Iodine in drinking water in Denmark is bound in humic substances

Andersen, Stig; Petersen, Steffen B.; Laurberg, Peter

doi:10.1530/eje.0.1470663

Cited by 57 publications

(65 citation statements)

References 22 publications

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“…Iodine-rich waters have been documented in some places [11,18,19], and iodine-rich drinking waters in China associated with an increased occurrence of goitre [17,20] and hypothyroidism [12].…”

Section: Introductionmentioning

confidence: 99%

“…These were found to hold iodine in iodine-rich waters from one area [18], and it was proposed that groundwater iodine suggests concurring humic substances of marine origin. This could be speculated to be more than a local phenomenon as iodine associated with humic substances [26] and may pass through aquifer transformation zone [27] and hence leach into well water.…”

Section: Introductionmentioning

confidence: 99%

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Speciation of Iodine in High Iodine Groundwater in China Associated with Goitre and Hypothyroidism

Andersen

Guan

Wang

et al. 2008

Biol Trace Elem Res

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Iodine intake affects the occurrence of disease in a population. Excessive iodine intake may be caused by a high iodine content of drinking water. Tap water in few locations in Europe contains up to 139 microg/L mostly bound to humic substances, probably leaching from marine sediments in the aquifers. Even higher iodine contents have been found in Chinese waters, previously shown to associate with goitre and hypothyroidism. The aims were to elucidate speciation of high iodine groundwater from deep wells in China and to compare with high iodine waters from Europe. Water was sampled from eight wells in five villages along Bohai Bay, China. Macro-molecules and low molecular weight (MW) substances were separated by size exclusion chromatography (high performance liquid chromatography, Superose 12 HR 10/30, buffer 0.1 M Tris, pH 7.0). Organic material was evaluated by A280 and iodine in fractions measured by the Ce/As method after alkaline incineration. Iodine content of well water varied from 135 to 880 microg/L (median 287 microg/L). The amount of organic material in water was low with A280, <1-5 mAU. The chromatographic traces were similar between samples: One peak of iodine eluted around K (AV) 0.65 corresponding to MW 5 kDa (humic substances) and one peak at V (total) (iodide/low MW substances). The fraction of iodine in macro-molecules, suggested to be humic substances, varied from 8% to 70% (median 27%). Iodine and peak absorbance were associated (p = 0.006). In conclusion, iodine in iodine-rich deep well water in northern China may have marine origin and may associate with humic substances, comparable to shallow well iodine-rich water in Europe. High iodine intake from iodine-rich water suggests the cause of endemic goitre and hypothyroidism in some areas in China being iodine.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Speciation of Iodine in High Iodine Groundwater in China Associated with Goitre and Hypothyroidism

Andersen

Guan

Wang

et al. 2008

Biol Trace Elem Res

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“…However, it most often occurs in natural waters inorganically in the -1 (iodide) and +5 (iodate) oxidation states which are the most stable thermodynamically (Jones, 1981;Jones and Truesdale, 1984;Truesdale and Jones, 1996;Moran et al, 2002). Iodine can also be present in significant concentrations as organo-iodine in waters and fixed onto humic substances (Warwick et al, 1993;Radlinger and Heumann, 2000;Andersen et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Dissolved iodine in rainfall, cloud, stream and groundwater in the Plynlimon area of mid-Wales

Neal¹,

Neal²,

Wickham³

et al. 2007

Hydrol. Earth Syst. Sci.

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Iodine concentrations in rainfall, cloud water, throughfall, stemflow, stream water and groundwater are described for the upper River Severn Plynlimon catchments in mid-Wales. Iodine concentrations average 1.55 mg l 1 in rainfall while the corresponding averages of iodine concentrations in cloud water, throughfall and stemflow iodine concentrations are three to eight times higher. For the atmospheric inputs, there are both marine and anthropogenic sources while, for stemflow and throughfall, humic substances may be a dominant component. The average concentrations in the streams and groundwaters vary between 1.00 to 4.22 mg l 1 and 0.57 to 8.51 mg l 1 , respectively. The higher averages are for waters associated with gley soils that are high in dissolved organic carbon (DOC). For the streams draining forested catchments, iodine concentrations have increased over time, probably due to wetting up of the soils because of reduction in transpiration as the trees are maturing and felling activities. The increases vary between 0.025±0.003 and 0.044±0.010 mg l 1 per year and are associated partly with an increase in DOC concentration: adjusted for the effect of DOC, the increases range between 0.013±0.003 and 0.023±0.009 mg l 1 per year. For the moorland areas, no such trend is observed but the value is lower. For most of the Plynlimon catchments, a net uptake of iodine of around 40% is lower for streams draining gley soils with even a net export for the smaller streams. Within the streams, iodine concentrations are highly correlated with DOC and there is an annual cycle of iodine and DOC concentration change, with maxima between July and November. For the groundwaters, a loss of iodine and DOC relative to the streams probably reflects within catchment losses in the lower inorganic soils and bedrock areas. However, in one case, groundwater iodine concentrations were relatively high and this coincided with high DOC concentrations.

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“…The apparent lack of any correlation between the inorganic and the organic iodine system is also notable, especially as organic iodine is expected to be fairly closely linked to that of iodide and natural organic matter (Rädlinger & Heumann, 2000;Andersen et al, 2002;Steinberg et al, 2008). As with alkalinity and silica, the profiles for organic iodine support the idea that the dilution of the cave water was by water from within the karst, and not rainfall, as otherwise the profile in January 2010 would have been displaced toward lower concentrations (Figs.…”

Section: Organic Iodine: a Refractory Iodine Poolmentioning

confidence: 83%

Nutrient speciation and hydrography in two anchialine caves in Croatia: tools to understand iodine speciation

et al. 2011

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Despite iodine being one of the most abundant of the minor elements in oxic seawater, the principal processes controlling its interconversion from iodate to iodide and vice versa, are still either elusive or largely unknown. The two major hypotheses for iodate reduction involve either phytoplankton growth in primary production, or bacteria during regeneration. An earlier study intended to exploit the unusual nature of anchialine environments revealed that iodide is oxidised to iodate in the bottom of such caves, whereas reduction of iodate occurs in the shallower parts of the water column. This investigation was made on the hypothesis that study of the nitrogen and phosphorus nutrient systems within the caves might offer a bridge between the iodine chemistry and the marine bacteria which are assumed to be the agent of change of the iodine in the caves. Accordingly, the hydrography, the nutrient chemistry, and some further iodine studies were made of two anchialine caves on the east coast of the Adriatic Sea in Croatia. Iodate and iodide were determined by differential pulse voltammetry and cathodic stripping square-wave voltammetry, respectively. Total iodine was determined indirectly, as iodate, after oxidation of reduced iodine species with UV irradiation and strong chemical oxidants. Nutrient concentrations were measured by spectrophotometry. Nutrient profiles within the well stratified water columns indicate a relatively short-lived surface source of nitrate and phosphate to the caves, with a more conventional, mid-water, nutrient regeneration system. The latter involves nitrite and ammonium at the bottom of the halocline, suggestive of both autotrophic and heterotrophic microbial activity. High iodate/low iodide deep water, and conservative behaviour of total inorganic iodine were confirmed in both systems. Iodate is reduced to iodide in the hypoxic region where nutrient regeneration occurs. The concentrations of organic iodine were surprisingly high in both systems, generally increasing toward the surface, where it comprised almost 80% of total iodine. As with alkalinity and silica, the results suggest that this refractive iodine component is liberated during dissolution of the surrounding karst rock. A major, natural flushing of one of the caves with fresh water was confirmed, showing that the cave systems offer the opportunity to re-start investigations periodically.

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Iodine in drinking water in Denmark is bound in humic substances

Cited by 57 publications

References 22 publications

Speciation of Iodine in High Iodine Groundwater in China Associated with Goitre and Hypothyroidism

Speciation of Iodine in High Iodine Groundwater in China Associated with Goitre and Hypothyroidism

Dissolved iodine in rainfall, cloud, stream and groundwater in the Plynlimon area of mid-Wales

Nutrient speciation and hydrography in two anchialine caves in Croatia: tools to understand iodine speciation

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