Radon-222 Concentration in Air: A Case Study of Ayeduase Township, Kumasi, Ghana

Abstract

Objective: Radon levels in structures (interior environment) were measured in many dwellings and hostels in Ayeduase Township, Ashanti Region, Ghana. The purpose of this study was to quantify radon toxicity in the Ayeduase community, which houses approximately half of the students at Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, and to determine the risk levels for individuals (categorized as infants, children, and adults) living in the community's various suburbs.
 Materials and Methods: Households in Ayeduase had an average of four people per room. The radon in air concentration was measured with a continuous radon monitor using continuous active sampling approach. Multiple measurements were taken at tight space-time intervals over a period of 24 hours. The Continuous Radon Monitor was installed in dwelling rooms in zones where the monitor could record fresh air entering the room. The yearly effective dose was computed using the Mondal 3 Software.
 Results: The continuous sample air radon concentration in Ayeduase Township was found to be in the range of 8.510 0.05607 Bq/m3 to 11.100 0.6379 Bq/m3. The manually computed effective annual dose rate for indoor air radon was 0.3494 mSv/year to 0.4558 mSv/year for babies, 0.0683 mSv/year to 0.0891 mSv/year for children, and 0.0559 mSv/year to 0.0729 mSv/year for adults. The comparative results from the Mondal 3 Software showed that the effective annual dose rate for indoor air ranged from 0.32 mSv/year to 0.37 mSv/year, with an average of 0.36 mSv/year for infants, 0.11 mSv/year to 0.14 mSv/year, with an average of 0.12 mSv/year for children, and 0.084 mSv/year to 0.097 mSv/year, with an average of 0.94 mSv/year for adults.
 Conclusion: Ayeduase's radon toxicity profile in terms of air showed distinct features. The maximum value of indoor air radon concentration level determined was lower than the global average value of 40 Bq/m3 of indoor radon concentration level and also lower than the reference level of 100 Bq/m3. In Ayeduase, the estimated average effective dosage over a year for babies, children, and adults were lower than the 1.2 mSv/year indicated by ICRP Publication 126.
 Recommendation: Radon toxicity due to water and soil sources are required to access the total toxicity levels in the township. Reliable evaluation of the potential for human exposure to radon depends in part on the reliability of supporting analytical data from environmental samples and biological specimens is highly recommended, as well as, concentrations of radon in unpolluted atmospheres and in pristine surface waters are typically within the limits of current analytical methods.