Measurement of natural radioactivity and radiation hazard assessment in the soil samples of Visakhapatnam, Andhra Pradesh, India

The present work aims to measure and estimate radioactivity and hazardous radiation indices of the soil. Soil samples were collected from various locations in the Visakhapatnam district in Andhra Pradesh, India. The measurement of specific activity of 226Ra, 232Th, and 40K radionuclides is carried out with the help of HP-Ge based gamma spectrometer system. Activity concentration of radionuclides in the samples 226Ra, 232Th and 40K ranged from 20 +/- 2 to 91 +/- 2 Bq.kg-1, 45 +/- 3 to 365 +/- 3 Bq.kg-1, and 400 +/- 9 to 607 +/- 8 Bq.kg-1, and the respective mean values are 53.36 Bq.kg-1, 203.74 Bq.kg-1 and 479.19 Bq.kg-1. The measured mean value of the absorbed dose rate is 171.41 nGy.h-1, which was beyond the worldwide mean outdoor value of 60 nGy.h-1. Thus, the annual effective dose estimated from the above value is 1.04 mSv.y-1. The correlation was done among the measured 226Ra, 232Th, and 40K activity concentrations. The estimated radium equivalent dose is 381.60Bq.kg-1. The estimated health hazard index and annual effective dose rates of dwellers of Visakhapatnam were studied and compared to Indian average values. The study will help to generate the baseline data for assessing hazard indices to the public and geological mapping of natural radiation in India.