Problems
Lake Monoun disaster
Monoun is a crater lake in northern Cameroon. High-mountain Lake Monoun is formed by the waters that fill the crater of a volcano. On the opposite slope of the mountain formation, at a distance of 95 km, there is another high-mountain lake similar to Lake Monoun, Lake Nyos. The waters of Lake Monoun contain deadly concentrations of dissolved carbon dioxide. In August 1984, there was an unexpected gas explosion over Monoun Lake. A cloud of carbon dioxide gas formed, killing 37 people and many animals. Invited the USA volcanologists H. Sigurdsson and J. Devine, having examined the lake, came to the following conclusions: Lake Monoun was formed in the crater of one of the numerous volcanoes in this region of Africa. The volcano's crater is at the bottom of the lake and its diameter is 300 m. Volcanic gases may have escaped from the crater to the lake's surface and formed a suffocating cloud over it. Chemical analysis of the water showed a very high content of bicarbonate ions and carbon dioxide in the deep parts of the lake. According to American volcanologists, the release of carbon dioxide into the atmosphere was not the result of a spontaneous volcanic release - the gas gradually accumulated at the bottom of the lake. The water in a deep lake has a clear layered structure, i.e. it is stratified: cold and dense layers at the bottom and warmer and less dense ones at the surface. When asked how the toxic cloud formed, the volcanologists answered that in their opinion, something disturbed the stratification of the lake waters and the bicarbonate-saturated deep waters rose to the surface. The gas burst to the surface and formed a cloud that was carried by the wind onto the road. Because carbon dioxide is heavier than air, the cloud began to drift across the ground near the lake. People could not see the cloud at night and in the pre-dawn twilight, but in the daytime, it became visible due to the presence of nitrogen oxides. These oxides could cause chemical burns on the bodies of dead people. Volcanologists warned Cameroonians that such catastrophic processes could occur not only in Lake Monoun but also in many other lakes in Cameroon formed in the craters of volcanoes.
Gallery
3
Timelines
2013
December 10
The degassing pipe, which had lost its ability to self-lift due to the bubbling effect in the riser as significant amounts of CO2 were removed from the lower layers, was upgraded with a small solar-powered rotary pump. However, the degassing capability is less than the natural inflow of CO2-rich water, so two more solar pumps had to be installed to avoid the long-term accumulation of higher and more dangerous levels of CO2 in the stratified water layers.
2005
July 15
The study found that the gas was not being removed from the lake fast enough to ensure that the disaster would never happen again. It was recommended that the inlet of the existing pipe be lowered to 97 m and a second pipe be added to release more carbon dioxide. Since the lake is a fishing spot for community members, it was necessary to consider the effect of a higher rate of iron intake into the upper water layer on fish life before increasing the rate of degassing.
2003
February 15
A venting pipe was inserted into the lake, to prevent the disaster from recurring. In the initial degassing phase, an 8 m fountain developed from the water tapped at 73 m depth.
1992
March 30
Preliminary tests were conducted on Monoun Lake using the gas-lift method known in the oil industry. Initially, a pump (or better, a compressed gas injection) was needed to pull the water from the bottom, but as the carbon dioxide began to escape from the solution, it created buoyancy in the water pipes, providing a self-sustaining process without the need for an external power supply. However, CO2-rich and oxygen-depleted water from depth posed a problem for the steel fittings, as corrosion occurred, forming siderite and corroding the iron.
1986
August 21
An even more deadly event occurred in Lake Nyos, killing 1,746 people and over 3,000 animals. Along with Lake Nyos and Lake Kivu, Lake Monoun is one of only three lakes in the world known to have high concentrations of gas dissolved deep below the surface and which have the right conditions for limnic eruption.
1984
August 17
After examining the corpses, a doctor and a police officer found that the mouths and noses of the dead were leaking frothy blood and mucus before they died, and the bodies were frozen in convulsions. There were first-degree chemical burns on the skin, but the clothes were intact. The grass and shrubbery between the road and the lake were scorched and the animals were dead. The doctor was the first to suggest that the motorcyclist and other locals had died of asphyxiation before dawn, trapped in a mysterious poisonous white cloud.
August 16
In the early morning hours of August 16, 1984, a group of residents found a motorcyclist dead on the road leading to Monoun Lake, who had died under mysterious circumstances. The villagers around him soon smelled a choking odor, and one of them immediately lost consciousness and died on the spot, while others tried to flee to a nearby village. However, they did not manage to do this and died as well. At that time a passing truck stopped near the lake. There were twelve people in the open body. At that moment a cloud of carbon dioxide covered them. None of them survived. A doctor and a policeman arrived on the scene. They found 37 human and numerous animal corpses on the road leading to Monoun Lake. Nearby, a smoke-like white cloud about 200 meters long hung over the road.
August 15
A limnic eruption occurred at the lake, which resulted in the release of a large amount of carbon dioxide (CO2) that killed 37 people.