Radioactivity in decorative building materials: insights from Johor, Malaysia

Abstract

The appearance and atmosphere of a building can be enhanced by the aesthetic appeal of its decoration. Building materials used for construction purposes, such as rocks, stones, and dyes, are typically of natural origin and may contain naturally occurring radioactive materials (NORM) within their elements. Hence, evaluating the potential risk of radiation exposure to occupants is crucial to ensure that it falls within acceptable levels. In this regard, a study was conducted in Johor, Malaysia using gamma spectroscopy to measure the natural radioactivity of 18 indoor decorative stones, including granite, porcelain, marble, and quartz. The observed radioactivity concentration ranged from 0.23 to 317.25 Bq kg−1, 1.35–116.81 Bq kg−1 and 0.74–2712.55 Bq kg−1 for 238U, 232Th and 4 K, respectively. Various radiological quantities were calculated and compared with recommended values established by the international commission bodies and findings from previous research conducted in other countries. Furthermore, the study employed Virtual Monte Carlo software (VMC-DC) to estimate dose equivalents for all samples through simulation. The highest dose rate was observed in sample G6 at 0.0852 μSv h−1, and with an exposure time of 19 h per day, the annual effective dose was calculated to be 0.5906 mSv y−1, which is well below the maximum dose limit of 1 mSv y−1 as recommended by IAEA. It can be concluded that the indoor decorative stones examined in Johor, Malaysia are safe for use in buildings from a radiological perspective, as they do not pose any significant radiological hazards.