Time-Integrated Bioavailability Proxy for Actinides in a Contaminated Estuary

Actinides accumulate within aquatic biota in concentrations several orders of magnitude higher than in the seawater [the concentration factor (CF)], presenting an elevated radiological and biotoxicological risk to human consumers. CFs currently vary widely for the same radionuclide and species, which limits the accuracy of the modeled radiation dose to the public through seafood consumption. We propose that CFs will show less dispersion if calculated using a time-integrated measure of the labile (bioavailable) fraction instead of a specific spot sample of bulk water. Herein, we assess recently developed configurations of the diffusive gradients in thin films (DGT) sampling technique to provide a more accurate predictor for the bioaccumulation of uranium, plutonium, and americium within the biota of the Sellafield-impacted Esk Estuary (UK). We complement DGT data with the cross-flow ultrafiltration of bulk seawater to assess the DGT-labile fraction versus the bulk concentration. Sequential elution of Fucus vesiculosis reveals preferential internalization and strong intracellular binding of less particle-reactive uranium. We find significant variations between CF values in biota calculated using a spot sample versus using DGT, which suggest an underestimation of the CF by spot sampling in some cases. We therefore recommend a revision of CF values using time-integrated bioavailability proxies.

Unveiling the extreme environmental radioactivity of cryoconite from a Norwegian glacier

This study is a first survey of the occurrence of artificial (¹³⁷Cs, ²⁴¹Am, ²⁰⁷Bi, Pu isotopes) and natural (²¹⁰Pb, ²²⁸Ac, ²¹⁴Bi, ⁴⁰K) radionuclides in Norwegian cryoconite. Cryoconite samples were collected before (12 samples) and after (5 samples) a rainfall event, after which 7 cryoconite holes dissapeared. The concentrations of radionuclides in cryoconite samples from the Blåisen Glacier are compared with data from the Arctic and Alpine glaciers. Cryoconite samples from the studied glacier had extremely high activity concentrations of ¹³⁷Cs, ²⁴¹Am, ²⁰⁷Bi and ^239+240Pu (up to 25,000 Bq/kg, 58 Bq/kg, 13 Bq/kg and 131 Bq/kg, respectively) and also high concentrations of organic matter (OM), comparing to other Scandinavian and Arctic glaciers, reaching up to ~40% of total mass. The outstandingly high concentrations of ¹³⁷Cs, ²⁴¹Am, Pu isotopes, and ²⁰⁷Bi on the Blåisen Glacier are primarily related to bioaccumulation of radionuclides in organic-rich cryoconite and might be enhanced by additional transfers of contamination from the tundra by lemmings during their population peaks. The presumed influence of intense rainfall on radionuclide concentrations in the cryoconite was not confirmed.

Temporal variability of Pu signatures in a 210Pb-dated Sphagnum peat profile from the Northern Ural, Russian Federation

The peat archives are one of the stratigraphic records revealing clearly physical, chemical and biological signals of human influence on the Earth System since the 1950s, at least. The presented study was aimed mainly to identify the level and origin of anthropogenic radionuclides such as ^{238, 239, 240}Pu in a ²¹⁰Pb-dated peat profile derived from the Northern Ural, Russian Federation. As stated, the vertical variability of ²⁴⁰Pu/²³⁹Pu isotopic compositions reflects the nuclear weapons testing history with the maximum in the 1960s and small regional impact most likely of high-yielded tests in the 1950s as well as Chinese detonations in the 1970s. Peat accumulations rates were similar to those obtained in adjacent areas, whereas ²¹⁰Pb flux slightly exceeded the reference level established for adequate latitude belt.

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.

Plutonium and thorium isotopes in the bottom sediments of some Mazurian Lakes (Poland)

Presented are results on the Pu and Th isotopes activity concentration found in the upper part of bottom sediments collected from a deep part of 29 lakes in N-E Poland by diving in 2000. Analyses of Pu isotopic ratios allowed for the discussion of Pu origin. Maximum percentage of 239+240Pu activity from Chernobyl fallout was 24%. Surface deposition of 239+240Pu was calculated. No relationship was found between the plutonium and main chemical matrix components of sample nor with the trophic status of the lake. Pu activities were weakly correlated with measured previously 137Cs activities.

The sources of high airborne radioactivity in cryoconite holes from the Caucasus (Georgia)

Cryoconite granules are mixtures of mineral particles, organic substances and organisms on the surface of glaciers where they decrease the ice albedo and are responsible for formation of water-filled holes. The contaminants are effectively trapped in the cryoconite granules and stay there for many years. This study evaluates the contamination level of artificial and natural radionuclides in cryoconite holes from Adishi glacier (Georgia) and identifies the sources of contamination based on activity or mass ratios among artificial radionuclides. Results revealed high activity concentrations of fallout radionuclides reaching 4900 Bq/kg, 2.5 Bq/kg, 107 Bq/kg and 68 Bq/kg for ¹³⁷Cs, ²³⁸Pu, ^239+240Pu and ²⁴¹Am, respectively. The main source of Pu is global fallout, but the low ²⁴⁰Pu/²³⁹Pu atomic ratios also indicated local tropospheric source of ²³⁹Pu, probably from the Kapustin Yar nuclear test site. Also, high activity ratios of ²⁴¹Am/^239+240Pu could originate from Kapustin Yar. The natural radionuclides originate from the surrounding rocks and were measured to control the environmental processes. ²¹⁰Pb in cryoconite granules comes predominantly from the atmospheric deposition, and its activity concentrations reach high values up to 12000 Bq/kg.

Plutonium, 137Cs and 90Sr in selected invertebrates from some areas around Chernobyl nuclear power plant

Results are presented for (137)Cs, (90)Sr and plutonium activity concentrations in more than 20 samples of terrestrial invertebrates, including species of beetles, ants, spiders and millipedes, collected in the highly contaminated area of the Chernobyl exclusion zone. The majority of samples were collected in Belarus, with some also collected in the Ukraine. Three other samples were collected in an area of lower contamination. Results show that seven samples exceed an activity concentration of 100 kBq/kg (ash weight--a.w.) for (137)Cs. The maximum activity concentration for this isotope was 1.52+/-0.08 MBq/kg (a.w.) determined in ants (Formica cynerea). Seven results for (90)Sr exceeded 100 kBq/kg (a.w.), mostly for millipedes. Relatively high plutonium activity concentrations were found in some ants and earth-boring dung beetles. Analyses of activity ratios showed differences in transfer of radionuclides between species. To reveal the correlation structure of the multivariate data set, the Partial Least-Squares method (PLS) was used. Results of the PLS model suggest that high radiocesium activity concentrations in animal bodies can be expected mainly for relatively small creatures living on the litter surface. In contrast, high strontium activity concentrations can be expected for creatures which conduct their lives within litter, having mixed trophic habits and a moderate lifespan. No clear conclusions could be made for plutonium.

Ghrelin ameliorates colonic inflammation. Role of nitric oxide and sensory nerves

Ghrelin is a novel growth hormone (GH)-releasing and orexigenic peptide with anti-inflammatory activities. However, the role of ghrelin in the colonic inflammation is still controversial. The aim of the present study was: 1) to examine the expression of ghrelin and TNF-alpha mRNA in the inflamed colonic mucosa of patients with ulcerative colitis (UC), 2) to analyze the effect of treatment with exogenous ghrelin on the healing of trinitrobenze sulphonic acid (TNBS)-induced colitis in rats, and 3) to assess the effects of ghrelin treatment on mRNA expression for iNOS and protein expression for COX-2 and PPARalpha in intact colonic mucosa and in that with TNBS-induced colitis. Fifteen patients with UC and fifteen healthy controls were enrolled in this study. Expression of ghrelin and TNF-alpha was assessed by semi-quantitative RT-PCR in the colonic mucosal biopsies from UC patients and healthy controls. In addition, the effect of exogenous ghrelin on healing of TNBS colitis was tested in rats without or with capsaicin-induced functional ablation of sensory nerves. Patients with UC showed a significant upregulation of mRNA for ghrelin and TNF-alpha in colonic mucosa as compared to that observed in healthy controls. The expression of ghrelin correlated with the grade of inflammation and expression of TNF-alpha. In rats the exogenous ghrelin administered daily at a dose of 20 microg/kg i.p. significantly accelerated the healing of TNBS colitis and this effect was accompanied by an increase in mRNA expression for iNOS and protein expression for COX-2 in the colonic mucosa. The protein expression for PPARgamma, which was down-regulated in rat colonic mucosa after exposure to TNBS as compared to that in intact colonic mucosa, was not significantly influenced by ghrelin treatment. We conclude that 1) patients with UC show an increased mucosal expression of mRNA for ghrelin in the colonic mucosa which could trigger protective response in inflamed colon; and 2) exogenous ghrelin accelerates healing of colonic lesions in animal model of ulcerative colitis via increased release of NO and PGE(2) due to an increase in iNOS and COX-2 expression and stimulation of sensory neuropeptides such as CGRP released from sensory afferent endings.

Traces of DU in samples of environmental bio-monitors (non-flowering plants, fungi) and soil from target sites of the Western Balkan region

This paper reports results of gamma and alpha spectrometric measurements for mosses, lichens, fungi and soil samples from areas in the Balkans targeted by depleted uranium (DU). Samples were collected in 2002 and 2003 in the vicinity of several villages, principally Han Pijesak (Bosnia and Herzegovina, hit by DU in 1995) and Bratoselce (South Serbia, hit by DU in 1999) and in lesser numbers from Gornja Stubla, Kosovo (which is identified as a high natural radon/thoron area) and Presevo close to the Kosovo border. In the course of gamma spectrometric measurements some results suggested samples with unusual high uranium contents which might be considered to be a signature for the presence of DU, although many samples had very high detection limits. Alpha spectrometric measurements directly proved the presence of DU for five samples, all from directly targeted places. These were samples of mosses, lichens and soil. For some samples homogeneity tests were applied which showed a rather even distribution of DU in these samples. No trace of DU was found in any sample from a dwelling.

Inhalation dose due to presence of 131I in air above septic tank system of an endocrinology hospital

We present here measurements of the 131I concentration for both: gaseous and aerosol fraction of 131I in the air above the septic tank containing wastes from medical application of this isotope. Aerosols were collected using air filters, whereas gaseous forms of iodine were trapped in KI impregnated charcoal double layer cartridge. Besides an active method (pumping of the air through system of filters) an attempt for using a passive method (charcoal traps) for monitoring of radio-iodine is described. For better characterisation of a site the external kerma was determined by means of G-M and TLD techniques as well as the activity kept in the septic tank was measured by gamma spectrometry. Results show that the activity of the aerosol fraction can be neglected compared to that of the gaseous fraction. He measured activity of air is low, on the level of 1 Bq m(-3), even during simulated failure of the ventilation system. Estimated inhalation dose for the serviceman of septic tanks is low ( approximately 10%) compared with external dose obtained by such person due to gamma radiation from the tank (on the level approximately 500 nSv h(-1)). Therefore, the concept of passive monitoring of the iodine in air was abandoned. Also estimated is the efficiency of 131I reduction by a charcoal filter of the ventilation system and 131I input to the environment by the ventilation chimney.

40K, 137Cs, 90Sr, 238,239+240Pu and 241Am in mammals' skulls from owls' pellets and owl skeletons in Poland

Skulls of small mammals belonging to two species of rodents and three species of insectivores collected in Eastern Poland were the subject of the present investigation. The skulls were separated from owl pellets. Activities of 40K, 137Cs, 90Sr, 238,239+240Pu and 241Am were determined by means of gamma spectrometry as well as liquid scintillation spectrometry or alpha spectrometry along with relevant radiochemical procedures. A detailed description of the procedures is provided. The research was supplied with the analysis of three skeletons of owls. No measurable difference between the skulls of rodents and insectivorous animals with regard to activity of any of the examined radionuclides was found. No accumulation effect in the owl skeletons was detected. Though measured activities of 137Cs and 40K for the skulls were of the same magnitude as those found previously for large wild herbivorous animals from typical locations in Poland, those for 90Sr were even lower than previously determined. A big difference was found for activities of plutonium and americium isotopes. Their mean activities were higher by an order of magnitude when compared to the examined previously values. The maximum 239+240Pu activity was equal to 97.5+/-7.7 mBq/kg, with 65% of it originating from global fallout. Relatively high content of transuranic elements found for rodents and insectivorous mammals seems to be unrelated to their feeding habits and should rather be attributed to the living conditions. It is suggested that small mammals, together with tiny soil particles present in mid-soil living tunnels, can inhale the transuranic elements.

Transuranic isotopes and 90Sr in attic dust in the vicinity of two nuclear establishments in northern Germany

Attic dust was chosen as the test medium in order to search for traces of man-made bone seeking alpha and beta emitters. The samples were taken from 5 houses in the community of Elbmarsch situated at the river Elbe, adjacent to the Krümmel nuclear power plant and the nuclear research center of Geesthacht. Five houses in other regions of northern Germany were taken as a control. 238Pu, (239,240)Pu, 241Am, and 244Cm were measured by alpha spectrometry after chemical separation. Additionally, 241Pu was measured by liquid scintillation spectrometry, and the fission product 90Sr was measured in a separate investigation. All nuclides except 244Cm showed activities above the detection limit in the Elbmarsch samples and an elevated mean concentration compared to the control. It can be concluded from the activity ratio 241Am/(239,240)Pu that the Elbmarsch contamination cannot be accounted for by the background levels of transuranic nuclides resulting from weapons fallout. The derived release of alpha emitters is assumed to have contributed to the induction of a leukemia cluster in children, which was observed in Elbmarsch between 1990 and 1996.

Geotrupine beetles (Coleoptera: Scarabaeoidea) as bio-monitors of man-made radioactivity

Adults of the geotrupine beetle Anoplotrupes stercorosus (Coleoptera, Geotrupidae), a common European forest insect species, were used in the role of bio-monitors for mainly man-made radionuclides in a forest environment. Activities of 137Cs, 40K, 238Pu, (239+240)Pu, 90Sr and 241Am were studied. Samples originated from four areas in Poland, two from the north-east and two from the south of the country. The north-eastern areas were previously recognized as the places where hot particle fallout from Chernobyl took place. Results confirmed the differences in the activities between north-eastern and southern locations. Significant correlations were found between activities of 40K and 137Cs, and between activities of plutonium and americium isotopes. An additional study of the concentration of radionuclides within the bodies of beetles showed a general pattern of distribution of radioisotopes in the insect body.

Plutonium and other alpha emitters in mushrooms from Poland, Spain and Ukraine

The paper presents results on Pu, U and Th isotope activity concentration measurements in some mushroom samples collected in Poland, Spain and Ukraine. The sampling sites differ a lot with regard to observed levels of Pu, its origin and isotope ratios as well as the environmental properties. Some of the Polish samples were collected in the northeastern part of the country with up to 30 Bq/m2 of Chernobyl Pu deposition. Other Polish and the Spanish samples are from areas with almost exclusively global fallout Pu present. Ukrainian samples were collected in a highly contaminated area with a deposition of about 3.7 kBq/m2 of Chernobyl (239-240)Pu. The maximum (239+240)Pu activity concentration was found equal to (54+/-4) Bq/kg (dw--dry weight) for a Ukrainian Cantharellus cibarius sample. Ukrainian samples have an extremely high radiocesium level, with maximum of (51+/-4) MBq/kg (dw). The maximum (239+240)Pu activity concentration for Polish samples was (81+/-5) mBq/kg (dw) for Xerocomus badius. From the isotopic ratio in this sample it can be concluded that Chernobyl fallout is the origin of Pu. More than twice as large was the Spanish maximum for Hebeloma cylindrosporum but with only global fallout Pu. Some aspects of the transfer of nuclides to fruit bodies is discussed and in some cases the transfer factors or aggregation coefficients were calculated. Especially high transfer factors were found for Hebeloma cylindrosporum from Spain.

Radionuclides in raised bogs: a case study of Bór za Lasem

Bór za Lasem is a raised bog in the Orawsko-Nowotarska Valley (southern Poland). About half of the Bór za Lasem area has been exploited while the rest is undisturbed. Peat samples from both parts of the bog were analysed. Measurements of 137Cs, 134Cs, 239,240Pu, 238Pu, 40K, 228Ra, and 226Ra activity concentrations in all samples were performed. Comparison of the results of radiocaesium and plutonium activity concentrations reveals the highest activity concentrations of radionuclides in the undisturbed part of the peat-bog area. The radiocaesium content decreased with depth, whereas the plutonium concentration had a maximum value at a depth of 15-20 cm. The lowest activity concentrations were found in the exploited part of the bog. Potassium and radium isotopes were detected only in shallow openings within the heavily exploited part of the bog, which might suggest partial mixing of the peat with the mineral sub-soil. The growth rate of the top layer of the undisturbed part of the bog obtained from plutonium distribution was estimated as approximately 0.5 cm per year.

Plutonium and other alpha-emitters in bones of wild, herbivorous animals from north-eastern Poland

The results of the investigation of (239+240)Pu, 241Am and thorium isotope activity concentrations in bones of wild herbivorous animals (deer, roe-deer, boars, elks) from north-eastern Poland are presented. The area on which the animals were living had relatively high Chernobyl plutonium fallout. Possible traces of plutonium were seen only in four samples, but only for one it was it 3sigma above background, at 6.2 +/- 2.4 mBq/kg (ash). The 241Am activity concentration was below the detection limits in all samples. The maximum 228Th concentration in the samples was 7.81 +/- 0.44 Bq/kg (ash), calculated under the assumption of 100% thorium recovery. This isotope seems to originate in bones not from direct incorporation but from the decay of 228Ra. Large variations in activity concentration wose observed, as well as some differences between boars and the chewing animals.