Distribution of natural and artificial radioactivity concentration in soils of two districts (Ballia and Deoria) of Uttar Pradesh, India

This paper presents the activity concentrations of naturally occurring radionuclide 226Ra, 232Th, and 40K and the anthropogenic radionuclide, 137Cs in soil samples collected from Ballia and Deoria district of Uttar Pradesh, India. The mean activity concentrations of radionuclides in 43 soil samples from the two districts were measured using HPGe gamma spectrometry system. The activity level in soil samples varied from 23 to 50 Bq/kg with a mean of 30 Bq/kg for 226Ra, 30–74 Bq/kg with a mean of 47 Bq/kg for 232Th, 287–728 Bq/kg with a mean of 466 Bq/kg for 40K, and ≤0.1–1.4 Bq/kg with a mean of 0.4 Bq/kg for137Cs. The mean activity of naturally occurring 226Ra and 232Th is comparable with the international values reported by UNSCEAR while concentration of 40K is slightly higher. 137Cs activity is found to be comparable with the activities reported at other parts of India. Correlation of 226Ra and 40K activity with 232Th activity was observed as 0.85 and 0.75, respectively. A positive correlation (0.71) between 40K and 137Cs was found in the present study. The absorbed gamma dose rates in air were in the range of 44.6–98.3 nGy/h with a mean of 63.4 nGy/h, while the annual effective dose rates were observed in the range of 54.7–120.6 μSv/y with a mean of 77.8 μSv/y. The average value of radium equivalent activity in soil was 136.9 Bq/kg. This study provides a baseline data of natural radioactivity and 137Cs activity in soils of these two districts.