DISTRIBUTION OF GAMMA RADIATION DOSE RATE AND ACTIVITY CONCENTRATION IN SOIL RELATED WITH NATURAL RADIONUCLIDES ON TAIWAN MAIN ISLAND

Abstract

Abstract To enable precise assessment of health impacts following a nuclear power plant accident, extensive and detailed data on environmental radiation levels are needed. This study was undertaken to investigate the air and the soil radiation levels using a car-borne survey on the main island of Taiwan where no extensive environmental radiation distribution survey had been conducted before. The mean air absorbed dose rate on this island was 57 ± 10 nGy h−1. The measured dose rate distribution varied depending on the geology of the soils, and ranged from 22 to 113 nGy h−1. The mean radiation level in soil was 539 ± 124 Bq kg−1 for 40K, 23 ± 8 Bq kg−1 for 238U and 41 ± 22 Bq kg−1 for 232Th. The air absorbed dose rate (58 nGy h−1) calculated from these data of mean radiation level in soil was comparable to that determined by the car-borne survey method. Thus, this study yielded detailed data on air absorbed dose rate depending primarily on the geology of the soils on the main island of Taiwan.