The geogenic influence on 220rn activity concentration in soil gas of Johor state, Malaysia

Abstract

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