Terrestrial background radiation studies in South Konkan, Maharashtra, India

Background: The natural radionuclides are always present in soil and care needs to be taken to minimize the radiation dose to humans. These radionuclides are mostly gamma ray emitting radionuclides which contribute to the radiation dose in long term behavior of radionuclides in soil. Health hazards associated with natural radioactivity are of great concern and it is necessary to assess risk due to them. The most common radionuclides found are 238U, 232Th and 40K. Materials and Methods: The activity concentration of natural radionuclides in the soil samples collected from South Konkan region of Maharashtra, India were analyzed using HPGe based gamma spectrometry. Results: The activity concentrations from the selected villages are found to be ranging from 24.78 ± 0.14 to 76.38 ± 0.31Bq kg-1 for 238U, 30.08 ± 0.14 to 96.18 ± 31Bq kg-1 for 232Th and 105.34 ± 0.24Bq kg-1 to 432.51 ± 0.48Bq kg-1 for 40K. The average absorbed dose rate in air was calculated as 66.89nGy h-1.The annual effective dose rates were varied from 0.27mSv y-1 to 0.85mSv y-1 with an average of 0.49mSv y-1. The mean radium equivalent activity value for soil samples of South Konkan was 144.84 Bq kg-1 which is lower than 370Bqkg-1 of world average. Conclusion: It is observed that the study area is free from hazards of Radium and its progeny nuclides like Radon. The external hazard index for all soil samples from South Konkan was lower than unity denoting that the villages from this study area are safe for human health.