Pollution Suspected In Diver Death - Vietnam

[Joaz Banbeck]

...slow reaction...

Hmm...interesting. I didn't know that. Any idea what the half life is?

 

[John C. Ratliff]

Hmm...interesting. I didn't know that. Any idea what the half life is?

Nope, that one is beyond my knowledge. I may be able to look it up, but not right now.

SeaRat

 

[John C. Ratliff]

Hmm...interesting. I didn't know that. Any idea what the half life is?

Joaz,

Here are a couple of links:

DrThrasher_Hydrogen Sulfide
H2S in air has a half life of 12-37 hours.

In water, or intracellular, this paper discusses it, but does not give a half-life. It is an interesting read for anyone interested in the chemical, H2S, however.

The physiology of hydrogen sulfide

Physiological concentrations of H2S are generally thought to be quite high with many reports of concentrations of around 10- 100 μmol L-1 or higher in blood or tissue samples [14–16]. For a long time we have believed that these values are too high, and ex- pected much lower levels to be reported once the inherent problems with current analytical methods to measure sulfide were corrected. More recently other investigators have estimated the concentration of sulfide in tissues or plasma to be in the nanomolar range [17,18].

H2S is known to exert effects in the cardiovascular, endocrine and central nervous systems. Thus, H2S activates ATP-sensitive K+ channels, exhibits anti-inflammatory effects and promotes healing [19]. Human penile tissue also contains cystathionine-γ-lyase and cystathionine-β-synthetase and it appears that, like nitric oxide, H2S is also involved in mediating penile erection in humans and other mammalian animals [20].

An H2S-releasing group has been chemically linked to the non- steroidal anti-inflammatory drug diclofenac, with a resulting increase in its anti-inflammatory action [21]. The protective effects of garlic against cardiovascular disease are thought to be secondary to the formation of hydrogen sulfide from garlic-derived organic polysul- fides by the action of red blood cells [22]. Furthermore, a range of sulfur compounds, shown in Fig. 2 (structures 1 to 5), and present in algae, mushrooms and onions, are believed to undergo chemical and enzymatic reactions during digestion that enhance the formation of H2S in humans [23]. The physiological and pharmacological actions of hydrogen sulfide have recently been extensively reviewed [24].

Fig. 1. Hydrogen sulfide can be generated by at least 3 metabolic pathways.

Fig. 2. (a) Structures of some polysulfides in food that release H2S on digestion [21]. (1) Allyl mercaptan, (2) Diallyl disulfide, (3) Diallyl trisulfide, (4) Diallyl tetrasulfide, (5) Lenthionine [21]. (b) Structure of an H2S releasing compound, GYY4137 [34].

Deficiency of cystathionine-β-synthase and cystathionine gamma lyase in humans

In humans, a deficiency of CBS results in homocysteinuria, with increased concentrations of homocysteine and methionine in plasma and decreased levels of cysteine [25]. CBS deficiency may lead to mental retardation, optic lens dislocation, skeletal abnor- malities, and a tendency to thromboembolic episodes that demon- strate the biochemical and medical significance of H2S in health [26].

http://www.sfrbm.org/pdf/Hydrogensulfide_Moore_FRBM2009.pdf

SeaRat

 

[Maverick17]

Hate to drag up an old thread, but for some closure -- the suspected company, Formosa Steel, indeed turned out to be the culprit in this they announced a month or so ago. First $250 million payment was just made (how much is used on environment or to those affected out of that, is up to you to guess/infer). One more payment of the same amount will be made.

Formosa pays first $250 mln as compensation for fish kill disater in Vietnam