Dunkonaa, another Nyos in the making
“On the morning of August 22, 1986, a man hopped onto his bicycle and began riding from Wum, a village in Cameroun, towards the village of Nyos.
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On the way, he noticed an antelope lying dead next to the road. Why let it go to waste? The man tied the antelope onto his bicycle and continued . A short distance later, he noticed two dead rats, and further on, a dead dog and other dead animals.
Soon the man came upon a group of huts. He decided to see if anyone there knew what had happened to the animals. But as he walked up to the huts, he was stunned to see dead bodies strewn everywhere. He didn't find a single person still alive - everyone in the huts was dead. The man threw down his bicycle and ran…”
The above chilling narrative was extracted from Uncle John’s Bathroom Reader: The World of Odd. It gives a graphic account of the horrific aftermath of a disaster that claimed the lives of approximately 1,800 human beings and over 37,000 cattle.
They were overwhelmed and suffocated to death by an avalanche of carbon dioxide that burst from the depth of Lake Nyos and wreaked havoc within 18 kilometre radius of the lake.
Before the disaster, it had been known for ages that Lakes Nyos and Manoum in Cameroun and Lake Kivu on the Rwandan border, which are deep crater lakes, contain very high concentration of carbon dioxide and methane. These gases are highly concentrated at the bottom of the lakes.
In the living memory of the people, these gases had never caused any harm to human beings and animals in the vicinity of the lakes.
Nevertheless around Nyos, local folklore claims that in the middle of one night in a distant millennium, some unseen dangerous visitors came out of the lake to kill all life-forms.
The story in the Daily Graphic of Thursday of June 13, 2013 titled, “Killer gas found at Dunkonaa” conjures a disaster waiting to happen in the future.
The signs of a looming disaster have been there for centuries in the form of a perpetual smoke which has been identified as radon.
Literature on radon is provided in any good Advanced Chemistry Textbook and the International Atomic Commission (IAC) has been concerned about its effect on human health.
The earth’s crust, mainly rock, contains many elements and their degradation products termed “Naturally occurring Radioactive Material Substances (NORMS)” which are hazardous to human life when they leak into the environment. Some forms of Carbon, Uranium, Phosphates and Radium are examples.
Radium-226 is one of the decay products of uranium-238, which is widespread in most rocks and soils. When this radium decays, it produces radon-222, an inert gas with a half-life of almost four days.It further decays to a number of compounds termed alpha-products.
According to IAC, because radon is so short-lived, and alpha-decays to a number of daughter products which are solid, there is a high probability of its decay when breathed in, or when the daughter products in dust are breathed in. Alpha particles in the lung are hazardous.
Radon exposure is affected by factors such as local geography, building construction and lifestyle.
For example, an earthquake or volcanic eruption may cause a sudden surge in the Dunkonaa environment above the 20,000Bq/m3 reported.
Also, use of certain sands for building dwelling houses or ignorant use of decorative stones of high concentration of radio active metals can cause high radon concentration.
Indoor radon levels vary from one continent to another. The average actionable level set by Environmental Protection Agency (EPA) in USA is 150 Bq/m3 but levels up to 100,000 Bq/m3 have been reported in some US homes.
Levels in Scandinavian homes are about double the US average, and those in Australian homes average one fifth of those in USA.
The high Dunkonaa outdoor level calls for immediate action to avoid a repetition of Nyos.
Piping and venting which is normally recommended does not eliminate the hazardous components of its decay because they are solids and are bound to precipitate and get buried into the soil.
The regulations for choice of site by developers of human settlements and the safety standards for building materials are addressed in the National Building Regulations, LI 1630 (1996) and the Local Government Act, Act 462 (1993).
They spell out the requirements including geo-technical investigations at the planning stage and are meant to reveal any condition such as Dunkonaa’s.
In this regard, the district and municipal assemblies have the power to deny issuance of building permits or demolish structures constructed with hazardous materials or built on geo-technically risky areas. Dunkonaa cries for action from the regulators and the Ghana Institute of Architects.
There are many sources of hazards. A hazard could be that over-powering stench emanating from a well that kills any human that enters it in a Brong Ahafo village.
It could be that unexplained agent that produces unbearable heat at random in a house at Lartebiokorshie. Or, it could be the patch of soil in your garden enriched by NPK fertiliser that produces nkontomire of funny taste. Constant smoke from the ground?
There is always a tell-tale sign that something is not right. It might not kill on the scale of Nyos but the cumulative effects on the human body could be devastating.
Article by Joe Frazier
Writer's email: [email protected]