210Po Activity Concentrations Research Articles

Assessment of the committed effective dose due to the 210Po intake from fish consumption for the Arabian Gulf population

This study aims to assess the committed effective dose due to the intake of 210Po from the consumption of fish in Arabian Gulf countries. Twenty different kinds of fish, which represent the most common fish species consumed in the Arabian Gulf countries, were analyzed using alpha spectrometer technique. 210Po activity concentrations in fish samples were found to vary over a wide range from 0.1 to 14.7 Bq kg−1 fresh weight. This variation of 210Po concentrations between various type of fish samples might be attributed to the feeding type pattern and the size of fish. The annual committed effective dose due to ingestion of 210Po in fish species for adults in the Arabian Gulf countries was estimated and found to vary from 38 μSv in Bahrain to 85 μSv in Oman with an average value of 59 μSv. These values are considered relatively high compared to those reported in some other regions. However, it is still much lower than the world average ingestion dose due to natural radiation sources.

Baseline activity concentration of 210Po and 210Pb and dose assessment in bivalve molluscs at the Andalusian coast

In this study, the activity concentrations of 210Po and 210Pb were determined in different types of bivalve molluscs sampled during the period of May 2014–June 2015 along the Andalusian littoral. Radioactivity concentrations of 210Po were determined through alpha-particle spectrometry using 209Po as an internal tracer. Radioactivity concentrations of 210Pb were determined through low-level gamma-ray spectrometry. The activity concentrations of 210Po and 210Pb varied between 40 ± 2 and 515 ± 9 Bq kg−1 dry weight (d.w.), and ND (lower than limit of detection) and 73 ± 10 Bq kg−1 d.w., respectively. The committed effective dose to humans was calculated to range from 39 to 477 μSv year−1. Radioactivity and dose levels were compared with previous studies from other countries.

Dose estimates to the public due to 210Po ingestion via cocoa powder from Lolodorf high background radiation area, Cameroon

210Po activity concentrations have been measured in Lolodorf high background radiation area in cocoa beans which are hand-processed into cocoa powder for breakfast purposes to estimate radiological dose to human. 210Po has been also measured in cocoa leaves and compared to the cocoa beans 210Po content. The analysis has been carried out by CANBERRA alpha spectrometry using ion-implanted silicon detectors. 210Po activity concentrations in cocoa beans varied from 2.31 ± 0.23 to 8.09 ± 0.56 Bq.kg−1, while these values varied from 21.7 ± 0.87 to 66.67 ± 1.58 Bq.kg−1 in cocoa leaves. The corresponding mean values are 4.96 ± 1.86 and 42.54 ± 16 Bq.kg−1 on a dry weight basis respectively. The obtained values confirm the fact that 210Po activity concentrations in cocoa leaves are high compared to the cocoa beans due to the deposition of 222Rn daughters in the atmosphere. The mean radiological doses to human were founded to be 0.227, 0.134, 0.083 and 0.062 mSv/year for children 2- to 7-year-olds, 7- to 12-year-olds, 12- to 17-year-olds and for adult respectively. Ingestion of cocoa powder by the most exposed group ages (children) might not exceed the recommended dose limit for members of the public, which is 1 mSv/year.

Determination of 210Po and 210Pb depositions in lichen and soil samples collected from Köprübaşı-Manisa, Turkey

In this study, we aimed to determine the accumulations of 210Po and 210Pb in soil and lichen samples in Koprubasi. The Koprubasi district is home to the largest uranium deposits in Turkey. To date, there has been no study recorded in the literature related to 210Po and 210Pb depositions in lichens in Koprubasi. Six different lichen species (Cladonia convoluta, Parmelina tiliacea, Physcia stellaris, Pleurosticta acetabulum, Xanthoparmelia conspersa, and Xanthoria parietina) as well as soil samples were collected from seven sampling locations around Koprubasi. Lichens were used as biomonitors for 210Po and 210Pb deposition. The 210Po and 210Pb activity concentrations were measured in all the samples by alpha spectrometry. The activity concentrations in the lichen samples ranged from 64 to 577 Bq kg−1 with an average of 266 Bq kg−1 for 210Po and from 78 to 565 Bq kg−1 with an average of 333 Bq kg−1 for 210Pb. The activity ratios of 210Po/210Pb ranged from 0.80 to 1.99. In the lichen species, the mean 210Po activity values varied from 154 Bq kg−1 in Pleurosticta acetabulum to 390 Bq kg−1 in Xanthoparmelia conspersa. The range of the mean 210Pb activity was between 153 Bq kg−1 in Cladonia convoluta and 378 Bq kg−1 in Parmelina tiliacea. In the soil samples, 210Po and 210Pb activity concentrations were ranged from 14 to 1268 Bq kg−1 and from 19 to 1113 Bq kg−1, respectively. While the values of 210Po and 210Pb measured in the lichen samples are comparable with those of the literature, the results of 210Po and 210Pb in the soil taken from the uranium mine are higher than the results of the literature studies.

Retrospective radon measurements based on implanted 210Po in glass objects using polycarbonate detectors

In the present investigation, a surface-deposited polonium was measured in 37 houses in Rasht and Ramsar cities of Iran with the aim of evaluating the retrospective radon concentration. The CR-LR technique is widely used in this regard, but for the first time, Lexan polycarbonate detectors were used to measure the activity of 210Po planted in glassy objects. These detectors were placed on glassy surfaces for 153 to 365 days. A passive cylindrical diffusion chamber was used for the contemporary radon concentration measurements. The diffusion chamber consists of the Lexan polycarbonate films as a solid state nuclear track detectors and filter. The surface-deposited 210Po activity concentration was found to vary from 0.26 to 11.96 mBqcm-2 with average of 2.62 mBqcm-2. The sensitivity of 210Po to polycarbonate was determined to be 0.06456 track per cm2 per mBqhcm-2. Thus, the radon concentration was found to vary from 122 to 4840 Bqm-3 with an average value 1243 Bqm-3 and the contemporary radon concentration in the area was found to vary from 15 to 2420 Bqm-3 with an average 513 Bqm-3. The results indicate that there is a significant correlation between the concentration of the retrospective radon and the concentration of the contemporary radon gas in the indicated areas with a coefficient of 0.80672.

Descriptive statistics and risk assessment for the control of seasonal pollutant effects of 210Po and 210Pb in coastal waters (Çanakkale, Turkey)

210Po is absorbed into the human body by seafood intake. Especially, mollusks and mussels are known to have much higher 210Po concentration than fish among various other types of seafood and are consumed in large quantities in Aegean Sea. 210Po and 210Pb radionuclide concentrations are obtained in the Mediterranean mussel (Mytilus galloprovincialis) and in the sediment samples collected from the Canakkale. The activity concentrations of 210Po and 210Pb are counted using alpha spectrometry. Activity concentrations of 210Po and 210Pb in mussels are in the ranged of 227 ± 11–540 ± 38 and 17 ± 4–48 ± 5 Bq kg−1 dw (dry weight), for sediments the ranges are 23 ± 6–41 ± 3 and 15 ± 3–44 ± 1 Bq kg−1 dw, respectively. Additionally, annual committed effective dose are calculated due to consumption mussel in Canakkale coastal region. The highest effective doses of 210Po and 210Po are found as 3187 and 56 μSv, respectively. Finally, risk analysis assessment is recommended to determine the pollutant effects of radionuclides. The risk fractions at the concentrations are easily determined with this evaluation process. This methodology has made a great contribution to risk assessments.

210Po and 210Pb bioaccumulation and possible related dose assessment in parasol mushroom (Macrolepiota procera)

Presented are results of a study on accumulation and distribution of 210Po and 210Pb in the fruitbodies of parasol mushroom (Macrolepiota procera) and risk to human consumer due to exposure from highly radiotoxic decay particles emitted by both radionuclides. Mushrooms were collected from 16 forested places in central and northern regions of Poland. Activity concentrations of 210Po and 210Pb were determined after radiochemical separation of nuclides and subsequent measurement using validated method and alpha spectrometer. Results showed on spatially heterogeneous distribution of the 210Po and 210Po activity concentrations in M. procera and two interpolation maps were prepared. Activity concentrations of nuclides in dried caps of M. procera were in the range from 3.38 ± 0.41 to 16.70 ± 0.33 Bq∙210Po ∙kg−1 and from 5.11 ± 0.21 to 13.42 ± 0.30 Bq∙210Pb ∙kg−1. Consumption of M. procera foraged in central and northern Poland should not contribute significantly to the annual effective radiation doses from 210Po and 210Pb due to amount of both nuclides accumulated by fungus in caps.

Evaluation of mean transit time of aerosols from the area of origin to the Arctic with 210Pb/210Po daily monitoring data

In this study, the activity concentrations of 210Pb and 210Po on the 22 daily air filter samples, collected at CTBT Yellowknife station from September 2015 to April 2016, were analysed. To estimate the time scale of atmospheric long-range transport aerosol bearing 210Pb in the Arctic during winter, the mean transit time of aerosol bearing 210Pb from its origin was determined based on the activity ratios of 210Po/210Pb and the parent-progeny decay/ingrowth equation. The activity ratios of 210Po/210Pb varied between 0.06 and 0.21 with a median value of 0.11. The aerosol mean transit time based the activity ratio of 210Po/210Pb suggests longer mean transit time of 210Pb aerosols in winter (12 d) than in autumn (3.7 d) and spring (2.9 d).Four years 210Pb and 212Pb monitoring results and meteorological conditions at the Yellowknife station indicate that the 212Pb activity is mostly of local origin, and that 210Pb aerosol in wintertime are mainly from outside of the Arctic regions in common with other pollutants and sources contributing to the Arctic. The activity concentration ratios of 210Pb and 212Pb have a relatively constant value in summer with a significant peak observed in winter, centered in the month of February. Comparison of the 210Pb/212Pb activity ratios and the estimated mean 210Pb transit time, the mean aerosol transit times were real reflection of the atmosphere transport characteristics, which can be used as a radio-chronometer for the transport of air masses to the Arctic region.

Is ecological food also radioecological? – 210Po and 210Pb studies

Presented are results of a study on accumulation of naturally occurring 210Po and 210Pb in ecological and conventional farming food products in Poland: fruits, vegetables and cereals. The main idea behind this research was to determine the activity concentrations of 210Po and 210Pb in ecological and commercial food as well as calculate and compare the effective dose (radiation) connected to different origin of analyzed food products consumption. The studies showed the majority of all compared food samples contained similar 210Po and 210Pb activities and statistically, the consumption of organic and commercial food would give similar annual effective dose.

Enrichment of naturally occurring radionuclides and trace elements in Yatagan and Yenikoy coal-fired thermal power plants, Turkey

Coal, residues and waste produced by the combustion of the coal contain naturally occurring radionuclides such as 238U, 226Ra, 210Pb, 232Th and 40K and trace elements such as Cd, Cr, Pb, Ni and Zn. In this work, coal and its combustion residues collected from Yatagan and Yenikoy coal fired thermal power plants (CPPs) in Turkey were studied to determine the concentrations of natural radionuclides and trace elements, and their enrichments factors to better understand the radionuclide concentration processes within the combustion system. In addition, the utilization of coal fly ash as a secondary raw material in building industry was also studied in terms of radiological aspects. Fly ash samples were taken at different stages along the emission control system of the thermal power plants. Activity concentrations of naturally occurring radionuclides were determined with Canberra Broad Energy Germanium (BEGe) detector BE3830-P and ORTEC Soloist PIPS type semiconductor detector. The particle size distribution and trace elements contents were determined in various ash fractions by the laser scattering particle size distribution analyzer and inductively coupled plasma (ICP-OES). From the obtained data, natural radionuclides tend to condense on fly ash with and the activity concentrations increase as the temperature drop in CPPs. Measured 210Pb and 210Po concentration varied between 186 ± 20–1153 ± 44 Bq kg−1, and 56 ± 5–1174 ± 45 Bq kg−1, respectively. The highest 210Pb and 210Po activity concentrations were determined in fly ash taken from the temporary storage point as 1153 ± 44 Bq kg−1 and 1174 ± 45 Bq kg−1, respectively. There were significant differences in the activity concentrations of some natural radionuclide and trace elements (Pb and Zn) contents in ash fractions among the sampling point inside both of the plants (ANOVA, p < 0.001). Coal and ash sample analysis showed an increase activity concentration and enrichment factors towards the electrostatic precipitators for both of the power plants. The enrichment factors for Zn follow a similar trend as Pb, increasing in value towards the end of the emission control system. The calculated activity indexes were above 1.0 value for both of the power plants, assuming the utilization of fly ash at 100%. It can be concluded that the reuse of fly ash as a secondary raw material may not be hazardous depending on the percentage of utilization of ash.

Uranium, polonium and thorium in infant formulas (powder milk) and assessment of a cumulative ingestion dose

It is well known that all food and foodstuffs contain naturally occurring radionuclides originating from uranium and thorium decay chains. Since a dose coefficient is always related to a specific radionuclide, it is therefore necessary to determine the activity concentrations of particular radionuclides when completing a radiological risk assessment. Dose coefficients, however, are age dependent, with the highest values being prescribed for infants. Due to the fact that the data on particular radionuclide content in infant formula are scarce, the aim of our research was their determination in infant formulas available on the Slovenian market. 238U, 234U, 230Th and 210Po activity concentrations were determined in five samples and dose assessment was carried out with dose coefficients listed in the IAEA International Basic Safety Standards (2014). The results obtained show that the main contributors to the estimated cumulative radiation dose (230 to 350μSvy−1) is 210Po.

Kinetics of 210Po accumulation in moss body profiles

Radionuclide concentration analysis of total moss bodies often gave relatively different results than a separate analysis of each different morphological part of the same sample. The dynamics of the transfer of metals by dust uplifted from the soil and another approach, based on the diffusion of the two radionuclides to the moss, have been analyzed. In the proposed model, short- and long-term approaches have been applied. Each part of a moss’s profile can show different radionuclides accumulation ability, including both 210Pb and 210Po isotopes. A first-order kinetic model has been used for 210Po and 210Pb transport between three body components of mosses. This mathematical approach has been applied for 210Po activity concentration in the air estimation. For relatively clean deep forest region, calculated concentrations were from 17.2 to 43.8 μBqm−3, while for urban air concentrations were higher from 49.1 to 104.9 μBqm−3.

Radioactivity measurements and dosimetric evaluation in meat of wild birds

ABSTRACTThe aim of this study was to determine the background activity concentration of natural radionuclides and 137Cesium (Cs) in meat of 14 migratory birds originating from central and northern Europe. This meat is largely consumed by the Italian population. 40K, 210Pb, and 137Cs were determined by gamma spectrometry and 210Po by alpha spectrometry. The mean 40K activity concentration detected was 490 ± 117 Bq/kgdw. In all the samples, 210Pb was below the limit of detection (LOD), and therefore it was not possible to calculate the ratio 210Po/210Pb. The 210Po activity concentration ranged between 0.11 ± 0.02 Bq/kgdw and 6.2 ± 0.93 Bq/kgdw with a mean value of 1.03 ± 1.75 Bq/kgdw. The 137Cs activity concentration was not detectable or near LOD except in two samples with 45 ± 0.7 Bq/kgdw (wood pigeon, from Italy) and 139.1 ± 1.9 Bq/kgdw (woodcock, from Sweden). The effective dose of 210Po ingested by consumption of wild birds meat accounts for only 0.01–0.6% of natural radiation exposure in Italy. These data indicate that the meat analyzed was safe.

Mobility indices and doses from 210Po and 210Pb activity concentrations data in Brazilian spas groundwaters

210Po and 210Pb activity concentrations in spas groundwaters occurring at São Paulo (SP) and Minas Gerais (MG) states, Brazil, have been reported in this paper with a dual purpose: to compare different indices for evaluating the radionuclides mobility into waters and to evaluate the drinking water quality from dose calculations. The waters (75 sampling points) are extensively used for drinking in public places, bottling and bathing purposes, among other. The samples were taken from springs and wells drilled at different aquifer systems inserted in Paraná and Southeastern Shield hydrogeological provinces. The WHO guideline reference value for 210Pb and 210Po of 0.1 Bq/L in drinking water was not reached for 210Pb but the 210Po levels were equal or above it in four spas groundwaters from MG State. The maximum WHO guidance dose level of 0.1 mSv/yr was also reached or surpassed in them. The 210Pb “mobility index” taking into account the ratio of the weight of the dissolved 210Pb per unit volume of solution to its weight per unit weight of the rock matrix yielded values in the range of 0.01–5.2 kg/m3. Another “mobility index” (Preference Ratio) expressing the ratio of 210Pb and 238U in the waters divided by the ratio of 210Pb and 238U in the rock matrices provided values between 0.004 and 7994. The 210Pb/238U activity ratios of some spas groundwaters suggested preferential 238U transport relative to 210Pb into the liquid phase, whereas the ratio of the 210Pb to 238U mobility indices indicated the opposite. Such finding showed a better usefulness of the mobility indices for evaluating processes affecting the radionuclides release into the liquid phase during the water/rock interactions.

Study about the radionuclides implanted on glass surfaces for the estimation of retrospective indoor radon concentrations

Indoor radon retrospective dosimetry can be performed by measuring the 210Po activity concentration deposited on surfaces. An experimental study about the implantation of 210Po on mirrors exposed to radon has been performed. Two cases were studied: exposure to high and low 222Rn concentrations. Results were compared with those calculated by using the activity evolution equations. Experimental results can be only explained assuming additional deposition of the long-lived 222Rn descendants.

Removal of 210Po from aqueous media and its thermodynamics and kinetics

In this study, the composite adsorbent as granule was prepared by mixing of polyacrylonitrile (PAN) and a natural zeolite (clinoptilolite) in specific conditions. The prepared composite adsorbent was used for investigating the adsorption behaviour of 210Po. Adsorption of 210Po was studied in a column system. The effective parameters such as initial activity concentration of 210Po, pH of the aqueous solution, contact time and temperature of solution for adsorption behaviour of 210Po were studied. Adsorption yield of 210Po on composite adsorbent from aqueous solution in optimum conditions were determined as 75.00 ± 0.15%. The adsorption equilibrium data was examined using various well-known isotherm models such as Freundlich, Langmuir, Dubinin and Radushkevish and Tempkin, and it was observed that the experimental equilibrium data well fitted and found to be in good agreement with the Tempkin model. Adsorption thermodynamics and kinetics of the polonium were studied. It was found that the processes for 210Po were exothermic and spontaneous. The kinetic data conformed better to the pseudo-second order equation.

Occurrence of 210Po in marine macroalgae inhabiting a coastal nuclear zone, southeast coast of India

The activity concentration of 210Po in 26 species of marine macroalgae found along coast near to a nuclear installation in southeast coast of India was studied. Phaeophytes were found to accumulate the maximum 210Po concentration and chlorophytes the minimum. The average 210Po activity concentration values in the three groups were 6.2 ± 2.5 Bq kg−1 (Chlorophyta), 14.4 ± 5.2 Bq kg−1 (Phaeophyta) and 11.3 ± 3.9 Bq kg−1 (Rhodophyta). A statistically significant variation in accumulation was found between groups (p < 0.05). The un-weighted dose rate to these algae due to 210Po was calculated to be well below the benchmark dose limit of 10 μGy h−1.

Activity concentration measurements of selected radionuclides in seals from Canadian Arctic

The activity concentrations of naturally occurring radionuclides (such as 226Ra, 210Pb and 210Po) and long lived 137Cs were measured in a total of 119 tissue samples (43 blubber, 43 liver, and 33 muscle samples) from 40 ringed seals and 4 bearded seals collected in the Arviat area of Canada during the fall of 2014. Activity concentration of 210Po was measured in all seal liver and muscle samples individually. The average 210Po activity concentrations were 25 ± 7.6 Bq/kg fresh weight (fw) in muscle and 211 ± 58 Bq/kg fw in liver for ringed seals, and 20 ± 6.1 Bq/kg fw in muscle and 231 ± 150 Bq/kg fw in liver for bearded seals. Due to insufficient sample material for most samples collected, gamma counting for radioactive caesium and radiochemical analysis for 226Ra and 210Pb were performed for pooled samples. Activity concentrations of 210Pb and 226Ra were generally below detection limits. While 134Cs activity concentration was not detectable, 137Cs activity concentration was detected in muscle and liver samples. On average, the 137Cs activity concentrations were 0.25 ± 0.05 and 0.12 ± 0.04 Bq/kg fw in muscle and liver samples of ringed seals, and 0.11 ± 0.02 and 0.10 ± 0.03 Bq/kg fw in muscle and liver samples of bearded seals, respectively. Neither 210Po nor 137Cs were detected in the blubber samples. This study confirmed that 210Po is the dominant contributor to radiation doses resulting from seal consumption. Man-made contaminant 137Cs only contributes less than 0.01% of the total ingestion dose obtained from Arviat seals.

Pb-210 and Po-210 atmospheric releases via fly ash from oil shale-fired power plants

During high temperature processes in the furnace volatile and semi-volatile elements and radionuclides are partially emitted to the environment, depending on their chemical form in the original fuel, the technological set-up of the combustion system, and the prevailing combustion conditions. Two of the world's largest oil shale-fired power plants (PPs) have been operational in Estonia from the 1960s, during which time creation of significant environmental emissions and waste containing naturally occurring radionuclides has occurred. Pb-210 and 210Po are considered natural radionuclides with the highest emission rates from PPs and possess elevated potential radiation exposure risks to humans and the environment. These radionuclides have the highest activity concentration values in fine ash fractions, especially in fractions remaining below 2.5 μm. To determine the activity concentrations of 210Pb and 210Po in the PPs' outlet, sampling was conducted from boilers operating on pulverized fuel (PF) technology with novel integrated desulphurization (NID) system and bag filters as well as with electrostatic precipitators (ESPs). The 210Pb and 210Po activity concentrations remained around 300 Bq kg−1 for the NID system compared to 60–80 Bq kg−1 in the ESP system. The dominant ash fraction in both systems was PM2.5, constituting over 50% of the fly ash mass collected from the outlet. The authors estimate that the total atmospherically emitted activity for the modernized PPs remains dominantly below 1% of the activity that is inserted via fuel. The implementation of higher efficiency purifications systems has significantly reduced the negative effect of these PPs. Based on annually emitted fly ash and boilers' working hours, the 210Pb and 210Po activity released relative to energy production were up to 68.3 kBq GWhel−1 for 210Pb and 64.6 kBq GWhel−1 for 210Po. These values are 1 to 2 orders of magnitude lower compared to the situation in the 1980s. These findings represent the first publicly available quantitative results estimating the 210Po emissions from large oil shale-fired PPs.

210Po Activity Concentrations in Cooked Marine Food

In this work the 210Po activity concentrations determined in the most common marine species consumed by the population of Southern Spain are shown and discussed. The determinations have been done on aliquots of the raw edible materials and in aliquots previously cooked in the usual way they are ingested. The obtained activity concentrations in the edible parts of the cooked products ranged up to three orders of magnitude with concentration factors for some species as high as 104-105 L/kg fresh weight, and due to the cooking processes in some cases a considerable variation in the 210Po activity concentrations have been observed in relation with the determined ones in the aliquots not processed. The importance of this study is based in the fact that 210Po is one of the main contributors to the radiation dose received by the population by ingestion, being the 210Po doses by ingestion particularly high when a population has a diet with a high proportion of marine products.