Wild European perch (Perca fluviatilis) is one of the most important freshwater fish species, in Sweden, due to its widespread and his value for recreational fishing. Little it is known regarding the ...biodistribution of naturally occurring radionuclides such as 238U, 234U, 226Ra, 210Po in perch. Therefore, in this study, perches from five lakes located in different counties in Sweden were collected to investigate the biodistribution of 238U, 234U, 226Ra, 210Po and 137Cs in organs and tissues of perch as well as their radiological impact. The results showed that uranium radionuclides ranged between 0.1 and 6 Bq/kg with an average value of 1.1 ± 1.5 Bq/kg. 226Ra varied from 0.4 to 8 Bq/kg with a mean concentration of 1.7 ± 1.9 Bq/kg. The ranged of 210Po was 0.5 – 250 Bq/kg, with an average value of 24 ± 52 Bq/kg. On the other hand, the highest activity concentration of 137Cs, 151 ± 1 Bq/kg, was detected in muscle samples of perch from Redsjösjön lake. For uranium radionuclides and 226Ra uptake from water is the main source whereas for 210Po and 137Cs the uptake is controlled by the perch diet. Regarding naturally occurring radionuclides, the perch tended to accumulated uranium radionuclides in fins, gills, and skin; 226Ra in bones, fins and skin and 210Po in the organs linked to digestive system. Finally, in case of consumption, it is advised the consumption of skinned fillets of perch due to the higher bioaccumulation of the radionuclides investigated in the skin and scales.
•210Po is easily bioaccumulated, while bioaccumulation of 210Pb was not significant.•Direct uptake from water controls the intake of 226Ra in perch.•The largest maternal transfer in perch was detected for 210Po and 137Cs.•Fins tends to bioaccumulate uranium radionuclides and 226Ra.•Consumption of skinned fillets of perch does not represents any radiological risk.
This paper presents a new procedure to optimize the geometric parameters of a n-type coaxial HPGe detector. It is based on a statistical technique called “Design of Experiments” (DoE). This technique ...aims to identify the most influential parameters and to determine the optimal configuration. In this work, The effects of each parameter on the detector responses have been investigated by a fractional factorial design. Only the most influential factors contributing to the detector response have been selected. Precise modeling of these factors was then performed using a full factorial design. Based on the results obtained from this design, the full energy peak efficiencies according to the geometric parameters were modeled by a multiple-linear regression. These models have been statistically validated by analysis of variance (ANOVA). The optimal combination of the geometric parameters has been identified using the desirability function approach, which is a useful tool to optimize multi-response problems. A verification test was performed to validate the results obtained. It was observed that the relative deviation found between experimental and simulated values was less than 5%.
•Optimization of geometrical dimensions of an HPGe detector.•Application of Monte Carlo simulation and “Design of Experiments” technique.•Investigating influence of each detector parameter on the FEPE.•Achieving good agreement between the measured and the simulated results.
The entrance of radionuclides to the human food chain together with the ingestion favour tissues deposition of radionuclides throughout the human body, which may have long-term implications for ...radiation doses. That affects world population, since it represents approximately 12% of the annual effective dose received for the public. This contribution will be quite variable depending on the food habits, food origin and the background levels of the place of residence. It is therefore necessary to monitor the food to be able to control and quantify the risk of exposure of the public. A wide range of food products (vegetables, fruits, meat, fish etc.) have been collected and analysed by different radiometric techniques in order to measure the activity concentration of naturally occurring and anthropogenic radionuclides (40K, 137Cs, 210Po, 226Ra, 228Ra, 234U and 238U). The results of the investigation highlighted that the average committed effective dose from one year's food consumption in Sweden ranged from 82 to 142 μSv for children and it was around 134 μSv for adults. Additionally, considering the consumption percentile 95 (P95), the total ingestion exposure could raise up to 560 μSv/y for children and 340 μSv/y for adults. In all population groups analysed, the internal exposure was mainly controlled by the intake of 210Po (∼ 94–98%), in particular via seafood consumption for example, as a result of the high levels of 210Po in shellfish such as shrimp (30 ± 2 Bq/kg) or blue mussel (55 ± 7 Bq/kg).
•The highest 210Po intake came from shrimp 30 Bq/kg and blue mussel 55 Bq/kg.•High 137Cs intake was related to wild boar food: meat 65 Bq/kg or sausage 75 Bq/kg.•Ingestion exposure for children with high intake of seafood could raise up to 354 μSv.•Ingestion exposure for adults with high intake of seafood could raise up to 261 μSv.
This paper studies the uranium content and uranium isotopic disequilibria as a tool to identify hydrogeochemical processes from 52 groundwater samples in the province of Granada (Betic Cordillera, ...southeastern Spain). According to the geological complexity of the zone, three groups of samples have been considered. In Group 1 (thermal waters; longest residence time), the average uranium content was 2.63 ± 0.16 μg/L, and 234U/238U activity ratios (AR) were the highest of all samples, averaging 1.92 ± 0.30. In Group 2 (mainly springs from carbonate aquifers; intermediate residence time), dissolved uranium presented an average value of 1.34 ± 0.13 μg/L, while AR average value was 1.38 ± 0.25. Group 3 comes from pumping wells in a highly anthropized alluvial aquifer. In this group, where the residence time of the groundwater is the shortest of the three, average uranium content was 5.28 ± 0.26 μg/L, and average AR is the lowest (1.17 ± 0.12). In addition, the high dissolved uranium value and the low AR brought to light the contribution of fertilizers (Group 3). In the three groups, 235U/238U activity ratios were similar to the natural value of 0.046. Therefore, 235U detected in the samples comes from natural sources. This study is completed with the determination of major ions and physicochemical parameters in the groundwater samples and the statistical analysis of the data by using the Principal Component Analysis. This calculation indicates the correlation between uranium isotopes and bicarbonate and nitrate anions.
•Natural uranium isotopic ratios have been calculated and used as a prospecting tool in hydrogeochemical processes in groundwater samples.•Anthropogenic contribution to the presence of uranium has been found.•234U/238U activity ratio has demonstrated to be a key factor to distinguish different geological environments.•A statistical study has been performed and some chemical processes that take place in water have been remarked.
Seafood consumption per capita, in Sweden, is larger than World and European average. Although, 36% of Swedes consume seafood meals at least two times per week, the Swedish National Food Agency ...advises the necessity to increase this ratio. Seafood is one of the main entrances of 210Po in the human food chain. Due to the high radiotoxicity, the intake of 210Po plays an important role in the human health, even in extremely small quantities. In this study, 114 seafood samples representing 52 different marine species were analyzed. The biodistribution of 210Po in seafood species were not uniformly distributed being higher in digestive system and gonads, and lower in seafood muscle. The activity concentration of 210Po in fish ranged between 0.01 and 26 Bq/kg with an average value of 4 Bq/kg, whereas in shellfish fluctuated between 0.1 and 239 Bq/kg, with a mean concentration of 18 Bq/kg. In general, the activity concentration of 210Po in processed products were lower than fresh samples due to the decay of 210Po from seafood capture to purchase. However, in boiled seafood such as Norway Lobster, with short elapsed time from collection to purchase, the boil samples presented higher activity concentration of 210Po than fresh products. The results of the study showed that the annual intake of 210Po via seafood consumption in Sweden exponentially increased by age and it was slightly higher in males than females. As a result, the annual committed dose ranged from 60 to 154 μSv, with an average value of 103 ± 31 μSv, being controlled by fish consumption below 14 years old and by seafood consumption above 14 years old. Finally, the committed effective dose could increase up to 479 μSv/y for population group with higher seafood consumption.
•Consumption of clam, mussel, oyster, anchovy and canned tuna favour 210Po intake.•The annual intake of 210Po from seafood in Sweden exponentially increased by age.•High 210Po concentrations were detected in digestive system and gonads.•High committed effective dose was found in population below 4 y/o and above 45 y/o.
Consumption of bottled water is increasing year after year in Europe. Due to the local geology from where the water is extracted; bottled water could be enhanced with radionuclides. This study ...focuses on the activity concentrations of 210Po, 210Pb, 226Ra, 228Ra, 234U and 238U in bottled water available in the Swedish market, to assess the radiological impact to different age groups. The results showed that among the 26 brands studied, only three could exceed the threshold value for drinking water: 0.1 mSv/year. For two brands, the dose was mainly due to the activity concentrations of 238U and 234U being up to 714 and 1162 mBq/L, respectively. While for one brand, the dose was mainly due to the activity concentration of both 210Po and 210Pb being around 100 mBq/L. For the remainder brands, 228Ra was the main contributor to the committed effective dose.
•The analysed bottled water showed good quality from the radiological point of view.•The highest contribution to the committed effective dose comes from 228Ra.•Three bottled water of 26 exceeded the threshold value for drinking water 0.1 Sv/year.•It is unclear if sparkling water could influence on the radioactivity levels.
This research is focused on studying the preferred source regions and the pathways of the air masses with high particulate concentrations impacting on the activity concentrations of 7Be and 210Pb ...aerosols in Granada atmosphere. For this purpose, three different source-receptor methods have been used: Cluster Analysis, Potential Source Contribution Function (PSCF), and Concentration Weighted Trajectory (CWT). Air filter samples were weekly collected and analysed in Granada university (Spain 37.177N, 3.598 W, 687m a.s.l.) during 12 years (2006–2017) for the activity concentration of 7Be, and during 5 years (2010–2014) for the one of 210Pb. The time series of the collected data indicate that the concentration of both radiotracers present a cyclical and seasonal pattern, in association with their origins and atmospheric conditions. Clustering analysis showed that the air masses arriving to Granada can be classified as: (1) tropical continental air masses coming from the Mediterranean Sea, (2) tropical and warm polar maritime air masses produced over the Atlantic Ocean, and (3) continental air masses originated over Europe and Northern Africa. The PSCF and CWT methods confirmed that the main source areas of 7Be are located in the Atlantic coast of southern Morocco, and Northern Africa. On the other hand, southern France and the Algerian desert were found to be the main region sources of 210Pb. In addition, the Mediterranean Basin has been postulated as a strong source region for 7Be and 210Pb. Furthermore, the PSCF and CWT models show that the regions with larger 7Be/210Pb ratios are located in the Atlantic Ocean, due to frequent stratospheric intrusions specially during the winter months.
•A seasonal pattern of 7Be and 210Pb was identified in Granada, Spain.•Back trajectory analysis was used to identify the origin and pathway of air masses.•Potential sources regions of 7Be and 210Pb activity were investigated.•Granada is affected by Mediterranean Sea, Atlantic Ocean, and Sahara.•Mediterranean basin is the main source common of 210Pb and 7Be.
We have carried out a study to figure out the influence of crystal inactive-layer thickness on gamma spectra measured by an HPGe detector. The thickness of this dead layer (DL) is not known (no ...information about it was delivered by the manufacturer) due to the existence of a transition zone where photons are increasingly absorbed. To perform this analyses a virtual model of a Canberra HPGe detector was produced with the aid of MCNPX 2.7 code.
The main objective of this work is to produce an optimal modeling for our GPGe detector. To this end, the study included the analysis of the total inactive germanium layer thickness and the active volume that are needed in order to obtain the smallest discrepancy between calculated and experimental efficiencies. Calculations and measurements were performed for all of the radionuclides included in a standard calibration gamma cocktail solution. Different geometry sources were used: a Marinelli and two other new sources represented as S(1) and S(2). The former was used for the determination of the active volume, whereas the two latter were used for the determination of the face and lateral DL, respectively. The model was validated by comparing calculated and experimental full energy peak efficiencies in the 50–1900keV energy range. the results show that the insertion of the DL parameter in the modeling is absolutely essential to reproduce the experimental results, and that the thickness of this DL varies from one position to the other on the detector surface.
•Modeling of a HpGe detector was realized with the manufacture’s data.•Inclusion of dead layer has improved the simulation of the experimental efficiencies.•Dead layer and volume of crystal are the parameters most influent on calculations.•Lower energies are more sensitive to the change in the dead layer thickness.•Variation of the active volume has a clear effect on the higher energies.
Since the early days, clays, plant extracts and raw materials have been used for therapeutic and beauty purposes. Nowadays, this use is widely spread, as a huge amount of companies have developed new ...cosmetics based on natural sources. This may lead to an accumulation of radionuclides that can be hazardous for people. Especially dangerous are radium isotopes (226,228Ra), which can be part of the raw materials that cosmetics are made from. In this paper, the concentration of radium isotopes of 18 natural cosmetics was determined. Concentrations resulted in the range 7.9 ± 5.0-37.6 ± 12.5 Bq kg-1 for 226Ra; and 2.5 ± 1.7-35.4 ± 2.6 Bq kg-1 for 228Ra. The effective dose in the skin has been estimated, obtaining a mean value of 13.1 ± 4.9 μSv y-1. This value is far from the reference level of 50 mSv y-1 for the public members. Therefore, no radiological risk derived from the use of these samples, has been found.
This study presents a comprehensive statistical analysis of the cosmogenic radioisotope 7Be measured in surface air in ten stations over Spain for a 9 years period (from January 2006 to December ...2014).
Besides the analysis of 7Be seasonal and inter-annual variability, 7Be frequency distributions and its correlations with meteorological variables observed in the 10 sampling sites were investigated.
The second part of this paper focuses on a feasibility study for the application of the Artificial Neural Networks (ANNs) to predict monthly 7Be activity concentrations using meteorological variables, PM10 concentrations and the sunspot number as input parameters. Notwithstanding the low correlations found between 7Be and input parameter, the performance of the ANNs, as evaluated by the relevant statistical parameters, demonstrates their capability to correctly predict 7Be monthly activities in the 10 Spanish sampling sites.
•9 years of monthly measurements of 7Be in 10 sampling sites were investigated.•Temporal, spatial, and frequency distribution of the 7Be activity were treated.•The ANN method was proposed to forecast 7Be activity.•The ANN model provides robust forecasts of 7Be air concentrations for all stations.
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