Radon Isotopes: Kenyan Perspective

Author: Dr. Margaret Chege, PhD | Posted on: Sat, 6th Nov 2021, 07:24 AM | All views: 271 | Unique views: 189

Key Word(s): radon | thoron | lung cancer | earthen building materials | Kenya

Majority of Kenyans are agreeable to the notion that cancer may be more prevalent today than it was a few decades ago. Whether this is the reality or the result of improved awareness, the percentage of deaths in the recent past attributed to the scourge is worrying so much so that the Kenyan government has urged people to periodically undergo cancer screening to increase chances of early detection and subsequently effective treatment. Though a step in the right direction, more needs to be done to address the cancer situation in Kenya, more so with regard to the possible causes and how best they can be addressed.

January is a radon awareness month. But what is radon and what is its significance in the matter at hand, cancer? Radon is an odourless colourless radioactive gas that forms naturally in soil, rocks and groundwater. It exists as many isotopes though Rn-222 (commonly referred to as radon) and Rn-220 (thoron) are the most significant in relation to cancer. Rn-222 and Rn-220 belong to the decay chains of U-238 and Th-232 respectively, primordial radionuclides that occur as trace elements in soil, rocks and groundwater. When soil and rock are used as building materials, and groundwater used in confined spaces, the radon isotopes may exhale to indoor air and potentially build-up to elevated levels. Prolonged exposure to elevated levels of the radon isotopes has conclusively been shown to increase the risk of lung cancer. Radon is a class A carcinogen and according to the World Health Organization the number one cause of lung cancer among non-smokers. While in Kenya lung cancer is not ranked among the most prevalent forms of cancer, documented research shows that lung cancer has on a number of cases been misdiagnosed and managed as TB , one of the leading killer disease in the country. This means that lung cancer may be more prevalent in the country than is reported.

Many countries especially in the developed world have enacted laws, regulations and guidelines regarding Rn-222 in buildings. Very little is however said about Rn-220. This is not surprising given that in many developed countries, Rn-220 is not considered a risk owing to its relatively short half-life vis-a vis the nature of buildings involved. Most buildings in the developed world are constructed using modern materials such as bricks. Being more compact, Rn-220 atoms generated within the building materials or in the underlying soil to a large extent decay before exhaling into indoor air. In Kenya on the other hand, a significant proportion of houses particularly in rural areas where majority of Kenyans live are constructed using soil as the main building material. Earthen building materials are fairly porous and are highly likely to result in considerable exhalation of both Rn-222 and Rn-220. Despite the apparent double risk, there are no existing laws or guidelines regarding indoor radon isotopes in the country.

Majority of Kenyans including policy makers and enforcers are oblivious to the fact that radon isotopes may be present in their homes in concentrations that are probably making them sick, stealthy and quietly eating their  lives away one cancerous cell at a time. But the narrative need not remain as such. It is our duty as researchers, with the goodwill of other stakeholders, to map the radon isotope levels in the country as well as educate fellow Kenyans on the dangers of radon exposure, and what can be done about it.

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