Interdependency of Soil-gas Radon-222 Concentration on Soil Porosity at different Soil-depths

Abstract

Origination of Radon-222 (222Rn) from soil and its concentration, contributing to the highest exposure of ionizing radiation to the public is natural. It is a known radioactive gas and its percentage in concentrations contributing to outdoor radon atmospheric level depends on some physical parameters of the soil. To ascertain some of its dependency on soil porosity, a radiometric survey was carried out on soil depths at varying locations and the laboratory analysis was carried out on the soil sample at each location and depth in order to determine its porosity. The measurements were done using radon detector at five (5) locations. At each location, data were collected at four (4) different soil depths of 20, 40, 60 and 100 cm respectively. In addition, soil samples at these locations and depths were taken to the laboratory for porosity test. The result showed that highest value of 222Rn concentration at 100 cm depth is 24680 ± 1960 Bqm−3 with maximum porosity level of 69.92%, while the lowest concentration at 100 cm depth is 7370 ± 1139 Bqm−3 with minimum porosity level 51.61% respectively. Inferentially, a statistical analysis carried out using Pearson correlation showed that there exist some relationships between soil-gas 222Rn concentrations measured and soil porosity determined at each measurement soil-depths. The nature of the established relationship shows interdependency of 222Rn on soil porosity at different depths, such that if the soil porosity is known, its corresponding soil-gas radon concentration can be determined.