. The estimated outdoor annual effective dose varied between 0.22 and 1.79 mSv/year with a mean value of 0.55 mSv/year, which is higher than the world average for outdoor annual effective dose (0.07 mSv/year). The external hazard indices for the samples varied from 0.17 to 1.43 with the average value of 0.44, which is less than the unity. The average value of radium equivalent activity was estimated and found to be 161.40 BqKg -1 which is less than the acceptable limit of world average value of 370 BqKg -1 .

The radioactivity concentrations of 24 samples of soil and sand sediments from Cox's Bazar were determined using high purity germanium detector.