ACTIVITY CONCENTRATION OF 137Cs AND NATURALLY OCCURRING RADIONUCLIDES IN SOIL AND WATER SITE OF GOAINGHAT AND JAINTAPUR AREA OF SYLHET, BANGLADESH

Abstract

The concentration of anthropogenic 137Cs and naturally occurring 226Ra, 232Th and 40K radionuclides were measured in the undisturbed soil at 0-5 cm depth and water collected from the natural reservoir in the Terrene of Goainghat and Jaintapur area of Sylhet district of Bangladesh near the Indian border area by gamma ray spectrometry, with the aim of evaluating the environmental radiation hazard. The activity concentration of 137Cs was observed in all the soil and water samples, ranging from 5.22 4 - 31.74 and 1.1 - 2.2 Bqkg-1respectively. The activity level of 137Cs in this area was lower than that of Cox’ s Bazar (27.38-45.51 Bq kg-1) and higher than that of Chittagong (2.66 Bq kg-1). Values of the natural radionuclides present in the samples were greatly influenced by the geomorphological conditions in the area. The average activity of 226Ra, 232Th and 40K in soil were 57.5, 167.6 and 1202.3 Bq kg-1 respectively. The average activities of 232Th and 40K in the soil samples of this area were higher than the world average value of 25.0 and 350.0 Bq kg-1 respectively. The average γ-ray dose rate due to naturally occurring radionuclides in soil samples was found 180 nGy h-1.