The geogenic influence on ~(220)Rn activity concentration in soil gas of Johor state, Malaysia

摘要

The contribution of thoron (Rn-220) to natural radiation exposure is commonly neglected. However, dry porous surfaces with relatively high Th-232 content can pose a thoron radiation hazard to the environment. Therefore, this research aims at establishing a baseline data for Rn-220 activity concentration in soil gas and categorise the measured data based on the geology of Johor state, Malaysia. The activity concentration of Rn-220 in soil gas was measured using RAD7 alpha detector. The measured Rn-220 activity concentration data varied from MDA to 159.07 +/- 3.40 Bq/L. Kruskal-Wallis test on the Rn-220 concentration data among the geological formations and soil types reveals a statistically significant result, p=0.006 and p=0.005, respectively. An isoconcentration map of Rn-220 in soil gas is created. The map indicates higher concentration values generally characterised the Districts of Muar and Ledang.