Abstract:
The main source of natural internal irradiation of man is radon and its decay products. In this study, the radon concentration levels in selected homes in Aburi of the Akuapim North Municipal Assembly in Eastern Region, Ghana were estimated using time-integrated passive radon detector; LR-115 Type II solid state nuclear track detector (SSNTD) technique. The primary objective ofthe study was to measure radon levels in 30 selected homes in the Aburi municipality and determine the uncertainties associated with the measured radon concentrations in order to take a decision on remedial actions to be adopted in case of any abnormalityusing simple qualitative decision analysis method. Measurements were carried out from December, 2013 to March, 2014. After each month of exposure for a period of three months, the detectors were subjected to chemical etching in a 2.5M analytical grade of sodium hydroxide solution at (60 ± 1)oC, for 90mins in a constant temperature water bath to enlarge the latent tracks produced by alpha particles from the decay of radon. The etched tracks were magnified using the microfiche reader and counted with a tally counter. The results obtained from the study revealed that concentration of radon in most of the selected homes in the Aburi municipality is low and it is within the internationally accepted action level of 100Bqm-3 set by WHO (2009). The analysis of the results established that the average radon concentrations vary in the range 23.72-92.24Bqm-3, 19.07- 124.36 Bqm-3 and 31.63-123.87 Bqm-3 for month 1, month 2 and month 3 respectively. The corresponding mean values are 46.77, 45.92 and 56.66 Bqm-3 respectively with standard deviations of ±2.18, ±2.38 and ±2.76. These gave a mean of 49.78 ±12.50 for the three months. Two (2) of the rooms investigated had values above 20 % of the remedial action level of 100Bqm-3 in two of the months but with their average values slightly lower than the remedial action level. From the uncertainty evaluation and decision analysis it is clear that the rather low
values of radonindicates that there is no need for any remediation action in almost all the rooms with the exception of room A26 and perhaps A29, which may require a relatively inexpensive mitigation action by improving ventilation in theserooms. The radon activity has not only been found to vary with the construction mode of the houses but also with the ventilation conditions, the climatic conditions, the geology and topography among others.
