Determination of Radium and Radon Exhalation Rate as a Function of Soil Depth of Duhok Province - Iraq

Radon is a naturally occurring radioactive gas; generated during the decay process of radium, when alpha particles start to be emitted, turning the radium into radon. The rate of radon gas that escapes from the soil into the atmosphere is called radon exhalation rate. In this study, radon, radium, and both radon surface and mass exhalation rates were measured for 40 samples of soil at four sampling depths (10, 20, 30, and 40 cm) in three districts of Duhok province. For the radon measurement, alpha-sensitive RAD7 detector was used. While radium concentration measured by well type NaI (Tl) detector. Analysis, shows radon surface exhalation rate vary from 24 ± 10.7 to 57 ± 2.5 Bq.m−2h−1 with an average value of 38.7 ± 8.9 Bq.m−2h−1. While mass exhalation rate vary from 1.2 ± 0.9 to 6.7 ± 1.6 Bq.kg−1.h−1 with an average of 4.2 Bq.kg−1.h−1. Furthermore, the results showed that radon exhalation rate and radon concentrations in soil have direct proportion to soil depths. Overall, radon concentration, radium content and both surface and mass exhalation rate in all sample points present a good correlation and less than global mean average recommendation [30].