Radiocesium (137Cs) concentrations in the two-toed amphiuma (Amphiuma means) and the lesser siren (Siren intermedia) Publication date: March 2020 Source: Journal of Environmental Radioactivity, Volume 213 Author(s): David L. Haskins, Albert L. Bryan Abstract This study sought to determine radiocesium (137Cs) concentrations in two species of aquatic salamanders – the two-toed amphiuma (Amphiuma means) and the lesser siren (Siren intermedia) on the Savannah River Site. Concentrations (137Cs Bq/g, dry wt) of the two species were similar at both 137Cs-contaminated (A. means = 0.733 ± 0.242, n = 5; S. intermedia = 0.839 ± 0.722, n = 5) and reference sites (A. means = 0.028 ± 0.020, n = 5; S. intermedia = 0.042 ± 0.027, n = 11). Salamanders captured in areas impacted by 137Cs contamination exhibited significantly higher 137Cs concentrations than individuals captured at reference sites (U = 146, p < 0.001). Salamander size (snout-vent length) was not correlated with whole-body 137Cs. An analysis of our data using the ERICA tool suggests that negative impacts due to 137Cs exposure are unlikely in these species. Overall, these data indicate that A. means and S. intermedia inhabiting contaminated sites bioaccumulate but do not biomagnify 137Cs.

90Sr/137Cs ratios in soil of epicentral zones of «Experimental Field» testing site of Semipalatinsk Test Site Publication date: March 2020 Source: Journal of Environmental Radioactivity, Volume 213 Author(s): Yu.V. Baklanova, M.A. Umarov, M.T. Dyuisembaeva, S.N. Lukashenko Abstract The paper presents the results of 90Sr/137Cs isotopic ratios in the soil surface layer in the venues of surface and atmospheric nuclear tests at the territory of the «Experimental Field » site of the Semipalatinsk Test Site. One of the main factors in the radiation impact of a nuclear explosion on the environment is the decay of fission products. The determination of 137Cs activity in soil is carried out by accurate, rapid and sufficiently cheap gamma-spectrometric method, while the existing methods of determining 90Sr activity are quite problematic: they either have sufficiently high detection limits or are time-consuming. As an alternative method, 90Sr activity can be determined using its correlation dependence with 137Cs activity. According to the literature, each test has its own fission product ratio, depending on the nuclear charge. As a result of the conducted research it was revealed that one epicenter is located at the technical site P-1, the ratio of 90Sr/137Cs is equal to 4,8; at the technical site P-3 - 2 epicenters, the ratio of 90Sr/137Cs is equal to 0,8 and 0,9; at the technical site P-5 - 6 epicenters, the ratio of 90Sr/137Cs is in the range of 0,9-2,1; at the technical sites P-2, P-7 - 19 epicenters, the ratio of 90Sr/137Cs is in the range of 0,6-2,1. It is assumed that the differences in the value of fission product ratios are due to different types and capacities of nuclear charges, as well as different explosion altitudes. The obtained ratios allow to calculate 90Sr by 137Cs activity in soil of the epicentral zones at the territory of the «Experimental Field » testing site by the computational method.

Investigation of interaction behaviours of cesium and strontium ions with engineering barrier material to prevent leakage to environmental Publication date: March 2020 Source: Journal of Environmental Radioactivity, Volume 213 Author(s): S. Akyil Erenturk, S. Haciyakupoglu, B.F. Senkal Abstract This study deals with performance of removal of cesium (Cs+) and strontium (Sr2+) ions from synthetic aqueous solution using amino pyridine sulfone amid resin as a barrier material for nuclear waste storage areas to reduce environmental risk. The effects of adsorbate concentration, temperature and contact time on the efficiencies of the engineering barrier material for Cs+ and Sr2+ ions were investigated and evaluated. It was found that total adsorption capacity was higher for cesium ions than strontium ions. Dubinin–Radushkevich (D-R) isotherm model was well fitted to the adsorption data for both ions. The micropore capacity of the barrier material was found as 4.20 mg for strontium ions and 5.40 mg for cesium ions. ΔH values were indicated that the interaction process is exothermic for both ions. The positive value of entropy for both ions show that randomness at the solid-solution interface increased. Pseudo-second-order model was well fitted the kinetic data.

Ecological association between residential natural background radiation exposure and the incidence rate of childhood central nervous system tumors in France, 2000–2012 Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Justine Berlivet, Denis Hémon, Énora Cléro, Géraldine Ielsch, Dominique Laurier, Sandra Guissou, Brigitte Lacour, Jacqueline Clavel, Stéphanie Goujon Abstract Background High-dose ionizing radiation is an established risk factor for childhood central nervous system tumors (CNST) but the role of low doses remains debated. In particular, there are few studies of natural background radiation (NBR, gamma radiation and radon) and childhood CNST, and their results are inconclusive. Objectives This study aimed to investigate the ecological association between NBR exposure and childhood CNST incidence in France, considering childhood CNST overall and by subgroups. Methods Incidence data were provided by the French national registry of childhood cancers, which has high completeness. We included 5471 childhood CNST cases registered over the period 2000-2012, and their municipality of residence at diagnosis was recorded. Municipality NBR exposures were estimated by cokriging models, using NBR measurements and additional geographic data. The incidence rate ratio (IRR) per unit variation of exposure was estimated with Poisson regression models. NBR exposures were considered at the time of diagnosis, and cumulatively from birth to diagnosis. In an exploratory analysis, the total brain dose due to NBR was used. Results Overall, there was no association between NBR exposure and childhood CNST incidence (IRR = 1.03 (0.98,1.09) per 50 nSv/h for gamma radiation, and IRR = 1.02 (0,96,1.07) per 100 Bq/m3 for radon). An association was suggested between pilocytic astrocytomas and gamma radiation (IRR = 1.12 (1.00,1.24) per 50 nSv/h) but not with radon (IRR = 1.07 (0.95,1.20) per 100 Bq/m3). Upward trends for this CNST subtype were also suggested with the cumulative exposures to gamma radiation and the total brain dose. NBR exposure was not associated with other CNST subgroups (ependymomas, embryonal tumors, and gliomas other than pilocytic astrocytomas). Adjustment for socio-demographic factors did not change the findings. Conclusions Our study was based on high quality incidence data, large numbers of CNST cases, and validated models of NBR exposure assessment. Results suggest an association between gamma radiation, as a component of NBR, and pilocytic astrocytomas incidence in France.

Biomonitoring of radioactive contamination of the Yenisei River using aquatic plants Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Alexander Bolsunovsky, Dmitry Dementyev, Elena Trofimova Abstract The Yenisei River is contaminated by artificial radionuclides released by one of the Russian facilities producing weapons-grade plutonium (the Mining-and-Chemical Combine, MCC), which has been in operation for 60 years. The paper presents results of long-term monitoring of radionuclide concentrations in six aquatic plant species collected from the 1400 km Yenisei River stretch downstream of the city of Krasnoyarsk. Before the last MCC reactor was shut down (in 2010), up to 30 artificial radionuclides were detected in the plant biomass, and 2 and 5 years after the reactor shutdown, 11 and 3–5 radionuclides, respectively, were detected. The highest concentrations of radionuclides were recorded in Fontinalis antipyretica. The aquatic plant Elodea canadensis, which commonly occurs in the Yenisei River, was used in the cytogenetic study. High frequencies of chromosomal aberrations (up to 33%) were revealed in cells of Elodea canadensis roots from the Yenisei region affected by the MCC radioactive discharge, at dose rates of 45–72 μGy/d, while in the cells of the plant roots from the reference areas, the frequency of chromosomal aberrations was 5–7%, at dose rates below 2 μGy/d. The higher frequencies of chromosomal aberrations in Elodea canadensis collected from the parts of the River with increased concentrations of artificial radionuclides are associated with the radiation factor. The aquatic plant Elodea canadensis can be recommended as a bio-indicator for radioactively contaminated aquatic ecosystems.

A method for the determination of organically bound tritium in marine biota based on an improved tubular-combustion system Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Feng Lin, Wen Yu, Junpeng Guo, Hui Liao, Yong Wang Abstract A method for the measurement of organically bound tritium (OBT) in marine biota has been developed using a combustion device designed with three independent temperature control zones and a two-stage intake mode to ensure full combustion of samples. The versatility of the combustion device and combustion water recoveries were tested on nine different types of marine biota, with recoveries varying from 85.15% to 92.67%, with an average of 89.4 ± 11.34%. This indicates that our developed combustion method (combustion program and apparatus) provides stable results. Finally, the OBT activity of the marine samples measured varied from 1.88 to 12.9 Bq/L, with an average of 5.61 ± 3.21 Bq/L.

Rapid separation of Po-210 from Pb-210 based on the usage of a commercial Sr-Specific chromatographic resin Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Fuyou Fan, Haoran Liu, Juncheng Liang, Haowen Sun, Jian Zhang, Duoqiang Pan, Yu Zou Abstract The efficient extraction of small quantities of 210Po is necessary for preparing 210Po standard reference materials. Herein, a commercially available strontrium-specific chromatographic resin (Sr spec resin) was used to rapidly and selectively extract 210Po from a 210Pb–210Bi-210Po mixture, and the distribution ratios of Pb, Bi, and 210Po on Sr spec resin were probed using batch experiments. In contrast to 210Pb and 210Bi, 210Po was retained on the Sr spec cartridge in 8 M HCl and was then effectively eluted by 0.1 M HNO3. The contents of 210Pb and 210Bi in the thus obtained 210Po solution were checked using a high purity germanium gamma-ray detector and the corresponding decay curve, respectively, and were found not to exceed 2%. Moreover, the 210Pb and 210Bi eluates could be used to regenerate 210Po by the same method after a certain time period. Therefore, the extracted 210Po solution was suitable for the preparation of the 210Po standard area source and 210Po standard reference materials. Graphical abstract

Analytical techniques for charactering radioactive particles deposited in the environment Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Brit Salbu, Ole Christian Lind Abstract Since 1945, a series of nuclear and radiological sources have contributed to the release of radioactive particles containing refractory elements into the environment. Several years of research have demonstrated that the particle composition will depend on the source, while the release scenarios will influence particle properties of relevance for environmental transfer. Radioactive particles can also carry sufficient amount of radioactivity (MBq) and represent point sources of radiological concern. Most radiological assessment models, however, are based on bulk concentrations, assuming that radionuclides in the environment are evenly distributed. In contrast, radioactive particles and thereby doses are unevenly distributed, while leaching of radionuclides from particles prior to measurements can be partial, potentially leading to underestimation of inventories. For areas affected by particle contamination, information on particle characteristics controlling the particle weathering rates and remobilization of particle associated radionuclides will therefore be essential to reduce the overall uncertainties of the impact assessments. The present paper will focus on analytical strategies, from screening techniques applicable for identifying hot spots in the field, fractionation techniques and single particle extraction techniques as a preparatory mean to apply non-destructive solid state speciation techniques, till leaching techniques applied sequentially to obtain information on binding mechanisms, mobility and potential bioavailability. Thus, a combination of techniques should be utilized to characterize radioactive particles in order to improve environmental assessments for areas affected by radioactive particle fallout.

Nanometer-micrometer sized depleted uranium (DU) particles in the environment Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Ole Christian Lind, Jochen Tschiersch, Brit Salbu Abstract Depleted uranium (DU) is a waste product from uranium enrichment that has several civilian and military applications. Significant amounts of DU in the form of particles or as fragments have been released into the environment as a consequence of military use of DU munitions, of industrial releases and of aircraft accidents. Thus, the present paper summarizes present knowledge on nanometer-micrometer sized depleted uranium (DU) particles collected in areas contaminated with such particles. Analysis of DU particles released to the environment has shown that uranium can be present in different crystalline structures and in different oxidation states. The weathering rates of DU particles and the subsequent remobilization of uranium species are also strongly connected to the oxidation state and crystalline phases of uranium, influencing the mobility and potential ecosystem transfer. Therefore, as has been observed for radioactive particles released from most nuclear events, the characteristics of DU particles can be linked to the source term and the release scenario as well as to environmental transformation processes. Although the radiation dose and radiotoxicity of DU is less than from natural occurring uranium, the mobility of U from oxidized DU and the associated chemical toxicity could be significantly higher than from natural UO2. The present paper summarizes present knowledge on depleted uranium particles identified in the environment.

Dose and risk estimation of Cs-137 and I-131 released from a hypothetical accident in Akkuyu Nuclear Power Plant Publication date: January 2020 Source: Journal of Environmental Radioactivity, Volume 211 Author(s): Efem Bilgiç, Orhan Gündüz Abstract The construction of Akkuyu Nuclear Power Plant (NPP) was launched in 2018 and the plant is expected to be operative by the year 2023. Being situated in the Mediterranean coastline, Akkuyu NPP will be the first nuclear power generation facility in Turkey. The plant will have four Russian VVER-1200 type pressurized water reactors with a total installed capacity of 4800 MW. In this study, atmospheric dispersion and ground level deposition of Cs-137 and I-131 released from a possible accident in Akkuyu NPP was estimated using a Lagrangian particle dispersion model, FLEXPART, for different time periods representing relatively extreme meteorological conditions for Mersin. The source term used in simulations was assumed the same with that of the Chernobyl NPP accident that occurred in 1986. In addition, cumulative dose and risk values were calculated from FLEXPART output datasets considering potential exposure pathways such as inhalation, ground-shine exposure and cloud-shine exposure. The results were further analyzed with python codes and dose and risk maps were created for local and regional scales. According to results of the study, it was found that the vicinity of Mersin and Central Anatolia were simulated to be the most significantly affected areas from the accident under both scenario conditions. The northern and western parts and all coastlines of Turkey were simulated to be more contaminated in the simulations conducted under December 2009 conditions, whereas southern and western parts of Turkey and some parts of Middle East countries like Syria, Iraq and Lebanon were simulated to be comparatively more contaminated under August 2010 conditions. The results indicated that radioactivity levels exceeding 100 kBq/m2 were observed near the accident site under both scenario conditions. Values exceeding 10 kBq/m2 level were simulated in western Turkey in the first scenario whereas similar values were found in eastern Turkey in the second scenario. Furthermore, the results indicated 7-day thyroid dose values ranging between 0.10 mSv and 10.0 mSv in western and eastern parts of Mediterranean region for the first and the second scenario, respectively. Similarly, 1-year effective dose of only Cs-137 ranged between 0.1 mSv and 1.0 mSv around Akkuyu NPP site in both scenarios. The results revealed that meteorological conditions were among the most important parameter for the fate and transport of radioactivity originating from such a catastrophic event.