IS 3025-34 (1988): Methods of sampling and test (physical and chemical) for water and wastewater, Part 34: Nitrogen [CHD 32: Environmental Protection and Waste Management] ‘UDC 628’11.3 : 543’37 ( First Reprint APRIL 1992 ) IS : 3025 ( Part 34 ) - 1988. Its use as a photoconductor in plain-paper copiers once was a leading application, but in the 1980s, the photoconductor application declined (although it was still a large end-use) as more and more copiers switched to organic photoconductors. Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot. The pyrite from the Falun Mine created a red precipitate in the lead chambers which was presumed to be an arsenic compound, so the pyrite's use to make acid was discontinued. Selenium is a chemical element with the symbol Se and atomic number 34. Some analytical techniques are capable of distinguishing organic from inorganic forms of the element. (Only the deiodinase iodotyrosine deiodinase, which works on the last breakdown products of thyroid hormone, does not use selenium. In the Se8 rings, the Se-Se distance is 233.5 pm and Se-Se-Se angle is 105.7° . To the knowledge of researchers, there are no reports of mercury levels exceeding that of selenium levels in ocean fish. the preparation of Se7). It is prepared by treating selenium with sulfuryl chloride (SO2Cl2). This process leaches natural soluble selenium compounds (such as selenates) into the water, which may then be concentrated in new "wetlands" as the water evaporates. [130], Selenium interacts with other nutrients, such as iodine and vitamin E. The effect of selenium deficiency on health remains uncertain, particularly in relation to Kashin-Beck disease. The selenium cell was used in the photophone developed by Alexander Graham Bell in 1879. [133] Ruminants are particularly susceptible. Indian Standard. Applications of 13C nuclear magnetic resonance in elucidation of the structures of flavonoids - Journal of the Chemical Society, Perkin Transactions 1 (RSC Publishing) Issue 6, 1978. In fact, 16.7% of the worlds animal protein intake came from fish in 2010. [98] Marine fishes and vertebrate thyroid glands have the highest concentration of selenium and iodine. Sodium is the principal cation of the extracellular fluid and plays a large part in fluid and electrolyte replacement therapies. At levels of 1 mg/m3, selenium is immediately dangerous to life and health. Their use continued into the 1990s. #Class 7 #Standard 7 # Changes: Physical and Chemical #General Science # Maharashtra State Board [118] The resultant high selenium levels in waterways were found to cause congenital disorders in oviparous species, including wetland birds[119] and fish. [59] Like lead and sulfur, selenium improves the machinability of steel at concentrations around 0.15%. When prepared in chemical reactions, selenium is usually an amorphous, brick-red powder. Selenium occurs naturally in a number of inorganic forms, including selenide, selenate, and selenite, but these minerals are rare. It is recommended that a water concentration of 2 μg Se/L be considered highly hazardous to sensitive fish and aquatic birds. Five of these, 74Se, 76Se, 77Se, 78Se, 80Se, are stable, with 80Se being the most abundant (49.6% natural abundance). [75][76][77], 75Se is used as a gamma source in industrial radiography.[78]. National Research Council, Committee on Nutrient Requirements of Small Ruminants (2007). Appendix A to Part 27. The demand for selenium by the electronics industry is declining. The minimum distance between chains is 343.6 pm. Addeddate 2013-01-08 18:27:49 Identifier gov.law.is.3025.34.1988 Ocr ABBYY FineReader 8.0 Ppi 600. plus-circle Add … For this purpose, various selenite and selenate salts are added. Fish affected by selenium may experience swelling of the gill lamellae, which impedes oxygen diffusion across the gills and blood flow within the gills. Occupational Safety and Health Administration, National Institute for Occupational Safety and Health, "Atomic weights of the elements 2013 (IUPAC Technical Report)", Magnetic susceptibility of the elements and inorganic compounds, "The NUBASE2016 evaluation of nuclear properties", "Lettre de M. Berzelius à M. Berthollet sur deux métaux nouveaux", "Effect of light on selenium during the passage of an electric current", "The need for selenite and molybdate in the formation of formic dehydrogenase by members of the Coli-aerogenes group of bacteria", "How Selenium Has Altered Our Understanding of the Genetic Code", 10.1579/0044-7447(2007)36[94:SGAH]2.0.CO;2, "How to use the world's scarce selenium resources efficiently to increase the selenium concentration in food", "Public Health Statement: Selenium – Production, Import/Export, Use, and Disposal", "Chemistry: Periodic Table: selenium: key information", "Selenium and Tellurium: Statistics and Information", "Radiography of Welds Using Selenium 75, Ir 192 and X-rays", "Aquatic selenium pollution is a global environmental safety issue", "Mercury, selenium and fish oils in marine food webs and implications for human health", "Review of selenium toxicity in the aquatic food chain", Linus Pauling Institute at Oregon State University, "Dietary and tissue selenium in relation to methylmercury toxicity", "Post-transcriptional defects of antioxidant selenoenzymes cause oxidative stress under methylmercury exposure", "Protective effect of selenite against methylmercury toxicity: observations concerning time, dose and route factors in the development of selenium attenuation", "Inhibition of the human thioredoxin system: A molecular mechanism of mercury toxicity", Strong antioxidant activity of the novel selenium-containing imidazole compound ″selenoneine″, "Discovery of the strong antioxidant selenoneine in tuna and selenium redox metabolism", "Mercury: selenium interactions and health implications", "Selenocysteine-containing proteins in mammals", "Evolutionary dynamics of eukaryotic selenoproteomes: large selenoproteomes may associate with aquatic life and small with terrestrial life", "Evolution of Dietary Antioxidant Defences", "Reconsidering the evolution of eukaryotic selenoproteins: a novel nonmammalian family with scattered phylogenetic distribution", "The microbial selenoproteome of the Sargasso Sea", "FDA Issues Final Rule to Add Selenium to List of Required Nutrients for Infant Formula", "Dietary Supplement Fact Sheet: Selenium", "Public Health Statement: Health Effects", "Polo pony selenium levels up to 20 times higher than normal", "A teratogenic deformity index for evaluating impacts of selenium on fish populations", "CDC - NIOSH Pocket Guide to Chemical Hazards - Selenium", "Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged ≥90 y", "Selenium and iodine supplementation of rural Tibetan children affected by Kashin-Beck osteoarthropathy", National Institutes of Health page on Selenium, CDC - NIOSH Pocket Guide to Chemical Hazards, https://en.wikipedia.org/w/index.php?title=Selenium&oldid=999381397, Biology and pharmacology of chemical elements, Articles with dead external links from November 2020, Short description is different from Wikidata, Wikipedia articles needing clarification from August 2018, Wikipedia articles needing clarification from November 2015, Articles with unsourced statements from June 2016, Pages using Sister project links with hidden wikidata, Creative Commons Attribution-ShareAlike License, grey metallic-looking, red, and vitreous black (not pictured) allotropes, This page was last edited on 9 January 2021, at 22:00. During the 1980s, selenocysteine was shown to be encoded by the codon UGA. China is the largest consumer of selenium dioxide for this purpose. These COI are categorized under three main security issues: Release: Toxic, flammable, or explosive chemicals or materials that can be released at a facility. [131] Also, selenium interacts with other minerals, such as zinc and copper. [120] Elevated dietary methylmercury levels can amplify the harm of selenium toxicity in oviparous species. Journal of the Chemical Society, Perkin Transactions 1; Photochemical transformations. [7], The most stable and dense form of selenium is gray and has a hexagonal crystal lattice consisting of helical polymeric chains, where the Se-Se distance is 237.3 pm and Se-Se-Se angle is 130.1° . With strong reducing agents, it forms polyselenides. [20] Selenium disulfide has been used in shampoo as an antidandruff agent, an inhibitor in polymer chemistry, a glass dye, and a reducing agent in fireworks. [107], Certain species of plants are considered indicators of high selenium content of the soil because they require high levels of selenium to thrive. Sheets of amorphous selenium convert X-ray images to patterns of charge in xeroradiography and in solid-state, flat-panel X-ray cameras. [15], Selenium trioxide may be synthesized by dehydrating selenic acid, H2SeO4, which is itself produced by the oxidation of selenium dioxide with hydrogen peroxide:[17], Hot, concentrated selenic acid can react with gold to form gold(III) selenate.[18]. However, the lack of tellurium compounds in the Falun Mine minerals eventually led Berzelius to reanalyze the red precipitate, and in 1818 he wrote a second letter to Marcet describing a newly found element similar to sulfur and tellurium. In general, absorption of dietary selenium is lower in ruminants than other animals, and is lower from forages than from grain. In fact, the angiosperms (the dominant type of plant today) and most of their antioxidant pigments evolved during the late Jurassic period. Whereas other Se forms are insulators, gray Se is a semiconductor showing appreciable photoconductivity. Anwar Hossain, Ken Touhata, Takeshi Yabu, and Yumiko Yamashita, CS1 maint: multiple names: authors list (. Selenium dioxide is formed by the reaction of elemental selenium with oxygen:[6], It is a polymeric solid that forms monomeric SeO2 molecules in the gas phase. [73], Selenium is a catalyst in some chemical reactions, but it is not widely used because of issues with toxicity. [72] Ionized selenium (Se+24) is one of the active mediums used in X-ray lasers. Inorganic selenium bioaccumulates more readily in phytoplankton than zooplankton. Journal of the Chemical Society, Perkin Transactions 1 ; Allenes. It is a strongly odiferous, toxic, and colorless gas. These materials are semiconductors. [123], The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for selenium in the workplace at 0.2 mg/m3 over an 8-hour workday. [51] This changes the availability of selenium because only a comparably small part of the selenium in the ore is leached with the copper. [clarification needed]. The glutathione peroxidase family of enzymes (GSH-Px) catalyze certain reactions that remove reactive oxygen species such as hydrogen peroxide and organic hydroperoxides: The thyroid gland and every cell that uses thyroid hormone use selenium, which is a cofactor for the three of the four known types of thyroid hormone deiodinases, which activate and then deactivate various thyroid hormones and their metabolites; the iodothyronine deiodinases are the subfamily of deiodinase enzymes that use selenium as the otherwise rare amino acid selenocysteine. These data exclude two major producers: the United States and China. pH-dependent plant pigments that can be used as pH indicators occur in many plants, including hibiscus, red cabbage (anthocyanin), and grapes ().The juice of citrus fruits is acidic mainly because it contains citric acid.Other carboxylic acids occur in many living systems. Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. [71] Cadmium selenide was an important component in quantum dots. 10, 2020 Filed Under: Coronavirus , Industry Tagged With: coronavirus , Daicel , Kao , Shin-Etsu Chemical , Teijin , Tokuyama , Toray In June 2015, the US Food and Drug Administration (FDA) published its final rule establishing the requirement of minimum and maximum levels of selenium in infant formula. Especially common are selenides (R2Se, analogues of thioethers), diselenides (R2Se2, analogues of disulfides), and selenols (RSeH, analogues of thiols). The common mineral selenite is not a selenium mineral, and contains no selenite ion, but is rather a type of gypsum (calcium sulfate hydrate) named like selenium for the moon well before the discovery of selenium. Hence, Berzelius's first letter to Alexander Marcet stated that this was a tellurium compound. [82] To help reduce the amount of selenium entering our oceans, policies can be put into place such as using microbes or enzymes that target and break down metalloids like selenium. selenium, vanadium, magnesium, copper, and zinc, may have been lacking in some terrestrial mineral-deficient areas. [6][8], Owing to its use as a photoconductor in flat-panel x-ray detectors (see below), the optical properties of amorphous selenium (α-Se) thin films have been the subject of intense research.[9][10][11]. Also naturally occurring is the long-lived primordial radionuclide 82Se, with a half-life of 9.2×1019 years. Another source was the mud from the lead chambers of sulfuric acid plants, a process that is no longer used. In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light. [82] It has also been suggested that season could have an impact on the harmful effects of selenium on fish. Kolaflavanone, a new biflavanone from the nuts of Garcinia kola Heckel. Coronavirus Report – Part 34: Chemical Companies to Continue Operations as Japan Declares State of Emergency Apr. [132], In the regions (e.g. These findings suggest that, with the exception of vertebrates, aquatic life supports selenium use, whereas terrestrial habitats lead to reduced use of this trace element. [citation needed], The deiodinase isoenzymes constitute another family of eukaryotic selenoproteins with identified enzyme function. The National Institute for Occupational Safety and Health (NIOSH) has set a Recommended exposure limit (REL) of 0.2 mg/m3 over an 8-hour workday. Selenium does not exhibit the changes in viscosity that sulfur undergoes when gradually heated. [106], The selenium content in the human body is believed to be in the 13–20 mg range. [83], Although it is toxic in large doses, selenium is an essential micronutrient for animals. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. High doses of Se supplements in pregnant animals might disturb the Zn:Cu ratio and lead to Zn reduction; in such treatment cases, Zn levels should be monitored. Adult fish may appear healthy despite their inability to produce viable offspring. Selenium—from Ancient Greek σελήνη (selḗnē) "Moon" – was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). [116] Selenium also occurs in organic compounds, such as dimethyl selenide, selenomethionine, selenocysteine and methylselenocysteine, all of which have high bioavailability and are toxic in large doses. [7], The red α, β, and γ forms are produced from solutions of black selenium by varying the evaporation rate of the solvent (usually CS2). For example, lactic acid is produced by muscle activity. Gray Se is formed by mild heating of other allotropes, by slow cooling of molten Se, or by condensing Se vapor just below the melting point. For other applications, a red color may be desired, produced by mixtures of CdSe and CdS. Selenium pollution is impacting oceans across the world and is mainly caused by anthropogenic factors such as farming runoff and industrial processes. [5], Selenium forms several allotropes that interconvert with temperature changes, depending somewhat on the rate of temperature change. Other problems include degeneration of liver tissue, swelling around the heart, damaged egg follicles in ovaries, cataracts, and accumulation of fluid in the body cavity and head. ), and false goldenweed (Oonopsis sp. They all have relatively low, monoclinic crystal symmetries and contain nearly identical puckered Se8 rings with different arrangements, as in sulfur. [128], Selenium deficiency, defined by low (<60% of normal) selenoenzyme activity levels in brain and endocrine tissues, occurs only when a low selenium level is linked with an additional stress, such as high exposures to mercury[129] or increased oxidant stress from vitamin E deficiency. The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day. China is the dominant consumer of selenium at 1,500–2,000 tonnes/year. This was followed by the discovery of selenocysteine in proteins. Selenium is bioaccumulated in aquatic habitats, this results in higher concentrations in organisms than the surrounding water. [117], Selenium poisoning of water systems may result whenever new agricultural runoff courses through normally dry, undeveloped lands. [56], During the electrowinning of manganese, the addition of selenium dioxide decreases the power necessary to operate the electrolysis cells. Native (i.e., elemental) selenium is a rare mineral, which does not usually form good crystals, but, when it does, they are steep rhombohedra or tiny acicular (hair-like) crystals. Black Se is a brittle, lustrous solid that is slightly soluble in CS2. Nearly 200 years ago, Alexis St. Martin was shot in the stomach. The solubility of 408 gaseous compounds in water at 298 K has been correlated through eqn. [36][37] It was discovered to be essential for mammalian life in 1957. [41] Isolation of selenium is often complicated by the presence of other compounds and elements. [42][43], In living systems, selenium is found in the amino acids selenomethionine, selenocysteine, and methylselenocysteine. Michael H. Abraham, Jenik Andonian-Haftvan, Gary S. Whiting, Albert Leo and Robert S. Taft Abstract. [115] Hydrogen selenide is an extremely toxic, corrosive gas. Se compounds confer a red color to glass. [137], It has been suggested that selenium supplementation may help prevent cancer incidence in people, but research has established there is no evidence to support such claims. [121][122], In fish and other wildlife, selenium is necessary for life, but toxic in high doses. In humans, selenium is a trace element nutrient that functions as cofactor for reduction of antioxidant enzymes, such as glutathione peroxidases[84] and certain forms of thioredoxin reductase found in animals and some plants (this enzyme occurs in all living organisms, but not all forms of it in plants require selenium). Selenium is a chemical element with the symbol Se and atomic number 34. Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. [111] The 1992 study actually found the maximum safe dietary Se intake to be approximately 800 micrograms per day (15 micrograms per kilogram body weight), but suggested 400 micrograms per day to avoid creating an imbalance of nutrients in the diet and to accord with data from other countries. Upon heating, it softens at 50 °C and converts to gray selenium at 180 °C; the transformation temperature is reduced by presence of halogens and amines. [112] In China, people who ingested corn grown in extremely selenium-rich stony coal (carbonaceous shale) have suffered from selenium toxicity. Although trace amounts of selenium are necessary for cellular function in many animals, including humans, both elemental selenium and (especially) selenium salts are toxic in even small doses, causing selenosis. The renal tubular actions of dopamine that cause natriuresis may be augmented by the increase in renal blood flow and the small increase in the glomerular filtration rate that follow its administration. Iodides of selenium are not well known. [44][45], Certain soils are selenium-rich, and selenium can be bioconcentrated by some plants. Although New Zealand soil has low levels of selenium, adverse health effects have not been detected in the residents. Structures of the toxisterols 2. The main selenium indicator plants are Astragalus species (including some locoweeds), prince's plume (Stanleya sp. Selenous acid is bubbled with sulfur dioxide (reduction step) to give elemental selenium. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic.It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium as a dietary supplement is available in many forms, including multi-vitamins/mineral supplements, which typically contain 55 or 70 µg/serving. Selenium has seven naturally occurring isotopes. Another selenium-bearing enzyme in some plants and in animals (thioredoxin reductase) generates reduced thioredoxin, a dithiol that serves as an electron source for peroxidases and also the important reducing enzyme ribonucleotide reductase that makes DNA precursors from RNA precursors. Export articles to Mendeley. COVID-19 is an emerging, rapidly evolving situation. Brazil nuts are the richest dietary source (though this is soil-dependent, since the Brazil nut does not require high levels of the element for its own needs).[104][105]. This color cancels out the green or yellow tints that arise from iron impurities typical for most glass. Selenium can be refined from these muds by a number of methods. Chemical Watch empowers our members to transform product safety management and unlock the full value of regulatory compliance within their business. Selenium is a component of the unusual amino acids selenocysteine and selenomethionine. The consumption in 2010 was divided as follows: metallurgy – 30%, glass manufacturing – 30%, agriculture – 10%, chemicals and pigments – 10%, and electronics – 10%. Both organic and inorganic forms of selenium are largely converted to monosaccharide conjugates (selenosugars) in the body prior to elimination in the urine. A few of these appeared more recently, in the last 50–200 million years, in fruits and flowers of angiosperm plants. At the Kesterson National Wildlife Refuge in California, thousands of fish and waterbirds were poisoned by selenium in agricultural irrigation drainage. [82] There are, however, a few species that have been seen to survive these events and tolerate the increased selenium. The selenide dianion Se2− forms a variety of compounds, including the minerals from which selenium is obtained commercially. The packing is most dense in the α form. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). By contrast, selenates and selenites have an oxidant mode of action similar to that of arsenic trioxide and are very toxic. [97], Trace elements involved in GSH-Px and superoxide dismutase enzymes activities, i.e. Selenous acid can also be made directly by oxidizing elemental selenium with nitric acid:[15], Unlike sulfur, which forms a stable trioxide, selenium trioxide is thermodynamically unstable and decomposes to the dioxide above 185 °C:[6][15], Selenium trioxide is produced in the laboratory by the reaction of anhydrous potassium selenate (K2SeO4) and sulfur trioxide (SO3).[16]. Extreme cases of selenosis can exhibit cirrhosis of the liver, pulmonary edema, or death. [134] Ruminants grazing certain forages, e.g., some white clover varieties containing cyanogenic glycosides, may have higher selenium requirements,[134] presumably because cyanide is released from the aglycone by glucosidase activity in the rumen[135] and glutathione peroxidases is deactivated by the cyanide acting on the glutathione moiety. [6] The structure of black selenium is irregular and complex and consists of polymeric rings with up to 1000 atoms per ring. Applications in electronics, once important, have been mostly replaced with silicon semiconductor devices. 1-Bromoallenes give allenic carbenes under basic conditions, which react with methylindoles to give alkenylquinolines by ring expansion and alkynyl- and allenyl-3H-indoles. Representatives of selenides, diselenides, and selenols include respectively selenomethionine, diphenyldiselenide, and benzeneselenol. [109], Although selenium is an essential trace element, it is toxic if taken in excess. Consistent with trends indicated by the double bond rule, selenoketones, R(C=Se)R, and selenaldehydes, R(C=Se)H, are rarely observed. Many benthic invertebrates can tolerate selenium concentrations up to 300 μg/L of Se in their diet.[79]. The only stable chloride is selenium monochloride (Se2Cl2), which might be better known as selenium(I) chloride; the corresponding bromide is also known. In 1954, the first hints of specific biological functions of selenium were discovered in microorganisms by biochemist, Jane Pinsent. Polylactic acid, or polylactide (PLA) is a thermoplastic polyester with backbone formula (C 3 H 4 O 2) n or [–C(CH 3)HC(=O)O–] n, formally obtained by condensation of lactic acid C(CH 3)(OH)HCOOH with loss of water (hence its name). Copper indium gallium selenide is a material used in solar cells. [6], Analogous to the behavior of other chalcogens, selenium forms hydrogen selenide, H2Se. However, it can damage plants at higher doses. [110] This 400 µg Tolerable Upper Intake Level is based primarily on a 1986 study of five Chinese patients who exhibited overt signs of selenosis and a follow up study on the same five people in 1992. In low doses, selenium has shown a beneficial effect on plant resistance to various environmental stress factors including drought, UV-B, soil salinity, and cold or hot temperatures. Small amounts of organoselenium compounds have been used to modify the catalysts used for the vulcanization for the production of rubber.[52]. Within the Chemical Engineering Journal, the Environmental Chemical Engineering section presents papers dealing with emerging topics in environmental chemical and process engineering, including pollution control, separation processes, advanced oxidation processes, adsorption of contaminants, resources recovery, waste-to-energy, environmental nanotechnology and bioprocesses, CO2 capture … Morphine | C17H19NO3 | CID 5288826 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more. [80] Fish are a major source of protein for humans. Selenium's semiconductor properties found numerous other applications in electronics. )[85], Selenium may inhibit Hashimoto's disease, in which the body's own thyroid cells are attacked as foreign. Selenium requirements in plants differ by species, with some plants requiring relatively large amounts and others apparently requiring none.