Talk:Lake Nyos

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"... a cloud of carbon dioxide gas suddenly boiled at Lake Nyos, ..."
boiled is the wrong word, but I can't lay my hands on the right one for 'came out of solution' ...
—wwoods
The only word I can think of is parcipitated. --Silver86 23:04, 28 Dec 2004 (UTC)
Try vented Revmachine21 03:16, 18 June 2006 (UTC)
Or disgorged. --Psm 05:59, 19 October 2007 (UTC)

Contents

[edit] Call for Clarification on Burns

The victims are reported in this article to have suffered "burns", which could not have been caused by C02 alone (unless it was very hot, which it doesn't seem to have been). The limnic eruption article mentions a theory that there was acid as well as C02 but suggests that this theory is not widely accepted, and doesn't mention the burns. Could someone clarify this please. Zargulon 14:15, 27 September 2005 (UTC)

My understanding is that the victims were originally reported to have skin burns, but the reports were later clarified to describe "skin damage" such as discoloration.[1] Here's one explanation[2]:
the skin lesions were in fact attributable to some combination of the following: (1) exposure to a direct heat source such as a cooking fire, (2) pressure sores from prolonged lying in a fixed position, (3) postmortem decomposition, and (4) sores that predated the event. Observed skin blisters were associated with extended unconsciousness, similar to symptoms found in comatose drug overdose patients.
As far as I know there's no clear consensus, since that still doesn't explain the symptoms of the survivors, for example. Wmahan. 14:56, 27 September 2005 (UTC)

The skin burns to skin damage clarification in that source refers to a different limnic eruption, that of Lake Monoun. Are we sure that the survivors of lake Nyos are really supposed to have had burn symptoms? Zargulon 16:06, 27 September 2005 (UTC)

You're right about the first link referring to Lake Monoun, but links like [3] appear to refer to Nyos: though these lesions were initially believed to be burns from acidic gases, further investigation suggested that they were associated with coma states caused by exposure to carbon dioxide in air. Wmahan. 16:26, 27 September 2005 (UTC)

Ok - thanks.Zargulon 16:32, 27 September 2005 (UTC)

I found this source (http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1836556) so I'll change the word "burn" to "lesion" and add the ref. --Psm 05:54, 19 October 2007 (UTC)

[edit] degassing the lakes

 Has any consideration ever been made towards using the pressure generated in the degassing process to generate electricity?

Could this electrical generation be used to offset the long term costs of adding more degassing pipes to these lakes?

I have been unable to find discussion on this topic. If you are aware of any papers or research towards this subject please post it.

I can't answer your question, but you might also try asking at the Science Reference Desk. Hopefully, between here and there someone can at least hazard a guess. —Amcaja 02:36, 3 November 2005 (UTC)

[edit] biology

There must be rather interesting plants an possibly fish in there. Bacteria at least. Is anything known about that? 84.160.210.182 17:54, 4 December 2005 (UTC)

[edit] Weakening Dam

Engineers could also introduce a channel to allow excess water to drain; if the water level were lowered by about 20 metres, the pressure on the wall would be reduced significantly.

Would this not also have the effect of lowering the limnic eruption threshhold? -Antonius- 05:16, 11 December 2006 (UTC)

[edit] Carbon Dioxide Toxicity, and Possible Other Gasses Involved

I think that most of the information about this disaster and the way in which people were killed has been repeated over and over from a single flawed source and contains some misinformation.

First, Carbon Dioxide can cause asphyxiation by displacement of oxygenated air. However, it is more complicated than that. CO2 is also a toxin. That is, it is not simply displacement of oxygen that can kill or harm people. Concentrations of over 10 percent are lethal if breathed for long enough periods (Could not source for this level but I learned it in my First Aid/First Responder training).

Here is one source: What are the main health hazards associated with breathing in carbon dioxide gas?

High CO2 levels have effects on the nervous system, and consequent harmfull physical effects. CO2 levels naturally effect breathing rates which helps regulate and keep our body's blood oxygen level within tolerable limits. If CO2 builds up in our lungs, a result of increased muscular activity or decreased inhalations, our brain signals our diaphragm muscles to breath more and more deeply. In air with a high level of CO2, this regulatory system becomes dysfunctional. This can lead to rapid loss of consciousness. This is a much more rapid transition than would occur from simply holding ones breath. I'm not sure how this would differ from breathing in, let's say pure nitrogen, but I suspect pure nitrogen would not cause immediate unconsciousness.

The main point then, is that the concentration of CO2 would not have to be so high that oxygen concentration was too low for life. It only would have to be high enough to cause unconsciousness and then remain at a significant level for a period of time to cause death.

Here is more info on danger of CO2 (from http://www.epa.gov/ozone/snap/fire/co2/appendixb.pdf): --Psm 06:10, 19 October 2007 (UTC)

Carbon dioxide acts as both a stimulant and depressant on the central nervous system (OSHA 1989, Wong 1992). Table B-1 summarizes the acute health effects that are seen following exposure to high concentrations of carbon dioxide. Exposure of humans to carbon dioxide concentrations ranging from 17 percent to 30 percent quickly (within 1 minute) leads to loss of controlled and purposeful activity, unconsciousness, coma, convulsions, and death (OSHA 1989, CCOHS 1990, Dalgaard et al. 1972, CATAMA 1953, Lambertsen 1971). Exposure to concentrations from greater than 10 percent to 15 percent carbon dioxide leads to dizziness, drowsiness, severe muscle twitching, and unconsciousness within a minute to several minutes (Wong 1992, CATAMA 1953, Sechzer et al. 1960). Exposure to 7 to 10 percent carbon dioxide can produce unconsciousness or near unconsciousness within a few minutes (Schulte 1964, CATAMA 1953, Dripps and Comroe 1947). Other symptoms associated with the inhalation of carbon dioxide in this range include headache, increased heart rate, shortness of breath, dizziness, sweating, rapid breathing, mental depression, shaking, and visual and hearing dysfunction that were seen following exposure periods of 1.5 minutes to 1 hour (Wong 1992, Sechzer et al. 1960, OSHA 1989). In a study of 42 human volunteers, following inhalation of 7.6 and 10.4 percent carbon dioxide for short periods of time (2.5 to 10 minutes), it was reported that only about 30 percent of the subjects complained of difficult breathing (dyspnea), although respiration was vigorously stimulated (Lambertsen 1971, Dripps and Comroe 1947). In this study, the most common symptoms were headache and dizziness (Lambertsen 1971, Dripps and Comroe 1947). Other symptoms described included mental clouding or depression, muscle tremors or twitching, tingling or cold extremities, and exhaustion (Lambertsen 1971, Dripps and Comroe 1947). Confusion to the point of unconsciousness was reported in several subjects at both concentrations (Lambertsen 1971). Increasing concentrations of carbon dioxide up to 7.5 percent for a period of 20 minutes had no significant effects on accuracy of reasoning and short-term memory, although speed of performance of reasoning tasks was significantly slowed at the higher levels (Sayers et al. 1987). Exposure to a concentration of 6 percent carbon dioxide can produce hearing and visual disturbances within 1 to 2 minutes (Gellhorn 1936, Gellhorn and Spiesman 1935). Acute exposures (minutes) to 6 percent carbon dioxide affected vision by decreasing visual intensity discrimination in 1 to 2 minutes (Gellhorn 1936) and resulted in a 3 to 8 percent decrease in hearing.

I would love a medically trained research person with access to scientific articles/ first sources to add info here. I only have access if I go up to the University - I can't get access to full article at home.

Also, from the reports of burns and such, I find it very hard to believe that CO2 alone was responsible in the Lake Nyos disaster. I could find nothing that refers to burns caused by CO2. Carbonic acid is formed by CO2 and water, but it is not usually damaging to tissue immediately. And at least one survivor reported burns and irritation immediately after the event. The Lake Nyos Disaster 20 Years After (II):Explaining Death by Toxic Carbon Dioxide Cloud

I think that other gasses, including hydrogen sulphide and sulfur dioxide could have played a role. Hydrogen sulphide is highly toxic, and is rated right up there with cyanide. Sulfur dioxide forms sulphuric acid when combined with water. It is also a toxic gas. Both compounds are toxic at rather low concentrations (H2S - lethal between 530 and 1000 ppm, and for SO2 it is over 400 ppm for 1 minute).

I don't know why these other gasses are not mentioned in reference to this disaster. However they are apparently known to have been released in the efflorescent event in Lake Nyo. Both gasses are commonly associated with volcanism, and breakdown of organic debris (common on lake bottoms, swamps, marshes, etc. when oxygen is low). They both have strong odors at very low levels, however at toxic and subtoxic levels the olfactory senses are overwhelmed and they are rendered undetectable. I wonder, however at Mr. Joseph Nkwain's description in the "The Lake Nyos Disaster 20 Years After" article : "All of a sudden, my skin became very hot and I perceived something making some dry smell." And: "I did not really know what the smell was, the smell was terrible"

Respiratory symptoms and peak expiratory flow in survivors of the Nyos disaster

What the effects of CO2 combined with hydrogen sulfide and sulpher dioxide is may be even more devastating than any of them alone, and may require only moderate levels of exposure to be lethal. —The preceding unsigned comment was added by Loki-dog (talk • contribs) 22:24, 21 January 2007 (UTC).

[edit] Good article on disaster

Can be found here [4]. Remember 16:10, 22 May 2007 (UTC)

[edit] what's the source for the "five pipes"??

Again this has crept into the article: "The solution proposed by scientists was that five pipes should be extended into the lower regions of the lake, allowing a controlled and continuous outgassing." The current pipe was installed in 2001, following an experiment in 1995. Various researchers argue that more pipes are needed, and I've found several references to that effect. But I can't find references that imply that there was some objective level of number of pipes decided early on in some manner, and that only one has been installed. Please don't reinsert language to that effect without a reference. —Preceding unsigned comment added by Psm (talk • contribs) 21:24, 8 November 2007 (UTC)

Lol, never mind, with some more searching I found the reference. The original, mostly French, team that set up the 1995 experiment had proposed five columns. --Psm 21:31, 8 November 2007 (UTC)