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A drained pond, showing the layer of sludge on the bottom; its black colour is due to the presence of metal sulfides, the result of reactions with hydrogen sulfide produced by bacteria. Hydrogen sulfide is a central participant in the sulfur cycle, the biogeochemical cycle of sulfur on Earth. [112]
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.
Histotoxic hypoxia results from tissue poisoning, such as that caused by cyanide (which acts by inhibiting cytochrome oxidase) and certain other poisons like hydrogen sulfide (byproduct of sewage and used in leather tanning).
Most subspecies of Salmonella produce hydrogen sulfide, [21] which can readily be detected by growing them on media containing ferrous sulfate, such as is used in the triple sugar iron test. Most isolates exist in two phases, a motile phase and a non-motile phase.
Poisoning often involves compounds that chemically bond to a catalyst's active sites. Poisoning decreases the number of active sites, and the average distance that a reactant molecule must diffuse through the pore structure before undergoing reaction increases as a result. [4] As a result, poisoned sites can no longer alter the rate of reaction ...
While the determination of the specific toxin can be time-consuming due to the number of different substances that can cause injury or death, certain clues can narrow down the possibilities. For example, carbon monoxide poisoning would result in bright red blood while death from hydrogen sulfide poisoning would cause the brain to have a green hue.
To avoid carbon monoxide poisoning in your vehicle, the CDC recommends having your exhaust system checked every year, as even a small exhaust leak results in CO buildup inside a car or truck. If ...
In 1832, a certain John Bodle was brought to trial for poisoning his grandfather by putting arsenic in his coffee. James Marsh, a chemist working at the Royal Arsenal in Woolwich, was called by the prosecution to try to detect its presence. He performed the standard test by passing hydrogen sulfide through the suspect fluid.