Cancer patients receiving daily oral doses of selenothionine may achieve very high plasma and urine selenium concentrations. [132], 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. What channel number is One America News on Dish Network? Although New Zealand soil has low levels of selenium, adverse health effects have not been detected in the residents. Small amounts of organoselenium compounds have been used to modify the catalysts used for the vulcanization for the production of rubber.[52]. [42][43] Ocean water contains significant amounts of selenium. 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. It is recommended that a water concentration of 2 Î¼g Se/L be considered highly hazardous to sensitive fish and aquatic birds. As the temperature of a reaction increases, it is expected that the reacting particles collide? Like sulfur and phosphorus it is solid but nonetheless a non metal. 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. The price was relatively stable during 2004–2010 at about US$30 per pound (in 100 pound lots) but increased to $65/lb in 2011. In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light. 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. Which element is least likely to conduct heat and electricity? 1 decade ago. Selenous acid is bubbled with sulfur dioxide (reduction step) to give elemental selenium. Selenium rectifiers were first used in 1933. greendawn. Nonmetal. This phenomenon was used in the design of light meters and similar devices. Fish affected by selenium may experience swelling of the gill lamellae, which impedes oxygen diffusion across the gills and blood flow within the gills. In humans, selenium is a trace element nutrient that functions as cofactor for reduction of antioxidant enzymes, such as glutathione peroxidases[86] 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). [117] Hydrogen selenide is an extremely toxic, corrosive gas. Metalloid, in chemistry, an imprecise term used to describe a chemical element that forms a simple substance having properties intermediate between those of a typical metal and a typical nonmetal. During the 1980s, selenocysteine was shown to be encoded by the codon UGA. Some analytical techniques are capable of distinguishing organic from inorganic forms of the element. Selenium was later confirmed to be the toxic factor. Electrolytic metal refining is particularly productive of selenium as a byproduct, obtained from the anode mud of copper refineries. Adult fish may appear healthy despite their inability to produce viable offspring. Selenium is a toxic metalloid that was first established as a causative agent for a condition in animals known as alkali disease. )[110], Selenium may be measured in blood, plasma, serum, or urine to monitor excessive environmental or occupational exposure, to confirm a diagnosis of poisoning in hospitalized victims, or investigate a suspected case of fatal overdose. [49][50] Since its invention, solvent extraction and electrowinning (SX/EW) production of copper produces an increasing share of the worldwide copper supply. The demand for selenium by the electronics industry is declining. 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. Chemistry. Selenium pollution is impacting oceans across the world and is mainly caused by anthropogenic factors such as farming runoff and industrial processes. answer choices . Selenium is a semiconductor and used in photocells boron, silicon, germanium, arsenic, … 31 During this period (1930s) the toxicity of metals and metalloids was being evaluated for animal disease and nutrition. Berzelius and Gahn wanted to use the pyrite and they also observed that the red precipitate gave off a smell like horseradish when burned. Selenium's semiconductor properties found numerous other applications in electronics. [74], Selenium is used in the toning of photographic prints, and it is sold as a toner by numerous photographic manufacturers. Much below that level, young salmon die from deficiency;[126] much above, they die from toxic excess. Why don't libraries smell like bookstores? There is no single property which can be used to unambiguously identify an element as a metalloid. [140], This article is about the chemical element. A few of these appeared more recently, in the last 50–200 million years, in fruits and flowers of angiosperm plants. Deiodinases are able to extract electrons from iodides, and iodides from iodothyronines. 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. Silicon is a metalloid meanind it both metal and nonmetal. Is mark weinstein related to Harvey Weinstein? [52], Industrial production of selenium usually involves the extraction of selenium dioxide from residues obtained during the purification of copper. Naming Se as metalloid and C and P only as nonmetal is Three days later, a pharmacy released a statement explaining that the horses had received an incorrect dose of one of the ingredients used in a vitamin/mineral supplement compound that had been incorrectly prepared by a compounding pharmacy. Selenium can be refined from these muds by a number of methods. Selenium is bioaccumulated in aquatic habitats, this results in higher concentrations in organisms than the surrounding water. It moves through the aquatic environment similarly to arsenic and antimony; [454] its water-soluble salts, in higher concentrations, have a similar toxicological profile to that of arsenic. Source: quora.com. This shows selenium is more likely to be a non-metal, just like sulphur. Anwar Hossain, Ken Touhata, Takeshi Yabu, and Yumiko Yamashita, CS1 maint: multiple names: authors list (. Metalloid is a term used in chemistry when classifying the chemical elements.On the basis of their general physical and chemical properties, nearly every element in the periodic table can be termed either a metal or a nonmetal - however a few elements with intermediate properties are referred to as metalloids. [102][103][104][105], Dietary selenium comes from meat, nuts, cereals and mushrooms. ), woody asters (Xylorhiza sp. Start studying Metal, Nonmetal, or Metalloid?. To the knowledge of researchers, there are no reports of mercury levels exceeding that of selenium levels in ocean fish. [99], Trace elements involved in GSH-Px and superoxide dismutase enzymes activities, i.e. 30 seconds . [59] Like lead and sulfur, selenium improves the machinability of steel at concentrations around 0.15%. 4 years ago. 100% (1/1) Si silicon revolution silicium. selene meaning "Moon") was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn. Properties of the Semimetals or Metalloids . What is a sample Christmas party welcome address? Selenium occurs in the earth's crust most commonly as selenite, selenate, and selenides associated with sulfide minerals (NRC, 1983). Source(s): https://owly.im/a9znU. [134], In the regions (e.g. For other applications, a red color may be desired, produced by mixtures of CdSe and CdS. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Phytoplankton can concentrate inorganic selenium by a factor of 3000. Elements sometimes also classified as nonmetals are the metalloids boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), and astatine (At). It's a gas, honey. Selenium, in particular, is commonly designated as a metalloid in environmental … 4 Answers. China is the dominant consumer of selenium at 1,500–2,000 tonnes/year. [46][47], Anthropogenic sources of selenium include coal burning, and the mining and smelting of sulfide ores. [55] Its photovoltaic and photoconductive properties are still useful in photocopying,[67][68][69][70] photocells, light meters and solar cells. Selenium (Se), a chemical element in the oxygen group (Group 16 [VIa] of the periodic table), closely allied in chemical and physical properties with the elements sulfur and tellurium. Selenium is a chemical element with the symbol Se and atomic number 34. [30][31][32] The development of selenium rectifiers began during the early 1930s, and these replaced copper oxide rectifiers because they were more efficient. Who is the longest reigning WWE Champion of all time? [100] Marine fishes and vertebrate thyroid glands have the highest concentration of selenium and iodine. Selenium came to medical notice later because of its toxicity to industrial workers. Se, C and P have very similar metallic Generally, The key difference between selenium and tellurium is that selenium is a non-metal, whereas tellurium is a metalloid. The Se concentration in soil varies with type, texture and organic matter content of the soil and with rainfall. Sheets of amorphous selenium convert X-ray images to patterns of charge in xeroradiography and in solid-state, flat-panel X-ray cameras. O. Si. SURVEY . Selenium has the characteristics of non-metals and metals evenly divided, being a metalloid or semi-metal. Check all that apply. (Only the deiodinase iodotyrosine deiodinase, which works on the last breakdown products of thyroid hormone, does not use selenium. Join … National Research Council, Subcommittee on Sheep Nutrition (1985). At the Kesterson National Wildlife Refuge in California, thousands of fish and waterbirds were poisoned by selenium in agricultural irrigation drainage. Signs and symptoms of selenosis include a garlic odor on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability, and neurological damage. Sedimentary. In high concentrations, selenium acts as an environmental contaminant. Favorite Answer. [139], 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. Analysis of blood levels of inorganic compounds in the supplement indicated the selenium concentrations were 10 to 15 times higher than normal in the blood samples, and 15 to 20 times higher than normal in the liver samples. In these compounds, selenium plays a role analogous to that of sulfur. In fact, the angiosperms (the dominant type of plant today) and most of their antioxidant pigments evolved during the late Jurassic period. For the software testing framework, see. 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. [101] About 200 million years ago, new selenoproteins were developed as mammalian GSH-Px enzymes. 0 0. However, most elemental selenium comes as a byproduct of refining copper or producing sulfuric acid. non-metal. How is Selenium classified? The regulation of lead in drinking water applications such as in the US with the Safe Drinking Water Act of 1974, made a reduction of lead in brass necessary. On the periodic table, the elements colored yellow, which generally border the stair-step line, are considered to be metalloids. [56], During the electrowinning of manganese, the addition of selenium dioxide decreases the power necessary to operate the electrolysis cells. The lithium–selenium (Li–Se) battery is one of the most promising systems for energy storage in the family of lithium batteries. Is Selenium A Metalloid. Lv 4. In soils, selenium most often occurs in soluble forms such as selenate (analogous to sulfate), which are leached into rivers very easily by runoff. [64], Amorphous selenium (α-Se) thin films have found application as photoconductors in flat panel x-ray detectors. [80] Fish are a major source of protein for humans. Selenium intensifies and extends the tonal range of black-and-white photographic images and improves the permanence of prints. Learn more. answer choices . The material on this site can not be reproduced, distributed, transmitted, cached or otherwise used, except with prior written permission of Multiply. Common production from the residue then begins by oxidation with sodium carbonate to produce selenium dioxide, which is mixed with water and acidified to form selenous acid (oxidation step). [95][96] It seems as though when mercury levels in a marine fish rise, so do the selenium levels. [5] See more on plant nutrition below. (In Greek metallon = metal and eidos = sort) selenium (Se) polonium (Po) silicon (Si) iodine (I) tin (Sn) antimony (Sb) phosphorus (P) LOGIN TO VIEW ANSWER. Titanium. Another source was the mud from the lead chambers of sulfuric acid plants, a process that is no longer used. 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. Tags: Question 8 . It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. Related Questions in Chemistry. [60][61] Selenium produces the same machinability improvement in copper alloys.[62]. Source(s): https://shrink.im/a9AFZ. Naming Se as metalloid and C and P only as nonmetal is inappriopiate and flawful. Answer Save. [119], Selenium poisoning of water systems may result whenever new agricultural runoff courses through normally dry, undeveloped lands. In X-ray crystallography, incorporation of one or more selenium atoms in place of sulfur helps with multiple-wavelength anomalous dispersion and single wavelength anomalous dispersion phasing. How many candles are on a Hanukkah menorah? Selenium poisoning can be passed from parents to offspring through the egg, and selenium poisoning may persist for many generations. Q. The US Recommended Dietary Allowance (RDA) of selenium for teenagers and adults is 55 Âµg/day. 9 years ago. [53][54], About 2,000 tonnes of selenium were produced in 2011 worldwide, mostly in Germany (650 t), Japan (630 t), Belgium (200 t), and Russia (140 t), and the total reserves were estimated at 93,000 tonnes. Is Selenium a metalloid or a non-metal? [clarification needed]. Inorganic selenium bioaccumulates more readily in phytoplankton than zooplankton. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. 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).[106][107]. [33][34][35] These lasted in commercial applications until the 1970s, following which they were replaced with less expensive and even more efficient silicon rectifiers. Both these are in the solid-state at room temperature. This smell was not typical of arsenic, but a similar odor was known from tellurium compounds. [63] The Li–Se battery is an alternative to the lithium–sulfur battery, with an advantage of high electrical conductivity. Both organic and inorganic forms of selenium are largely converted to monosaccharide conjugates (selenosugars) in the body prior to elimination in the urine. Arsenic is a metalloid element. Selenium is most commonly found as an impurity, replacing a small part of the sulfur in sulfide ores of many metals. Are gases metal or metalloid? [125], 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. The Se concentration in soil varies with type, texture and organic matter content of the soil and with rainfall. Moreover, there is no reaction between selenium and water/acid. [73], Selenium is a catalyst in some chemical reactions, but it is not widely used because of issues with toxicity. … [44][45], Certain soils are selenium-rich, and selenium can be bioconcentrated by some plants. various regions within North America) where low selenium soil levels lead to low concentrations in the plants, some animal species may be deficient unless selenium is supplemented with diet or injection. This coal was shown to have selenium content as high as 9.1%, the highest concentration in coal ever recorded.[115]. Selenium transmits an electric current proportional to the amount of light falling on its surface. In general, absorption of dietary selenium is lower in ruminants than other animals, and is lower from forages than from grain. Lv 4. Asked By adminstaff @ 01/01/2020 02:35 AM. [135] Ruminants are particularly susceptible. No, gallium is not a metalloid. It is in the p block. 0 0. Which element is a metalloid? Matt. The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day. 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. Ask Question + 100. The consumption in 2010 was divided as follows: metallurgy – 30%, glass manufacturing – 30%, agriculture – 10%, chemicals and pigments – 10%, and electronics – 10%. The new brass is marketed under the name EnviroBrass. Selenium is a metalloid that has an atomic number of 34, an atomic weight of 78.96, four natural oxidation states (−2, 0, +4, and +6), and many different chemical forms in nature. [36][37] It was discovered to be essential for mammalian life in 1957. [133] Also, selenium interacts with other minerals, such as zinc and copper. Selenium. Also, people dependent on food grown from selenium-deficient soil are at risk. [123][124], In fish and other wildlife, selenium is necessary for life, but toxic in high doses. These data exclude two major producers: the United States and China. Exceeding the Tolerable Upper Intake Level of 400 micrograms per day can lead to selenosis. 9 years ago. Selenium is a component of the unusual amino acids selenocysteine and selenomethionine. In fact, 16.7% of the worlds animal protein intake came from fish in 2010. What is the best way to fold a fitted sheet? Selenium and tellurium are chemical elements in the p-block of the periodic table. Get your answers by asking now. 0 0. 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. For this purpose, various selenite and selenate salts are added. 397 Related Articles [filter] Silicon. For every tonne of manganese, an average 2 kg selenium oxide is used. [118] 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. SURVEY . it is a metalloid because it is a metal and non-metal at the same time. selenium (Se) polonium (Po) phosphorus (P) iodine (I) Selenium is one of the most important metalloid [84] 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. In 1954, the first hints of specific biological functions of selenium were discovered in microorganisms by biochemist, Jane Pinsent. Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. properties. Answer Save. [120] The resultant high selenium levels in waterways were found to cause congenital disorders in oviparous species, including wetland birds[121] and fish. also. Metalloids can also be called semimetals. Tags: Question 9 . 9 years ago. One family of selenium-bearing molecules (the glutathione peroxidases) destroys peroxide and repairs damaged peroxidized cell membranes, using glutathione. There are neither a standard definition of a metalloid nor complete agreement on the elements appropriately classified as such. Another naturally occurring organoselenium compound is dimethyl selenide. Copper indium gallium selenide is a material used in solar cells. 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. Is selenium a metal, nonmetal, or metalloid? Selenium pollution of waterways also occurs when selenium is leached from coal flue ash, mining and metal smelting, crude oil processing, and landfill. Tags: Question 7 . Anonymous. 30 seconds . [116] Elemental selenium and most metallic selenides have relatively low toxicities because of low bioavailability. This was followed by the discovery of selenocysteine in proteins. [93][94] An antioxidant, selenoneine, which is derived from selenium and has been found to be present in the blood of bluefin tuna, is the subject of scientific research regarding its possible roles in inflammatory and chronic diseases, methylmercury detoxification, and oxidative damages. 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. [108], The selenium content in the human body is believed to be in the 13–20 mg range. However, it can damage plants at higher doses. Still have questions? 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. Selenium-specific supplements typically contain either 100 or 200 Âµg/serving. National Research Council, Committee on Nutrient Requirements of Small Ruminants (2007). Selenium is commonly described as a metalloid in the environmental chemistry literature. Relevance. Sources of pollution include waste materials from certain mining, agricultural, petrochemical, and industrial manufacturing operations. [83] It has also been suggested that season could have an impact on the harmful effects of selenium on fish. [citation needed], The deiodinase isoenzymes constitute another family of eukaryotic selenoproteins with identified enzyme function. inappriopiate and flawful. SURVEY . Germanium, natural metalloid element raising body's immunity and easing pain. Selenium is however commonly described as a metalloid in the environmental chemistry literature. Further concentration through bioaccumulation occurs along the food chain, as predators consume selenium rich prey. From the perspective of the wisdom of the masses, selenium is classified as a metalloid only around half as often as polonium and astatine and they, in turn, are classified as metalloids only half as often as the commonly recognized metalloids B, Si, Ge, As, Sb, and Te. In plants, it occurs as a bystander mineral[clarification needed], sometimes in toxic proportions in forage (some plants may accumulate selenium as a defense against being eaten by animals, but other plants, such as locoweed, require selenium, and their growth indicates the presence of selenium in soil). [55][57], The largest commercial use of Se, accounting for about 50% of consumption, is for the production of glass. Peaches and pears given a foliar selenium spray contained higher levels selenium and also stayed firm and ripe longer when in storage. [109], Certain species of plants are considered indicators of high selenium content of the soil because they require high levels of selenium to thrive. Selenium is incorporated into several prokaryotic selenoprotein families in bacteria, archaea, and eukaryotes as selenocysteine,[98] where selenoprotein peroxiredoxins protect bacterial and eukaryotic cells against oxidative damage. Selenium—from Selenium enzymes are involved in the small reducing molecules glutathione and thioredoxin. Q. Extreme cases of selenosis can exhibit cirrhosis of the liver, pulmonary edema, or death. The most notable exception is in power DC surge protection, where the superior energy capabilities of selenium suppressors make them more desirable than metal-oxide varistors. Selenium occurs naturally in a number of inorganic forms, including selenide, selenate, and selenite, but these minerals are rare. Selenium as a dietary supplement is available in many forms, including multi-vitamins/mineral supplements, which typically contain 55 or 70 Âµg/serving. [38][39] In the 1970s, it was shown to be present in two independent sets of enzymes. The selenocysteine-containing form occurs in species as diverse as green algae, diatoms, sea urchins, fish, and chickens. 2. 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. A metalloid is an element that has properties that are intermediate between those of metals and nonmetals. Many benthic invertebrates can tolerate selenium concentrations up to 300 Î¼g/L of Se in their diet.[79]. Metalloid. It moves through the aquatic environment similarly to arsenic and antimony; its water-soluble salts, in higher concentrations, have a similar toxicological profile to that of arsenic. Hence, Berzelius's first letter to Alexander Marcet stated that this was a tellurium compound. )[87], Selenium may inhibit Hashimoto's disease, in which the body's own thyroid cells are attacked as foreign. Selenium (Se³â´â‚‡â‚‰) is a metalloid which is close to sulfur (S) in terms of properties. For salmon, the optimal concentration of selenium is about 1 microgram selenium per gram of whole body weight. [82] There are, however, a few species that have been seen to survive these events and tolerate the increased selenium. Relevance. China is the largest consumer of selenium dioxide for this purpose. Selenium is a metalloid (an element intermediate in properties between the metals and the nonmetals). Se compounds confer a red color to glass. Its assimilation by plants is influenced by the physico-chemical properties of the soil (redox status, pH and microbial activity). [25] Both chemists owned a chemistry plant near Gripsholm, Sweden, producing sulfuric acid by the lead chamber process. The recoding mechanism was worked out first in bacteria and then in mammals (see SECIS element).[40]. [92] Evidence suggests that the molecular mechanisms of mercury toxicity includes the irreversible inhibition of selenoenzymes that are required to prevent and reverse oxidative damage in brain and endocrine tissues. The main selenium indicator plants are Astragalus species (including some locoweeds), prince's plume (Stanleya sp. [55], Researchers found that application of selenium fertilizer to lettuce crops decreased the accumulation of lead and cadmium. Potassium. From about 500 million years ago, freshwater and terrestrial plants slowly optimized the production of "new" endogenous antioxidants such as ascorbic acid (vitamin C), polyphenols (including flavonoids), tocopherols, etc. [42][43], In living systems, selenium is found in the amino acids selenomethionine, selenocysteine, and methylselenocysteine. metalloid definition: 1. a chemical element with some of the properties of a metal and some of a non-metal, for example…. [41] Isolation of selenium is often complicated by the presence of other compounds and elements. Organoselenium compounds can be concentrated over 200,000 times by zooplankton when water concentrations are in the 0.5 to 0.8 Î¼g Se/L range. Still have questions? The melting/ boiling point of selenium is closer to that of sulphur (a non-metal), compared with metals and metalloids. [72] Ionized selenium (Se+24) is one of the active mediums used in X-ray lasers. Michiaki Yamashita, Shintaro Imamura, Md. Metal. ), and false goldenweed (Oonopsis sp. 0 0. [128], Selenium deficiency can occur in patients with severely compromised intestinal function, those undergoing total parenteral nutrition, and[129] in those of advanced age (over 90). A metalloid is a type of chemical element which has properties in between, or that are a mixture of, those of metals and nonmetals.wikipedia. Reproduction of mallard ducks is impaired at dietary concentrations of 7 ug Se/L. At levels of 1 mg/m3, selenium is immediately dangerous to life and health. Tellurium is a metalloid and selenium is also sometimes considered as a metalloid, but it is actually a non-metal. [122] Elevated dietary methylmercury levels can amplify the harm of selenium toxicity in oviparous species. When did organ music become associated with baseball? selenium (such as carbon, phosphorus and iodine) is considered 3. The selenium cell was used in the photophone developed by Alexander Graham Bell in 1879. Selenium is considered to be a metalloid in environmental chemistry. Po. They are, thus, involved in thyroid-hormone regulation, participating in the protection of thyrocytes from damage by H2O2 produced for thyroid-hormone biosynthesis.

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