210Po Concentrations Research Articles

Po uptake in microalgae at different seawater pH: An experimental study simulating ocean acidification

Climate change effects such as ocean acidification (OA) are known to affect the trace metal distribution. This experimental study provides the first data on 209Po uptake rates and 210Po concentration in five microalgae species under different pH scenarios. The experiment was conducted in replicates at three pH conditions 8.2, 8.0, and 7.5, representing the current and future climate change scenario as per IPCC RCP8.5. The 209Po uptake in the phytoplankton was highest in Thalassiosira weissflogi, i.e. 83% of the 209Po tracer was taken up at 8.2 pH whereas the lowest uptake was observed in Dunaliella salina equivalent to 20% at 7.5 pH. Similar behavior was observed in 210Po concentrations in these microalgae, where 210Po ranged between 3.16 ± 0.03 and 11.6 ± 0.04 Bq kg−1 wet weight (ww), with the highest in the Thalassioria weissflogi at 8.2 pH, and the lowest in Dunaliella salina at 7.5 pH. The difference in 209Po uptake and 210Po concentration was statistically significant (p < 0.001) both among species and the pH treatments in the order: Thalassiosira weissflogi > Tetraselmis suecica > Chaetoceros muelleri > Isochrysis galbana > Dunaliella salina and 8.2 > 8.0 > 7.5. A higher concentration of 209Po in seawater was measured at low pH condition in all the experimental tanks. Though the data clearly show the difference in concentration and uptake of polonium at different pH conditions, it is not known if lower pH is affecting the adsorbed or absorbed fraction. A detailed investigation will be required to understand the process as it can have a significant effect on biomagnification and marine food chain transfer under changing climatic scenarios.

Levels of Polonium-210 in brain and pulmonary tissues: Preliminary study in autopsies conducted in the city of Sao Paulo, Brazil

The accumulation of detectable amounts of radon progeny in human tissues may be a risk factor for development and progression of chronic diseases. In this preliminary study, we analyzed the levels of alpha-emitting radon progeny Polonium-210 (210Po) in the olfactory epithelium, olfactory bulb, frontal lobe, and lung tissues in cadavers from the city of Sao Paulo, SP, Brazil. We also assessed the association between 210Po levels and exposure parameters for urban air pollution using linear regression models adjusted for age, sex, smoke, time living in Sao Paulo, daily commuting, socioeconomic index, and anthracosis (traffic-related black carbon accumulation in the pleural region and in lymph). Our findings show that the concentration of 210Po was associated with anthracosis in lungs of non-smokers (coefficient = 6.0; standard error = 2.9; p = 0.04). Individuals with lower socioeconomic status also had significantly higher 210Po levels in lungs (coefficient = −1.19; standard error = 0.58; p = 0.042). The olfactory bulb had higher 210Po levels than either olfactory epithelium (p = 0.071), frontal lobe (p < 0.001), or lungs (p = 0.037). Our findings of the deposition of 210Po in autopsy tissues suggest that airborne radionuclides may contribute to the development of chronic diseases, including neurodegenerative diseases.

210Po and 210Pb activity concentrations in Greenlandic seabirds and dose assessment

Naturally occurring radionuclides, in particular, polonium-210 (210Po), have a greater contribution than anthropogenic radionuclides to the annual effective dose received by the general public due to consumption of seafood. Knowledge of potential trophic sources and transfer of 210Po to seabird species and subsequently to the Greenlandic people is, however, still poor. Here, we assess the transfer of 210Po and 210Pb to seabirds sampled during autumn and winter 2017 and 2018 in Greenland and provide a dose assessment. The activity concentrations of 210Po in muscle and liver, respectively, ranged from 0.2 ± 0.1 Bq kg−1 w.w. in glaucous gull (Larus hyperboreus) to 21.2 ± 22.6 Bq kg−1 w.w. in thick-billed murre (Uria lomvia) and from 32.0 ± 9.4 Bq kg−1 w.w. in common eider (Somateria mollissima) to 40.5 ± 49.0 Bq kg−1 w.w. in thick-billed murre. 210Po was non-uniformly distributed in the body of thick-billed murre. Kidneys and feathers showed higher 210Po activity concentrations than heart and bone. The 210Po/210Pb activity concentration ratios are higher than unity, indicating that 210Po is preferentially taken up by seabirds compared to its progenitor 210Pb. The derived annual absorbed dose from 210Po to the whole body of thick-billed murre was 6.4 × 102 ± 3.0 × 102 μGy. The annual effective dose to the average adult and representative person in Greenland due to ingestion of 210Po in seabirds was estimated to 13.0 μSv and 57.0 μSv, respectively. This derived dose is low and poses a slight risk, and risk communication is therefore deemed unnecessary.

Radionuclide distributions in Olympic Dam copper concentrates: The significance of minor hosts, incorporation mechanisms, and the role of mineral surfaces

Some iron oxide-copper-gold (IOCG) deposits contain variable amounts of uranium. Developing mineral deportment models for the radiogenic isotopes resulting from decay of 238U presents a singular technical challenge, as concentrations of 226Ra, 210Pb, and 210Po fall far below the detection limits achievable for most in situ analytical methodologies. The nanoscale secondary ion mass spectrometry (nanoSIMS) platform combines low detection limits with sub-micron resolution, revealing previously unseen spatial distribution patterns of radionuclides (RNs) in (and on) particles of copper sulphide concentrates. Many potential host minerals for these radionuclides can be readily predicted based on chemical behaviour, periodic table trends, and published studies documenting likely host minerals. Using nanoSIMS data for ores and metallurgical products from the Olympic Dam IOCG deposit and associated processing facilities, we present compelling evidence for the ability of certain minerals within the copper concentrates to host daughter radionuclides derived from uranium decay. Many of these minerals had not traditionally been considered or previously documented as such. These include high-abundance minerals hosting low concentrations of radionuclides, and several relatively low abundance minerals exhibiting remarkable radionuclide enrichment. Rutile, fluorapatite, fluorite, hematite, zircon, covellite, and molybdenite are all proven to be minor hosts of at least some members of the 238U decay chain, and are, collectively, important for establishing the overall RN budget. Surface effects are found to play a significant role, with elevated levels of 226Ra and 210Pb found on most available surfaces, irrespective of mineral, in acid-leached concentrate. Some rRNs, particularly 226Ra and 210Pb liberated from uranium minerals during sulphuric acid leaching, can become extensively redistributed throughout the concentrate, creating newly-formed RN hosts. This new mineralogical deportment information can be used in developing new flowsheets to enhance radionuclide removal without a corresponding loss of Cu. NanoSIMS has proven invaluable for elucidating the mineral-scale deportment of ultra-trace radionuclides throughout the processing circuit at Olympic Dam.

Modeling of 210Pb and 210Po radionuclide emissions from local power plants in central Poland.

Due to the more volatile nature of 210Po in relation to 210Pb, an imbalance of activity concentrations in high temperature combustion processes can be observed, especially in fine particulates (diameter < 0.1, 0.2 and 0.5 μm). In the atmosphere and in the soil around coal-fired power plants, 210Pb and 210Po concentrations are a combination of activities from natural and anthropogenic sources. In this study only portions of 210Po and 210Pb radionuclides resulting from energy production activities were analyzed. Due to the high mobility of fine particles, a surface area of 172 km × 140 km in central Poland was chosen for simulation. For validation of the modeling approach, three grid versions were applied: 1 km, 2 km and 4 km. Simulated results confirmed experimental-computational values of an excess of both radionuclides in the atmosphere in 2017 in the city of Lodz. Different aerosol fractions, seasons and various grids in the selected area were subjected to 36 individual simulations. The 210Po activity concentrations measured in winter and summer 2017 were 42.5 and 8.99 μBq m-3, respectively. Simulated and measured values of artificial 210Po and 210Pb activities are well correlated.

Activity concentration of polonium-210 and lead-210 in tobacco products and annual committed effective dose to tobacco users in Tiruchirappalli District (Tamil Nadu, India)

The present study has carried out with an objective of determining the activity concentrations of two radionuclides namely polonium-210 (210Po) and lead-210 (210Pb) in smoke tobacco products (cigarette, bidi and cigar) and smokeless tobacco products (chewing tobacco and snuff) consumed in Tiruchirappalli District, Tamil Nadu (India) and their annual committed effective dose to tobacco consumers. The concentration of 210Po was always higher than that of 210Pb in all the analyzed tobacco products. It also revealed that 79% of Annual committed effective dose comes from 210Po and about 21% from 210Pb. Maximum concentration (13.2 mBq g−1) of 210Po recorded in cigarette and lowest concentration was observed in snuff (6.4 mBq g−1). The highest mean committed effective dose of 210Po and 210Pb in various tobacco products were found in cigarette followed by bidi, cigar, chewing tobacco and snuff. The study revealed that the tobacco products available in Tiruchirappalli District contain a relatively lower concentration of radionuclides when compared to other regional studies. Since this kind of study in India is fragmentary, the present study has generated a base data for the first time for entire Tiruchirappalli District.

Determination of 210Po in air filters from metallurgic industry

The elevated concentration of 210Po attached to aerosol particles inside a non-ferrous metal refinery was studied. The aerosols were collected on Petrianov or glass-fiber filters and subsequently subjected to radiochemical procedure consisting of acid leaching and concentration by micro co-precipitation with manganese oxide. For the activity determination alpha spectrometry and liquid scintillation counting (LSC) were applied. The obtained results showed that usually observed polonium concentration inside the plant was lower than 78 mBq m−3, however short spikes up to 7430 ± 710 mBq m−3 (related to the specific thermal process) were also observed.

Spatial variability in Polonium-210 and Lead-210 activity concentration in New Zealand shellfish and dose assessment

The activity concentrations of Polonium-210 (210Po) and Lead-210 (210Pb) were determined in shellfish (Perna canaliculus and Paphies subtriangulata) sampled bimonthly from March 2018 to February 2019 from 14 sites around New Zealand. Activity concentrations of 210Po ranged from 4.7 ± 1.1 to 324 ± 17 Bq. kg−1 with a mean value of 57 ± 72 Bq. kg−1 (wet weight). The activity concentrations of 210Pb were lower than those for 210Po (0.1 ± 0.4 and 1.9 ± 0.4 Bq. kg−1, with a mean value of 0.7 ± 0.4 Bq. kg−1, wet weight). The calculated 210Po/210Pb activity concentration ratios were higher than unity in all samples indicating that radionuclides are not in equilibrium in shellfish and most of the 210Po was unsupported by its grandparent 210Pb. No significant difference was noted in 210Po activity concentration between different seasons, species or shellfish condition index. Significant spatial variability in 210Po activity concentration was observed with elevated 210Po activity concentration in two sampling sites: Ninety Mile Beach (mean 257 ± 47 Bq. kg−1) and Maunganui Bluff (mean 127 ± 22 Bq. kg−1). Elevated 210Po is hypothesised to be related to an increase of 210Po accumulation through diet. Individuals who consume large quantities of shellfish (10 g per day or more) from areas affected by elevated 210Po activity concentration may be exposed to an annual committed effective dose from 210Po in shellfish in excess of 1 mSv.

Po-210 production in the European DEMO fusion reactor

The radionuclide inventory plays a central role in the safety of nuclear installations both during operation and their decommissioning. In nuclear fusion reactors using Pb–Li tritium breeding blankets, the undesired production of radiotoxic 210Po is still an unresolved safety issue. In this work, neutron transport calculations and inventory calculations are combined to predict the 210Po inventory in a DEMO fusion reactor using either a helium cooled lithium lead or a water cooled lithium lead breeding blanket. In order to guarantee that the environmental 210Po release associated with an ex-vessel leak-of-PbLi accident remains below the no-evacuation limit, the 210Po concentration in the Pb–Li should be kept below 1500 appt. It was found that no Pb–Li purification is required to keep the 210Po concentration in DEMO below this limit. However, in case the Pb–Li makes direct contact with water, more volatile Po-containing (oxy-)hydroxides could form. If these species increase the 210Po release rate by more than a factor of two, safety measures will be required. Therefore, 210Po generation in DEMO does not pose a hazard in case of a regular ex-vessel leak-of-PbLi accident, unless possibly in case the Pb–Li makes contact with water.

Assessment of 210Po and 210Pb by moss biomonitoring technique in Thrace region of Turkey

This study presents the first data of 210Po and 210Pb activity concentrations using moss species Hypnum cupressiforme from Thrace region, the northwestern part of Turkey. The moss samples were systematically collected from 40 locations in the study area. The average with standard deviation and range of 210Po and 210Pb activity concentrations were found to be 409 ± 128, 188–777 and 494 ± 183, 178–852 Bq kg−1 at dry weight, respectively. Comparatively higher radionuclide activities were found in the northeastern Thrace, probably due to 222Rn daughters attached to aerosols through high rainfall in this part of the region. A significant positive correlation was found between 210Po and 210Pb, which shows that their source and/or bioaccumulation behavior are similar. The average and range of 210Po/210Pb ratio were calculated to be 0.89 and 0.47–2.67, respectively. Those levels were calculated to be mostly lower than unity that addressed the abundance of 210Pb, probably due to predominantly inorganic particles through atmospheric deposition.

Levels of radionuclide concentrations in benthic invertebrate species from the Balearic Islands, Western Mediterranean, during 2012-2018.

Baseline levels of radionuclides in the marine environment of the Balearic Islands in Western Mediterranean have not been reported in literature. Because of their ecological role and acknowledged sensitivity to pollutants, herein, the activity concentrations of 210Po, 40K, 210Pb, 90Sr, and 234Th were measured in two types of benthic invertebrate species (mussels and sea urchins) sampled during 2012-2018. The activity concentrations of 210Po, 40K, 210Pb, and 234Th ranged from 38 ± 1 to 325 ± 11 Bq kg-1 dry weight (d.w.), 220 ± 10 to 996 ± 46 Bq kg-1 d.w., ND (lower than the limit of detection) to 55 ± 8 Bq kg-1 d.w., and ND to 70 ± 15 Bq kg-1 d.w., respectively. In all cases, no artificial 90Sr activity was detected in the collected samples. The committed effective dose to humans was calculated to be in the range of 48-640 μSv year-1.

Distribution of 210Po and 210Pb radionuclides and their dependence on physico-chemical parameters of soil in Madikeri taluk, Coorg district, Karnataka, India

The paper deals with distribution of 210Po and 210Pb radionuclides in a vertical profile of illuviated soil, in Madikeri taluk of Coorg district, Karnataka, India. The activity concentration of 210Po and 210Pb radionuclides was determined using radioanalytical method and the dependence of these radionuclides on physico-chemical parameters of soil was also investigated through a statistical study. In all the layers of the soil in a vertical profile, the 210Po nuclides were found to be in disequilibrium with 210Pb. The frequency distribution of 210Po and 210Pb radionuclides was analysed using Kolgomorov–Smirnov test.

Natural radioactivity concentration in traditional Thai herbal medicine

The aim of this study is to create a database of radioactivity concentration and annual effective dose of the naturally occurring radionuclides: 226Ra, 228Ra, 40K and 210Po in Thai medicinal herb plants. 99 types of popular Thai medicinal herb plants (total of 214 samples) such as Curcuma comosa Roxb., mucuna, white kwao krua, barbed grass, black galingale, lingzhi mushroom, Ginkgo biloba, jiaogulan, plu kaow, turmeric, ginger, safflower, moringa, gotu kola and garlic were randomly collected from drug stores and herbal fair. The activity concentration of 226Ra, 228Ra and 40K in all herb samples was determined by gamma-ray spectrometry while that of 210Po was determined by alpha spectrometry. The activity concentration was found to range from <0.20 to 89.92 Bq kg−1 for 226Ra, from <0.10 to 39.62 Bq kg−1 for 228Ra and from 4.83 to 2761.33 Bq kg−1 for 40K and from 0.32 to 47.13 Bq kg−1 for 210Po. The highest activities concentration of 226Ra, 228Ra, 40K and 210Po were found in the white kwao krua, jiaogulan, plu kaow and ginkgo, respectively. The average total annual effective dose due to ingestion of these herbal plants was assessed to range from 0.0001 to 0.0327 mSv y−1, with highest dose found in jiaogulan.

Accumulation of natural and anthropogenic radionuclides in body profiles of Bryidae, a subgroup of mosses.

Mosses can be used as biomonitors to monitor radionuclide deposition and heavy metal pollution in cities, forests, and grasslands. The aims of this work were to determine the activity concentrations of natural (210Po, 210Pb or 210Pbex (excess 210Pb is defined as the activity of 210Pb minus the activity of 226Ra), 7Be, 40K, 226Ra, 238U, and 232Th) and anthropogenic radionuclides (137Cs) in moss body profiles and in situ underlying soils of moss samples and to assess/determine the distribution features and accumulation of these radionuclides. Activity concentrations of radionuclides in the samples were measured using a low-background gamma spectrometer and a low-background alpha spectrometer. Consistent with their source, the studied radionuclides in the moss samples and underlying soils were divided according to the principal component analysis (PCA) results into an airborne group (210Po, 210Pb (210Pbex), 7Be, and 137Cs) and a terrestrial group (40K, 238U, 226Ra, and 232Th). The activity concentrations of 210Po and 210Pbex in moss body profiles were mainly concentrated in the stems-rhizoid parts, in which we measured some of the highest 210Po and 210Pbex levels compared to the results in the literature. 7Be mainly accumulated in the leaves-stem parts. Different positive correlations were observed between 210Po and 210Pb and between 7Be and 210Pb, which indicated that the uptake mechanisms of 210Po, 210Pb, and 7Be by moss plants were different, to some extent. 137Cs was detected only in some moss samples, and the fraction of 137Cs in the underlying soils was much lower than that in the moss, suggesting that mosses were protecting the underlying soils from further pollution. Except for 40K, the terrestrial radionuclide (238U, 226Ra, and 232Th) content in mosses was predominantly at low levels, which indicated not only the inability of mosses to use those elements for metabolic purposes but also the rather poor capability of mosses to directly mobilize, absorb, and transport elements (U, Ra, or Th) not dissolved in water.

The radiation dose and distribution coefficient of 210Po and 210Pb concentrations in aquatic environs of major rivers of coastal Karnataka

The activity of 210Po and 210Pb was measured in different matrices of aquatic ecosystem of the major rivers of Coastal Karnataka viz, Kali, Sharavathi and Netravathi. The environmental samples such as surface water, suspended particulate matter and sediment have been subjected to analyses. The activity of these two radionuclides were determined by radiochemical separation of 210Po and counting the activity using a ZnS(Ag) alpha counter. The activity ratio of 210Po and 210Pb and correlation between the activity of these radionuclides were studied. From the measured concentration of 210Po and 210Pb, the internal Committed Effective Dose to the population for the study area was calculated. The distribution coefficient Kd between water, suspended particulate matter and sediments have been calculated to understand the distribution and accumulation of these radionuclides in different matrices of the aquatic environment.

Concentration of 210Po and 210Pb in macroalgae from the northern Gulf

This baseline study highlights the 210Po and 210Pb concentration in seven macroalgae species from the northern Gulf that are frequently washed ashore during the bloom season from February to April. The highest concentrations of 210Po and 210Pb were 2.947 ± 0.032 and 1.057 ± 0.145 Bq kg−1 wwt, respectively, in brown algae Sargassum boveanum, and the lowest in green algae Ulva prolifera with 1.533 ± 0.058 and 0.170 ± 0.069 Bq kg−1 wwt, respectively. A 210Po enrichment was observed in both brown and green algae species, with the 210Po/210Pb ratio being >1 for all the samples. The mean concentration of 210Po in all species was an order of magnitude higher than 210Pb, and the difference in mean concentration is statistically significant (p < 0.001). At the same time, the mean concentration of dissolved 210Po and 210Pb in seawater was 0.28 ± 0.01 and 0.52 ± 0.01Bq m−3 with a 210Po/210Pb ratio of 0.54 ± 0.02 indicating that 210Po was absorbed from water and more concentrated by macroalgae. The measured concentration factor (CF) for 210Po in these macroalgae for the northern Gulf varied between 5 × 103–1 × 104, higher than the IAEA recommended value of 1 × 103 which suggests that a revision of that value may be needed. The field derived CFs for 210Pb vary between 3 × 102–1.8 × 103, comparable to the ICRP recommended value of 2 × 103.

Determination of 210Po in low-level wild bilberries reference material for quality control assurance in environmental analysis using extraction chromatography and α-particle spectroscopy

Abstract Certified reference materials (CRM) are being widely used for quality control assurance in environmental analysis. For certain CRM, the analytes and/or the range of concentrations are not be available or certified at all. The Joint Research Centre – Institute for Reference Materials and Measurements (JRC-IRMM) of the European Commission has issued a CRM of Wild Berries (IRMM-426) in order to validate radionuclide measurement methods for activity concentrations of the natural radionuclide 40K and the anthropogenic nuclides 90Sr and 137Cs, but not for 210Po. The aim of the work was to determine low-level activity concentration of 210Po in these wild berries. The activity concentration of 210Po was assessed by α-particle spectroscopy after dissolution of the sample by wet digestion and chemical isolation of Po by extraction chromatography. According to the time elapsed since sample collection, the results here shown can be useful not only for ultra low-level analysis of 210Po but also for 210Pb in the reference material.

Trace elements, 210Po and 210Pb in a selection of berries on commercial sale in Italy

The occurrence of 210Pb, 210Po, trace elements was assessed in a selection of berries on commercial sale in Italy. Data confirmed that berries might serve as an important source of essential elements. The 210Pb, 210Po concentrations found were higher than the reference values reported by UNSCEAR for roots and fruits in the world. There is no risk whatsoever from the intake of toxic elements as Al, As, Cd, Pb, Ni, Hg in berriberries analyzed; it is necessary, however, continuously monitored the levels of these elements to protect consumers against potential adverse health effects especially when consumed in large quantities.

210Po and 210Pb concentration in zooplankton of the Syrian coastal waters (eastern Mediterranean Sea)

210Po and 210Pb activity concentrations and their concentration ratio (CR) in marine zooplankton collected for the first time from the Syrian coastal waters (the eastern Mediterranean Sea) have been determined. The average activity concentrations of 210Po and 210Pb were 243±36 and 26.4±4.3 Bqkg-1 dw. The 210Po/210Pb activity ratio was found to be more than one in all zooplankton samples with an average of 9.2 (8.4 to 10), which indicates that the accumulation of 210Po in zooplankton does not come from the decay of the 210Pb only, and reflects a preferential bioaccumulation of 210Po over 210Pb. In addition, the Concentration Ratio (CR) for 210Po and 210Pb reached 104 and 103, respectively. This study will contribute to the radioecological reference database for zooplankton in the Mediterranean Sea.

A REVIEW ON 210Po AND 210Pb IN INDIAN SEAFOOD AND DOSE TO CONSUMERS.

India is the second largest seafood producer in the world marketing more than 7000 edible species. In this regard, commendable studies have been conducted since the 1970s by different research groups and more data are reported. In this work, all the studies on 210Po and 210Pb measurements in abiotic and biotic components of India have been combined and reviewed. The concentrations of 210Po and 210Pb are estimated by radiochemical separation followed by alpha counting. Grain size, season, Tsunami waves and place of sampling have a decisive bearing on 210Po and 210Pb concentration in abiotic components. Plankton shows a higher Kd factor (104) compared to seaweeds and sea grass (103). Pond ecosystems recorded the highest Kd factor (4·3 × 104) compared to other freshwater and marine ecosystems. Bioaccumulation of 210Po and 210Pb varies with respect to variety of seafood. The committed effective dose (CED) calculated for shellfish species maintained a higher range of 2.5 × 10-2 mSv/y to 9.8 × 10-1 mSv/y and for fish species fluctuated from 3.8 × 10-4 mSv/y to 2.0 × 10-1 mSv/y. The studies conducted so far are scattered, and need to be gathered for future reference and planning (i.e. There is not much information available for Kerala, Karnataka, Maharashtra, Gujarat, Andhra, West Bengal and Odessa coast). Therefore, it is strongly recommended that further and more complete research is undertaken to study the bioaccumulation of 210Po and 210Pb from seafood. Overall, the present review concludes that Indian seafood is radiologically safe.