Soil gas radon, indoor radon and its diurnal variation in the northern region of Cameroon.

Abstract

Soil gas radon and indoor radon measurements have been carried out in Mayo-Louti and Benoué Divisions in northern Cameroon. Concentrations of radon in soil have been measured using Markus 10 at the depth of about 1 m. Radon concentration in soil varies from 0.9 to 13.8 kBq m^-3 with a mean value of 4.6 kBq m^-3. Average daily indoor radon concentrations measured with RadonEye+² detectors vary from 7 to 60 Bq m^-3 with an average of 17 Bq m^-3. Indoor radon concentrations measured with passive RADTRAK detectors range between 15 and 104 Bq m^-3 with a geometric value of 38 Bq m^-3 and a geometric standard deviation of 1.5. This geometric value is lower than the value of 30 Bq m^-3 given by UNSCEAR. Indoor radon inhalation dose ranges between 0.28 and 1.97 mSv a^-1 with geometric value of 0.72 mSv a^-1 (at 0.03 standard deviation). Outdoor radon inhalation ranges between 0.02 and 0.26 mSv a^-1 with a mean value of 0.09 mSv a^-1. The total annual effective dose due to indoor and outdoor radon exposure for this study area is 0.81 mSv a^-1, less than 1.15 mSv a^-1 the world average value given by UNSCEAR. There is no significant radiological risk for the inhabitants.