A COMPARATIVE STUDY OF THE INDOOR RADON LEVEL WITH THE RADON EXHALATION RATE FROM SOIL IN ALEXANDRIA CITY

摘要

The assessment of the radiological risk related to the inhalation of radon and radon its progeny is based mainly on the integrated measurement of radon in both indoor and outdoor environments. The exhalation of radon from the earth's crust and building materials forms the main source of radon in the indoor environment. This study has been undertaken for the purpose of health risk assessment. In this comparative study, the indoor radon level, radium content, radon exhalation rate and concentration of soil radon are measured using the Can Technique. Soil samples were collected simultaneously from different geological formations of the same area for laboratory measurement of the radon exhalation rate. The radon exhalation rate was measured in the laboratory using LR-115 type Ⅱ plastic track detectors. The indoor radon concentrations in this study area were found to vary from 44 ± 9 to 132 ± 31 Bq m~(-3) with an average of 72 ± 29 Bq m~(-3). The seasonal variations of the indoor radon reveal the maximum values in the winter and in summer in different dwellings of Alexandria city. The annual effective dose varies from 0.75 to 2.2 mSv with an average value of 1.34 mSv. The radon exhalation rate was found to vary in the ranges 8.31-233.70×10~(-3) Bq kg~(-1) h~(-1), 0.48-15.37 Bq m~(-2) h~(-1) with an average 47.97×10~(-3) Bq kg~(-1) h~(-1), (3.14 Bq m~(-2) h~(-1)). The radium content in soil varies from 3.14 to 39.60 Bq kg~(-1) with an average of 11.55 Bq kg~(-1). The significance of this study is discussed in details from the point of view of radiation protection.