Effect of soil and sand moisture content on radon diffusion using plastic track etched detector

Radon diffusion from soil and sand has been studied as a function of moisture content of soil and sand using plastic track etched detectors (LR-115 type II). It is observed that in soil and sand as the percentage of water is increased from dry state to 21% and 26%, respectively, a slow decrease in radon concentration (295 to 250 and 315 to 240 Bq/1) takes place; thereafter it reduces sharply to 27 and 50 Bq/1 when soil and sand become saturated (25% and 40% water). The water-saturated soil and sand give the lowest concentration because of the much lower diffusion coefficient of radon through water.