Radiation safety assessment of Malaysian consumer products with possible radioactive elements

• Main Author: Hassan, Halmat Jalal
• Format: Thesis
• Language: English
• Published: 2022
• Subjects: QC Physics
• Online Access: http://eprints.utm.my/id/eprint/101706/1/HalmatJalalHassanPFS2022.pdf; http://eprints.utm.my/id/eprint/101706/; http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:149109

A wide range of consumer products containing radioactive materials are marketed for everyday use. Users are generally unaware of the presence of radioactivity in these products and the potential harm due to radiation exposures. Consumer products (CPs) containing naturally occurring radioactive material (NORM) continue to be sold in local and online markets in Malaysia, including lantern mantle, jewellery accessories, negative ion, healthcare, tourmaline products, tungsten welding rods, and gaseous tritium light sources (GTLS). A hyper-pure germanium detector was used to perform the gamma spectroscopy analysis and investigation of the spatial distribution of long-lived radionuclides (238U, 232Th, and 40K) in these consumer products. The samples were prepared for elemental analyses which provide the composition of radioactive elements as well as rare earth elements (REEs) using X-Ray Fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES), and X-Ray photoelectron spectroscopy (XPS). Monte Carlo (MC) simulations were performed to calculate the dose conversion factors (DCFs) that are used in estimating the equivalent organ doses and the annual effective dose (AED) from usage of these consumer products. Different scenarios in terms of use durations and consumer product placements on the human phantom were studied. The lantern mantle in sample M5 recorded the highest thorium activity at 12517 ± 1173 kBq, exceeding the exemption limit for thorium of 10 kBq adopted by the International Atomic Energy Agency (IAEA). Among the jewellery accessories products, glass pendant sample, GP11 recorded the highest activity at 6969 ± 483 and 687 ± 130 Bq of 232Th and 40K, respectively, while sample A14 (pendant pen shape) recorded the highest level of 238U at 1168 ± 131 Bq. The annual effective dose for GP11 can reach up to 3 mSv y-1, exceeding the public dose limit of 1 mSv y-1 recommended by the International Commission on Radiological Protection (ICRP). The glass disc coded A13 was estimated to give an AED of up to 2.5 mSv y-1 whereas the AED received from undergarment usage can be up to 2 mSv y-1. However, the estimation of AED from the use of tourmaline products ranged between 0.8 µSv y-1 to 640 µSv y-1. Currently, the investigated consumer products are available for purchase without information concerning their radioactivity content. Additionally, there is no impediment to the purchase of these products in Malaysia. There is a need to set specific criteria for the approval of these consumer products before their release for purchase and use by members of the public.