Radiation dose to Malaysian populace via the consumption of roasted ground and instant coffee

https://doi.org/10.1016/j.radphyschem.2020.108886Get rights and content

Highlights

  • Information on the distribution and enrichment of radionuclides in coffee found to be sparse.

  • Addressed in investigating 12 popular brands of coffee from seven countries, assessed for U-, Ra- and K- content.

  • Committed effective dose from their consumption low compared to UNSCEAR guidance limit of 290 μSv/y.

Abstract

Accompanying the busy lifestyles of modern Malaysia, coffee is becoming one of the nations’ most popular stimulating drinks. In association with nutrients uptake, natural radionuclides in soil are also being taken up by the coffee plant, subsequently appearing in the human body through consumption of coffee. Present study concerns the assessment of the natural radionuclides 226Ra, 228Ra, and 40K in roasted ground and instant coffee consumed in Malaysia. A total of 12 sampled brands of coffee, originating from seven different countries including Malaysia, were collected from various supermarkets in Kuala Lumpur. The samples were analyzed by HPGe γ-ray spectrometry, obtaining a range of activities (in Bq/kg) 6.4 ± 1.3–21.4 ± 2.4, 6.6 ± 1.8–47.9 ± 10.6, and 220 ± 12–1510 ± 72 for 226Ra, 228Ra and 40K respectively. The annual committed effective dose estimate from such coffee consumption was found to be in the range 13.2–55.7 μSv/y, low in comparison with the UNSCEAR (2000) reference dose guidance limit of 290 μSv/y. The estimated threshold coffee consumption rates indicates a guidance limitation for Sample L of not more than 21 g/d (some 2 cups/d) to avoid deleterious health effect. While the presently sampled coffee brands do not represent a public concern in terms of radiological risk, cumulative daily dietary exposures from other or present brands may not be totally negligible because of the UNSCEAR reference limit is due to the contribution from all natural sources. Thus, periodic monitoring of radiation levels in coffee is suggested to be of importance.

Introduction

Coffee, produced from the seeds and berries of the coffee plant, has become one of the most popular and widely consumed beverages in the world. It is slightly acidic (5.0–5.1 pH) and due to its caffeine content it can have a stimulating effect on humans (Roselli et al., 2013). Increasing in popularity and also accompanied in many countries by the establishment of many popular brand coffeehouses, coffee consumption accompanies the holding of many social gatherings and meetings, Malaysia included.

Coffee, apparently basic, is more properly a complex mixture of neutriceuticals including minerals, lipids, caffeine, proteins, fats, carbohydrates and water (ICS, 2001); micro-roasted coffee may provide particular additional supplements, one instance being niacin (vitamin B3) in the range 10–40 mg/100 g, potentially reducing cholesterol levels and lowering cardiovascular risks (Adrian and Frangne, 1991). A recent study by Montagnana et al. (2012) suggests a lower risk of cardiovascular diseases is associated with coffee consumption down to less than one cup of coffee per day while it becomes higher for ≥ 4 cups per day. Such health benefits are said to be directly related to coffee contents of bioactive compounds, chemical elements, minerals, micronutrients etc. The accumulation of mineral elements and other micronutrients in the coffee bean generally depends on many factors; species, age, root distribution of the plant, physical and chemical nature of the soil, proportions and distributions of elements, the use of fertilizers and the general climatic conditions (Anderson and Smith, 2002; Nabrzyski and Szefer, 2006). In the process of minerals and micronutrients uptake, the plant root system is incapable of differentiating between the nutrients (potassium and calcium included) and their chemically analogous radioactive nuclides (Asaduzzaman et al., 2014). Thus there are potential radiological dose considerations that need to be accounted for.

Three categories of radionuclide/radioactive material (primordial, cosmogenic and man-made) are commonly found in soil, water and other environmental media. The primordial radionuclides (40K, 238U, 232Th etc.) have very long half-lives, prevailing since the creation of the Earth. Additionally, cosmic bombardment of stable nuclides in the atmospheric produces cosmogenic radionuclides which in falling to the ground then deposit in the soil. Finally, consideration needs to be made of the presence in the environment of artificial/anthropomorphic radionuclides, produced for use of radiation in medicine, industry, agriculture etc. as well as being the residues of nuclear energy generation and nuclear device testing and utilisation. These can be deposited in the soil by the various potential pathways (e.g., airborne, aquifer etc) (Alrefae et al., 2018). All these radionuclides appear in plant life together with the minerals and nutrients necessary for vitality, either through uptake by the root system via specific transporter or ion channels or through direct atmospheric interception onto external plant surfaces, also indirectly from re-suspended material (Khandaker et al., 2019a). Such existence enables transport into the human food chain, humans ingesting the radionuclides via daily food and water intake, also through inhalation, the soil-plant-human pathway acting as a primary route for the transfer of radionuclides to humans (Khandaker et al., 2016). Tettey-Larbi et al. (2013) reported that under normal environmental conditions, some 90% of the load of 226Ra (one of the major progeny of 238U) within the human enters into the human body via the food chain. The radionuclides can subsequently accumulate in various parts of the body, the long biological half-lives of many radionuclides making them a potential risk to human health via internal exposure, in particular from the high LET/low range alpha and beta particle emissions from the radionuclides.

A general survey on literature reveals that a considerable studies on natural radioactivity in soil, water and foodstuffs are conducted and reported in scientific platform including the leading journal of Radiation Physics and Chemistry. Some of the published works from different region in the world are as follows: Madruga et al. (2020) performed a detailed study on estimation of the internal effective dose to the Portuguese population due to the inhalation and intake of radionuclides through the ingestion of milk, foodstuffs and drinking water. Domingo et al. (2017) studied the level of radio-caesium and potassium in sockeye salmon (Oncorhynchus nerka) collected from the Alberni Inlet on the west coast of Vancouver Island, British Columbia, Canada using low-background gamma-ray spectroscopy. Mohery et al. (2014) studied the level of natural radioactivity in soil and sediment samples in the Jeddah region of Saudi Arabia to realize the radiation hazards due to the technological development of industry, agriculture and other sources around the region. Maxwell et al. (2015) measured the activity concentrations of uranium and toxic elements in borehole and hand-dug well water from Abuja, Nigeria to assess the human radiological risk over lifetime consumption by the inhabitants in the area. Acknowledging mineral water to form a vital component of the intake in maintaining the healthy life of an individual, Khandaker et al. (2017) studied the associated radiological implications due to the presence of naturally occurring radioactive materials (NORMs) in bottled mineral water collected from Malaysia. Almayahi et al. (2014) performed a detailed study on the accumulation of natural and artificial radionuclides in human teeth, animal bones, and soil from the Northern Malaysian Peninsula, and reported higher concentrations in teeth than in bones, in teeth from smokers than those in non-smokers and in female teeth than in male teeth. Recognizing their importance in the average Malaysian daily diet, Khandaker et al. (2013) determined the radioactivity concentrations in mollusc- and crustacean-based foodstuffs, and estimated the committed effective dose to Malaysian population following the consumption characteristics of the studied foodstuffs. Bajoga et al. (2017) carried out a detailed study of natural radioactivity in soil samples from the state of Kuwait to ascertain the NORM concentration values across the country, and concludes an indication of no evidence for a radiologically significant dispersion of additional depleted uranium across the entire State of Kuwait from the 1991 Gulf War. Cetiner et al. (2011) measured background radiation at the Çanakkale region in Turkey as a part of a general survey program for evaluation of the environmental radioactivity by the Turkish Atomic Energy Authority, and reported a higher dose rates at some spas and beaches than general values. Saleh et al. (2014) reported a baseline data of environmental terrestrial radiation and assess the corresponding health risk in the ambient environment in Muar District, Johor, Malaysia in view of the possible construction of nuclear power plant in the future. Charro and Moyano (2017) evaluated the uptake and transfer of natural radionuclides in different tissues of native plants from uranium mining-impacted soils in Central-West of Spain. Melquiades and Appoloni (2001) measured the natural and artificial radioactivities in powdered milk produced at Londrina, Brazil by using HPGe gamma ray spectrometry. El-Marakby et al. (2020) performed an assessment of chronic exposure effects and radioadaptive response of NORMs by considering their production as by-products or waste from the technologically enhanced activities of gas and oil industries. Natural radioactivity in soil and the associated radiation hazards were studied by Ravisankar et al. (2012) to provide the background radioactivity concentrations in Yelagiri hills, India.

While studies of natural radionuclide concentrations in various foodstuffs are available in the literature, information on the distribution and enrichment of radionuclides in coffee is sparse. Notable among the few published studies on radioactivity of coffee are an Italian study of natural radioactivity in coffee powder and coffee beverage (Roselli et al., 2013), Alharbi and Alamoudi (2017) making a comparative study between Arabian and Turkish coffee powder samples and Abd El Wahab and Morsy (2006) determined the concentration of natural radionuclides in a particular brand distributed in Egypt. Malaysian coffee plantations are prominent, Malaysia also having a strong coffee drinks culture (on average, in Malaysia 2.38 cups of coffee are consumed daily; https://www.ukessays.com/essays/marketing/coffee-culture-in-malaysia-marketing-essay.php). Thus said, no previous estimation of radiological dose via the consumption of coffee in Malaysia has been published. Thus, the purpose of present research has been to determine the natural radioactivity in coffee consumed by the Malaysian populace, also evaluating the radiological risk.

Section snippets

Collection and processing of samples

A total of twelve of the most popular brands of roasted ground/instant coffee available in Malaysia were collected from a number of supermarkets in Kuala Lumpur and Perak, the coffee originating from a number of countries, including Malaysia. Details of the selected samples are shown in Table 1.

The samples, codes A to L, were dried at 80 °C in an oven, for durations of between 10 to 24 h, the choice mitigating against physical changes in the samples (eg sample gaseous evolution). The dried

Results and discussion

The activity concentration of 226Ra, 228Ra and 40K and their mean values are presented in Table 1, 226Ra showing a range from 6.4 ± 1.3 to 21.4 ± 2.4 Bq/kg with a mean of 11.3 ± 1.7 Bq/kg. The greatest activity concentration of 226Ra was in Sample C, the lowest being in Sample B, both from Malaysia. The activity concentrations of 228Ra were observed to be in the range 6.6 ± 1.8–47.9 ± 10.6 Bq/kg with a mean of 19.3 ± 4.3 Bq/kg. The greatest value for this was found in Sample L, with the lowest

Conclusion

The activity concentrations of naturally occurring 226Ra, 228Ra and 40K radionuclides in ground/instant coffee were measured using gamma ray spectrometry. Twelve varieties of coffee, imported from seven different countries were collected and studied, with 40K representing the greatest contributor in all samples followed by 228Ra and 226Ra with varying amounts; no trace (below detection limits) of artificial radioactivity was found. Sample E from Brunei showed the greatest value for 40K of

CRediT authorship contribution statement

Mayeen Uddin Khandaker: Conceptualization, Supervision, Funding acquisition, Writing - review & editing. Nur Khairunnisa Zainuddin: Data curation, Formal analysis, Writing - original draft. D.A. Bradley: Writing - review & editing. M.R.I. Faruque: Visualization. F.I. Almasoud: Formal analysis. M.I. Sayyed: Data curation, Investigation. A. Sulieman: Software, Validation. P.J. Jojo: Methodology.

Declaration of competing interest

The authors declare no competing financial interest.

Acknowledgements

Sunway University, Malaysia internal Grant no.: INT-2019-SHMS-CBP-02 has been acknowledged.

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