Naturally Occurring Radioactive Materials Research Articles

Background gamma radiation and associated health implications for Ifo-Dagbolu-Ajakaye, Ogun state

The need for safe habitat in view of the demands of Sustainable Development Goal 3 - sound health and wellbeing, calls for attention to ascertain the level of exposure of gamma radiation to man and the environment. Keeping the levels of specific activities of naturally occurring radionuclides (NORs) within safety limits will help in attaining the Sustainable Development Goal 3-“Good Health and Well-being”. Background gamma dose rates and activity concentrations of NORs: 40K, 238U, and 232Th in an agrarian settlement, Ifo-Dagbolu-Ajakaye, Ogun State, Southwest Nigeria, was surveyed using an Ultra-rugged Super-spec RS-125 gamma spectrometer. The respective mean values of the background gamma dose rates and specific activities of 40K, 238U, and 232Th were 14.96 nGyh−1; 31.60, 16.54 and 12.91 Bqkg−1. The values of the specific activities were used to estimate the associated radiological health parameters and the values obtained were lower when compared with their corresponding United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) permissible limits. Hence the levels of the activity concentrations of the studied NORs do not present health hazards to the dwellers in the examined station.

Radiometric examination of fertilizers and assessment of their health hazards, commonly used in Pakistan

The radioactivity concentrations of Naturally Occurring Radioactive Materials (NORM) i.e., 226Ra, 232Th, and 4 K in various chemical fertilizers being used in the agricultural soil of Pakistan were determined utilizing gamma spectrometry by employing a High Purity Germanium (HPGe) detector. The radioactivity concentrations of 226Ra, 232Th, and 4 K extended from 2.58 ± 0.8–265.7 ± 8.8 Bq kg−1, 1.53 ± 0.14–76.6 ± 1.07 Bq kg−1 and 36.5 ± 1.34–15606.7 ± 30.2 Bq kg−1 respectively. The radiological hazard parameters such as internal and external indices and annual effective dose rates were calculated, while excessive lifetime cancer risk factors for the indoor and outdoor areas were found in the range from 0.3 × 10−3 to 10.723 × 10−3 and 0.03 × 10−3 to 2.7948 × 10−3 of most fertilizers, however, some values were slightly higher than the UNSCEAR (The United Nations Scientific Committee on the Effects of Atomic Radiation) recommended values for potash-containing fertilizers such as MOP (Muriate of Potash).

Characterization of NORM‐type scales from the oil industry through spectrometry techniques and multivariate analysis

AbstractThe oil industries have as main problem in their activities of formation of scales containing material of the naturally occurring radioactive material (NORM) type on the internal walls of pipes and in some equipment that make up the process lines plant. This NORM can contribute to the exposure of workers during routine activities, either through external exposure, or internal, through inhalation or ingestion. Considering the concern with occupational exposure, environmental impacts and the plant's production capacity, resulting from the formation of the scales, this work characterized samples of scale by means of techniques of x‐ray fluorescence (XRF), x‐ray diffraction (XRD) and high‐resolution gamma spectrometry. The XRF showed concentrations of P, S, Cl, Ca, Mn, Fe, Sr, and Ba as the main elements of the sample; the XRD showed calcite and barite as predominant composition; in the gamma analysis, the concentrations of the activities varied from 104.6 to 1112.6 Bq kg−1 for 226Ra and from 16.4 to 385.2 Bq kg−1 for 228Ra, within the limits set by the International Atomic Energy Agency. The indices radium equivalent activity, absorbed dose rate and annual effective dose indices varied from 128.4 to 1665.9 Bq kg1; 58.4 to 748.0 nGy h−1 and 0.072 to 0.918 mSv y−1, respectively. Only the effective dose values ​​were within the limits established by United Nations Scientific Committee on the Effects of Atomic Radiation, reinforcing the need for continuous monitoring on the platforms and the importance of keeping the radiological protection plan up to date, since the mobilization of NORM increases proportionally with the useful life of the production wells, thus increasing exposure indices.

Alpha radiation from polymetallic nodules and potential health risks from deep-sea mining

In search for critical elements, polymetallic nodules at the deep abyssal seafloor are targeted for mining operations. Nodules efficiently scavenge and retain several naturally occurring uranium-series radioisotopes, which predominantly emit alpha radiation during decay. Here, we present new data on the activity concentrations of thorium-230, radium-226, and protactinium-231, as well as on the release of radon-222 in and from nodules from the NE Pacific Ocean. In line with abundantly published data from historic studies, we demonstrate that the activity concentrations for several alpha emitters are often higher than 5 Bq g−1 at the surface of the nodules. These observed values can exceed current exemption levels by up to a factor of 1000, and even entire nodules commonly exceed these limits. Exemption levels are in place for naturally occurring radioactive materials (NORM) such as ores and slags, to protect the public and to ensure occupational health and radiation safety. In this context, we discuss three ways of radiation exposure from nodules, including the inhalation or ingestion of nodule fines, the inhalation of radon gas in enclosed spaces and the potential concentration of some radioisotopes during nodule processing. Seen in this light, inappropriate handling of polymetallic nodules poses serious health risks.

Radioactivity in decorative building materials: Insights from Johor, Malaysia

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.

Tools for harmonized data collection at exposure situations with naturally occurring radioactive materials (NORM)

Naturally occurring radioactive materials (NORM) contribute to the dose arising from radiation exposure for workers, public and non-human biota in different working and environmental conditions. Within the EURATOM Horizon 2020 RadoNorm project, work is ongoing to identify NORM exposure situations and scenarios in European countries and to collect qualitative and quantitative data of relevance for radiation protection. The data obtained will contribute to improved understanding of the extent of activities involving NORM, radionuclide behaviours and the associated radiation exposure, and will provide an insight into related scientific, practical and regulatory challenges.The development of a tiered methodology for identification of NORM exposure situations and complementary tools to support uniform data collection were the first activities in the mentioned project NORM work. While NORM identification methodology is given in Michalik et al., 2023, in this paper, the main details of tools for NORM data collection are presented and they are made publicly available.The tools are a series of NORM registers in Microsoft Excel form, that have been comprehensively designed to help (a) identify the main NORM issues of radiation protection concern at given exposure situations, (b) gain an overview of materials involved (i.e., raw materials, products, by-products, residues, effluents), c) collect qualitative and quantitative data on NORM, and (d) characterise multiple hazards exposure scenarios and make further steps towards development of an integrated risk and exposure dose assessment for workers, public and non-human biota.Furthermore, the NORM registers ensure standardised and unified characterisation of NORM situations in a manner that supports and complements the effective management and regulatory control of NORM processes, products and wastes, and related exposures to natural radiation worldwide.

Evaluation of transfer factors of 226Ra, 232Th, and 40K radionuclides from soil to grass and mango in the northern region of Bangladesh

Bangladesh is a rapidly developing country, which is vulnerable to various types of pollution due to the large-scale industrial and associated human activities that might potentially affect the locally harvested foodstuffs. Therefore, the transfer factor is an essential tool to assess the safety of foodstuffs due to the presence of natural radioactivity in environmental matrix and/or strata. This is a first study of its kind conducted in a well-known region for mango farming in Bangladesh, measuring the uptake of naturally occurring radioactive materials (NORMs) by grass and mango from soil to assess the ingestion doses to humans. The HPGe gamma-ray detector was used to determine the concentrations of NORMs in samples of soil (20), grass (10), and mango (10), which were then used to calculate the transfer factors of soil to grass and soil to mango. Average activity concentrations of 226Ra, 232Th, and 40K in associated soil samples (47.27 ± 4.10, 64.49 ± 4.32, 421.60 ± 28.85) of mango and 226Ra and 232Th in associated soil samples (45.07 ± 3.93, 52.17 ± 3.95) of grass were found to exceed the world average values. The average transfer factors (TFs) for mango were obtained in the order of 40K(0.80) > 226Ra (0.61) > 232Th (0.31), and for grass, it shows the order of 40K (0.78) > 232Th (0.64) > 226Ra (0.56). However, a few values (3 mango samples and 3 grass samples) of the estimated TFs exceeded the recommended limits. Moreover, Bangladesh lacks the transfer factors for most of the food crops; therefore, calculation of TFs in the major agricultural products is required all over Bangladesh, especially the foodstuffs produced near the Rooppur Nuclear Power Plant, which is scheduled to be commissioned in 2023.

A methodology for the systematic identification of naturally occurring radioactive materials (NORM)

Naturally occurring radioactive materials (NORM) are present worldwide and under certain circumstances (e.g., human activities) may give radiation exposure to workers, local public or occasional visitors and non-human biota (NHB) of the surrounding ecosystems. This may occur during planned or existing exposure situations which, under current radiation protection standards, require identification, management, and regulatory control as for other practices associated with man-made radionuclides that may result in the exposure of people and NHB. However, knowledge gaps exist with respect to the extent of global and European NORM exposure situations and their exposure scenario characteristics, including information on the presence of other physical hazards, such as chemical and biological ones. One of the main reasons for this is the wide variety of industries, practices and situations that may utilise NORM. Additionally, the lack of a comprehensive methodology for identification of NORM exposure situations and the absence of tools to support a systematic characterisation and data collection at identified sites may also lead to a gap in knowledge.Within the EURATOM Horizon 2020 RadoNorm project, a methodology for systematic NORM exposure identification has been developed. The methodology, containing consecutive tiers, comprehensively covers situations where NORM may occur (i.e., minerals and raw materials deposits, industrial activities, industrial products and residues and their applications, waste, legacies), and thus, allows detailed investigation and complete identification of situations where NORM may present a radiation protection concern in a country. Details of the tiered methodology, with practical examples on harmonised data collection using a variety of existing sources of information to establish NORM inventories, are presented in this paper. This methodology is flexible and thus applicable to a diversity of situations. It is intended to be used to make NORM inventory starting from the scratch, however it can be used also to systematise and complete existing data.

New Approach to Determine the Activity Concentration Index in Cements, Fly Ashes, and Slags on the Basis of Their Chemical Composition

The manufacture of Portland cement entails high energy and environmental costs, and various solutions have been implemented in recent years to mitigate this negative impact. These solutions include improvements in the manufacture of cement clinker or the use of supplementary cementitious materials (SCMs), such as fly ash (FA) or slag as a replacement for a portion of the clinker in cement. The incorporation of these SCMs in cement may increase its radiological content as they are naturally occurring radioactive materials (NORMs). The Activity Concentration Index (ACI) is a screening tool established in the European EURATOM Directive 2013/59 to determine the radiation protection suitability of a final construction material. The ACI is determined by the activity concentrations of 226Ra, 232Th and 40K, usually determined by gamma spectrometry. The methodology of gamma spectrometry is accurate and appropriate, but this technique is not available in all laboratories. For this reason, and taking into account that there is a relationship between the chemical and radiological composition of these building materials, a new approach is proposed to determine the radiological content of these materials from a chemical analysis such as X-ray fluorescence (XRF). In this paper, principal component analysis (PCA) is used to establish the relationships between the chemical composition and radiological content of cements, FAs, and slags of different natures. Through PCA it was possible to group the cements based on two variables: CaO content and Fe2O3-Al2O3-TiO2 content. A lower correlation was observed for the FAs and slags, as the sample scores were centered around the origin of the coordinates and showed greater dispersion than the cements. The clusters obtained in the HJ-Biplots allowed the determination, using multiple regression, of models relating the activity concentration of 226Ra, 232Th (212Pb), and 40K to the oxide percentages obtained for the three matrices studied. The models were validated using five cements, one FA and one slag with relative percentage deviations (RSD(%)) equal to or less than 30% for 89% of the activity concentrations and 100% of the ACI determined.

Radiological Protection in Industries Involving NORM: A (Graded) Methodological Approach to Characterize the Exposure Situations

The interest in radiation protection in industrial sectors involving Naturally Occurring Radioactive Materials (NORM) is increasingly growing. This is due also to the recent implementation of the European Council Directive 59/2013/Euratom which in Italy and in the other European Union Member States extends the field of application to industrial sectors never involved before. This paper reports main results of a research project on radiation protection in industries involving NORM carried out in Italy aimed to provide useful tools for stakeholders to comply new legal obligations. The project activities were mainly focused on different aspects relevant to the NORM involving industries, accounting for the positive list reported in the Italian law. Firstly, the inventory of the industries currently operating in Italy in order to identify the industrial sectors with an important radiological impact on population and workers was updated. Based on this information, a general methodology was elaborated taking into account a graded approach. The first phase consists in the identification and characterization of the most critical exposure scenarios and of the radiological content of NORMs involved in the different phases of the industrial processes. In the second phase calculation methods were developed for dose estimation for workers and members of public. These tools require the use of existing and well tested calculation codes, and the development of a dedicated user-friendly software.

Chronic Ionizing Radiation of Plants: An Evolutionary Factor from Direct Damage to Non-Target Effects.

In present times, the levels of ionizing radiation (IR) on the surface of Earth are relatively low, posing no high challenges for the survival of contemporary life forms. IR derives from natural sources and naturally occurring radioactive materials (NORM), the nuclear industry, medical applications, and as a result of radiation disasters or nuclear tests. In the current review, we discuss modern sources of radioactivity, its direct and indirect effects on different plant species, and the scope of the radiation protection of plants. We present an overview of the molecular mechanisms of radiation responses in plants, which leads to a tempting conjecture of the evolutionary role of IR as a limiting factor for land colonization and plant diversification rates. The hypothesis-driven analysis of available plant genomic data suggests an overall DNA repair gene families' depletion in land plants compared to ancestral groups, which overlaps with a decrease in levels of radiation exposure on the surface of Earth millions of years ago. The potential contribution of chronic IR as an evolutionary factor in combination with other environmental factors is discussed.

Internal radiation exposure from TENORM for workers conducting cleaning activities on equipment used at geothermal energy plant.

Geothermal energy is predicted to be one of the most important renewable energy sources in the near future. In geothermal energy plants, the secondary products such as the scale containing naturally occurring radioactive material (NORM) and adhering to the surface of equipment produce radiation fields. The workers who maintain and clean such equipment are at a risk to be exposed by the technically enhanced NORM (TENORM). To estimate the risks of radiation exposure to the workers, we assessed internal doses resulting from the cleaning activities on 150 heat exchanging boards used at a geothermal energy plant, focusing on 222Rn, 226Ra, 210Pb, 228Ra and 228Th. The experiment was performed with the subjects of workers and office workers as control, supplying prepared foods and drinks. Using the analytical results of 210Pb, 226Ra, 228Ra, and 228Th in the excretions of subjects, committed effect doses were determined. The annual internal dose for the workers with protective clothing due to the cleaning activities on removing scale, assuming the cleaning activities requires 170h (standard monthly working time) a year, was obtained as 26μSv/y and the total dose including 222Rn inhalation dose was calculated as 323 μSv/y. The additional dose for the cleaning workers was less than the dose limit of 20000 μSv/y for radiation workers, even less than for general population (1000 μSv/y) recommended by International Commission on Radiological Protection (ICRP). However, the elevated inhalation dose for workers conducting cleaning activities may present a health hazard to workers if they deal with excessive materials containing TENORM, work for excessive time or are under inappropriate safety measures.

Improved toxic and radioactive elements immobilization in tin slag-blended lithium aluminate borate glass

Ever-increasing production of tin slag (TS) by various tin smelting industries in Malaysia remains a major environmental concern, wherein a large amount of naturally occurring radioactive materials (NORM) as wastes are dumped annually since 1982 due to the rare earth elements extraction-related activities. Based on this fact, we proposed some tin slag-included lithium aluminate borate (LAB) glass for improved immobilization of both toxic and radioactive elements present in waste using vitrification. These glasses of composition (50–0.5x)Li2O-xAl2O3-(50–0.5x)B2O3 (0.0 ≤ x ≤ 4.0 mol%) blended with 5, 15 and 30 wt% of TS were made by the standard melt-quenching method and characterized to determine their radioactive wastes immobilization potency. The obtained glasses were immersed in deionized water (DW) at 90 °C for up to 28 days to evaluate their durability. The weight loss of the samples was assessed by applying leaching tests. Inductively coupled plasma-optical electron spectra confirmed the ion exchange-mediate interdiffusion leaching of glass, indicating the presence of Li, Al, and Th in contacting water. The pH values of the solutions were increased from 7.00 to 11.93 with the increase in immersion time which was due to the leaching of Li (alkali metal) from the glass. FTIR spectra exhibited distinct absorption bands characteristics to the vibrations of various chemical functional groups like Al–O, B–O–B, BO4, BO3 and O–H stretching, confirming the association between radioactive waste and glass constituents. The observed bands at 850-1750 cm−1 and 3200 cm−1 corresponded to the vibration of the borate network and O–H bonds, indicating the occurrence of a leaching-mediated hydrolysis process. High-purity germanium gamma-ray spectroscopy was used to determine the radioactivity level of radionuclide (Bq g−1) in all samples powder. The radioactivity levels were found to be below the exempted waste limit set by IAEA safety standard for NORM wastes which is 1 Bq g−1 for 232Th and 238U and 10 Bq g−1 for 40K. In other words, the studied LAB glass containing NORM waste is suitable for conventional waste disposal as it is considered an ecologically safe material as other waste. The 90% reduction in radioactivity levels of the LAB glass containing TS compared to the TS itself indicated a successful dilution process of the studied glass, a part of excellent hydrolytic resistance characteristics. Therefore, it is suggested that the proposed LAB glass system in the present study is practical for NORM radioactive waste immobilization.

Vertical distributions of radionuclides along the tourist-attractive Marayon Tong Hill in the Bandarban district of Bangladesh.

This is the first attempt in the world to depict the vertical distribution of radionuclides in the soil samples along several heights (900 feet, 1550 feet, and 1650 feet) of Marayon Tong hill in the Chittagong Hill Tracts, Bandarban by HPGe gamma-ray spectrometry. The average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.15 ± 3.76 Bqkg-1, 19.69 ± 2.15 Bqkg-1, and 347.82 ± 24.50 Bqkg-1, respectively, where in most cases, 232Th exceeded the world average value of 30 Bqkg-1. According to soil characterization, soils ranged from slightly acidic to moderately acidic, with low soluble salts. The radium equivalent activity, outdoor and indoor absorbed dose rate, external and internal hazard indices, external and internal effective dose rates, gamma level index, and excess lifetime cancer risk were evaluated and found to be below the recommended or world average values; but a measurable activity of 137Cs was found at soils collected from ground level and at an altitude of 1550 feet, which possibly arises from the nuclear fallout. The evaluation of cumulative radiation doses to the inhabitants via periodic measurement is recommended due to the elevated levels of 232Th.This pioneering work in mapping the vertical distribution of naturally occurring radioactive materials (NORMs) can be an essential factual baseline data for the scientific community that may be used to evaluate the variation in NORMs in the future, especially after the commissioning of the Rooppur Nuclear Power Plant in Bangladesh in 2024.

Assessment of occupational radiation exposure of NORM scales residues from oil and gas production

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of 226Ra, 232Th, and 40K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of 226Ra, 232Th and 40K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg−1, respectively. Radiological hazard parameters, such as radium equivalent (Raeq), external and internal hazard indices (Hex, Hin), and gamma index (Iγ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y−1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y−1 is lower than recommended limit of 1 mSv y−1 for public.

Radiotoxicity and health risk assessment of 222Rn in groundwater using statistical and Monte Carlo simulation approaches

Water is an important natural resource to humans, and itsquality has been a big concern from time immemorial. Water is polluted by the increasing activities of man. Pollutants of major concern include naturally occurring radioactive materials (NORM), heavy and potentially toxic metals, which are ubiquitous in the environment. Naturally occurring radionuclides such as 222Rn are the major precursors of lung and other types of cancer in humans. Exposure to radon in drinking water in excess of 300 pCi/L is treated as a radiological risk, while toxic metals in excess of the World Health Organization (WHO) maximum permissible levels in drinking water are considered both environmental and health risks to humans. A total of 34 groundwater samples were collected in the Akoko area of Ondo State, Nigeria for 222Rn activity concentration determination. The water samples were collected using standard techniques. RAD7 solid-state-detector was utilized for the 222Rn measurements. The results show the activity concentration of 222Rn ranging from 76 pCi/L to 3593 pCi/L with a mean value of 705 ± 76 pCi/L. Inhalation and ingestion doses from 222Rn dissolved in groundwater were evaluated for the infants, children, and adult populations in the study area. Radiological risks were evaluated through statistical and Monte Carlos simulation methods. It can be concluded from this study that there exists a likelihood of radiation-induced health risks due to inhalation of 222Rn from the sampled water.

Accurate measurement of uranium and thorium in naturally occurring radioactive materials to overcome complex matrix interference

A standard addition (SA) calibration method for determining uranium and thorium in naturally-occurring radioactive materials (NORMs) was studied. Pretreatment method using fusion was established and optimized. The SA method was validated (LOD, LOQ, linearity, selectivity, and accuracy) using certified reference materials (SRM 2709a, RM-ZR, and RM-BX). The results were evaluated for bias, and a correction equation that included a contribution to the expanded uncertainty was used. All performance criteria were satisfied; the results agreed well with certified and reference values.

Usage of alternative cementitious binders containing naturally occurring radioactive by-products: The industry's perspective

In 2021, global cement production was responsible for around 7% of anthropogenic greenhouse gas (GHG) emissions. Alternative cementitious binders from secondary raw materials that replace traditional cement can reduce the need for the use of virgin raw materials and can thereby reduce GHGs associated with cement. Some of these secondary materials include industrial by-products categorised as NORM (Naturally Occurring Radioactive Material). While prior research has investigated the technical aspects of using NORM-contained by-products in cementitious binders, to date, no attention has been given to non-technical aspects such as perceived risks and concerns of the main stakeholders. This study brings novel insights into these overlooked aspects through a series of semi-structured interviews with concrete industry representatives in Belgium. Through a thematic analysis of the data, we found six themes that represent industry's concerns regarding the usage of NORM-contained cementitious binders: (1) availability of the by-products, (2) financial factors, (3) quality and performance, (4) common sustainability parameters, (5) customer demand, and (6) acceptance of NORM-contained by-products. Regulatory certainty was found to be a key driver in all six themes. With regard to the expected role of governments, we can synthesise three core expectations highlighted by interviewees: a) Policymakers need to revisit the current regulations regarding the performance and quality to facilitate innovation in the concrete industry such as the use of alternative cementitious binders. b) They should implement EU-level regulations that can provide a level playing field for the industry during their transition to net-zero targets, including import regulations and certification for the usage of NORM-contained by-products. c) As an important public buyer, the government should expedite the transition to alternative binders through their procurement policies for governmental buildings and infrastructure projects.

ASSESSMENT OF DOSES FROM INGESTION OF NATURALLY OCCURRING RADIONUCLIDES K-40 AND RA-226 IN RICE CONSUMED IN TAIWAN.

This study investigated natural gamma emitting radionuclides 40K and 226Ra in rice consumed in Taiwan. Thirty rice samples, collected from local markets, included 24 local rice and 6 imported rice samples. Radionuclide activities were 24.05±10.21 and 0.62±0.61Bq/kg for 40Kand 226Ra for all rice samples. The activity of each radionuclide was insignificantly different for local and imported samples (p=0.33 and 0.52 for 40K and 226Ra, respectively). The annual effective doses from rice consumption were estimated to be 6.80±2.89 and 7.86±7.81μSv/y for 40K and 226Ra, respectively, and the sum ingestion dose of 226Ra and 40K was 14.66±8.57μSv/y. These values were one order of magnitude less than the 290μSv/y world average of the ingestion exposure from natural sources. The results suggest that rice consumption in Taiwan is radiologically safe for the investigated radionuclides.

A review on current status of radioactivity monitoring in Indian nonnuclear industries

The distribution of naturally occurring radioactive materials (NORM) generated/discharged in nonnuclear industries such as coal combustion residuals from different coal-based power plants, fertilizer, construction, tobacco, and other industries into the environment, has not been reviewed in the Indian context. In the present review, systematic survey and analysis of the reported occurrence of U238, Th232, and K40 in these nonnuclear industrial sectors is discussed. Most of the data compiled and described in this review are sourced from major popularly referred, peer-reviewed scientific journal publications since the year 2005. Apart from radioactivity levels in products from nonnuclear industrial sectors different radiological indices such as absorbed dose, dose rate, etc., are also compared and discussed. Overall, this review presents a comprehensive analysis of NORMs in nonnuclear industrial sectors of India.