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http://www.cleanmpg.com/photos/data/2/European_Union_Flag.jpg attacks the respiratory system and can kill a man or an animal in minutes (http://www.timesonline.co.uk/tol/news/world/article6740746.ece#cid=OTC-RSS&attr=2015164)

http://www.cleanmpg.com/photos/data/501/algae_in_France.jpgAdam Sage - TIMESONLINE (http://www.timesonline.co.uk) - 08/06/09

I'll bet this happens in the US as well - think about this when walking on a beach covered in sea weed --Ed.

Holidaymakers have been told to keep away from beaches in northern France covered in seaweed after doctors gave warning that it could give off lethal fumes when it rots.

A stretch of beach had to be closed after a horse rider lost consciousness as a result of the putrefying algae. His horse was killed. Local residents have also been treated in hospital.

The incident was in Brittany, where green seaweed is spreading across the region’s beaches as nitrates pollute the water supply as a result of intensive agriculture.

Scientists say that as the seaweed — known locally as sea lettuce — decomposes, it forms an impermeable white crust under which hydrogen sulphide accumulates. When the crust is broken, the gas is released.

Alain Menesguen, director of research at the French Institute for Sea Research and Exploitation, said: “This is a very toxic gas, which smells like rotten eggs. It attacks the respiratory system and can kill a man or an animal in minutes.” Some scientists believe that a build-up of hydrogen sulphide in the atmosphere wiped out the dinosaurs 300 million years ago.

Pierre Philippe, of the Lannion hospital in Brittany, said that hydrogen sulphide was as dangerous as cyanide. He said that he had treated several cases of poisoning caused by the seaweed among local residents, including a council worker paid to clear beaches of the algae who was taken to hospital in a coma.

The health scare is a new blow to the French tourism industry, already suffering from a big fall in the number of British visitors.

The dangers were highlighted after Vincent Petit, 27, a veterinary surgeon from Paris, said that rotting seaweed a metre deep had killed his horse last week as he rode across St-Michel-en-Grève beach. Mr Petit lost consciousness and was pulled off the beach. A post-mortem on the horse showed that it had died of pulmonary oedema caused by inhaling hydrogen sulphide given off by the rotting seaweed. ... http://www.timesonline.co.uk/tol/news/world/article6740746.ece#cid=OTC-RSS&attr=2015164

The sulfur gas posiibly linked to dinosaur extinction is sulfur dioxide, not hydrogen sulfide. The mode of action is purported to be global cooling (and subsequent changes), not asphixiation.

There are several other possible causes and not quite enough evidence for any to clinch it. But that's another matter no doubt.

Once again, I don't much like getting science from the media. Childrens' brains in adult bodies.

DAS

The sulfur gas posiibly linked to dinosaur extinction is sulfur dioxide, not hydrogen sulfide. The mode of action is purported to be global cooling (and subsequent changes), not asphixiation.

There are several other possible causes and not quite enough evidence for any to clinch it. But that's another matter no doubt.

Once again, I don't much like getting science from the media. Childrens' brains in adult bodies.

DAS

There's a "hydrogen sulfide" theory of extinction too, but I'm not sure I buy it.

What I've been taught about H2S in confined space training is that it has an odor, but when it is present as a decay product there is likely to be other pungent stuff around that drowns out its smell. It's famous for killing sewer workers and guys cleaning grain silos.

I remember reading about how they used to use hydrogen sulfide as a refrigerant. Of course, disaster arose when a pipe burst, prompting the search for a "safe" refrigerant. Unfortunately, what they discovered were CFCs, which had their own problems.

Maybe they should figure out a way to make biofuels from the seaweed.

TIMESONLINE - 08/06/09
... Some scientists believe that a build-up of hydrogen sulphide in the atmosphere wiped out the dinosaurs 300 million years ago. ...

In addition to the other dinosaur problems mentioned, this extinction date is way off. Dinosaurs didn't become a separate group until about 230 million years ago, then were mostly wiped out in the K-T event 65 million years ago.

You've got those chemicals mixed up, too, NiHaoMike. It's sulfur dioxide that was used as a refrigerant before Freon, not hydrogen sulfide.

I know because as a college student, two of my roommates were hacksawing an old refrigerator for its electrical parts for their model train setups. They were doing this on a Sunday morning in our co-op building, and accidentally cut through a refrigerant coil, releasing a brown cloud of SO2. We evacuated our room and set off the fire alarm, getting the 205 residents of the co-op building out of bed at 8:30 a.m. The fire department came and lectured my roommates.

You can confirm SO2's use as a refrigerant here on Wikipedia. (http://en.wikipedia.org/wiki/Sulfur_dioxide)

That article is riddled with inaccuracies.

What I've been taught about H2S in confined space training is that it has an odor, but when it is present as a decay product there is likely to be other pungent stuff around that drowns out its smell. It's famous for killing sewer workers and guys cleaning grain silos.

I was taught the dangers of hydrogen sulphide when I worked in the oilfields in Saudi Arabia. A major problem with hydrogen sulphide is that one of its first effects is that it deadens a person's sense of smell.

Harry

"Olfactory paralysis" is the medical term for that. See page 16: http://www.who.int/ipcs/publications/cicad/en/cicad53.pdf

Harry

300 MYA dinosaur ext? Good catch - I missed it

Grain silos: NO2, secondarily CO2
http://www.nasdonline.org/docs/d001601-d001700/d001621/d001621.html

Sewer gas: don't forget methane
http://www.envirochex.com/Topic_Other/Sewer_Gas.htm

Refrigerant working fluids: a long list including methyl formate, ammonia, methyl chloride, and sulfur dioxide. None would ba a good choice for breathing. Intl Space Station uses NH3

H2S extinction theory: please share that one with me; I've missed it. Not really compatible with the earth having an oxidising atmosphere.

Seaweed to biofuel: in theory no problem at all. All organic carbon molecules are candidates. The issues are always fast and cheap.

Maybe youse guys are more interested in chemsitry than I thought :)

DAS

300 MYA dinosaur ext? Good catch - I missed it

Grain silos: NO2, secondarily CO2
http://www.nasdonline.org/docs/d001601-d001700/d001621/d001621.html

Sewer gas: don't forget methane
http://www.envirochex.com/Topic_Other/Sewer_Gas.htm

Refrigerant working fluids: a long list including methyl formate, ammonia, methyl chloride, and sulfur dioxide. None would ba a good choice for breathing. Intl Space Station uses NH3

H2S extinction theory: please share that one with me; I've missed it. Not really compatible with the earth having an oxidising atmosphere.

Seaweed to biofuel: in theory no problem at all. All organic carbon molecules are candidates. The issues are always fast and cheap.

Maybe youse guys are more interested in chemsitry than I thought :)

DAS

Grain silos: NO2, secondarily CO2
http://www.nasdonline.org/docs/d001601-d001700/d001621/d001621.html


Maybe youse guys are more interested in chemsitry than I thought :)

DAS

I only know what wikipedia says about the H2S dinosaur extinction theory.

Among other things I'm a Hazardous Waste Operator/Supervisor, so I have to know enough about atmospheric chemistry to know when a three gas monitor says to run like hell. I know some of the regional hazmat fire-rescue guys and they say it's H2S that's in the grain silos when they're recovering bodies. This sounds right since, as I understand it, H2S is more potent toxin that can lead to death in one breath as opposed to NO2 which mainly leads to an oxygen deficient atmosphere issue? I think methane, H2S, and O2 is the usual combo on the three gas monitor, so I doubt that they have specific knowledge about nitrogen oxide concentrations.

"Olfactory paralysis" is the medical term for that. See page 16: http://www.who.int/ipcs/publications/cicad/en/cicad53.pdf

Harry


I have some first hand experience with Olfactory paralysis.

In the beer industry lager yeasts produce a sulfury aroma from ppb levels of H2S, and also skunky aromas from UV light breaking down hop acids to form 3-methyl-2 butene thiol. The reason for drinking corona with a lime is to mask the skunk, that is terrible beer for a premium and goes skunky in clear bottles.

Anyway I'm weak at detecting sulfur components and at a sensory evaluation class I wasn't detecting the sulfide aroma and the teacher had me and those that couldn't detect it take a whiff of a concentrate. I took a quick smell and got a hint of matchstick aroma and then nothing. No one could believe that I could smell nothing, as this was a grossly foul smell to everyone else. I was paralyzed.

That explains why my farts don't stink. :D

There was also a published theory of dinosaur extinction in the late '80s attributing it to the flatus of ceratopsians releasing so much methane that runaway global warming made the Earth uninhabitable for dinosaurs. I read it shortly before driving my daughter to a preschool program, which inspired me to sing this to the tune of that ever-popular preschool program song "The One Little Duck With The Feather On His Back":

Huge dinosaurs the Earth once knew,
Plant eaters, meat eaters, scary ones too,
But the large herbivores with the horns upon their snoots,
They killed all the others with their poot, poot, poots,
Poot, poot, poots,
Poot, poot, poots,
They killed all the others with their poot, poot, poots.

My little girl thought it clever and funny, anyway...

That explains why my farts don't stink. :D

And if they're silent, you know your ears have gone bad.

The global ocean apparently became anoxic before or during the Permian/Triassic extinction, 250MYA. So H2S could have played a role (or caused) that one. In an O2 rich atmosphere this is a harder sell. These days the atmospheric lifetime of H2S is on the order of hours.

As has been described well in this thread, being near a strong local source of H2S sounds very bad. I shall approach seaweed piles with caution.

DAS