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Highly Toxic: a gas that has a LC 50 in air of 200 ppm or less. [2] NFPA 704: Materials that, under emergency conditions, can cause serious or permanent injury are given a Health Hazard rating of 3. Their acute inhalation toxicity corresponds to those vapors or gases having LC 50 values greater than 1,000 ppm but less than or equal to 3,000 ppm ...
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 ...
Though elemental sulfur is only minimally absorbed through the skin and is of low toxicity to humans, inhalation of sulfur dust or contact with eyes or skin may cause irritation. Excessive ingestion of sulfur can cause a burning sensation or diarrhea, [ 134 ] and cases of life-threatening metabolic acidosis have been reported after patients ...
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.
Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. [1] They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin.
100 ppm IDLH (NIOSH): immediately dangerous to life and health (the level that interferes with the ability to escape) 0.00047 ppm or 0.47 ppb is the odor threshold, the point at which 50% of a human panel can detect the presence of an odor without being able to identify it. [71] 10–20 ppm is the borderline concentration for eye irritation.
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.
Sulfur reduction metabolism is an ancient process, found in the deep branches of the phylogenetic tree. [15] Sulfur reduction uses elemental sulfur (S 0) and generates hydrogen sulfide (H 2 S) as the main end product. This metabolism is largely present in extreme environments where, especially in recent years, many microorganisms have been ...