Selenium
Identification Number: CASRN | 7782-49-2

  Substance Attributes

• Carcinogenic Properties

  Accumulating evidence points to cancer potential. Exercise caution with this substance, explore your exposure routes and consider complete avoidance. See further details under Toxins.

• Reproductive Effects

  Interferes with fertility

• Birth/Developmental

  Known to effect development of fetus.

• Metabolic Interference or Disruption

  Interferes with human metabolism. This can be a very serious thing. Some of these interference mechanics are well established. However, often long term effects and health consequences remain largely unknown. Additionally an emerging area of concern and one that is not currently studied, is the combined synergistic effects these metabolically disrupting chemicals have on human health.

  
  

  Metabolic interference happens when the substance produces highly reactive and often damaging intermediates during detoxification or when the substance binds to specific enzymes, important structural groups on molecules, receptors and membranes or targets DNA or mimics key nutrients.

• Exposure Produces Health Symptoms

  Symptoms maybe short term or long term depending on the exposure duration and intensity and effects areas like Cardiovascular, Gastrointestinal, Cognition, Fatigue. A substance with this attribute may cause an allergic skin reaction, serious eye irritation, allergy or asthma symptoms or breathing difficulties if inhaled.

• Serious Acute Effects

  This is a serious nasty substance. Effects are Acute (seen immediately). Substances in this category may be FATAL or acutely toxic if inhaled, skin contact or swallowed. See further details.

• Toxic to specific organs

  Can damage liver, kidney, lungs, heart or gut. Ironically liver, kidneys and gut are the main detoxifications systems.

• Toxic to Wildlife

  May kill plants, fish, birds or other animals and insects or may be very toxic to aquatic life with long lasting effects. This then effects delicate environmental ecology and food supply in ways we don't fully understand yet.

These attributes are ONLY based on peer-reviewed evidence. See link to Data Sources below. Everyone benefits from knowing this stuff. Please Share.

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• CATEGORIES: Pit Chemicals | Chemicals detected in flowback and produced water - collectively referred to as - hydraulic fracturing wastewater | Pesticide | Household Toxin | Industrial/Workplace Toxin | Pollutant | Airborne Pollutant | Food Toxin | Natural Toxin | A Hazardous Substance that may be found in the Australian Workplace
• SUBSTANCE LINEAGE: Inorganic Compounds | Homogeneous Non-metal Compounds | Homogeneous Other Non-metal Compounds | | Homogeneous Other Non-metal Compounds
• SYNONYMS: Se(2-) | Selanediide | Selenide | Selenide(2-) | Selenium anion (2-) | Selenium ion (Se2-)
• DESCRIPTION: Has been used in CSG, Hydraulic Fracturing Operations (Fracking) as - Unknown | Selenium is a nonmetal element with the atomic number 34 and the chemical symbol Se. Isolated selenium occurs in several different forms, the most stable of which is a dense purplish-gray semiconductor form. Selenium rarely occurs in its elemental state in nature and is usually found in sulfide ores such as pyrite, partially replacing the sulfur in the ore matrix. It may also be found in silver, copper, lead, and nickel minerals. Selenium is mainly used in the electronics industry, in glassmaking, and in chemicals and pigments. Though selenium salts are toxic in large amounts, trace amounts of the element are necessary for cellular function in most animals, forming the active center of the enzymes glutathione peroxidase, thioredoxin reductase, and three known deiodinase enzymes. (L620)
• COMMENTS:
  
  From Safe Work Australia and the Hazardous Substances Information System (HSIS) in Australia:
  
  Toxic if inhaled. Toxic if swallowed. May cause damage to organs through prolonged or repeated exposure . May cause long lasting harmful effects to aquatic life | Chronic Health Hazard Acutely Toxic | A Hazardous Substance that may be found in the Australian Workplace. Check with your employer or health and safety officer. Stay informed and become aware of the dangers that surround you. This chemical is included on the list of recognised hazardous chemicals from the Safe Work Australia - Hazardous Substances Information System (HSIS) that is based on the Globally Harmonised System of Classification and Labelling of Chemicals (GHS)
  
  Work Health and Safety (WHS) Regulations are the basis for hazardous chemicals regulations in Commonwealth, State and Territory jurisdictions in Australia. Under the model WHS Regulations, manufacturers and importers of substances, mixtures and articles supplied for use in workplaces are required to determine whether they are hazardous to health and safety before supply. The model WHS Regulations mandate that the hazards of a chemical as determined by the Globally Harmonised System of Classification and Labelling of Chemicals (GHS) must be included in safety data sheets and on labels. There are transitional arrangements in place for moving to the GHS-based system.
  
  The GHS Hazardous Chemical Information List contains chemicals classified by an authoritative source (such as the European Commission or NICNAS) in accordance with the Globally Harmonized System of Classification and Labelling of Chemicals (the GHS). This list contains the vast majority of chemicals currently in HSIS. This list and its detail are regularly updated by Work Safe Australia. The model Work Health and Safety (WHS) Regulations require chemicals to be classified in accordance with the Globally Harmonised System of Classification and Labelling of Chemicals (GHS). However transitional arrangements allow use of classification information in HSIS derived from the Approved Criteria until the 31 December 2016.
• 
• FORMULA: Se
• DATA SOURCES: DATA SOURCES: T3DB | PubChem | IARC | TEDX | EPA in USA | Safe Work Australia - Hazardous Substances Information System (HSIS)
• LAST UPDATE: 28/04/2018

  Health Associations

Mostly focused on Health Implications of Long Term Exposure to this substance

• SYMPTOMS: Short-term oral exposure to high concentrations of selenium may cause nausea, vomiting, and diarrhea. Brief exposures to high levels of elemental selenium or selenium dioxide in air can result in respiratory tract irritation, bronchitis, difficulty breathing, and stomach pains. Longer-term exposure to either of these air-borne forms can cause respiratory irritation, bronchial spasms, and coughing. (L619)
• POSSIBLE HEALTH CONSEQUENCES: 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) | Selenium may be absorbed through inhalation and ingestion, while some selenium compounds may also be absorbed dermally. Once in the body, selenium is distributed mainly to the liver and kidney. Selenium is an essential micronutrient and is a component of glutathione peroxidase, iodothyronine 5'-deiodinases, and thioredoxin reductase. Organic selenium is first metabolized into inorganic selenium. Inorganic selenium is reduced stepwise to the intermediate hydrogen selenide, which is either incorporated into selenoproteins after being transformed to selenophosphate and selenocysteinyl tRNA or excreted into the urine after being transformed into methylated metabolites of selenide. Elemental selenium is also methylated before excretion. Selenium is primarily eliminated in the urine and feces, but certain selenium compounds may also be exhaled. (L619)
• ACTION OF TOXIN: 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) |
• TOXIN SITES OF ACTION IN CELL: "Cytoplasm", "Extracellular"
• Additional Exposure Routes: Most processed selenium is used in the electronics industry, but it is also used as a nutritional supplement, in the glass industry, in the preparation of pharmaceuticals, as a nutritional feed additive for poultry and livestock, in pesticide formulations, in rubber production, as an ingredient in antidandruff shampoos, and as a constituent of fungicides. It may also be found in pigments in plastics, paints, enamels, inks, and rubber. (L619)

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