Estimation of annual effective dose due to ingestion of natural radionuclides in foodstuffs and water at a proposed uranium mining site in India

Abstract

Purpose: To study the distribution of ²¹⁰Po, ²²⁶Ra, ²³⁰Th and U(nat) (naturally occurring radioisotopes of uranium [²³⁴U, ²³⁵U and ²³⁸U]) in food and water around the Bagjata uranium mining area in India.

Materials and methods: Radionuclides were analyzed in food samples of plant and animal origin after acid digestion. Intake and ingestion dose of the radionuclides were estimated.

Results: ²¹⁰Po, ²²⁶Ra, ²³⁰Th and U(nat) in all the dietary components ranged widely from < 0.2–36, < 0.02–1.58, < 0.01–2.8 and < 0.017–0.39 Bqkg^-1, respectively. The range of ²²⁶Ra and U(nat) in water was < 3.5–206 and < 12.6–693 mBql⁻¹, respectively. The intake of radionuclides considering food and water was calculated to be 760 BqY⁻¹ while the ingestion dose was 601 μSvY⁻¹. The estimated doses reflect the natural background dose via route of ingestion, which is below the 1 mSvY⁻¹ limit set by the International Commission on Radiological Protection (ICRP). However, the doses are more than the dose constraint of 300 μSvY⁻¹ as suggested by the ICRP for members of the public for planned disposal of long-lived radioactive waste.

Conclusion: The study confirms that current levels of radionuclides do not pose significant radiological risk to the local inhabitants, but they need close investigation in the near future.

Keywords::

• Dietary components
• natural radionuclides
• ingestion dose
• intake