Organically-Bound Iodine

Organically bound iodine is found in various invertebrates, but with one possible exception... 

Iodinated glycerol is used as a mucolytic agent in respiratory disorders, but its efficacy is controversial. Organically bound iodine is changed to unbound iodide after absorption. 

Kalant H, Roschlan W. Organically bound iodine. In Principles of Medical Pharmacology. 5th ed.. Washington DC Decker, 1989 484-5. 

Organically bound iodine is changed to unbound iodide after absorption. 

In general, soluble forms of iodine seem to be easily available to plants therefore, terrestrial plants contain much less iodine than do marine plants, which are known to concentrate iodine from 50 to 8800 mg kg DM (Shaklette and Cuthbert 1967). Organically bound iodine is scarcely available to plants soil iodine becomes available after the decomposition of organic matter by bacteria (Selezniev and Tiuriuka-nov 1971). Atmospheric iodine also contributes to the iodine content of plants (Kabata-Pendias and Pendias 1992), as plants can... 

The coexistence of various inorganic and organic iodine species, in different proportions, has been reported in various environments (Liss et al., 1973 Couture and Seitz, 1983 Yuita, 1992, 1994 Yamada et al., 1999 Muramatsu and Ohmono, 1988 Baker et al., 2001). Organically bound iodine can be a significant fraction of total iodine in aqueous systems and in the atmosphere. For example, methyl iodide is an important gaseous form of iodine in the marine atmosphere and in releases from nuclear fuel reprocessing facilities, while dissolved organo-I compounds comprise up to 50% of total iodine in aqueous samples from estuaries, rivers, and rain (Santschi and Schwehr, 2004). 

Various iodine species in different proportions exist in soil and sediments. Organically bound iodine, with fim-ited solubility and mobility, commonly comprises the major proportion of total iodine it is well-correlated with total organic matter, sesquioxides, and clay content. 

The typical environmental airborne radionuclide collection train consists of a filter followed by an activated-charcoal cartridge particulate iodine is retained on the filter and gaseous iodine on the cartridge (Corley etal. 1977). A more elaborate collector train distinguishes the various forms of radioiodine. The collectors, in order, are an air filter for particles, cadmium iodide on Chromosorb-P for I2, 4-iodophenol on alumina for HIO, and activated charcoal for organically bound iodine, such as CH3I (Keller et al. 1973). 

In normal, untreated rats, single injections of thyrotropin caused as much as a threefold rise in the thyroid-serum iodide ratio 50 hours after the injection. It appears therefore that the pituitary gland influences thyroid function at two stages the concentration of iodide and its conversion to organically bound iodine evidence for the second of these effects will be discussed in a later section. 

Recent work on the three main functions of the thyroid gland— the collection of iodide from the plasma, the transformation of iodide into organically bound iodine and the release of the hormone into the circulation—has been reviewed. 

The radioiodine content of milk can be determined on the basis of iodine extraction from milk with tetrachloromethane (carbon tetrachloride). In this way, only inorganic iodine in milk is determined, and organically bound iodine is obtained after alkali metal fusion and extraction. The activity is measured after the precipitation of silver iodide. 

It can be assumed that the fraction of organically bound iodine measured in various experiments was the result of secondary reactions occurring in the course of the analytical procedure. Numerous indications give rise to the conclusion that these compounds are not stable in the hot primary coolant imder the influence of ionizing radiation. Investigations of the behavior of methyl iodide in alkaline bo-... 

In the German Storfall-Berechnungsgrundlagen it is postulated that in such an incident all the fuel rods of one outer row of the respective assembly are damaged. It is further assumed that 10% of the fission product noble gas inventories of these rods is released to the containment atmosphere. As for the fission product iodine, 5% of the inventory has to be assumed to be transported to the pool water from there, a fraction of the iodine is assumed to be volatilized, in accordance with a partition coefficient of 1 - 10, which is calculated for a pool water volume of ISOOm and an atmosphere volume limited to 20,000 m. Airborne iodine is assumed to be present as 90% I2 and 10% organically bound iodine. 

Detection of Organic Iodine Gomjpounds, The most specific possible detection of organically bound iodine is of particular interest. According to Stahl and Peeiele [228] this is possible directly on a silica gel-starch layer by means of photochemical deiodination. The liberated iodine yields the blue-violet starch inclusion compound and amounts down to 0.5 [xg may be thus visualised. 

Since this transformation proceeds rapidly and with small amounts, the proof of the production of iodic acid may serve as the basis of an indirect test for organically bound iodine. 

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