Radiation distribution and associated hazard risks due to naturally occurring radioactive minerals at workplace

Saha Tumpa 1*, Rajib Mohammad 1,2, Debnath Premanondo 3 and Rasul Md. Golam 1

1 Institute of Nuclear Minerals, Atomic Energy Research Establishment, Bangladesh Atomic Energy Commission, Ganakbari, Savar, Dhaka-1349, Bangladesh.

2 Department of Environmental Science and Disaster Management, Daffodil International University, Daffodil Smart City, Ashulia, Savar, Dhaka-1341, Bangladesh.

3 Remote Sensing Division, Center for Environmental and Geographic Information Services, Dhaka-1212, Bangladesh.

✉ *Corresponding author: taposhi.tumpa@gmail.com

Research article first published online: 08 Sept 2025 | Open Access

DOI https://doi.org/10.18801/jstei.140126.88

Abstract

The study investigates radioactivity concentration and its associated health hazard indices as a part of workplace radiation monitoring. Institute of Nuclear Minerals (INM) deals with naturally occurring radioactive minerals (NORMs) and uses nuclear technology for the exploration of mineral resources for which elevated radioactivity is found at the workplace. A total of 34 measurements were conducted to identify those anomalous radioactive zones in and around INM. The measured radioactivity concentration of 238U, 232Th, and 40K were in the range of 52.49-170.31 bq/kg, 36.05-72.88 bq/kg and 291-697.99 bq/kg, respectively and corresponding dose rates were 0.09-0.21 μSv/h. The radioactivity levels found that its average concentration in the investigated area surpassed the world average values for each of uranium, thorium, and potassium. Concerning radiological risk measurements, radium equivalent activity index (Raeq), external hazard index (Hex), and internal hazard index (Hin) were generally below the world accepted limits, except for one case. Nevertheless, the recorded absorbed dose rate (DR) and the average annual effective dose equivalent (AEDE) from all devices exceeded world standards. The radioactivity distribution showed higher dose rates resulting from higher radionuclide presence in various types of samples collected from different geologically potential areas. Increased dose rates evident at the northern side of the building is probably from the combined effect of various radioactive samples, uncovered old mosaic floor and radon in air concentration in old storage.

Keywords

Spatial distribution, Occupational worker, Radiation exposure, NORMs, Annual effective dose, Gamma, survey meters, ALARA

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