Measurement of radon activity in soil samples of some selected towns across the Lake Bosumtwi basin, Ghana

The potential hazard of radiation exposures to radon and its daughter products from natural background has been highlighted in the world of scientific press and has become a matter of concern. The Lake Bosumtwi is one of the interesting research areas in Ghana due to the geological nature of the area, and also of its great importance based on the different uses of the lake and its surroundings. There is therefore the need to investigate the levels of radon activity in soil samples around Lake Bosumtwi basin as part of the national effort to establish base line data of radon levels in Ghana. The study was conducted to measure the levels of radon activity in soil samples within the lake Bosumtwi basin. Samples were collected from five selected villages around the lake at depths of 10 cm and 20 cm. The Role's Method was employed and measurements were made using specific cell counters. The measurements were performed with a Radon Degassing Unit (RDU-200) and a Radon Detector Analyzer (RDA-200). The calculated cell efficiency was obtained as 0.55 cpm/dpm. The average radon concentrations at the depths were calculated and the maximum concentration for the 10 cm depth was obtained from Tepaso with a value of 4801.71±678 Bq/m3 and the minimum concentration was obtained from Abonu with a value of 3887.07±815 Bq/m3. The maximum and minimum concentrations for the 20 cm depth were obtained from Tepaso and Kusuasi with values of 5602.10±943 Bq/m3 and 4877.93±404 Bq/m3 respectively. The overall average radon concentration obtained was 4745.31±559 Bq/m3. The results obtained were high when compared with results from previous studies. The values obtained are less than the World Health Organization's acceptable level for outdoor radon activity which is quoted as 9250 Bq/m3 and hence the public are not exposed to any significant radiological health hazard in these areas. The radon concentration at the depth of 20 cm was found to be higher than the 10 cm depth and this shows that radon gas in soil increases with depth. The values obtained are less than the World Health Organization's acceptable level for outdoor radon activity and life activities would not be at risk in these areas. (author)