Measurement of Interior and Exterior Gamma Dose Rate in Air in Mandya City, Karnataka

Human exposure to radioactive disintegration by radionuclides present in the lithosphere is unavoidable. A built-up environment makes effective use of building materials which contains natural radioactive elements. The changes of radionulides in the constructed environment are to be noticed. In this study, measurement of interior and exterior Gamma-ray dose rate has been carried out from 25 locations of Mandya city for the radiometric, geophysical and environmental surveys. The measurement has been done using a lightweight portable radiation dosimeter ER-709. The readings were recorded at about 1m from the ground surface. The finding indicates that, the absorbed gamma dose rate in interior and exterior air varied by 66.12x10-9Gyh-1 to 131.89x10-9Gyh-1 with average geometrical value of 95.11x10-9 Gyh-1 and 48.72x10-9 Gyh-1 to 77.60x10-9 Gyh-1 with average geometrical value of 58.45x10-9 Gyh-1. The yearly effective dose rate varies by 0.32x10-3 Svy-1 to 0.65x10-3 Svy-1 with average geometric value of 0.47x10-3 Svy-1 and 0.06x10-3 Svy-1 to 0.10x10-3 Svy-1 with average geometric value of 0.07x10-3 Svy-1. This is evidently upper than the worldwide average yearly effective dose.