Artificial Radionuclides Research Articles

Assessment of Natural and Anthropogenic Radioactivity of the Princes’ Islands in the Sea of Marmara

In this study, the activity concentrations of naturally occurring 238U, 232Th and 40K and anthropogenic 137Cs radionuclides were measured for 56 soil and beach sand samples collected from the Princes’ Islands (Istanbul) in the Sea of Marmara, using a gamma-ray spectrometer. In each case, the outdoor gamma-ray dose rates in air were measured at the coordinates where the samples were collected, using a portable gamma-ray detector. In addition, the 210Po specific activity concentrations were measured for 13 different types of fish and 3 black mussel samples that are consumed in the region, using an alpha spectrometer. The mean activity concentrations of natural 238U, 232Th and 40K and artificial 137Cs radionuclides were calculated to be 33.8 ± 0.5 Bq kg−1, 19.3 ± 0.3 Bq kg−1, 429.5 ± 4.5 Bq kg−1 and 8.9 ± 0.1 Bq kg−1, respectively, in the soil and beach sand samples. Activity concentration contour maps of the Princes’ Islands (Istanbul) were constructed. The mean annual effective dose values for natural and artificial radioactive nuclide activity concentrations were determined to be 55.4 μSv y−1 and 1.2 μSv y−1, respectively. The average outdoor gamma-ray dose rate measured in the air was 0.68 mSv y−1. The mean activity concentrations of 210Po in the fish and mussel samples were measured to be 16.2 ± 1.9 Bq kg−1 and 516.1 ± 25.8 Bq kg−1. The average annual effective ingestion doses due to 210Po from the consumption of these seafoods were calculated to be 106.9 μSv y−1 and 619.4 μSv y−1, respectively. The results of this study were compared with the limits proposed by UNSCEAR, ICRP and the values obtained in other similar studies worldwide.

A case study on possible radiological contamination in the Lo Uttaro landfill site (Caserta, Italy)

The prevention of radioactive pollution is a primary objective of environmental protection codes in the operation of solid waste landfill activities. Several studies have demonstrated the effectiveness of radiological monitoring of the main constituents of urban landfill waste. The present contribution reports on an investigation plan carried out to evaluate the possible radiological contamination in the municipal landfill Lo Uttaro, district of Caserta (Italy). The investigation focused primarily on the perimeter area of the landfill in order to assess the possible impact on the surrounding population. The results of measurements of the equivalent dose rate along the perimeter of the landfill show average values lower than the population dose limit due to natural background radiation. Several samples of soil, groundwater and leachate representative of the subsoil of the study area were collected and the radionuclides were measured by gamma spectrometry. The results of these measurements show the absence of artificial radionuclides, except for small amounts of 137Cs due to nuclear disasters occurring in the last 50 years on Earth, and the mere presence of 40K and other natural radionuclides belonging to natural radioactive chains of 238U, 235U and 232Th.

Assessment of natural and artificial radioactivity in infants’ powdered milk and their associated radiological health risks

A high-resolution gamma-ray spectrometer was applied to measure the activity concentration of natural and artificial radionuclides 226Ra, 232Th, 40K, and 137Cs in 14 brands of infants powdered milk consumed in Egypt. The average activity concentrations were 0.91 ± 0.20, 0.60 ± 0.11, 477 ± 25 and 0.42 ± 0.11 Bq kg−1 for 226Ra, 232Th, 40K, and 137Cs, respectively. The total annual effective dose for different infant’s age groups is estimated and also the total risk has been assessed. The results indicate that the consumption of the studied powdered milk would not pose any significant radiological impact to the infants.

Evaluation of Primordial Radionuclides in <I>Ocimum gratissimum</I> and health Risk to the Consumers at Ewekoro Southwest of Nigeria

Primordial radionuclides are transported in to the plants through the leaves and roots. Medicinal plants are widely used in Africa for prevention and treatment of diseases. Ocimum Gratissimum is medicinal plant that is so used in southwest of Nigeria due to its multifunctional traditional medicinal health uses and as spice in cooking. The research is to determine the radiological health risk of these primordial radionuclides to the consumers of Ocimum Gratissimum in the study area. Fresh leaves of the medicinal plant were plucked from ten (10) different locations at Ewekoro where mining of limestone had been taking place in Ogun State, southwest of Nigeria, been the part of the plant that was commonly used. The concentrations of 40K, 238U and 232Th in the fresh leaves were determined using gamma spectrometry method, and average annual committed effective dose to the adult consumers was determined. No artificial radionuclide was detected. The highest annual committed effective doses of 40K, 238U and 232Th to the consumers of Ocimum Gratissimum were obtained to be 0.00133mSvy-1, 0.00147mSvy-1 and 0.00336mSvy-1 respectively. The highest excess lifetime cancer risk of 40K, 238U and 232Th to the consumers were calculated to be 0.0211 x 10-3, 0.0136 x 10-3 and 0.1434 x 10-3 respectively. The average annual committed effective dose and average excess lifetime cancer risk of the radionuclides to the consumers were calculated to be 0.0109mSvy-1 and 0.0379 x 10-3 respectively. The values were below the limits of 0.3mSvy-1 and 0.29 x 10-3 respectively, recommended globally. The consumers of the medicinal plant do not have significant radiological health risk. Furthermore, the results obtained can serve as reference data for future studies in the study area and its environs.
 Keywords: Primordial Radionuclide, Medicinal plant, Dose, Cancer

Assessment of radionuclide contamination of plant resources of the Voronezh region by example of leaves of winter linden tree

As part of the study, the activity of artificial and natural radionuclides (strontium-90, cesium-137, potassium-40, thorium-232, radium-226) was determined in 36 samples of medicinal plant raw materials of the core and upper soil layers on which the plants were grown. All samples meet the existing requirements of regulatory documentation on radionuclide activity. The average value of the strontium-90 accumulation coefficient was 0.39, in different samples of the region it varied from 0.31 to 0.60. Cesium-137 accumulation coefficients ranged from 0.29 to 0.65 at an average of 0.39. For thorium-232, the average accumulation coefficient in the core lip flowers is 0.15 and took values in the samples studied from 0.09 to 0.231. For potassium-40, the average accumulation ratio in the feed was 0.98 and varied from 0.71 to 1.29, and for radium-226 - 0.47, with a variation from 0.39 to 0.59.

ACCUMULATION OF RADIONUCLDES BY LACTUCA SATIVA CULTURE IN SOILS OF DIFFERENT NATURE OF RADIOACTIVE CONTAMINATION IN MODEL EXPERIMENT CONDITIONS

The article shows the possibility of applying a simulation experiment to obtain representative values of the accumulation of artificial radionuclides by agricultural products the case of Lactuca sativa culture. The experiment used soils from areas of Semipalatinsk Test Site (STS) different in type and nature of radioactive contamination. Transfer factor (Tf) were derived for artificial 137Cs, 241Am, 90Sr and 239+240Pu for Lactuca sativa. A comparative analysis was carried out for Tf of radionuclides in STS areas with a different nature of radioactive contamination.

Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics: Insights from the Morteratsch glacier (Swiss Alps)

Cryoconite, a sediment found on the surface of glaciers, is known for its ability to accumulate radionuclides. New data on cryoconite from the Morteratsch glacier (Switzerland) are presented to shed light on the mechanisms that control the distribution of radioactivity in cryoconite. Among the radionuclides detected in our samples, we have identified 108mAg, an artificial species which has never been observed in terrestrial environments before. This finding supports that cryoconite has an extraordinary ability to accumulate radioactivity. Our results also show that the radioactivity of cryoconite from a single glacier is far from uniform. Both the absolute amount of radioactivity and the relative contribution of single radionuclides are highly variable in samples from the Morteratsch glacier. To investigate the processes responsible for such variability, we have explored the correlation between radionuclides, organic and inorganic carbon fractions and the morphological features of cryoconite deposits. We have found that the degree of connection between cryoconite and supraglacial hydrology is particularly important, since it strongly influences the accumulation of radionuclides in cryoconite. Cryoconite holes connected with supraglacial channels are rich in cosmogenic 7Be; in contrast, poorly connected deposits are rich in artificial fallout radionuclides and elemental carbon. The very different half-lives of 7Be and artificial radionuclides allowed us to discuss our findings in relation to the age and maturity of cryoconite deposits, highlighting the potential use of radionuclides to investigate hydrological supraglacial processes and material cycling at the surface of glaciers.

Biotope and biocenosis of cryoconite hole ecosystems on Ecology Glacier in the maritime Antarctic

Despite recent great interest in glacier ecosystems in the continental Antarctic, little is known about their maritime counterparts. Our study presents descriptive data on cryoconite sediments and cryoconite holes on Ecology Glacier (King George Island) to accomplish three main objectives: (a) to identify main eukaryotic (algae, invertebrates) and prokaryotic (cyanobacteria) components of microbial communities; (b) to provide a “baseline” of community composition, organic matter and artificial contamination; and (c) to identify key abiotic factors that might be important in community assembly. Cryoconite holes were sampled along an altitudinal gradient of Ecology Glacier in January, mid Austral Summer 2017. Cryoconite holes located in lower altitude were deeper than those located in the middle and the highest altitude. Seventeen species of algae and cyanobacteria with biomass of 0.79 to 5.37 μg/cm3 have been found in sediments. Dominant species were cyanobacterial Pseudanabaena frigida and Bacillariophyceae Microcostaus sp. Biomass of Bacillariophyceae was significantly higher than that of Chlorophyta and Cyanobacteria. We found three species of rotifers (potentially two new to science) and for the first time a glacier dwelling Acari (suspension feeder, Nanorchestes nivalis). Organic matter content ranged from 5.4% to 7.6%. Investigated artificial radionuclides included 137Cs, 238Pu, 239+240Pu and 241Am. 210Pb seems to be related to organic matter content. Overall, cryoconite holes on Ecology Glacier present unique habitats that serve as biodiversity hotspots of psychrophiles, source of organic matter, matrices for radioactivity tracking and model for observing changes in supraglacial ecosystems in the maritime Antarctic.

Radionuclides in waters and suspended sediments in the Rhone River (France) - Current contents, anthropic pressures and trajectories

The Rhone River is one of the most nuclearized river in the world. Radionuclide concentrations in water and suspended sediments transferred to the marine environment were intensively monitored in this river over the last decades (2002–2018). Over this period of time, >12 and 25 time integrating samples were collected each year in filtered waters and suspended sediments, respectively, and analyzed for their radionuclide contents at ultra-trace levels by using top performance analytical tools. While >60% of plutonium, americium, cesium, cobalt, silver, beryllium and actinium radioisotopes are carried by sedimentary particles, sodium, tritium, antimony and strontium are mainly exported as dissolved species (>90%) due to their low affinity with particles. Most natural radionuclides contents show low seasonal variation. No significant trends are observed over the last two decades for these elements, even for 40K widely used in fertilizers after the middle of the last century, indicating that the basin has currently converged towards geochemical equilibrium for all of them. In contrast, the concentrations of numerous anthropogenic radionuclides originating from nuclear industries significantly declined since the beginning of the 2000s. Assuming no change of the current anthropic and climatic pressures over the next decades, apparent periods, i.e. the time required for a reduction by half the concentrations in the downstream part of the Rhône River, would be close to 6 years for most artificial radionuclides, except for tritium and other artificial radionuclides conveyed to the river by soil leaching and erosion (90Sr, 241Am, plutonium isotopes) which would be far longer. Referring to regional referential backgrounds, only few anthropogenic radionuclides specifically produced by nuclear industries are still detectable at the downstream part of the Rhone River and excess contents of tritium, 238Pu and 241Am are observed in filtered waters.

Radioactivity measurement in glacier and Polar ice-caps: An overview

Glacier is an extended mass of ice formed by snow falling and accumulating over the years and moving very slowly either by descending from high mountains, as in valley glaciers or by moving out of accumulation centers, as in glaciers on the continent. Glaciers are a significant source of potable water and plant irrigation, any contamination of this significant source in glaciers due to radionuclides may affect freshwater supplies and livelihoods. It is well known that exposure to ionizing radiation could lead to health hazards and harm to the environment. Therefore, awareness of the distribution and concentrations of natural and artificial radionuclides in the glacier region is crucial, and that is why it provides and clarifies helpful information about radionuclide pollution in the environment. This evaluation gives insights into the overview of the radioactivity of natural and artificial radionuclides in the glacier region (Arctic and Antarctica). These information are crucial for predicting the effects of radionuclide distribution and transport in ecosystems, and can also be an indication of the effects of external human activities in the cold regions.

Assessment of Radioactivity and Radiological Hazard of Different Food Items Collected from Local Market in Bangladesh

Sixteen samples in three categories vegetables, cereals (rice, wheat, maize, pulse) and powdered milk were collected from local markets (Dhaka city) in Bangladesh and analyzed by using High Purity Germanium (HPGe) Detector for the assessment of natural and artificial radioactivity. In vegetables (potato, raw banana, giant taro, red amaranth), the average activity concentrations of 232Th, 226Ra, and 40K were found to be 37.82±11.57, 54.93±9.98 and 617.43±65.69 Bqkg-1 respectively, for cereals (rice, wheat, maize, pulse) 24.01±3.67, 31.46±4.00 and 474.83±27.68 Bqkg-1 respectively and for milk samples 15.01±3.65, 26.73±6.77 and 494.21±38.71 Bqkg-1 respectively. The average values of outdoor annual effective dose were found to be 92.18, 61.19 and 52.37μSvy-1 in vegetables, cereals and milk samples respectively. No artificial radionuclide was found in any of these samples. The average value of radium equivalent activity in all samples was 113.89 Bqkg-1 which was less than maximum permissible value 370 Bqkg-1. The values of external hazard indices for vegetables, cereals and milk samples varied from 0.31 to 0.66, 0.17 to 0.40 and 0.11 to 0.36 respectively which is less than unity in all samples that indicate the non-hazardous nature of the samples. The average values of annual effective ingestion dose rate from foods (for adult) were 274.33 μSvy-1, 533.60μSvy-1, and 132.73μSvy-1for 232Th, 226Ra and 40K respectively. These data would be useful to establish a baseline for natural radioactivity concentrations in food items consumed in Bangladesh.
 Journal of Bangladesh Academy of Sciences, Vol. 43, No. 2, 141-148, 2019

Possible Factors Influencing the Accumulation of Different Radionuclides in Sludge from a Drinking Water Treatment Plant Located in Southern Catalonia Between 2002 and 2018

The drinking water treatment plant (DWTP) in L’Ampolla collects water from the River Ebro. The sludge generated during the water treatment processes applied accumulates some of the radionuclides present in the ingoing water. Gamma spectrometry measurements of the sludge were carried out monthly for a period of 17 years (2002–2018) to evaluate possible factors that might influence the radioactive content. These included the geology, river flow rate, suspended particulate matter, turbidity, water treatment processes, and industrial activities in the area of the river basin. The activity concentrations of 214Pb, 214Bi, 228Ac, 228Ra, and 226Ra from both the 238U and 232Th decay chains decreased significantly from 2012 onwards. This may be related to a change in the water treatment process in the L’Ampolla DWTP, and in particular, that potassium permanganate was no longer added to the raw water from 2011. Other isotopes such as 40K, 7Be, and 234U/238U have not displayed the same behavior, which could support our hypothesis that the accumulation of radium isotopes in the sludge could be influenced by the use and nonuse of permanganate. A number of artificial radionuclides were also determined, which is consistent since L’Ampolla DWTP is located 70 km from a nuclear power plant, and the activities found for some of these radionuclides correlate with its annual liquid discharges into the river. The results therefore indicate that a relationship exists between the different factors in connection with the raw water and the radioactive content of the sludge generated by the plant under study.

Use of natural and artificial radionuclides to determine the sedimentation rates in two North Caucasus lakes

The specific activities of natural (210Pb, 226Ra, and 232Th) and artificial (137Cs, 239,240Pu, and 241Am) radionuclides in the sediments of two North Caucasus lakes were determined. The two lakes, Lake Khuko and Lake Donguz-Orun, differ in their sedimentation conditions. Based on the use of unsupported 210Pbex and both Chernobyl-derived and bomb-derived 137Cs as chronological markers, it was established that the sedimentation rates in Lake Khuko over the past 55–60 y did not exceed 0.017 cm y−1. Sedimentation rates in Lake Donguz-Orun were found to be more than an order of magnitude higher. In the latter case, the sedimentation rates for the period from 1986 to the present were over 1.5 times higher than they were for the period 1963–1986. The differences in sedimentation rates were due to differences in the rates of denudation of their respective catchment areas. The specific activities of artificial radionuclides (137Cs, 2600 Bq kg−1; 239,240Pu, 162 Bq kg−1; and 241Am, 36 Bq kg−1) and their ratios in the sediments of Lake Khuko show that their deposition was mainly due to global stratospheric fallout of technogenic radionuclides associated with nuclear bomb testing during 1954–1963—rather than fallout from the Chernobyl accident. Several factors, including the mode of precipitation, features of the surface runoff, and location of Lake Khuko, were responsible for the accumulation of artificial radionuclides.

Evaluation of Artificial Radionuclides in Berries

Evaluation of Artificial Radionuclides in Berries

Long-lived radionuclides in marine sediments from the Beibu Gulf, South China Sea: Spatial distribution, controlling factors, and proxy for transport pathway

The source and transport process of sediments are of great concern in marine sedimentology. In this study, naturally occurring radionuclides (238U, 226Ra, 228Ra, and 40K) in surface sediments and sediment cores were comprehensively analysed using high-purity germanium (HPGe) γ spectrometry in order to explore radionuclide fingerprints as novel proxies for tracking the source and transport pathway of sediments in the Beibu Gulf. We found that the radioactivity level of sediments in the Beibu Gulf was lower than that in other Chinese seas, following a comprehensive compilation and comparison of radioactivity in the region, indicating the Beibu Gulf is a high-quality marine environment. An interesting “butterfly pattern” was exhibited in the horizontal distribution of radionuclides in surface sediments from the Beibu Gulf, mainly attributable to the controlling factors of the non-linear negative regulation of sediment grain size and positive role of total organic carbon in sediment. Furthermore, the vertical distribution of radionuclides in sediment cores was affected by the redox state and a physical/biological disturbance, which were demonstrated by the simultaneous analysis of redox-sensitive element Mn and 210Pb, respectively. Additionally, the 226Ra238U endmember model and 232Th238U endmember model were proposed for quantifying local input (85%) and trans-region input (15%) of marine sediments in the Beibu Gulf in the context of the Guangdong-Qiongzhou Strait-Guangxi framework. We inferred that the Beibu Gulf was at risk of contamination by artificial radionuclides derived from nearby Guangdong Province, which has the highest number of nuclear power plants in China, through a trans-region input by ocean currents. Our study not only provided spatiotemporal distributions of radionuclides in the Beibu Gulf and their controlling factors (sediment grain size, total organic carbon, redox state, physical/biological disturbance, and ocean currents) but also indicated the radionuclide fingerprints (226Ra/238U and 232Th/238U) as potential geochemical proxies for quantifying the distinct sources of radionuclides and other associated chemicals (e.g., heavy metals, organic pollutants) in sediments.

Cryoconite: an efficient accumulator of radioactive fallout in glacial environments

Abstract. Cryoconite is rich in natural and artificial radioactivity, but a discussion about its ability to accumulate radionuclides is lacking. A characterization of cryoconite from two Alpine glaciers is presented here. Results confirm that cryoconite is significantly more radioactive than the matrices usually adopted for the environmental monitoring of radioactivity, such as lichens and mosses, with activity concentrations exceeding 10 000 Bq kg−1 for single radionuclides. This makes cryoconite an ideal matrix to investigate the deposition and occurrence of radioactive species in glacial environments. In addition, cryoconite can be used to track environmental radioactivity sources. We have exploited atomic and activity ratios of artificial radionuclides to identify the sources of the anthropogenic radioactivity accumulated in our samples. The signature of cryoconite from different Alpine glaciers is compatible with the stratospheric global fallout and Chernobyl accident products. Differences are found when considering other geographic contexts. A comparison with data from literature shows that Alpine cryoconite is strongly influenced by the Chernobyl fallout, while cryoconite from other regions is more impacted by events such as nuclear test explosions and satellite reentries. To explain the accumulation of radionuclides in cryoconite, the glacial environment as a whole must be considered, and particularly the interaction between ice, meltwater, cryoconite and atmospheric deposition. We hypothesize that the impurities originally preserved into ice and mobilized with meltwater during summer, including radionuclides, are accumulated in cryoconite because of their affinity for organic matter, which is abundant in cryoconite. In relation to these processes, we have explored the possibility of exploiting radioactivity to date cryoconite.

Does Salinity Affect the Distribution of the Artificial Radionuclides 90Sr and 137Cs in Water of the Saline Lakes? A Case of the Crimean Peninsula

In the framework of radioecological monitoring, the features of the distribution of the post-Chernobyl nuclear power plant (NPP) accident artificial radionuclides of 137Cs and 90Sr in the Crimean saline lakes were studied. Samples were collected from 12 Crimean lakes with a salinity range from 2 to 400 g/L in 2014–2017. Concentration of 90Sr varied from 5.9 to 313.6 Bq/m3, and 137Cs from 0.8 to 106.7 Bq/m3. Closing of the North Crimean Canal resulted in a decrease in radionuclide concentration in the lakes. About 61% of the total variability of 90Sr and 33% of 137Cs in lake water can be explained by salinity changes. The salinity affects the behavior of radionuclides in water, mainly influencing their solubility, on isotope exchange between the solution and bottom sediments, and also, probably, through its influence on accumulation of isotopes by aquatic organisms. Salinity is not the alone factor determining the behavior of radionuclides in the lakes, it only acts by interacting with other factors.

Natural and artificial radioactivity in volcanic ash soils of Jeju Island, Republic of Korea, and assessment of the radiation hazards: importance of soil properties

In this study, we investigated the activity concentrations of natural (226Ra, 232Th, 40K) and artificial (137Cs) radionuclides of soils in Jeju Island, and radiation hazard indices arising from the activity concentrations. The activity concentrations of 232Th and 40K based on soil color were in the order of black volcanic ash soils (BVAS) < very dark brown volcanic ash soils (VDBAS) < dark brown soils, but 137Cs was highest in BVAS, and 226Ra was lowest in VDBAS. The radiation hazard indices calculated from the activity concentrations were negligible. In terms of annual outdoor effective dose rate (AEDRout), the contribution of radionuclides to the soils was 137Cs (5.1%) < 40K (24.7%) < 226Ra (29.0%) < 232Th (41.3%), i.e., dominated by natural radionuclides, but contributions were dependent on soil properties.

RADON IN THE WATER

Man and his environment are constantly exposed to the effects of ionizing radiation. Most of this radiation comes from natural and artificial radionuclides and the biggest radioecological problem is the 222Rn radioactive gas. Natural radioactivity comes from unstable radioisotopes that were present during the formation of the Earth, and are present today. According to the research by UNSCEAR(United Nations Scientific Committee on the Effects of Atomic Radiation) it is estimated that the radiation dose, which comes from natural radionuclides and to which man is exposed, is 2.4 mSv per year. Natural sources of radioactivity are cosmic radiation and Earth’s crust that contains primordial radioactive elements including those that are sources of radon (uranium). Radon is a natural inert radioactive gas without smell and taste. It is soluble in water and can easily diffuse with the gaseous and aqueous phase and in this way forms significant concentrations. The techniques and methods most commonly used to detect and determine the activities of radon in water are alpha spectrometry, gamma spectrometry and measurement techniques on a liquid scintillation detector. Throughout epidemiological studies, the World Health Organization has provided convincing evidence of the correlation of exposure to indoor radon and the development of lung cancer. Radon and its decomposition products are considered to be the second cause of lung cancer after consuming tobacco.

A review: Natural and artificial radionuclides and radiation hazard parameters in the soil of mountain regions in Serbia

This review paper discusses the content of natural (40K, 238U, 226Ra, and 232Th) and artificial (137Cs) radionuclides in the soil of the mountains of Maljen, Tara and Kopaonik in the Republic of Serbia over 2002-2015. In addition, the paper gives radiation hazard parameters, i.e., radium equivalent activity, absorbed dose rate, annual effective dose equivalent, external hazard index, annual gonadal dose equivalent, and excess lifetime cancer risk outdoors that we calculated from the obtained content of the natural radionuclides in the soil samples. We compared the parameters to previously published results for different parts of the country and looked into the radioecological status of the investigated areas.