## 1 Introduction  
Radiation can exist as waves or particles and is classified into ionizing and non-ionizing radiation. Ionizing radiation has sufficient energy to produce ions and exert biological effects when it interacts with matter and biological tissue. The sources of radiation are categorized into natural and artificial. Artificial sources include radiation emitted by nuclear power plants and used in medical sciences and other industries, whereas natural sources include radiation emitted by natural substances in terrestrial soil and rocks, building materials, the human body, cosmic rays, and solar radiation [1, 2]. Naturally occurring radioactive materials (NORMs) are natural substances such as rocks and minerals that may contain long-lived radioactive elements, specifically uranium (\({}^{238}\)U), thorium (\({}^{232}\)Th), potassium (\({}^{40}\)K), and their decay series. The activity concentration of NORMs, also known as source materials, significantly varies and is mostly relegated to the natural background level. Therefore, their radiological effect is regarded as insignificant. The activity concentration of radioactive material refers to activity per unit mass or volume of the material in which the radionuclides are essentially uniformly distributed [3]. Therefore, a wide range of activity concentration of NORM in different geological materials has been reported worldwide, as presented in Table 1[4, 5]. The average yearly radiation dose from naturally occurring radiation sources (NORM), including radon, is 2.4 mSv worldwide. In any big population, around 65% should receive annual doses of 1 to 3 mSv. Yearly doses of less than 1 mSv are expected in about 25% of the population, whereas annual doses of more than 3 mSv are expected in around 10% of the population [6; 7]. The greatest known level of background radiation impacting a large population occurs in India's Kerala and Madras states, where over 140,000 people receive gamma radiation doses of over 15 mSv/yr, in addition to radon doses of a comparable magnitude. Brazil and Sudan have also similar levels, with many people exposed to up to 40 mSv/yr on average. Moreover, the greatest level of natural background radiation ever recorded was 800 mSv/yr on a Brazilian beach, but no one lives there. About 200,000 people are also exposed to more than 10 mSv/yr in Ramsar County in Iran [8]. However, human activities such as industrial mining and processing could increase their activity concentrations and impose significant radiation exposures to workers that require regulatory control [9]. Phosphate, zircon and zirconia, oil and gas extraction, extraction of rare-earth elements, tantalum, mining ore other than uranium ore, combustion of coal, mining, and metal production (e.g., iron and steel, aluminum, copper, lead/zinc, ferroniobium, incorporating NORM into building materials, industrial uses of thorium, and water treatment) are industrial sectors associated with NORMs [10]. Technological advancement, market expansion, and free movement of goods have significantly triggered wide applications of source materials (NORM) concurrent with an increase in the number and types of consumer products containing NORM. NORM is used as a raw material or feedstock to produce various products and items. In addition, it is generated as waste material. NORM has also been used in some products for various applications, such as a thoriated gas mantle that emits bright light when heated and the addition of uranium compound to improve the appearance of dentures [11]. Therefore, consumer products are products or items that are actively added with natural or artificial radioactive materials and made available to the public for various consumptions without any regulatory control. Consumer products containing NORMs or source materials include bracelets, necklaces, mattresses, and latex pillows to mention a few [12; 13].