Total Iodine Content Research Articles

Characterization of iodide retention on Callovo-Oxfordian argillites and its influence on iodide migration

Iodine-129 is commonly considered to belong to the largest contributors to the calculated impact on health associated with the long-term nuclear underground waste disposal. Its behaviour in Callovo-Oxfordian argillites, an argillaceous host rock studied by ANDRA, therefore must be fully characterized. Investigated cores have been extracted from a place outside the Meuse/Haute Marne underground laboratory. Thus, batch and through-diffusion experiments were performed to investigate iodide sorption and transport, on two different test samples. Batch experiments give evidence of a kinetically limited slight retention of iodide at low total iodine concentration. This sorption, dependent on the oxic/anoxic conditions, has been modelled with an initial quick reaction and a long-term steady loss of iodide from the solution. Through-diffusion experiments have confirmed this retention but to a lower extent than observed in batch experiments and differences were found between both samples. These differences have been explained by anionic exclusion, which potentially blocks sorption site access.

Toxic effects of povidone–iodine on synovial cell and articular cartilage

The objective of this study was to investigate the toxic effects of povidone-iodine (PVI). A series of MTT assay of cultured synovial cells stimulated by PVI have been made. Test for assay of membrane-toxic effect of PVI and lactate dehydrogenase (LDH) has also been carried out. After making intraarticular injection into rats' hind knee joints with 0.1 ml of PVI every day for 1 week, we have extracted the knee joints and blood from rats in four divided groups on the 0, 1st, 3rd, and 7th day. Our microscopic analysis was performed that cartilage and synovium membrane were stained with hematoxylin, toluidine blue, and safranin O. Iodine, glutamic oxaloacetic transminase, creatine phosphokinase (CPK), and LDH in rat sera have been measured. We were able to confirm cytotoxicity in the synovial cells placed in PVI concentration of more than 6.25 x 10(-2)%. In comparison with the positive control, LDH, in this case, was released at the concentration level of 33.3%. Independent of period of stimulation, LDH was released the most in the PVI concentration of 6.25 x 10(-2). The histopathological analysis of articular cartilage has indicated clear morphological alterations in rats' synovium; especially, toluidine blue staining and safranin O staining were seen in the metachromasia of articular cartilage. However, no fissures or erosive changes in the articular cartilage, which were usually observable in the case of osteoarthritis, were observed. In the synovium inflammatory cells, which were mainly plasma cells and lymphoid cells, no neutrophils were infiltrated. The degree of infiltration has increased steadily day by day. Fibrin deposition has been observed even in the synovium of 1-day stimulation. On the 7th day, a serum total iodine concentration has been 544 microg/dl, 4,440 IU/ml for CPK concentration, and 2,049 IU/ml for LDH concentration, while the control concentrations have been 7.1 microg/dl, 491 IU/ml, and 700 IU/ml, respectively. Our experiment has disclosed that PVI preparation is strongly cytotoxic to synovial cell and articular cartilage.

EFFECTS OF OZONATION ON THE SPECIATION OF DISSOLVED IODINE IN ARTIFICIAL SEAWATER

Iodine in the form of iodide is required for synthesis of tri-iodothyronine and thyroxine in fish. Iodine chemical speciation in aliquots of raw artificial seawater mix was measured before, during, and after exposure for fixed time periods to air only and to concentrations of ozone required to achieve oxidation-reduction potentials typical of a protein skimmer (400 mV) and an ozone contact chamber (800 mV). Chemical species of iodine were also measured in tank water from a large, recirculating, ozonated aquarium system that has a low-grade incidence of thyroid lesions (e.g., thyroiditis, hyperplasia, adenoma, and adenocarcinoma) in its fish. With increasing exposure to ozone, concentrations of iodide and dissolved organic iodine (DOI) decreased, whereas iodate levels increased. As a result of exposure to 400 mV, iodide concentration dropped to less than half the amount found in raw artificial seawater mix. After exposure to 800 mV, initial iodide levels decreased by 67%, and DOI became undetectable, whereas iodate concentration increased by 155%, with no remarkable change in total iodine concentration. These results indicate ozone-induced conversions from iodide to iodate, and DOI to iodide or iodate (or both). Iodide and DOI were not detectable in the aquarium system's water samples. Ozonation of artificial seawater may alter the relative concentrations of iodine species in a closed tank system, so that iodide supplementation of the diet or tank water of captive teleosts and elasmobranchs living in ozonated seawater is advisable.

Application of inductively coupled plasma mass spectrometry and high-performance liquid chromatography—with parallel electrospray mass spectrometry to the investigation of the disposition and metabolic fate of 2-, 3- and 4-iodobenzoic acids in the rat

ICP-MS, HPLC-ICP-MS and HPLC-ICP-MS/ESI-MS have been applied to determine the disposition and metabolic fate of 2-, 3- and 4-iodobenzoic acids following intraperitoneal administration at 50 mg kg −1 to male bile duct cannulated rats. Quantitative excretion balance studies based on the determination of the total iodine content of urine and bile showed that all three iodobenzoic acids were rapidly excreted. Recoveries ranging from 95 to 105% of the administered doses were achieved within 24 h of administration. Metabolite profiles for urine and bile showed extensive metabolism with unchanged iodobenzoic acids forming a minor part of the total. A combination of alkaline hydrolysis and MS enabled the identification of the major metabolites of all three iodobenzoic acids as glycine and ester glucuronide conjugates with very little if any of the parent compounds excreted unchanged.

Effects of chronic iodine excess in a cohort of long-term American workers in West Africa.

A cross-sectional survey of 102 Peace Corps volunteers in Niger, West Africa, in 1998 had previously demonstrated a high rate of thyroid dysfunction and goiter attributable to excess iodine from their water filters. The Peace Corps volunteers were followed-up a mean of 30 wk after they ceased using iodine-based water filtration systems. Goiter was present in 44% of subjects during excess iodine ingestion and in 30% after removal of excess iodine. Mean serum iodine decreased from 293 micro g/liter during excess iodine ingestion to 84 micro g/liter after cessation of excess iodine. Mean total serum T(4) values increased from 100.4 to 113.3 nmol/liter (7.8 to 8.8 micro g/dl). Mean serum free T(4) increased from 32.2 to 34.7 pmol/liter (2.5 to 2.7 ng/dl). Mean serum TSH decreased from 4.9 to 1.8 mU/liter. Mean serum thyroid peroxidase antibody levels decreased from 33,000 to 22,000 IU/liter (33 to 22 IU/ml). We found that during prolonged excess iodine exposure there were marked increases in serum total iodine concentrations, and the prevalence of goiter, elevated serum TSH values, and elevated serum thyroid peroxidase antibody values increased. The prevalence of all abnormalities decreased after removal of excess iodine from the drinking water system.

Partitioning of 127I and 129I in an unconfined glaciofluvial aquifer on the Canadian shield

Summary At AECL – Chalk River Laboratories, Ontario, Canada solid, low-level radioactive wastes from industrial, academic and medical applications have been stored in trenches above unconsolidated sandy glacial tills and permeable very-fine to fine-grained sands overlying crystalline bedrock. The sandy aquifer system drains into a swamp comprised of approximately 3 m of sphagnum peat. A comprehensive field and analytical program, involving measurements of total iodine, 129I, tritium, 14C and 13C/12C ratios in groundwater and geologic materials (sands and peats), was initiated at this site to examine the partitioning of 127I and 129I amongst the various reservoirs in this system and the controlling factors. The maximum iodine concentration and 129I inside the groundwater contaminant plume at the recharge and discharge sites were 67.0 ng/ml and ∼8.3 × 1011 atoms/liter, and 32.4 ng/ml and ∼2.9 × 1011 atoms/liter, respectively, with positive correlations between iodine, 14C (0.82), and tritium (0.87). Maximum total iodine concentrations for in-plume, recharge-site sands and discharge-site peats were 190.1 µg/kg and 14100 µg/kg, respectively. 129I analyses on these same samples showed concentrations of 2.3 × 107 and 6.4 × 109 atoms/g of soil, respectively. K D values (concentration on porous medium/concentration in co-existing water) calculated from the contaminant plume data for 127I and 129I were 1.3 and 1.6 l/kg, respectively, at the recharge site and 486 and 93 l/kg, respectively, at the discharge area, indicating that both stable and radio-iodine are preferentially sorbed to the organic rich, aquifer materials at the discharge sites. Incremental leach experiments on these same geologic materials have borne out these differences, with 127I being more strongly sorbed than 129I, probably as the result of kinetically controlled sorption mechanisms and the differing residence times of stable and radio-iodine in this hydrologic regime.

The reaction of starch with iodine vapor. Determination of iodide-ion content of starch–iodine complexes

The molecular-iodine and iodide-ion contents of starch–iodine complexes, prepared by subjecting corn amylose (average degree of polymerization, dp 1050), low-molecular-weight amylose ( dp 61–69), amylose–cyclohexanol complexes, and native corn starches to iodine vapor for 30 days under different conditions of relative humidity (RH), were determined by a differential method requiring titrations with both KIO 3 and Na 2S 2O 3. Iodide content generally increased with increase in relative humidity. However, the analytical method was incapable of providing reliable iodide values for complexes of very low total iodine content (<5 wt%), such as those of ordinary corn starch, waxy maize starch, and low- dp amylose. A granular hybrid corn starch of 64% amylose content yielded, at 100% RH, a complex containing 10.0 wt% of total iodine (I/I −=3.7). Low- dp amylose exhibited low reactivity toward iodine vapor, even at 100% RH; however, a cyclohexanol complex of low- dp amylose reacted readily at 100% RH, with concurrent elimination of cyclohexanol, to produce a starch–iodine complex of unusually high iodine content (33.1 wt% of total iodine; I/I −=3.65). The behavior of corn amylose toward iodine was found to be dependent upon its method of preparation from corn starch. One method of preparation yielded an amylose that, under anhydrous conditions, was very resistant to complexation with iodine, but which was very reactive at 30–100% RH, producing a complex that contained as much as 18.5 wt% of total iodine (I/I −=3.49). A different procedure for preparing amylose gave a starch that reacted readily under anhydrous conditions to produce a complex containing 21.8 wt% of molecular iodine and no detectable amount of iodide ion. A cyclohexanol complex of corn amylose reacted with iodine vapor at 100% RH, with concurrent elimination of cyclohexanol, to form a starch–iodine complex having a total iodine content of 31.6 wt% (I/I −=3.91). For most of the iodine complexes, there was a close similarity between I − content and H + content, suggesting that the source of iodide ion was hydrolysis of molecular iodine by water of hydration in the starch.

Iodine chemistry reflects productivity and denitrification in the Arabian Sea: evidence for flux of dissolved species from sediments of western India into the OMZ

Abstract Dissolved iodine species and total iodine concentrations were measured in the Arabian Sea during the Spring Intermonsoon of 1995. Two separate regimes of iodine chemistry are highlighted in this study: (1) the well-oxygenated surface layer (WOSL) where iodide concentrations were in the range of 158–558 nM, and (2) the oxygen minimum zone (OMZ) where total iodine concentrations [primarily as iodide and in excess to the oceanic iodine/salinity ratio of ∼13] varied from ∼200 to 950 nM. Iodine data in the WOSL of the Arabian Sea are contrasted with data from the Bermuda Atlantic Time-series Station (BATS), the Hawaii Ocean Time-series Station ALOHA (HOT), VERTEX in the Pacific and the Black Sea. Total iodine concentrations in excess of 400 nM were observed in eastern portions of the OMZ. The eastern portion of the basin has a permanent denitrification zone as well as high concentrations of dissolved Mn2+ (d-Mn2+) and iodide. While there is precedent for high values of iodide and total iodine in several other isolated basins, this is the first report of such values in open-ocean waters. Potential sources of excess total iodine to the OMZ include advection along isopycnals, from hydrothermal vents or margin sediments; atmospheric deposition; and remineralization of sinking particulate organic iodine (POI) associated with elevated productivity in surface waters. We estimate that only 3.6% of the excess total iodine can result from remineralization of sinking POI from the WOSL to the OMZ. Advection from margin sediments off of India is the most plausible source of iodine to the OMZ and contributes ∼96% of the total excess iodine to the OMZ. I− is maintained as the dominant form of iodine via in situ reduction of iodate by bacteria.

Iodine distribution in the Southern Benguela system during an upwelling episode

Iodate and total iodine concentrations have been measured at eight stations along the coast of South Africa, between Cape Town and Cape Columbine, during a period of upwelling. At most, iodine uptake from the water amounted to 0.020 μM, and appeared to be entirely iodate; iodate reduction to iodide was negligible. Meanwhile the profiles of the major plant nutrients and chlorophyll- a showed that the water column was heavily influenced by processes of productivity. Overall then, the system reflected minimal iodate reduction accompanied by extensive uptake of nutrients. This challenges the conventional view, gained from the study of tropical and sub-tropical waters, that iodate reduction in the oceans is coupled closely to nutrient uptake and primary production. The implications of this are explored.

Determination of Iodine in Seafood by Inductively Coupled Plasma/Mass Spectrometry

A method was developed for determination of total iodine content in different standard reference materials (SRMs) and seafood products by inductively coupled plasma/mass spectrometry (ICP/MS). If iodine is present as iodide and nitric acid is used in the wet digestion system, the observed signal is not stable when iodine is measured by ICP/MS at m/z 127. To stabilize the iodine signal, 3% ammonia solution (1 + 1, v/v) was added to the digest. The limit of quantitation of the method, defined as 6 times the standard deviation in the blank solution (n = 20) was estimated to be 15 mg/kg (using 0.2 g dry mass and a dilution factor of 50). The precision, expressed as repeatability of the iodine concentration, varied between 3.2 and 12% in SRMs, with concentrations of 4.70-0.17 mg/kg dry matter. The described method was compared with a method using tetramethylammonium hydroxide extraction. Both methods showed good precision and trueness by analyses of SRMs. The 2 methods were used to determine iodine in seafood from the Barents Sea, the Norwegian Sea, and the North Sea. The results showed great variation between different fish species as well as between individuals within a species. The lowest values of iodine were recorded in muscle of ling (Molva molva) with a mean of 0.07 mg/kg fresh weight and a variation between 0.03 and 0.11 mg/kg fresh weight. The highest values were found in cod (Gadus morhua) from the Barents Sea, with a mean of 2.5 mg/kg and a variation between 0.7 and 12.7 mg/kg fresh weight.

Determination of iodine species in milk using ion chromatographic separation and ICP-MS detection

A combination of ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine iodine species in Thuringian milk samples. The developed method allows the fast and sensitive determination of iodine species with limits of determination for iodide and iodate <2 µg/L. Iodide was identified as the main iodine species in milk, but in a few samples also traces of iodate and several unidentified, presumably organoiodine compounds were observed as well. In addition, the total iodine concentration in the samples was determined by ICP-MS and gives an idea about the actual iodine state in Thuringian milk.

Estimation of total body iodine content in normal young men.

Total body iodine content was estimated in six normal young men, who underwent 125I balance studies during 64-92 days of daily 125I administration. Total body retention of 125I was measured as the difference between total administered 125I and that collected in the urine and feces. Extrathyroidal 125I was the difference between total and thyroidal 125I content. The time-activity data for the ratio of extrathyroidal to total retained 125I were fitted to a growth (inverse exponential) function. Fits of this growth function to the individual data sets yielded asymptotes, the equilibrium extrathyroidal/total 125I ratios. The slopes of this function predicted the time that would have been required to achieve 125I/127I equilibration (approximately 10 months). Geometric mean for the asymptotic extrathyroidal/total 125I ratio was 0.34 (range, 0.19-0.63), if it was assumed that measured urine and feces represented all of the 125I lost to the body. If 90% measurement of 125I loss was assumed, the geometric mean ratio was 0.32 (range, 0.17-0.60). Assuming that 90% of total loss is reflected in measured excreta and that total iodine content of the thyroid gland is 10 mg, geometric mean for total body iodine in these subjects was 14.6 mg (range, 12.1-25.3 mg).

Bromine and iodine in 1997 UK total diet study samples.

Concentrations of bromine and iodine were analysed in samples from the 1997 UK Total Diet Study (TDS) using ICP-MS. The data has been used to estimate dietary exposures of UK consumers to these elements from the typical UK diet. Samples for the 20 TDS food groups were obtained from 20 towns in the UK in 1997 and analysed in 1998/99 for total bromine and total iodine concentrations. These samples were also analysed for 12 other elements. The UK regulatory authority had considered iodine recently, but had not considered bromine before. This survey provides up-to-data baseline data for those two elements. Iodine concentrations are similar to those found in recent surveys. Levels of bromine were consistent with previous data where available. Dietary exposures to bromine and iodine were calculated to see if there were any risks to health from the levels of these elements found in the UK diet. The estimated population average exposure to iodine was 0.25 mg d-1, which is within the range of previous estimates (1995, 0.21 mg d-1; 1991, 0.17 mg d-1; 1985, 0.28 mg d-1). The estimated population average exposure to bromine was 3.6 mg d-1.

Changes in Thyroid Function in Puppies Fed a High Iodine Commercial Diet

Abnormally low131I uptakes were noticed in dogs fed with commercial diets at the University Animal Clinic in Buenos Aires, but the total iodine content of eight different commercial diets examined was found to provide an iodine intake above daily requirements. To investigate this anomaly, 18 dogs were distributed into three groups, fed either: (1) a home-prepared diet; (2) a commercial diet; (3) a home-prepared diet supplemented with potassium iodide equivalent to that found in the commercial diet.The131I uptake in dogs of groups B and C was significantly decreased, as was basal serum thyroxine (T4) and free thyroxine (FT4), whereas urinary iodide excretion and serum thyroid stimulating hormone (TSH), were increased. The thyroid releasing hormone (TRH)-TSH test showed an increased response in dogs from group B, while the TRH-T4test was inhibited in both groups B and C. The results demonstrate that the excessive amount of iodine present in some commercial diets in Argentina causes a significant impairment of thyroid function and hypothyroidism.

Steady-state mixing of iodine in shelf seas off the British Isles

A study of dissolved iodate and total iodine on the Hebridean shelf in several months of 1995/6 confirms an earlier hypothesis that the distribution of iodine in these waters is almost in steady state throughout the year. No evidence was found for changes in iodine chemistry that might correlate with seasonal changes in primary productivity, and the inappropriateness of adopting a Redfield-type model to explain the main trend of the iodine distribution is discussed. The system is determined by the mixing of three water types. To the west, the iodine distribution is governed by water of the North Atlantic Current (typically with salinity of 35.3 and iodate and total iodine concentrations close to 0.40 and 0.45 μM, respectively, and its mixing with deeper water containing a slightly higher concentration of iodate, but similar salinity. To the east, the distribution is governed by coastal waters with low salinity (∼33) and low iodate concentration (0.25 μM) but only a marginally lower total iodine concentration. The approximate iodate concentration, rationalised to 35 salinity, is given by RIO 3=0.060e −22 (35.42−S)+0.37e −0.20 (35.42−S)+0.010e −0.010 (35.42−S). Rationalised total iodine varied by only about 5%. Reasons are given for believing that the conditions found in the Hebridean waters probably applies to the whole of the shelf-seas of Britain, including the North Sea.

Dissolved Iodate and Total Iodine During an Extreme Hypoxic Event in the Southern Benguela System

Dissolved iodate and total iodine were studied in St Helena Bay, South Africa, during a period of acute hypoxia, following upwelling off Cape Columbine. Despite the generally high concentrations of chlorophyll α (10–30mgm−3) total iodine concentration was essentially constant in the main part of the Bay, and similar to that found elsewhere in the oceans. Occasional, lower concentrations of total iodine (0·28 to 0·42μM) were found with exceptionally high chlorophyll α concentrations (500mgm−3) in shallow waters. In contrast, iodate was found to be reduced to iodide at both the surface and the bottom of the Bay. The implications of these changes are discussed, given that the surface waters reflect sustained eutrophication while the bottom waters are hypoxic as a result of the organic-rich sediment from the waters above.

Properties of an enzyme-based low-level iodine disinfectant

An enzyme-based iodine (EBI) disinfectant that continuously generates free molecular iodine in a controlled fashion was developed and evaluated for use in disinfecting flexible fibreoptic endoscopes (FFEs). EBI is a powder concentrate that produces iodine from sodium iodide and calcium peroxide when catalyzed by horseradish peroxidase. After dissolution in water, it delivers relatively high concentrations of free molecular iodine (>15 ppm) at relatively low concentrations of total iodine (30–40 ppm). It demonstrates the ability to function as an effective low level iodine disinfectant by rapidly inactivating bacteria, fungi and viruses. A unique feature of the EBI system is the ability to reoxidize reduced iodine which results in a constant level of active (free molecular) iodine during use. EBI inactivates Mycobacterium bovis var BCG more rapidly than 2% glutaraldehyde (Cidex-7). Its sporicidal activity, however, was found to be slower than the aldehyde formulation. The qualification of EBI for use as a practical disinfectant was shown by its negligible toxicity in dermal, ocular, oral and inhalation studies on animals, which is attributed to the low level of total iodine in the solution.

Wakame seaweed suppresses the proliferation of 7,12-dimethylbenz(a)-anthracene-induced mammary tumors in rats.

We examined the anti‐tumor proliferation effects of wakame seaweed on 7,12‐dimethylbenz(a)‐anthracene (DMBA)‐induced rat mammary tumor. DMBA was administered to 8‐week‐old female Sprague‐Dawley rats, and rats which developed mammary tumors were assigned randomly to three groups. Commercial rat feed was used in a control group (group I‐A), and two feed mixtures were prepared, which contained commercial rat feed blended with wakame at 1.0% (group I‐B) and 5.0% (group I‐C) by weight. The respective feeds were given to each group for 8 weeks, and changes in mammary tumor size were compared. At the end of the experiment, mammary tumors and thyroid glands were resected to compare their weights. Serum total iodine and thyroxin (T4) levels were measured. Immunohistochemical studies for bromodeoxyuridine (BrdU) labeling, transforming growth factor (TGF)‐β, and apoptosis were carried out in the resected tumor. Significant suppression of tumor growth was observed in groups I‐B and I‐C compared with I‐A. In groups I‐B and I‐C, the weights of resected mammary tumors were significantly lower and serum total iodine concentration was significantly higher than in I‐A. BrdU indices were significantly lower in groups I‐B and I‐C, compared with I‐A. TGF‐β and apoptotic index were inversely related to BrdU. These results suggest that iodine is transported from the serum into mammary tissues and induces apoptosis through the expression of TGF‐β. In conclusion, wakame suppressed the proliferation of DMBA‐induced mammary tumors.

Study of chemical species of iodine in human liver.

The distribution and chemical species of iodine in various subcellular fractions of human liver were studied by using epithermal neutron activation analysis combined with chemical and biochemical separation techniques, such as gradient centrifugation and gel chromatography. It was found that the total iodine content orders in various subcellular fractions is as follows: nuclei > cytosol > mitochondria > lysosome > microsome. In the lysosomal fraction, iodine is mainly bound to macromolecules, whereas in the nuclei and mitochondrial fractions, mainly with lower-molecular-weight organic compounds. In the cytosol fraction, iodine is combined with three proteins, in which iodine is chiefly bound with mid- and high-molecular-weight proteins.

EXAFS studies of iodine-doped poly(octylthiophene)

Iodine doping of poly(octylthiophene) has been studied by EXAFS. At low doping levels, the average interatomic I-I distance is close to 2.9 Å, which shows that the iodine is present mainly as triiodide. When the doping level is increased towards saturation (two I atoms per monomer), the distance decreases gradually to 2.73 Å. This is interpreted as the presence of higher iodine complexes, involving I2-like units, such as pentaiodide. The measured coordination numbers support this interpretation. The ratio between I3− and I5− decreases monotonically with the total I content. In this model, the i3− content saturates at a total iodine content around 0.5 I atoms per monomer.