Assessment of activity and effective dose rate of222Rn in several dwellings in Bamako, Mali

We used CR-39 detectors to evaluate radon activity concentrations in several habitations of Bamako. The calibration factor of the dosimeters was determined experimentally with known radon activity concentrations inside a radon chamber, and was also simulated with MCNPX. The experimental and simulated calibration factors are, respectively, kexp = 0.119 ± 0.017 and ksim = 0.126 ± 0.007 tr.cm-2.d-1.Bq-1.m3. Indoor radon activity concentrations in Bamako were found to vary from 70 ± 18 to 154 ± 35 Bq.m-3. No significant differences were observed in the mean radon activity concentrations compared with five other African countries. Taking into account an occupancy factor of 0.8 and an equilibrium factor of 0.4 for radon indoors, the effective dose rate ranges from 1.77 to 2.35 mSv.y-1. In all cases the radon activity concentrations measured were below the action limits recommended by the International Commission on Radiological Protection (ICRP) Statement on Radon.