Toxno Substance Profile
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Substance Name

Selenous acid
Identification Number: CASRN | 7783-00-8

  Substance Attributes


  • 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.

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



  • CATEGORIES: Industrial/Workplace Toxin | Pollutant | Airborne Pollutant | Synthetic Toxin
  • SUBSTANCE LINEAGE: Inorganic Compounds | Mixed Metal/Non-metal Compounds | Other Mixed Metal/Non-Metal Oxoanionic Compounds | Non-metal Selenites | Non-metal Selenites
  • SYNONYMS: Dihydroxidooxidoselenium | Hydrogen selenite | Monohydrated selenium dioxide | Selenige saeure | Selenious acid | Selenious acid (H2seo3) | SELENIOUS ACID | H2SeO3 | Selenium dioxide | Selenium dioxide | monohydrated | [SeO(OH)2]
  • DESCRIPTION: Selenous acid is the principal oxoacid of selenium. It is used in organic synthesis. Selenium is a nonmetal element with the atomic number 34 and the chemical symbol Se. 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. 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, L736)
  • COMMENTS:
  • toxin chemical structure pubchem
  • FORMULA: H2O3Se
  • DATA SOURCES: DATA SOURCES: ARTICLE 4 | T3DB | PubChem
  • 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: Selenous acid is used in organic synthesis. (L736)

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  Exposure Routes

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