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This is an accepted version of this page This is the latest accepted revision, reviewed on 6 January 2025. This article is about the chemical element. For other uses, see Sulfur (disambiguation). Chemical element with atomic number 16 (S) Sulfur, 16 S Sulfur Alternative name Sulphur (pre-1992 British spelling) Allotropes see Allotropes of sulfur Appearance Lemon yellow sintered microcrystals ...
Highly toxic to humans in its elemental form. [11] iridium: 77: 1a: Due to its extreme rarity, iridium has no biological role. [11] The chloride is moderately toxic to humans. [11] iron: 26: 5: Essential to almost all living things, usually as a ligand in a protein; it is most familiar as an essential element in the protein hemoglobin. [11 ...
Many gases have toxic properties, which are often assessed using the LC 50 (median lethal concentration) measure. In the United States, many of these gases have been assigned an NFPA 704 health rating of 4 (may be fatal) or 3 (may cause serious or permanent injury), and/or exposure limits (TLV, TWA/PEL, STEL, or REL) determined by the ACGIH professional association.
Many metals, particularly heavy metals are toxic, but some are essential, and some, such as bismuth, have a low toxicity. Metals in an oxidation state abnormal to the body may also become toxic: chromium(III) is an essential trace element, but chromium(VI) is a carcinogen. Only soluble metal-containing compounds are toxic.
Treatment of sulfur with hydrogen gives hydrogen sulfide.When dissolved in water, hydrogen sulfide is mildly acidic: [5] H 2 S ⇌ HS − + H +. Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide.
Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death.
[7] [6] It is the fourth-largest risk factor overall for human health [8] as 99% of people are exposed to harmful levels of air pollution. [9] Outdoor particulate pollution ( PM2.5 ) is the largest cause of death (4.7 million), followed by indoor air pollution (3.1 million) and ozone (0.5 million).
While not much is known about the exact metabolism the bacterium performs, it is known to exist in environments of high sulfur and little to no oxygen present. [8] This bacterium often uses anaerobic respiration due to its environment not supplying ample oxygen. [7] Sulfur oxidation is the main energy source for Thiomargarita namibiensis. [34]