HuagongsheHuagongshe Chemistry Print Report · For research reference only
Selenium
Se · Selen · Selenate · SELENIUM METAL · Selenium granules · Elemental selenium · Selenium nanoparticles · NANO-SELENIUM
Identifiers & Physical Properties
| CAS No. | 7782-49-2 |
|---|---|
| Molecular formula | Se |
| Average molar mass | 78.97 g/mol |
| Monoisotopic mass | 79.9165213 g/mol |
| SMILES | [Se] |
| InChIKey | BUGBHKTXTAQXES-UHFFFAOYSA-N |
| PubChem CID | 6326970 |
| ChEMBL | CHEMBL6068503 |
| ChEBI | CHEBI:27568 |
| EC No. | 231-957-4 |
| DTXSID | DTXSID9021261 |
Chemical & Physical Properties
| Topological polar surface area | 0 |
|---|---|
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 0 |
| Rotatable bonds | 0 |
| Heavy atoms | 1 |
| Formal charge | 0 |
| Complexity | 0 |
| Chemical classes | Hazardous Air Pollutants (HAPs)Other Classes -> Other Inorganic CompoundsTrace element |
| Cosmetics | Cosmetics ingredient -> Other (Specify) |
| SpringerMaterials Properties | phonon wavenumber |
| Pesticides | Pesticide -> EPA IRIS |
| Density | 4.28 (NIOSH, 2024) - Denser than waterwill sink4.39 g/cu cm (alpha form)4.809 g/cu cm (gray selenium)4.28 g/cu cm (vitreous selenium)Vitreous, Black seleniumdark red-brown to bluish-black soliddensity = 4.28softens at 50 to 60 °C and becomes elastic at 70 °C. Red amorphous formdensity = 4.26. When freshly precipitated, reacts with water at 50 °C forming selenious acid and hydrogen. Soluble in carbon disulfide, methylene iodide, benzene or quinoline /amorphous forms/Relative density (water = 1): 4.84.809 @25 °C4.81 g/mL at 25 °C (lit.) |
| Viscosity | 221 mPa-S (= cP) at 220 °C70 cP at 360 °C |
| Color/Form | Selenium exists in several allotropic forms. 3 are generally recognized ... Selenium can be prepd with either amorphous or crystalline structure. ... Amorphous is either red, in powder form or black, in vitreous form. Crystalline monoclinic selenium is deep redcrystalline hexagonal form, the most stable variety, is a metallic gray. |
| Solubility | Insoluble (NIOSH, 2024)Soluble in aq potassium cyanide soln, potassium sulfite soln, dilute aqueous caustic alkali solnInsoluble in water and alcoholSoluble in concentrated nitric acid.Soluble in carbon disulfide, 2 mg/100 mL at room temperaturesoluble in etherH2O: soluble |
| Corrosivity | Strongly corrosive, especially at high temperature. |
| Animal Drugs | Pharmaceuticals -> UK Veterinary Medicines Directorate List |
| Boiling point | 1265 °F at 760 mmHg (NIOSH, 2024)685 °C685 °C @760 [mm Hg]684.9 °C (lit.) |
| Decomposition | When heated to decomp ... emits toxic fumes of /selenium/. |
| Melting point | 217 °C (lit.) |
| Bulk density | 1270kg/m3 |
| Vapor pressure | <1 Pa (20 °C) |
| Storage conditions | no restrictions. |
| Physical state | powder |
| Color | White to creamy white |
| Specific gravity | 4.81 |
| Flame Color | Azure blue |
| Resistivity | 1.2 μΩ-cm, 0°C |
| Thermal conductivity | 0.52 W/(m·K) |
| Specific heat capacity | Cp(crystal): 0.32 J/(g·K)Cp(gas): 0.26 J/(g·K), at 25℃ |
| Merck | 13,8505 |
| Dielectric constant | 6.1(Ambient) |
| Exposure limits | ACGIH:TLV-TWA 0.2 mg/m3,as SeOSHA:PEL-TWA 0.2 mg/m3NIOSH:REL-TWA 0.2 mg/m3 |
| Stability | Stable. Incompatible with strong acids, strong oxidizing agents and most common metals. Combustible. |
| InChI | 1S/Se |
| InChIKey | SPVXKVOXSXTJOY-UHFFFAOYSA-N |
| EPA Primary Drinking Water Standard | MCL:0.05,MCLG:0.05 |
| SMILES | [Se] |
| Knoop Microhardness | 350, N/mm2 Microhardness Gray Selenium |
| Modulus of Elasticity | 57.9 GPa |
| Shear Modulus | 6.46 GPa |
| CAS DataBase Reference | 7782-49-2(CAS DataBase Reference) |
| FDA 21 CFR | 101.9107.10107.100165.110573.920 |
| EWG's Food Scores | 5-8 |
| NCI Dictionary of Cancer Terms | selenium |
| FDA UNII | H6241UJ22B |
| NCI Drug Dictionary | selenium |
| IARC | 3 (Vol. 9, Sup 7) 1987 |
| NIST Chemistry Reference | Selenium atom(7782-49-2) |
| EPA Substance Registry System | Selenium (7782-49-2) |
| Toxicological Profile|ATSDR | Selenium|Toxicological Profile|ATSDR |
| UNSPSC Code | 12352300 |
| NACRES | NA.23 |
| GHS pictogram | GHS06,GHS08 |
| Signal word | Danger |
| GHS hazard statements | H301+H331-H372-H370-H413 |
| GHS precautionary statements | P501-P273-P260-P270-P271-P264-P308+P311-P301+P310+P330-P304+P340+P311-P403+P233-P405 |
| Hazard symbols | T |
| Risk statements (R) | 36/38-53-33-23/25 |
| Safety statements (S) | 26-61-45-28-20/21-28A |
| UN transport number | UN 2630 (SELENATES or SELENITES) |
| Occupational exposure band (OEB) | C |
| Occupational exposure limit (OEL) | TWA: 0.2 mg/m3 [*Note: The REL also applies to other selenium compounds (as Se) except Selenium hexafluoride.] |
| Water hazard class (WGK) | 2 |
| RTECS number | VS7700000 |
| TSCA inventory status | TSCA listed |
| Hazard class | 6.1Acute Tox. 3 InhalationAcute Tox. 3 OralAquatic Chronic 4STOT RE 2 |
| Packing group | I |
| Customs code | 28049090 |
| Storage class | 6.1C - Combustible acute toxic Cat.3toxic compounds or compounds which causing chronic effects |
| Hazardous substances data | 7782-49-2(Hazardous Substances Data) |
| Toxicity | LD50 orally in Rabbit: 6700 mg/kg |
| Immediately dangerous to life or health concentration | 1 mg Se/m3 |
| REACH registrations | Active |
| Limited quantities | 5.0 kg (11 lbs) (solid) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (1Kg or 1L) |
Safety & Regulations
| GHS classification | DangerH301: Toxic if swallowed [Danger Acute toxicity, oral]P260, P261, P264, P270, P271, P273, P301+P316, P304+P340, P316, P319, P321, P330, P403+P233, P405, and P501 (click each P-code to see the statement)H301+H331 (27.4%): Toxic if swallowed or if inhaled [Danger Acute toxicity, oralacute toxicity, inhalation] |
|---|---|
| Regulatory information | Chemical: SeleniumRegulation (EC) No 1935/2004 (amended)Selenium is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Selenium are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)Status: Active Update: 04-10-2021 https://echa.europa.eu/registration-dossier/-/registered-dossier/15204Selenium: Does not have an individual approval but may be used under an appropriate group standardThe New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.) |
| Other safety information | IMAP assessments - Selenium: Human health tier I assessment |
| DOT label | Poison |
| Fire hazards | Excerpt from ERG Guide 151 [Substances - Toxic (Non-Combustible)]:Not combustible. Gives off irritating or toxic fumes (or gases) in a fire. Risk of fire and explosion on contact with oxidants. |
| Health hazards | Excerpt from ERG Guide 151 [Substances - Toxic (Non-Combustible)]: |
| Hazards summary | Selenium is a naturally occurring mineral element that is distributed widely in nature in most rocks and soils. In its pure form, it exists as metallic gray to black hexagonal crystals, but in nature it is usually combined with sulfide or with silver, copper, lead, and nickel minerals. Most processed selenium is used in the electronics industry, but it is also used: as a nutritional supplementin the glass industryas a component of pigments in plastics, paints, enamels, inks, and rubberin the preparation of pharmaceuticalsas a nutritional feed additive for poultry and livestockin pesticide formulationsin rubber productionas an ingredient in antidandruff shampoosand as a constituent of fungicides. Radioactive selenium is used in diagnostic medicine.Selenium is a naturally occurring substance that is toxic at high concentrations but is also a nutritionally essential element. Hydrogen selenide is the most acutely toxic selenium compound. Acute (short-term) exposure to elemental selenium, hydrogen selenide, and selenium dioxide by inhalation results primarily in respiratory effects, such as irritation of the mucous membranes, pulmonary edema, severe bronchitis, and bronchial pneumonia. Epidemiological studies of humans chronically (long-term) exposed to high levels of selenium in food and water have reported discoloration of the skin, pathological deformation and loss of nails, loss of hair, excessive tooth decay and discoloration, lack of mental alertness, and listlessness. Epidemiological studies have reported an inverse association between selenium levels in the blood and cancer occurrence and animal studies have reported that selenium supplementation, as sodium selenate, sodium selenite, and organic forms of selenium, results in a reduced incidence of several tumor types. The only selenium compound that has been shown to be carcinogenic in animals is selenium sulfide, which resulted in an increase in liver tumors from oral exposure. EPA has classified elemental selenium as a Group D, not classifiable as to human carcinogenicity, and selenium sulfide as a Group B2, probable human carcinogen.Selenosis has been documented in animals and humans living in areas with high selenium contamination of soil and groundwater. In humans, symptoms of this disease include fatigue, dermatitis, gastrointestinal disturbances, garlic odor of the breath and sweat, and increased dental caries. Liver injury is observed in feeding studies of experimental animals. [ACGIH] Burning selenium produces selenium dioxide fume, an irritant inhalant that can induce pulmonary edema at sufficient dose[Harber, p. 502] In high-dose reproductive studies in animals, selenium causes low birth weight and birth defects. [ATSDR Case Studies #29] Chinese villagers studied in 1983 developed selenosis after using coal ash as a crop fertilizer. They also inhaled smoke from burning coal indoors. In extreme cases with intake averaging 0.09 mg/kg/day, patients developed neurological disease including increased tendon reflexes, convulsions, and paralysis. Similar neurological problems have been observed in animals fed high doses of selenium. A NOAEL of 0.015 mg selenium/kg/day corresponding to a blood level of 0.97 mg/L was calculated. The calculated LOAEL was 0.023 mg selenium/kg/day. The recommended dietary allowance (RDA) for selenium is 0.001 mg/kg/day. Follow-up in 1992 revealed that villagers with hair loss and nail deformities recovered and that average blood levels dropped from 1.346 mg/L to 0.819 mg/L. [ATSDR ToxProfiles] The most common compound reported in cases of selenium poisoning by ingestion is 4% selenious acid in gun bluing (coating) solutions. As little as 15 ml can be fatal. Patients have corrosive gastroenteritis with vomiting, diarrhea, and garlic odor. Other compounds reported in poisoning cases by ingestion are selenium dioxide, sodium selenate, and sodium selenite. [Olson, p. 416-418] See Hydrogen selenide. |
| DOT ID and guide | 2658 152(powder) |
| Reactive group | Metals, Elemental and Powder, Active |
| EC classification | Symbol: TR: 23/25-33-53S: (1/2)-20/21-28-45-61 |
| Special Reports | DHHS/ATSDRToxicological Profile for Selenium (1989) ATSDR/TP-89/21WHOEnvironmental Health Criteria 58: Selenium (1987). EHC are designed for scientists and administrators responsible for the establishment of safety standards and regulations and provide basic scientific risk evaluations of a wide range of chemicals and groups of chemicals.[Available from, as of April 1, 2011: http://www.inchem.org/documents/ehc/ehc/ehc58.htm#SectionNumber:7.1]US Dept of Interior/Fish & Wildlife Service Contaminant ReviewsSelenium Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review Biol Rept No (85)1.5 (1985)U.S. Dept Health & Human Services/Agency for Toxic Substances & Disease RegistryToxicological Profile for Selenium (September 2003). The ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health effects information for a hazardous substance.[Available from, as of March 22, 2011: http://www.atsdr.cdc.gov/substances/indexAZ.asp#S] |
| RCRA requirements | D010A solid waste containing selenium (such as selenium, elemental) may become characterized as a hazardous waste when subjected to the Toxicity Characteristic Leaching Procedure listed in 40 CFR 261.24, and if so characterized, must be managed as a hazardous waste. |
| Reactivity Alerts | Strong Reducing Agent |
| Fire fighting | Excerpt from ERG Guide 151 [Substances - Toxic (Non-Combustible)]:Use foam, powder, carbon dioxide. NO water. |
| First aid measures | Fresh air, rest. Refer for medical attention.Rinse and then wash skin with water and soap.Rinse with plenty of water (remove contact lenses if easily possible).Rinse mouth. Refer for medical attention . |
| First aid | Excerpt from NIOSH Pocket Guide for Selenium:(General first aid procedures) |
| Safe storage | Separated from strong oxidants, strong acids and food and feedstuffs. Dry. Store in an area without drain or sewer access. Provision to contain effluent from fire extinguishing. |
| Exposure control and personal protection | TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].0.02 [mg/m3], as Se, inhalable fraction (metal and inorganic compds)[German Research Foundation (DFG)] |
| Fire fighting procedures | Extinguishant: For selenium, waterIf material on fire or involved in fire: Extinguish fire using agent suitable for type of surrounding fire. Material itself does not burn or burns with difficulty. Keep run-off water out of sewers and water sources. /Selenium compound, solid, nos/Personnel protection: Wear appropriate chemical protective clothing. Wear positive pressure self-contained breathing apparatus when fighting fires involving this material. /Selenium compound, solid, nos/ |
| Storage conditions | Usually stored at room temperature. Precautions must be taken to avoid contact with water or prolonged exposure to air and other materials with which it may react. Storage area construction must be such that rain water will not leak in or ground water will not enter. Used drums should be stored in this same dry area to avoid contamination /SRP: of the area/ and to minimize any hazard due to the residues. |
| Cleanup methods | SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.Persons not wearing protective equipment and clothing should be restricted from areas of spills until cleanup has been completed. /Selenium and its inorganic cmpd/If selenium or its inorganic compounds are spilled, the following steps should be taken: 1. Ventilate area of spill. 2. Collect spilled material in the most convenient and safe manner and deposit in sealed containers for reclamation or for disposal in a secured sanitary landfill. Liquid containing selenium and its inorganic compounds should be absorbed in vermiculite, dry sand, earth, or a similar material. Waste disposal method: Selenium and its inorganic compounds may be disposed of in sealed containers in a secured sanitary landfill. /Selenium and its inorganic cmpd/Environmental considersations: Land spill: Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. /Selenium compound, solid, nos/Environmental considerations: Water spill: Use natural barriers or oil spill control booms to limit spill travel. Use natural deep water pockets, excavated lagoons, or sand bag barriers to trap material at bottom. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates. /Selenium compound, solid, nos/ |
| Nonfire spill response | Excerpt from ERG Guide 151 [Substances - Toxic (Non-Combustible)]: |
| Disposal methods | Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D010, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.... As the price of selenium is very highrecovery of it by processing selenium containing waste is economical. For example, selenium refineries are equipped with wet scrubbers that employ an approx 50% soln of hydrobromic acid containing free bromine. The acid fumes are adsorbed in a lime and soda bed, and the selenium separated from the hydrobromic acid soln by distilliation is recycled. ... If possible, convert selenium compounds to an insoluble form with SO2 before landfill or solidification. Do not use metal and acid to reduce selenium compounds. This will produce toxic gaseous hydrogen selenide.Depending upon the industrial source, selenium occurs in either the particulate or the soluble form. For the former, physical treatment processes such as sedimentation or filtration are quite effective. Lime precipitation of soluble selenium has been shown to be ineffective. Alum coagulation/coprecipitation is somewhat effective, with removal efficiencies approaching 50% achievable. Iron coagulation/coprecipitation is capable of above 80% selenium removal, with efficiency increasing with decreasing pH. Activated carbon adsorption is not effective, except in one reported instance involving high pH pretreatment. The most efficient process for soluble selenium appears to be anion exchange. Preoxidation of the selenite to selenate is reported to enhance exchange capacity. /Selenium compounds/ |
| Spillage disposal | Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations. |
| Preventive Measures | Smoking, eating and drinking at the workplace should be prohibited and messrooms and sanitary facilities including showers and locker rooms should be provided at a point distant from exposure areas.Where there is any possibility of exposure of an employee's body to selenium, selenium oxychloride, sodium selenite, sodium selenate, selenium dioxide, or liquids containing these compounds, facilities for quick drenching of the body should be provided within the immediate work area for emergency use.Employees should be provided with and required to use impervious clothing, gloves, face shields (eight inch minimum), and other appropriate protective clothing necessary to prevent repeated or prolonged skin contact with selenium, sodium selenite, or sodium selenate.Non-impervious clothing which becomes contaminated with selenium, sodium selenite, sodium selenate, selenium dioxide or liquids containing these compounds should be removed promptly and not reworn until the contaminant is removed from the clothing.For more Preventive Measures (Complete) data for SELENIUM, ELEMENTAL (12 total), please visit the HSDB record page.If the concentration of selenium in the urine of workers on a particular process is above 0.1 mg/L then action should be taken to improve the industrial hygiene of that process. /Selenium compounds/ |
| Toxicological information | CDC-ATSDR Toxicological Profile |
| Body burden | Samples of lung tissue from deceased copper smelter workers contained a median selenium concentration of 152 ppbtissue samples from deceased rural and urban human control subjects contained 110 and 136 ppb Se, respectively(1). Selenium was detected in plasma at concentrations of 85.0 ug/L in non-smokers, 87.1 ug/L in ex-smokers, and 85.2 ug/L in smokers(2). The median selenium plasma concentration in three human subjects who never ate fish was 80.2 ug/Lin 32 subjects who ate fish at least twice per week the median plasma selenium level was 94 ug/L(2). The median plasma selenium level in 195 human subjects living in areas receiving acidic precipitation was 85.0 ug/Lmedian selenium plasma levels in a reference population, 91 subjects, was 89.7 ug/L(2). Selenium was detected in human hair samples from 17 ethnic and territorial groups from the former USSR, at mean concentrations ranging from 0.26 to 1.8 ppm dry weight for males and 0.23 to 2.02 ppm dry weight in femalesthe highest concentrations occurred in Tuvinians, Mong.-Taiga dist.(3). Selenium content of expressed human breast milk (foremilk) from Belgian mothers decreased with increasing time of lactation and plateaued at a concentration of about 9.4 ng/g(4). Forty-seven samples of human milk collected from five middle-class women from Burundi, Africa, contained selenium at an average concentration of 15.2 ng/mL 2 days after delivery and 5.2 ng/mL 2 weeks after delivery(5). Blood samples from the district of Angmagssalik, East Greenland contained selenium at concentrations ranging from 1.09 to 2.19 umol/L in males and 1.50 to 2.34 umol/L in females(6). Scalp hair from persons from different Mediterranean areas contained selenium at concentrations ranging from 0.30 to 0.74 ug/gscalp hair samples from controls contained 0.22 to 0.71 ug/g(7). Hair samples collected from a laboratory worker over a period of years contained selenium at concentrations ranging from 0.33 to 0.68 ug/g(7). Selenium concentrations in human placenta obtained after normal births in Genova, Italy ranged from 0.38 to 1.03 ug/g dry weight, average 0.77 ug/g dry weight(8). Median selenium concentrations in lung tissue of Swedish workers, employed in refining and smelting, were 0.13 ug/glung tissue from controls contained a median selenium concentration of 0.11 ug/g(9).Mean selenium concentrations in urine of healthy persons from the USA ranged from 7 to 76 ug/Lmean selenium levels in urine samples of burn patients were 16 ug over 24 hours and alcoholic subjects were 30 ug over 24 hours(1). Mean selenium concentrations in human nails from Japan, India, U.S.A., Canada, and Poland were 1.6, 0.79, 0.32, 0.45, and 1.0 ppm, respectively(2). Mean selenium concentrations in human hair collected from Canada, U.S.A., Poland, Japan, and India were 16.4, 21.7, 0.35, 3.90, and 10.8 ppm, respectively(3). Selenium was identified in 7 of 9 human adipose tissue samples at concentrations ranging from 0.030 to 0.056 ug/g(4). Mean selenium concentrations of 11.4 and 10.7 ng/mL for colostrum (<5 days postpartum) and transitional (6-15 days postpartum) milk, and 8.4 and 5.3 ng/mL for mature milk at one month and up to 2 months, respectively, were detected in Spanish human milk samples collected from April 1996 to September 1997 in Valencia and Castellon provinces(5). Selenium was detected in human serum samples from 27 non-fish-eating volunteers in Sweden, at concentrations ranging from 53 to 103 ug/L, with a median of 76 ug/L(6).The concentrations of selenium in 210 samples of blood from people in 16 cities of the United States ranged from 0.10 to 0.34 and averaged 0.206 ppm. There was some tendency for the blood values for selenium to be higher in geographic areas where the concentrations of selenium are higher in the soil and in plants. However, the variation in the selenium content of blood was much less pronounced than the variation in selenium in locally produced foods ... . The concentration in normal plasma does not exceed 0.15 ppm ... . /Selenium/In normal persons without unusual exposure, the concentration of selenium in the liver ranges from 0.55 to 1.34 ppmin the heart it ranges from 0.14 to 0.67 ppm ... . The concentration in normal urine is 0.01 -0.16 ppm ... .Normal values in selected human organs taken at autopsy from individuals with no record of exposure to excess selenium in the diet or otherwise (N = 11): blood 0.05 - 0.28 ppmliver 0.005 - 0.40 ppmspleen 0.10 - 0.45 ppm (sic)kidneys 0.21 - 1.00 ppm. |
| Interactions | Four groups of 20 female OSU-Brown rats were fed 150 mg N-2-fluorenyl-acetamide per kg of diet plus 2.5, 0.5, 0.1 or 0 mg selenium per kg of diet. Incidences of mammary adenocarcinomas and/or hepatic carcinomas at 200 days were 0/20, 2/20, and 12/20, respectively.Interaction has been studied in the rat. Selenite increased the whole-body retention of bismuth, but reduced the level in the kidneys. A redistribution of bismuth form a low-molecular-weight protein (molecular weight 7000) (metallothionein-like protein) to proteins of higher molecular weight was seen in the kidneys. Similar interaction has also been reported for inorganic mercury and cadmium. /Selenite/Arsenic, whether in organic or inorganic form...counteracts toxicity of selenium to animals. This action is not due to interference by arsenic with absorption of selenium but by its capacity to maintain the succinic hydrogenase of the liver which is lowered by selenium. ...The protective effect of arsenic (5 mg/kg sodium arsenite) against selenosis produced by feeding seleniferous grain (15 mg/kg) was discovered ... . Arsenite can increase the biliary and the fecal excretion of selenium up to 10 fold and because of effective inhibition of methylation, exhalation of methylated selenium compounds is reduced. Arsenic and selenium are excreted as a glutathione complex in the bile. ... /Selenium/For more Interactions (Complete) data for SELENIUM COMPOUNDS (23 total), please visit the HSDB record page. |
| Target organs | Cardiovascular (Heart and Blood Vessels), Dermal (Skin), Gastrointestinal (Stomach and Intestines, part of the digestive system), Hepatic (Liver), Neurological (Nervous System), Renal (Urinary System or Kidneys), Respiratory (From the Nose to the Lungs)Eyes, skin, respiratory system, liver, kidneys, blood, spleen |
| Health effects | Chronic oral exposure to high concentrations of selenium compounds can produce a disease called selenosis. The major signs of selenosis are hair loss, nail brittleness, and neurological abnormalities (such as numbness and other odd sensations in the extremities). Animal studies have shown that selenium may also affect sperm production and the female reproductive cycle. (L619) |
| Ecotoxicity values | LC50 Tanytarsus dissimilis (Chironomid) 42,400 ppb/96 hr /Selenium salts/LC50 Apeltes quadracus (Fourspine sickleback) 17,350 ppb/96 hr /Selenium salts/LC50 Lagodon rhomboides (Pinfish) 4400 ppb/96 hr /Selenium salts/LC50 Melanogrammus aeglefinus (Haddock, larvae) 600 ppb/96 hr /Selenium salts/For more Ecotoxicity Values (Complete) data for SELENIUM COMPOUNDS (34 total), please visit the HSDB record page. |
| Environmental fate | AQUATIC FATE: In aqueous solution, selenium forms oxyanions and exhibits anionic chemistry(1). Volatilization of the ionic forms of selenium is not expected to be an important fate process(SRC). Speciation of selenium is determined by the pH and redox potential of the solutionelemental selenium is favored by low pH and reducing conditions(1). At pHs <7 and under mildly reducing conditions, selenites are reduced to elemental selenium(1). Reducing conditions in surface sediments of ponded laboratory sediment columns promoted reduction of soluble Se(VI) to soluble Se(IV) to insoluble Se(0), allowing a net accumulation of insoluble elemental selenium(2). In sediments, reduced and tightly bound selenium will remain relatively immobile unless the sediments are chemically or biologically oxidized(3).ATMOSPHERIC FATE: Hydrogen selenide released to the air is unstable and will be oxidized to elemental selenium and water. Selenium dioxide released to the air from the combustion of fossil fuels is expected to be reduced to elemental selenium by sulfur dioxide formed during the combustion(1).TERRESTRIAL FATE: The behavior of selenium in soils is affected by redox conditions, pH, hydrous oxide content, clay content, organic materials and the presence of competing anions(1). Heavy metal selenides, which are insoluble, predominate in acidic soils and soils with high amounts of organic matterselenium in this form is immobile(2). Sodium and potassium selenites dominate in neutral, well-drained mineral soils(2). Selenite (Se(IV)) is soluble, but can strongly adsorb to soil minerals and organic material(3). Iron and manganese oxides sorb Se(IV), with iron oxides sorbing more than manganese(4). In alkaline, well-oxidized soil environments, selenates, Se(VI) predominateselenates are very mobile because of their high water solubility and low tendency to adsorb onto soil particles(2). No sorption of sodium selenate was observed in 10 of 11 soilsa log Kd value of 0.958 was determined in Kula soil (pH 5.9, 6.62% TOC, 73.7% sand, 25.4% silt, 0.9% clay)(5). Se(IV) adsorption was observed to decrease with increasing pH from 4 to 9 and Se(VI) adsorption was minimal under most pH conditions(4). In soils, elemental selenium and inorganic selenium compounds can be methylated by microorganisms and subsequently volatilize to the atmosphere(1,2)dimethylselenide and dimethyl diselenide are the principal products(2).elemental selenium is favored by low pH and reducing conditions(1). Selenates are stable under alkaline oxidizing conditions(1). Selenious acid species occur under the intermediate to slightly oxidizing conditions encountered in aerobic water(1). Over the pH range of 3 to 9, the biselenite species predominatesat pHs >9, selenite is the major species(1). At pHs <7 and under mildly reducing conditions, selenites are reduced to elemental selenium(1). Reducing conditions in surface sediments of ponded laboratory sediment columns promoted reduction of soluble Se(VI) to soluble Se(IV) to insoluble Se(0), allowing a net accumulation of insoluble elemental selenium(2). In sediments, reduced and tightly bound selenium will remain relatively immobile unless the sediments are chemically or biologically oxidized(3). Biological methylation of selenium may occur in aquatic environmentsinorganic selenium undergoes biological methylation to dimethyl selenide and dimethyl diselenide(1,4). Bioconcentration factors have been measured in a variety of aquatic organisms(SRC). Algae and daphnids concentrated (75)Se more strongly from selenite (BCFs ranged from 220 to 3,600) than selenate (BCFs ranged from 65 to 500)(5). BCF values for (75)Se after 28 days exposure to three selenium species were: 72 in macrophytes, 141 in periphyton, and 351 in zooplankton (as selenate)363 in macrophytes, 755 in periphyton, and 1,087 in zooplankton (as selenite)and 3,266 in macropytes, 16,836 in periphyton, and 28,870 in zooplankton (as Se-methionine)(6).ATMOSPHERIC FATE: Most selenium compounds are expected to exist solely in the particulate phase in the ambient atmosphere(1). Particulate-phase selenium may be removed from the air by wet or dry deposition(SRC). Volatile selenium compounds, selenium dioxide, hydrogen selenide, dimethyl selenide, and dimethyl diselenide, are expected to exist in the gaseous state in the atmosphere(1,2). Hydrogen selenide released to the air is unstable and will be oxidized to elemental selenium and water(2). Selenium dioxide released to the air from the combustion of fossil fuels is expected to be reduced to elemental selenium by sulfur dioxide formed during the combustion(2). |
| Food survey values | Selenium (Se) is an essential trace element ... In foods, Se is predominantly present as selenomethionine, which is an important source of dietary Se in humans, and also as a chemical form that is commonly used for Se supplements in clinical trials.Mean selenium concentrations in food ranged from 0.001 to 0.048 mg/100 g(1).Selenium has been detected in the following commonly consumed infant foods collected between 1982 and 1984, mean concentration (mg/100 g): dry infant mixed cereal prepared with whole milk, 0.002beef infant food, 0.005pork infant food, 0.011chicken/turkey infant food, 0.013chicken/turkey and vegetables infant food, 0.006beef and vegetables infant food, 0.003ham and vegetables infant food, 0.003chicken and noodles infant food, 0.002tomatoes, beef, and macaroni infant food, 0.002carrots infant food, 0.001and applesauce/applesauce with other fruit infant food, 0.001(1). Average concentration of selenium in the US infant diet by food group in Fiscal Year 1979 (81/82), ppm: whole milk, 0.004 (0.009)other dairy and dairy substitutes, 0.002 (0.015)meat, fish and poultry, 0.107 (0.112)grain and cereal products, 0.156 (0.192), potatoes, 0.002 (0.002)vegetables, 0.004 (0.007)oils and fats, 0.012 (0.005)sugar and adjuncts, 0.011and beverages, 0.002(2,3). Average concentration of selenium in the US toddler diet by food group in Fiscal Year 1979 (81/82), ppm: whole milk, 0.004 (0.009)other dairy and dairy substitutes, 0.018 (0.022)meat, fish and poultry, 0.160 (0.208)grain and cereal products, 0.158 (0.189)potatoes, 0.002 (0.003)vegetables, 0.007 (0.003)fruit and fruit juices, 0.011oils and fats, 0.013 (0.036)sugar and adjuncts, 0.008 (0.005)and beverages, 0.003(2,3).Selenium was detected in Brazil nuts collected from two regions in Brazil, Acre-Rondonia and Manaus-Belem, at average concentrations of 3.06 and 36.0 ppm, respectively(1). Concentrations of selenium in wheat flour from markets in different areas of Pakistan range from 0.13 to 0.24 ppm, mean 0.19 ppm(2). Selenium has been detected in different wheat products including wheat grain 0.129 ppm, wheat flour 0.127 ppm, Maida 0.122 ppm, and semolina 0.11 ppm(2). Selenium was detected in 15 edible mushroom species sampled from 1993-1999 around the central part of the Mexican Volcanic Belt in Mexico, at average, median, and geometric mean concentrations of 2.06, 1.44 and 1.59 mg/kg dry weight, respectively(3). Fifteen edible seaweed samples (six from British Columbia, seven from Japan, one from Norway, and one undisclosed) were analyzed and found to contain selenium at concentrations ranging from at or below the detection limit (0.1 ug/g) to 6.2 ug/g dry weight(4). |
| Adverse effects | Neurotoxin - Other CNS neurotoxinSelenium supplementation has a very low adverse effect profile. Most adverse reactions center on selenium sulfide. The more common adverse effects include redness, burning, itching, stinging, scalp sores, increased oiliness, nail hyperpigmentation, and skin irritation, creating contact dermatitis. Less common effects associated specifically with selenium sulfide shampoo include scalp hyperpigmentation, scalp discoloration, and alopecia. A rare non-dermatologic effect includes nausea due to the odor of the medication. There are no reported severe reactions to using this drug. |
| Exposure routes | The substance can be absorbed into the body by inhalation and by ingestion.inhalation, ingestion, skin and/or eye contactOral(L619)inhalation (L619)dermal (L619). |
| Milk Concentrations | ENVIRONMENTAL: Selenium content of processed cow milk from Belgium was 8.7 ng/mL in whole milk, 9.5 ng/mL in full cream milk, 8.4 ng/mL in semi-skimmed milk, and 8.8 ng/mL skimmed milk(1). Selenium was detected in goat and cow milk from Burundi, Africa: goat colostrum at mean concentrations of 135.1 ng/mL on day 1 and 65.4 ng/L on day 2, mature goat milk at 23.1 ng/mL, cow colostrum (day 2) at 63.3 ng/mL, mature cow milk, 25.9 ng/mL and processed cow milk at 12.3 ng/mL(2).ENVIRONMENTAL: Selenium content of expressed human breast milk (foremilk) from Belgian mothers decreased with increasing time of lactation and plateaued at a concentration level of about 9.4 ng/g(1). Forty-seven samples of human milk collected from five middle-class women from Burundi, Africa, contained selenium at an average concentration of 15.2 ng/mL 2 days after delivery and 5.2 ng/mL 2 weeks after delivery(2). Mean (range) selenium concentrations of 11.4 (6.7-20.3) and 10.7 (5.5-21.0) ng/mL for colostrum and transitional milk, and 8.4 (4.3-12.6) and 5.2 (3.0-8.7) ng/mL for mature milk at one month and up to 2 months, respectively, were detected in Spanish human milk samples collected from April 1996 to September 1997 in Valencia and Castellon provinces(3). Selenium contents of infant formulas ranged (mean concentration) from 2.7 to 9.6 (4.5) and 1.8 to 7.5 ng/mL for soy and milk-based formulas, respectively(3). |
| Toxicity summary | Selenium is an essential trace element and has been shown to be a natural component in the enzyme glutathione peroxidase and other proteins. Most selenium compounds are water-soluble and can efficiently be taken up in the intestine. Soluble as well as non-soluble compounds can be taken up by the lungs. When given in excess, selenium compounds are rapidly distributed to major organs of the body. ... Identified metabolites are trimethylselenide in urine and dimethylselenide in breath. ... in man ... toxic effects have been reported at 1 mg/dl. ... Toxic effects have been seen at blood levels ranging from 0.179 ug/ml-7.5 ug/ml. In most parts of the world normal urine levels do not exceed 0.03 ug/ml. Occupationally exposed workers usually excrete less than 0.1 ug/ml. The LD50 ranges between 1.5 and 6 mg/kg for many selenium compounds and animal species. The CNS seems to be the target organ ... but the liver, heart, and lungs may also be affected. A few cases of selenium poisoning in humans have been described ... either after consumption of selenium or after exposure via inhalation. Gastrointestinal and neurological symptoms predominated. Chronic poisoning due to long term exposure has been reported in livestock and humans from geographical areas where soil contains high levels of selenium. In rodent liver cirrhosis is a common effect while typical effects in domestic animals are: emaciation, deformation of hooves, loss of hair, and joint erosions. In humans consuming 5 mg selenium per day, hair and nail problems are very common. Skin lesions and depigmentation are also common signs of intoxication. In more severe cases neurological and gastrointestinal symptoms predominate. ... Several selenium compounds have been tested for possible carcinogenic potential. Selenium sulfide has been shown to induce liver cancer in two species while no convincing evidence of carcinogenicity has been presented for other selenium compounds. ... Some selenium compounds may induce DNA damage and some previous reports indicate a teratogenic potential ... . Selenium may prevent or alleviate toxic effects of arsenic, cadmium, mercury, platinum, and silver. Conversely, some of these metals protect against selenium toxicity.Selenium is considered a relatively non-toxic supplement. However, extremely high selenium intake can result in diarrhea, fatigue, hair loss, joint pain, nail discoloration or brittleness, and nausea. Due to selenium supplementation toxicity being extremely rare, there is no current treatment for selenium overdose. If selenium toxicity is suspected, it is best to stop using the supplement.Selenium readily substitutes for sulfur in biomolecules and in many biochemical reactions, especially when the concentration of selenium is high and the concentration of sulfur is low. Inactivation of the sulfhydryl enzymes necessary for oxidative reactions in cellular respiration, through effects on mitochondrial and microsomal electron transport, might contribute to acute selenium toxicity. Selenomethionine (a common organic selenium compound) also appears to randomly substitute for methionine in protein synthesis. This substitution may affect the structure and functionability of the protein, for example, by altering disulfide bridges. Inorganic forms of selenium appear to react with tissue thiols by redox catalysis, resulting in formation of reactive oxygen species and causing damage by oxidative stress. (L619) |
| Atmospheric standards | Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Selenium is included on this list.Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Selenium cmpds are included on this list. |
| CERCLA reportable quantities | Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b). [No reporting of releases of this hazardous substance is required if the diameter of the pieces of the solid metal released is larger than 100 micrometers (0.004 inches).]Reportable Quantities for Radionuclides [Table#4955] |
| Clean Water Act requirements | Toxic pollutant designated pursuant to section 307(a)(1) of the Federal Water Pollution Control Act and is subject to effluent limitations. /Selenium and compounds/ |
| State Drinking Water Standards | (AZ) ARIZONA 10 ug/L /Selenium/(NY) NEW YORK 10 ug/L /Selenium/ |
| State drinking water guidelines | (AZ) ARIZONA 45 ug/L /Selenium/(CT) CONNECTICUT 10 ug/L /Selenium/(ME) MAINE 35 ug/L /Selenium/(MN) MINNESOTA 30 ug/L /Selenium/ |
| Federal Drinking Water Standards | Maximum contaminant levels for inorganic contaminants: 0.05 mg/L /Selenium/ |
| Federal drinking water guidelines | Maximum contaminant level goals for inorganic contaminants: 0.05 mg/L /Selenium/ |
| Occupational exposure band (OEB) | C |
| Occupational exposure limit (OEL) | TWA: 0.2 mg/m3 [*Note: The REL also applies to other selenium compounds (as Se) except Selenium hexafluoride.] |
| Water hazard class (WGK) | 2 |
| Immediately dangerous to life or health concentration | 1 mg Se/m3 |
| TSCA inventory status | TSCA listed |
| RTECS number | VS7700000 |
| UN transport number | UN 2630 (SELENATES or SELENITES) |
| Customs code | 28049090 |
| Toxicity | LD50 orally in Rabbit: 6700 mg/kg |
| Risk statements (R) | 36/38-53-33-23/25 |
| Signal word | Danger |
| GHS pictogram | GHS06,GHS08 |
| Hazard symbols | T |
| Safety statements (S) | 26-61-45-28-20/21-28A |
| Hazard class | 6.1Acute Tox. 3 InhalationAcute Tox. 3 OralAquatic Chronic 4STOT RE 2 |
| Storage class | 6.1C - Combustible acute toxic Cat.3toxic compounds or compounds which causing chronic effects |
| Packing group | I |
| GHS hazard statements | H301+H331-H372-H370-H413 |
| Limited quantities | 5.0 kg (11 lbs) (solid) |
| Excepted quantities | Max Inner Pack (30g or 30ml) and Max Outer Pack (1Kg or 1L) |
| REACH registrations | Active |
| GHS precautionary statements | P501-P273-P260-P270-P271-P264-P308+P311-P301+P310+P330-P304+P340+P311-P403+P233-P405 |
| Hazardous substances data | 7782-49-2(Hazardous Substances Data) |
Applications & Uses
Description
Selenium was discovered in 1817 by Jns Jacob Berzelius. Especially noted was the similarity of the new element to the previously known tellurium. Selenium is an essential trace element atw0.1 ppm in diets. Selenium is a biologically active part of a number of important proteins, particularly enzymes involved in antioxidant defense mechanisms, thyroid hormone metabolism, and redox control of intracellular reactions. In humans and animals, selenium plays a role in protecting tissues from oxidative damage as a component of glutathione peroxidase.
Occurrence
Selenium is the 67th most abundant element in Earth’s crust. It is widely spread over theEarth, but does not exist in large quantities. As a free element it is often found with the elementsulfur.There is only one mineral ore that contains selenium: eucairite (CuAgSe). Although rich inselenium, it is too scarce to be of commercial use. Almost all selenium is recovered from theprocessing of copper and the manufacturing of sulfuric acid as a leftover sludge by-product.This makes selenium’s recovery profitable. Recovering it from eucairite is not profitable.Selenium is found in Mexico, Bosnia, Japan, and Canada. It can be found in recoverablequantities in some soils in many countries.
History
Discovered by Berzelius in 1817, who found it associated with tellurium, named for the Earth. Selenium is found in a few rare minerals, such as crooksite and clausthalite. In years past it has been obtained from flue dusts remaining from processing copper sulfide ores, but the anode muds from electrolytic copper refineries now provide the source of most of the world’s selenium. Selenium is recovered by roasting the muds with soda or sulfuric acid, or by smelting them with soda and niter. Selenium exists in several allotropic forms. Three are generally recognized, but as many as six have been claimed. Selenium can be prepared with either an amorphous or crystalline structure. The color of amorphous selenium is either red, in powder form, or black, in vitreous form. Crystalline monoclinic selenium is a deep red; crystalline hexagonal selenium, the most stable variety, is a metallic gray. Natural selenium contains six stable isotopes. Twentynine other isotopes and isomers have been characterized. The element is a member of the sulfur family and resembles sulfur both in its various forms and in its compounds. Selenium exhibits both photovoltaic action, where light is converted directly into electricity, and photoconductive action, where the electrical resistance decreases with increased illumination. These properties make selenium useful in the production of photocells and exposure meters for photographic use, as well as solar cells. Selenium is also able to convert a.c. electricity to d.c., and is extensively used in rectifiers. Below its melting point, selenium is a p-type semiconductor and is finding many uses in electronic and solid-state applications. It is used in xerography for reproducing and copying documents, letters, etc., but recently its use in this application has been decreasing in favor of certain organic compounds. It is used by the glass industry to decolorize glass and to make rubycolored glasses and enamels. It is also used as a photographic toner, and as an additive to stainless steel. Elemental selenium has been said to be practically nontoxic and is considered to be an essential trace element; however, hydrogen selenide and other selenium compounds are extremely toxic, and resemble arsenic in their physiological reactions. Hydrogen selenide in a concentration of 1.5 ppm is intolerable to man. Selenium occurs in some soils in amounts sufficient to produce serious effects on animals feeding on plants, such as locoweed, grown in such soils. Selenium (99.5%) is priced at about $250/kg. It is also available in high-purity form at a cost of about $350/kg (99.999%).
Uses
selenium is a trace mineral used for years in topical preparations for its anti-fungal properties. Selenium has been shown to have other protective effects such as repairing DnA, reducing the DnA-binding of carcinogens, and suppressing gene mutations. In laboratory studies, skin lotions containing selenium compounds have been shown to decrease uV-induced skin damage such as inflammation, blistering, and pigmentation.
Uses
The photosensitive nature of selenium makes it useful in devices that respond to theintensity of light, such as photocells, light meters for cameras, xerography, and electric “eyes.”Selenium also has the ability to produce electricity directly from sunlight, making it ideal foruse in solar cells. Selenium possesses semiconductor properties that make it useful in the electronicsindustry, where it is a component in some types of solid-state electronics and rectifiers.It is also used in the production of ruby-red glass and enamels and as an additive to improvethe quality of steel and copper. Additionally, it is a catalyst (to speed up chemical reactions)in the manufacture of rubber.Selenium is an essential trace element for both plants and animals, and it is a diet supplementin animal feed as well as for humans.
Uses
Selenium is used in the manufacture of colored glass, in photocells, in semiconductors,as a rectifier in radio and television sets, andas a vulcanizing agent in the manufacture ofrubber.Klaus Schwartz in 1957 discovered thattrace amounts of selenium in the feed protectedvitamin E-deficient rats from dietaryliver necrosis. Soon, thereafter, several animaland epidemiology studies showed thatits presence in the diet could provide protectiveaction in humans against several degenerativediseases including cirrhosis, cancer,diabetes and Keshan disease, a juvenile cardiomyopathy.The range between its beneficialand toxic character, however, is veryclose and, therefore, the daily dietary intakeshould be appropriately monitored (Naverro-Alarcon and Lopez-Martinez 2000). Thereis no accurate estimate of human requirementsof dietary selenium. Extrapolation ofanimal data to humans suggest an averagedaily requirement in the range 50 to 200 μg.Longnecker et al. (1991) observed no evidenceof adverse effects from selenium inhuman health at a daily intake level as highas 724 μg..
General Description
Selenium is a reddish colored powder that may become black upon exposure to air. Selenium is toxic by ingestion. Selenium is used to manufacture electronic components and rubber.