Spatial distribution of natural radioactivity levels in topsoil around the high-uranium mineralization zone of Kylleng-Pyndensohiong (Mawthabah) areas, West Khasi Hills District, Meghalaya, India

摘要

A study of background radiation and the distribution of radionuclides in the environment of the proposed uranium mining sites of Kylleng-Pyndensohiong (Mawthabah) areas. West Khasi Hills District, Meghalaya, India, has been carried out with the objective of establishing a baseline radiation level of the region. Topsoil samples collected from the region are analysed for radioactivity measurements of primordial radionuclides by gamma-spectrometry technique. Direct dose measurement using a survey meter was also carried out simultaneously. Measurement carried out in the region shows that the activity concentration of ~(238)U and ~(232)Th in soil samples is found to be highest in Kylleng with respective median values of 335.3 Bq kg~(-1) and 283.9 Bq kg~(-1) followed by Syngkai with activity concentration of 285.3 Bq kg~(-1) and 257.4 Bq kg~(-1) for ~(238)U and ~(232)Th, respectively. The distribution of ~(40)K concentration in the study area is found to be in the range of 173.1-359.0 Bq kg~(-1) which is below the global and Indian average values of 420 Bq kg~(-1) and 394 Bq kg~(-1), respectively. The contribution of the primordial radionuclides to the total dose of the study area is found to be very high with a range of 136.8-334.5 nGy h~(-1) in comparison to the global as well as Indian average values.