Toxicity of selenium

Selenium heterocycles receive far less mention in the literature than do such homologs as oxazole, thiazole, or imidazole. In fact, preparative methods of selenium heterocycles are much more limited than for the other series, mainly because of manipulatory difficulties arising from the toxicity of selenium (hydrogen selenide is even more toxic) that can produce severe damage to the skin, lungs, kidneys, and eyes. Another source of difficulty is the reactivity of the heterocycle itself, which can easily undergo fission, depending on the reaction medium and the nature of the substituents. 

In July, 1970, 14 trace elements were known to be essential to human health. One of these is cobalt. Yet at least one researcher suggests that the addition of small amounts of cobalt to stabilize beer foam may have resulted in the deaths of a number of people in Minneapolis and Omaha. He theorizes that cobalt was necessary to activate the toxicity of selenium, which is naturally present in those areas. This is another example of a synergistic affect. Separately neither would have been harmful, but together they could cause fatalities. 

Soltanpour P.N, Workman S.M. Use of NH4HCO3-DTPA soil test to assess the availability and toxicity of selenium to alfalfa paints. Commun Soil Sci Plant Anal 1980 11 1147-1156. 

The toxicity of selenium (Se) belies the fact that it is a required trace-nutrient for many biological organisms. The general order of toxicity for the most... 

Selenium dioxide is also an oxygen donor to alkenes. In this case, however, the initial reaction of the double bond is with the selenium center followed by two pericyclic steps. After hydrolysis of the organo-selenium intermediate, the result is a hydroxylation at the allylic carbon position65. Thus, limonene (2) yields racemic p-mentha-l,8(9)-dien-4-ol66. The high toxicity of selenium intermediates and prevalence of many rearrangements has limited the widespread use of the reagent in synthesis. 

Stowe, H.D. 1980. Effects of copper pretreatment upon the toxicity of selenium in ponies. Amer. Jour. Veterin. Res. 41 1925-1928. 

Table 31.3 Toxicity of Selenium Salts to Aquatic Biota (Values shown are in pg/L [ppb] in medium fatal to 50% of the organisms during exposure for various intervals.)...

Browne, C.L. and J.N. Dumont. 1979. Toxicity of selenium to developing Xenopus laevis embryos. Jour. Toxicol. Environ. Health 5 699-709. 

Cardwell, R.D., D.G. Foreman, T.R. Payne, and D.J. Wilbur. 1976. Acute toxicity of selenium dioxide to freshwater fishes. Arch. Environ. Contam. Toxicol. 4 129-144. 

Crane, M., T. flower, D. Holmes, and S. Watson. 1992. The toxicity of selenium in experimental freshwater ponds. Arch. Environ. Contamin. Toxicol. 23 440-452. 

Hilton, J.W., P.V. Hodson, and S.J. Slinger. 1980. The requirement and toxicity of selenium in rainbow trout (Salma gairdneri). Jour. Nutr. 110 2527-2535. 

Kumar, H.D. and G. Prakash. 1971. Toxicity of selenium to the blue-green algae, Anacystis nidulans and Anabaena variabilis. Ann. Bot. 35 697-705. 

Lemly, A.D. 1993c. Metabolic stress during winter increases the toxicity of selenium to fish. Aquat. Toxicol. 27 133-158. 

Ward, G.S., T.A. Hollister, P.T. Heitmuller, and P.R. Parrish. 1981. Acute and chronic toxicity of selenium to estuarine organisms. Northeast Gulf Sci. 4 73-78. 

Kimmerle G Comparative research on the inhalation toxicity of selenium sulfide and tellurium hexafluoride. Arch Toxicol 18 140-144, 1960... 

A thiolase (Eq. 13-35) from Clostridium kluyveri is one of only two known selenoproteins that contain selenomethionine.569 However, the selenomethionine is incorporated randomly in place of methionine. This occurs in all proteins of all organisms to some extent and the toxicity of selenium may result in part from excessive incorporation of selenomethionine into various proteins. 

E. P. Painter, The chemistry and toxicity of selenium compounds with special reference to the selenium problem, Chem. Rev., 28 (1941), 179-213. 

Despite the high toxicity of selenium compounds there has been a lot of activity in this field during the last decade. Not surprisingly, selenium-substituted cyclopropane derivatives have also been recommended for synthetic purposes. An example is disclosed in equation 119 one should remember, however, that most transformations can be achieved by other and less poisonous reagents. 

Tinggi, U. (2003). Essentiality and toxicity of selenium and its status in Australia a review. Toxicol. Lett. 137, 103-110. 

Sharpless has shown that phenylselenic acid catalyzes the epoxidation of olefins with hydrogen peroxide or f-BuOOH [41]. However, the toxicity of selenium compounds precludes many applications of this catalytic epoxidation. To avoid contamination of the reaction products with selenium compounds polystyrene-bound phenylselenic acid has been used [42]. An alternative to the solid phase chemistry is the immobilisation of the selenium catalyst in the fluorous phase... 

Selenium and tellurium are more electropositive elements than sulfur and, in general, the chemistry of organic selenium and tellurium compounds is more complicated and difficult than that of the sulfur analogues, not forgeting the toxicity of selenium and the noxiousness of low molecular organic selenium and tellurium compounds. 

Several factors should be considered when evaluating the toxicity of selenium compounds. The purity and grade of the particular test substance used in the testing are important factors. For example, in studies of selenium sulfide compounds, the amounts of mono- and disulfides are often not specified by the study authors. The solubility and the particle size of selenium compounds also influence their toxicity. 

Excretion of selenium by humans occurs in the urine, feces, expired air, and sweat, but urine and feces are the major routes of elimination. Some of the selenium in feces may be due to bilary excretion (Levander and Baumann 1966a, 1966b). Elimination is reduced in selenium-deficient individuals and may represent a mechanism by which selenium levels are regulated (Martin et al. 1989a Swanson et al. 1991). Methylation is an important mechanism of detoxification for selenium dimethyl selenide is exhaled, and the trimethylselenonium ion is the major urinary metabolite of selenium. Experiments in mice suggest that the hepatic toxicity of selenium may be at least partly due to depression of selenium methylation in the liver, resulting in the accumulation of excess selenides (Nakamuro et al. 2000). 

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