Hydrogen Sulfide (H2S)

[chickdiver]

Gotcha- FYI it may destroy olfactory nerves, but the odor lingers on your skin, hair , drysuit, gear, and anything else for QUITE some time!!

 

[TwoBitTxn]

Chick,

Welcome to the boards. It would be nice to have a cave instuctor around here.

Please drop into the Introductions board and tell us a little about yourself.

TwoBit

 

[Hamlet]

H2S can be absorbed through the skin? I find this hard to believe, people enter H2S environments without any protection other than SCBA. If this gas can be absorbed through the skin then there would be a lot of dead oil workers around. It’s been a good while since I last attended an H2S course but I’ll be sure and check up on this.

 

[MikeFerrara]

chickdiver once bubbled...
Sorry, my bad- I have always been told that it was absorbed through the skin- however, I am not a doc. scientist, or other who would actually **KNOW** this for a fact. As for the taste, yes I do know that for a fact. I dove a limerock pit N. of Tampa about 2 months ago, descending through the layer there was a distinctive metallic taste to the inside of the mouth, not around the mouthpeice, as you would expect, but more n the insides of the cheeks. Once through the layer it stopped, same effect on the ascent. BTW_ define "short time" as in smell of rotten eggs for a "short time"- I smelled it on my hands for 2 days

I too have been told it is obsorbed through the skin. I encounter the stuff in caves and quarries as well. And you can tast it. I'm no doc either but I know the stuff can be nasty to go through if you end up in it for any length of time.

 

[Norm]

If you do much quarry diving you will experience this gas u/w. It often forms in quarries (especially deep ones) as a result of the decompostion of materials, (such as vegetation). As chickdiver stated you can actually see it coming (like a halocline or some thermoclines) and you can truly taste it. I asked a diving lab tech about the dangers and he said there is no danger to divers as long as you do not ingest that particular layer of water. (Wonder why you can taste it though? Where does that come from?) Anyway, I've diving in it for years and it has never caused any equipment damage. JME
Norm

 

[pescador775]

Recent research has shown that some limestone caves may not be formed by carbonic acid as previously thought but by the action of percolating sulfuric acid. This acid and hydrogen sulfide gas are thought to be generated by decomposing organic matter in deeper strata. The corrosive products filter to the surface layers under pressure and dissolve the sedimentary limestone. The evidence for this is quite strong, IMO. If pools of dilute sulfuric acid exist in caves as has been demonstrated in tests done in Central America, for example, one should presume that certain metals such as aluminum and zinc would be attacked by these chemicals. WRT skin penetration, I'm trying to remember; I believe that some reputed medicinals depend on a sulfur compound as a carrier to be topically applied for entry into the bloodstream.

Pesky

 

[The Chairman]

egg water, whatever you want to call it, is quite common here in Florida. It is acidic and known for it's smell. I think it tastes "metallic" myself, but not having consumed my fair share of iron and aluminum, I could be wrong. I do think the taste is something to do with the reaction of the acid with your tongue.

It does seem to be absorbed into your tissues, for I have noticed the smell for up to a week after Scout Camp when I was a kid. I also noticed that those who drank a LOT of sulfer water were less bothered by mosquitos than the rest. They don't like the smell, and niether do ticks. Go figure!

As for diving in it, I can barely stand to swim in the stuff. Camp La-No-Che (Paisley Florida) is home of the infamous "Sulfer Springs". We always built our bridges over that spring for our Pioneering Merit badge. No mosquitos seemed to bother us in our tasks... which was cool! The Scouts taking this merit badge could be singled out by their smell alone. It was a badge of honor that you would endure such a smell to build a monkey bridge over a site avoided by many.

 

[pescador775]

The varous comments, including the ones about 'layers' of sulfur water are interesting since H2S is not particularly soluble in water at atmospheric pressure. When exposed to air, H2S seems to bubble off from its solute state fairly quickly. That's part of the reason for the intense odor. Of course, aquifers would normally be under heightened pressure and lower temperature. The compound H2SO4.H2O has a specific gravity of 1.7 and a refractive index of 1.4. It seems likely that this substance could form visible layers in an entrapped body of fresh water, much as salt water does in brackish bays. Layers of salt and fresh water are sometimes visible in the Chesapeake Bay and those small bays near Destin, Fla, etc. The mixing zone has an 'oily' appearance.

 

[Norm]

Perhaps thermoclines help to isolate/hold these layers in freshwater?

 

[Bubble Boy]

Studies have shown that acute exposure in the range of 0-20ppm range would have very little effect to skin. One study dating back to 1930 indicated that a 60 minute exposure to 100% resulted in darkening of the skin, red moles, rash etc.....

With regards to H2S getting into steel/alum the sulfer does not migrate its the Hydrogen.

H2S is deadly stuff.