226Ra, 232Th and 40K analysis in soil samples from some areas of Punjab and Himachal Pradesh, India using gamma ray spectrometry

The activity concentrations and the gamma-absorbed dose rates of the terrestrial naturally occurring radio nuclides viz. Ra-226, Th-232 and K-40 were determined in soil samples collected from some areas of Punjab and Himachal Pradesh, using gamma ray spectrometry. The soil activity ranges from 18.22 to 90.30 Bq kg(-1) for Ra-226, 34.80 to 124.68 Bq kg(-1) for Th-232 and 80.42 to 181.41 Bq kg(-1) for K-40 with mean values of 57, 87 and 143 Bq kg(-1), respectively. The concentrations of these radionuclides are compared with the available data from other countries. The measured activity concentration of Ra-226 and Th-232 in soil is higher and for K-40 is lower than the world average. Radium equivalent activities are calculated for the analyzed samples to assess the radiation hazards arising due to the use of these soil samples in the construction of dwellings. All the soil samples have radium equivalent activities lower than the limit set in the OECD report (370 Bq kg(-1)). The overall mean outdoor terrestrial gamma dose rate is 86.54 nGy h(-1) and the corresponding outdoor annual effective dose is 0.11 mSv. The activity concentration of U-238 has also been determined using fission track technique and the values range from 1.18 to 5.12 ppm with mean value of 2.13 ppm. The content of radioactive elements in the soil of Palmpur area is found to be more compared with the samples from the other study areas of Punjab and Himachal Pradesh. (C) 2004 Elsevier Ltd. All rights reserved.