the bather. In this study, the range of total iodine concentration in seawater (22-105µgL-1) and seaweed baths (808-13,734µg L-1) was measured over 1year. The seasonal trend shows minimum levels in summer (May-July) and maximum in winter (November-January). The bathwater pH was found to be acidic, average pH 5.9±0.3. An in vivo study with 30 volunteers was undertaken to measure the UIC of 15 bathers immersed in the bath and 15 non-bathers sitting adjacent to the bath. Their UIC was analysed pre- and post-seaweed bath and corrected for creatinine concentration. The corrected UIC of the population shows an increase following the seaweed bath from a pre-treatment median of 76µgL-1 to a post-treatment median of 95µgL-1. The pre-treatment UIC for both groups did not indicate significant difference (p=0.479); however, the post-treatment UIC for both did (p=0.015) where the median bather test UIC was 86µgL-1 and the non-bather UIC test was 105µgL-1. Results indicate the bath has the potential to increase the UIC by a significant amount and that inhalation of volatile iodine is a more significant contributor to UIC than previously documented.

The absorption of iodine from 5-iodosalicylic acid by hydroponically grown lettuce

Abstract The aim of the study was to determine the effect of various doses of 5-iodosalicylic acid (5I-SA; organoiodine compound) on the growth, chemical composition, and efficiency of iodine biofortification of lettuce cultivated in a nutrient film technique hydroponic system. The additional purpose was to compare the impact of 5I-SA with the effect of a selected KIO3 dose applied separately or together with salicylic acid (SA). The following combinations were tested with the introduction of 5I-SA and KIO3 (together with SA) into the nutrient solution: 1./Control, 2./KIO3 (40.0 μM I.), 3./KIO3 + SA (40.0 μM I and 40.0 μM SA), 4./5I-SA (1.6 μM I), 5./5I-SA (8.0 μM I), and 6./5I-SA (40.0 μM I). A strong toxic effect on plants was revealed only in the case of the highest iodine dose applied as 5I-SA (40.0 μM I). In the remaining combinations, lettuce head weight and its phenotype did not differ from the control. However, an unfavourable effect of 40.0 μM I applied as KIO3 on the chemical composition of plants (the content of sugars, phenolic compounds, and mineral nutrients) was not noted for 5I-SA applied in 1.6 and 8.0 μM I doses. The values of iodine transfer factor for the latter two combinations were higher than after the application of KIO3 or KIO3 + SA. Application of KIO3 + SA increased the uptake and accumulation of iodine in lettuce leaves as compared to the treatment with KIO3 alone. A higher content of 5I-SA was noted in roots than in leaves. The obtained share of 5I-SA in total iodine content indicates that most of this compound is in plants converted into other speciation forms.

Iodine in major Danish aquifers

Iodine in groundwater can have direct importance for human dietary iodine intake in areas where drinking water is of groundwater origin, as in Denmark. Knowledge on the sources and processes for the varying iodine concentrations in groundwater is of utmost importance for understanding the variation in iodine intake of the population via drinking water. The aim of this study was to characterize groundwater with elevated iodine concentrations and to investigate the sources and processes controlling natural iodine speciation and concentration at four study sites in Denmark with postglacial sandy, Quaternary sandy, and Cretaceous limestone aquifers. Analyses included iodide (I−), iodate (IO3 −), total iodine (TI), major ions, and stable H and O isotopes. Dissolved organic iodine (DOI) was calculated by subtracting I− and IO− 3 from TI. A diagram of stable δ18O and δ2H isotopes in Danish groundwater was compiled in order to interpret the groundwater iodine geochemistry. Groundwater had TI concentrations from 5 to 14,500 µg/L. Iodine speciation reflected the prevailing neutral to alkaline and reduced conditions at the investigated sites with domination of I− and DOI correlated with dissolved organic carbon. We found three different explanations for elevated TI concentrations at the four Danish sites: (1) leaching from soil enriched in iodine due to atmospheric deposition and proximity to the sea, (2) influence from the marine origin of the aquifer sediment due to desorption of iodine from iodine-enriched organic matter or minerals, and (3) influence from residual saline water due to upward advective or/and diffusive transport of iodine.

Medium-temperature molten sodium batteries with aqueous bromine and iodine cathodes

Medium-temperature sodium-bromine and sodium-iodine battery systems operating at 3.5V and 3.0V, respectively, are presented. The rechargeable molten-sodium systems work at approx. 100°C and use aqueous bromine/bromide or iodine/iodide solutions as catholyte and sodium-ion conductive NaSICON (Na3Zr2Si2.3P0.7O11.85) as solid electrolyte. The free halogen, which is formed upon charge, is complexed as highly soluble tribromide and triiodide, respectively. These systems can work in both, static and redox-flow setup, respectively, and aim at stationary energy storage applications. The sodium-halogen batteries were shown to run with high coulombic efficiency over several hundred hours. Long-term stability of the NaSICON ceramic material in contact with aqueous electrolytes, however, is still a concern. The sodium-bromine system suffers from a considerable bromine vapour pressure of the tribromide, whereas the sodium-iodine system was shown to operate in a stable manner with a catholyte allowing for a high total iodine concentration (≥2.0M). Catholyte concentrations up to 2.75M total iodine in redox-flow setup and up 3.7M in static setup are possible without iodine precipitation and correspond to specific energies of 198Whkg−1 and 228Whkg−1, respectively, on total active material level.

日本食品標準成分表における魚類中ヨウ素の新規分析法

魚類の脂質中にはマニュアル法では測定できない脂溶性ヨウ素化合物があり，魚種によっては定量値が低くなることが分かった．脂溶性ヨウ素化合物を測定するためにはアルカリ灰化処理が有効と考えられたが，GC法は真度の制御に課題があった．一方，アルカリ灰化—ICP-MS法は検量線，真度，精度および適用性が良好であり，脂溶性ヨウ素化合物も測定することができた．ただし，定量限界はマニュアル法の0.01mg/kgに及ばず0.20mg/kgであった．そのため，成分表に収載された魚類59食品のうち，27食品の一部については，同法では測定値を得ることができないものと考えられた．そこで，ヨウ素の含有量が0.20mg/kg以上の魚類に対し，同法を適用することを提案した．

Expanded oxygen minimum zones during the late Paleocene‐early Eocene: Hints from multiproxy comparison and ocean modeling

AbstractAnthropogenic warming could well drive depletion of oceanic oxygen in the future. Important insight into the relationship between deoxygenation and warming can be gleaned from the geological record, but evidence is limited because few ocean oxygenation records are available for past greenhouse climate conditions. We use I/Ca in benthic foraminifera to reconstruct late Paleocene through early Eocene bottom and pore water redox conditions in the South Atlantic and Southern Indian Oceans and compare our results with those derived from Mn speciation and the Ce anomaly in fish teeth. We conclude that waters with lower oxygen concentrations were widespread at intermediate depths (1.5–2 km), whereas bottom waters were more oxygenated at the deepest site, in the Southeast Atlantic Ocean (&gt;3 km). Epifaunal benthic foraminiferal I/Ca values were higher in the late Paleocene, especially at low‐oxygen sites, than at well‐oxygenated modern sites, indicating higher seawater total iodine concentrations in the late Paleocene than today. The proxy‐based bottom water oxygenation pattern agrees with the site‐to‐site O2 gradient as simulated in a comprehensive climate model (Community Climate System Model Version 3), but the simulated absolute dissolved O2 values are low (&lt; ~35 µmol/kg), while higher O2 values (~60–100 µmol/kg) were obtained in an Earth system model (Grid ENabled Integrated Earth system model). Multiproxy data together with improvements in boundary conditions and model parameterization are necessary if the details of past oceanographic oxygenation are to be resolved.

Availability of iron and iodine from commonly consumed recipesusing double fortified salt

Double fortified salt (DFS) having iron and iodine, has been formulated for tackling the problems of iron deficiency anemia (IDA) and iodine deficiency disorders (IDD). Since there is lack of scientific evidence on the effect of double fortified salt on different cooking methods, So the present research was designed to evaluate the availability of iron and iodine content from commonly consumed recipes using double fortified salt. Seven different recipes using different cooking methods were selected for the experimental trial. The findings of the present research work concludes that during boiling, open pan, pressure cooking and pan cooking method, salt should be used at the end stage of cooking process but for shallow frying, deep frying and steaming method, salt should be used at the beginning stage of cooking process for the maximum retention of total iodine and iron content (p&gt;0.05). So double fortified salt should be used in daily meal preparations to improve the nutritional status.

Speciation of &amp;lt;sup&amp;gt;127&amp;lt;/sup&amp;gt;I and &amp;lt;sup&amp;gt;129&amp;lt;/sup&amp;gt;I in atmospheric aerosols at Risø, Denmark: insight into sources of iodine isotopes and their species transformations

Abstract. Speciation analysis of iodine in aerosols is a very useful approach for understanding geochemical cycling of iodine in the atmosphere. In this study, overall iodine species, including water-soluble iodine species (iodide, iodate and water-soluble organic iodine), NaOH-soluble iodine, and insoluble iodine have been determined for 129I and 127I in the aerosols collected at Risø, Denmark, during March and May 2011 (shortly after the Fukushima nuclear accident) and in December 2014. The measured concentrations of total iodine are in the range of 1.04–2.48 ng m−3 for 127I and (11.3–97.0) × 105 atoms m−3 for 129I, corresponding to 129I ∕ 127I atomic ratios of (17.8–86.8) × 10−8. The contribution of Fukushima-derived 129I (peak value of 6.3 × 104 atoms m−3) is estimated to be negligible (less than 6 %) compared to the total 129I concentration in northern Europe. The concentrations and species of 129I and 127I in the aerosols are found to be strongly related to their sources and atmospheric pathways. Aerosols that were transported over the contaminated seas contained higher concentrations of 129I than aerosols transported over the European continent. The high 129I concentrations of the marine aerosols are attributed to secondary emission of marine discharged 129I in the contaminated seawater in the North Sea, North Atlantic Ocean, English Channel, Kattegat, etc., rather than direct gaseous release from the European nuclear reprocessing plants (NRPs). Water-soluble iodine was found to be a minor fraction to the total iodine for both 127I (7.8–13.7 %) and 129I (6.5–14.1 %) in ocean-derived aerosols, but accounted for 20.2–30.3 % for 127I and 25.6–29.5 % for 129I in land-derived aerosols. Iodide was the predominant form of water-soluble iodine, accounting for more than 97 % of the water-soluble iodine. NaOH-soluble iodine seems to be independent of the sources of aerosols. The significant proportion of 129I and 127I found in NaOH-soluble fractions is likely bound with organic substances. In contrast to water-soluble iodine, the sources of air masses exerted distinct influences on insoluble iodine for both 129I and 127I, with higher values for marine air masses and lower values for terrestrial air masses.

Occurrence and variability of iodinated trihalomethanes concentrations within two drinking-water distribution networks

Non-iodo-containing trihalomethanes (TTHM) are frequently detected in chlorinated tap water and currently regulated against their carcinogenic potential. Iodinated THM (ITHM) may also form in disinfected with chlorine waters that are high in iodine content, but little is known about their magnitude and variability within the drinking-water pipe distribution network of urban areas. The main objective of this study was to determine the magnitude and variability of ITHM and TTHM levels and their corresponding daily intake estimates within the drinking water distribution systems of Limassol and Nicosia cities of Cyprus, using tap samples collected from individual households (n=37). In Limassol, mean household tap water ITHM and TTHM levels was 0.58 and 38μgL−1, respectively. Dichloroiodomethane (DCIM) was the dominant species of the two measured ITHM compounds accounting for 77% of total ITHM and in the range of 0.032 and 1.65μgL−1. The range of DCIM concentrations in Nicosia tap water samples was narrower (0.032 – 0.848μgL−1). Mean total iodine concentration in tap water samples from the seaside city of Limassol was 15μgL−1 and approximately twice to those observed in samples from the mainland Nicosia city. However, iodine concentrations did not correlate with the ITHM levels. The calculated chronic daily intake rates of ITHM were low when compared with those of TTHM, but because of their widespread occurrence in tap water and their enhanced mammalian cell toxicity, additional research is warranted to assess the magnitude and variability of human ITHM exposures.

Effectiveness of activated carbon disk for the analysis of iodine in water samples using wavelength dispersive X-ray fluorescence spectrometry

A novel approach using wavelength dispersive X-ray fluorescence (WDXRF) spectrometry combined with an activated carbon (AC) disk was developed for the determination of total iodine concentrations in water samples. Dissolved iodine species (i.e., I− and IO3−) in water samples were preconcentrated on the AC disk and directly analyzed by WDXRF spectrometry. The adsorption behavior of I− and IO3− on the AC disk was assessed at varying pH levels (4, 6, and 8). The AC disks completely retained the I− and IO3− for all the pH levels tested. The calibration curve obtained from the iodine concentrations (i.e., 0, 20, 200, and 400μg) of AC disks and the measured X-ray intensity from the WDXRF analysis showed a good linearity (R2=0.9960), with a relatively low limit of detection (0.575μg). The durability of the AC disk for repeatable measurements was also assessed to validate the sustainability of the proposed method and consequently the measured X-ray intensity for the AC disks was constant until 8d of analysis time. The accuracy of the proposed AC-WDXRF method was confirmed by measuring iodine concentration spiked in drinking water using inductively coupled plasma-mass spectrometry (ICP-MS). The proposed method is simple, rapid, efficient, and environmental friendly for iodine analysis in water samples. As a precursor of disinfection by products (DBPs), it is important to determine the total iodine concentrations in raw water.

Analysis of iodine and its species in animal tissues

A method allowing the determination of the total iodine content and iodine species in samples of animal tissues using inductively coupled plasma mass spectrometry (ICP-MS) as an element-specific detector was developed. The total iodine content was determined after microwave digestion with 25% (w/w) water solution of tetramethylammonium hydroxide. The detection limit was 26.9 μg kg−1 I, and the accuracy of the determination was proven through the analysis of SRM “Non-Fat Milk Powder,” porcine liver, and Atlantic Cod muscle samples using standard addition methods. The extracts for the speciation analysis were prepared through sample dispersion in water using an Ultra-Turrax® T10. The extraction yields ranged from 46 to 84% for different types of tissues. The determination of the inorganic iodine species was performed using ion-exchange chromatography (PRP X100, mobile phase 100 mmol L−1 ammonium nitrate, pH 7.4) coupled to ICP-MS. A detection limit of 1.1 μg kg−1 I was obtained for both species. The organic iodine species were separated using size-exclusion chromatography (Superdex 75 column, mobile phase 20 mmol L−1 Tris–HCl, pH 7.5) and also detected using ICP-MS. Samples of porcine muscle, liver, kidney and thyroid gland, chicken muscle and liver and Atlantic Cod muscle were analyzed. The porcine thyroid gland and Atlantic Cod muscle samples were the richest in iodine (a more than 10× greater content of iodine than the other samples). With respect to the inorganic species, only iodide was found in the sample extracts. Conversely, many organic iodine species were found in the extracts.