External dose assessment of NORM added consumer products using Geant4 Monte Carlo simulations

Abstract

Radioactive consumer products (RCP) are widely marketed for everyday use. The study herein was conducted on 21 commercially available RCP, including bio-glass discs, energy cards, scalar energy products, and anti-radiation stickers, all purposefully designed to contain naturally occurring radioactive material (NORM). This study investigates the dose influence of such consumer products which acts as external radiation sources that may be in contact with human body. The goal of this study is to assess the potential risk of using NORM-added consumer products, the presence of such products in the living environment unnecessarily exposing members of the public to radiation. A Pb-shielded high purity Ge (HPGe) spectrometer was used to perform the analysis of samples radioactivity levels. Simulations were performed using Geant4 Monte Carlo (GMC) simulations to estimate the equivalent organ doses and annual effective dose (AED) in the use of such products. The total activity in such radioactive consumer products ranges from 2.0 ± 0.1 to 7413 ± 576 Bq, 1.9 ± 0.8 to 1168 ± 131 Bq, and 21 ± 5–574 ± 103 Bq, for 232Th, 238U, and 4 K, respectively. It was found that RCP contains monazite, giving a relatively high concentration of uranium and thorium. The radiological risk posed by the use of such items as healthcare products is assessed, with the daily external exposure doses of particular concern. Dose assessments of the organ equivalent and average effective doses were performed by measuring the activity of 232Th, 238U, and 4 K using the aforementioned products for various exposure duration scenarios. Accordingly, sample A13 a bio-glass disc offered concentrations with mean percentages of 1.29 ± 0.003% and 0.043 ± 0.0003% for Th and U, respectively, giving rise to estimate the greatest annual effective dose exposure of 2.54 mSv among samples, considerably in excess of the public dose limit of 1 mSv y-1.