A numerical model has been applied to simulate the fate of 226Ra radionuclides in the ocean, generated from discharges of produced water in the Norwegian Sector of the North Sea. The model simulates the transport, dilution and the (possible) deposition on the sea floor of 226Ra. Figures are presented for the concentration levels and deposition rates of 226Ra in the ambient for various assumptions for the fate of the 226Ra in the ocean (as dissolved, as adsorbed to ambient organic particles that sink down on the sea floor, and as forming Ba(Ra)SO4 particles). Concentration levels and deposition rates are compared with natural levels and fluxes of 226Ra in the ocean and to the sediment, respectively. The added concentration levels/fluxes are found to be generally relatively small, compared to natural levels/fluxes. The reason for this is attributed to the presence of fairly high natural levels/fluxes of 226Ra.

On the basis of previous survey results of indoor radon for schools, detailed radon survey was conducted in one hundred three selected schools in Korea during the second semester in 2010. According to the results of effective dose assessment due to inhaled radon of during occupancy time, fourteen schools for requiring urgent mitigation action were selected, and recommended to the government.

One of the primary goals was to estimate the impact of the concentration of radioactive caesium on meio- and macrobenthic organisms in Barents and Kara Seas. It is determine that macrobenthos is more inert component, less subjected to the influence of this factor. Meiobenthos reacts to the radioactive pollution by the change of the taxonomic diversity and quantitative characteristics faster then.

Le tritium est un radionucléide dont l’utilisation et la production vont croitre du fait du développement des nouveaux réacteurs à fusion et de la relance des programmes nucléaires dans le monde. La toxicité du tritium est bien connue mais ses effets sanitaires restent délicats à appréhender du fait d’une dosimétrie difficile et du faible nombre de cas de contamination survenus depuis son utilisation. L’estimation des risques liés à son utilisation repose sur les modèles de la CIPR qui permettent de calculer les doses délivrées dans les tissus grâce à un facteur de pondération WR qui tient compte de l’efficacité biologique relative des différents rayonnements. Quelques voix s’élèvent pour réclamer une révision du facteur de pondération utilisé pour les rayonnements bêta du tritium, arguant que celui-ci peut s’incorporer dans l’ADN et donc être plus toxique que les autres radionucléides émetteurs bêta. Une revue des différents travaux menés sur le sujet et publiés dans la littérature montre en réalité que l’efficacité biologique relative du tritium n’est pas très différente de celle des rayonnements gamma, pris comme rayonnements de référence. Ceci plaide pour un maintien du facteur de pondération unitaire actuel, initialement proposé puis réaffirmé récemment par la CIPR.

In the context of protecting the environment from the effects of ionizing radiation associated with uranium mining, the alpha-emitting radium 226 is the uranium progeny of most interest as it is known to bioaccumulate and confers a high effective dose to biota. For the Ranger uranium mine in northern Australia, total radium 226 activity concentrations were determined in water samples from Magela Creek both upstream and downstream of the mine over two years. Those data were evaluated within three different frameworks and were found to comply with respective limits: human dose estimations, site-specific guideline `trigger' values for ecosystem health (derived from the distributional properties of values from a reference (upstream) dataset) and estimations of absorbed dose to freshwater mussels residing in Magela Creek (long-lived organisms with high rate of uptake and exposure). We propose that the currently-used, human-dose limit of 10 mBq.L-1 be applied to the difference of the wet season arithmetic means calculated for the upstream and downstream locations. In addition, the statistically derived trigger values (e.g. a moving 80$^{\scriptsize\textrm{th}}$ percentile of upstream data) could be used to assess if radium 226 measured downstream of the uranium mine has resulted in an additional dose to biota.

The LLW Repository Limited has recognised the potential importance of the processes being considered in the BIOPROTA 14C working group and funded the development a new 14C model that addresses the exchange of gas in a soil-plant-atmosphere system. This model considers two regions in the above-ground atmosphere and utilises concepts from the field of micrometeorology to describe the exchange of air between these regions and losses from the area of interest. The lower layer only experiences molecular diffusion processes in relation to the movement of molecules of CO2, whereas the upper layer experiences some degree of turbulent mixing as a result of winds which flow over the area of interest. The thicknesses of these layers depend upon the canopy density, which will affect the light intensity and thus the rate of photosynthetic uptake of carbon in the canopy profile. Model results demonstrate the impacts of 14C-labelled gas from the soil upon the calculated 14C concentration in plants for a variety of plant species (pasture and garden crops) and subsequent doses to human exposure groups. The technical modelling work described has been funded by the LLW Repository Ltd in support of its 2011 Environmental Safety Case.

The results of the analyses of plant production and parasitic resistance of common reed (Phragmites australis (Cav.) Trin. ex. Steud) from water bodies within the Chernobyl accident exclusion zone are represented. The heavy damage of common reed by the ergot (Claviceps purpurea (Fr.) Tul.) (up to 50%) from water bodies of the left-bank flood lands of the Pripyat River, which is the most contaminated region of the Chernobyl NPP exclusion zone, has been investigated. Deviations in morphological indexes of reproductive organs of common reed from water bodies of right- and left-bank flood lands of the Pripyat River within 10-km exclusion zone are registered. There are: decrease of panicle width, length and flowers number at inflorescence; differences in seed shape and color. The direct correlation between the absorbed dose rate for higher aquatic plants and plant productivity indexes as well as damage events of common reed by the ergot is proved. The parasitic resistance of common reed from water bodies within Chernobyl accident exclusion zone are decreased according to the increase of absorbed dose rate as well.

Magnetophosphenes are described as flickering lights appearing in the visual field, dueto retinal exposure to time-varying magnetic fields (MF). Human magnetophospheneperception (MP) serves as a scientific basis for international guidelines intending tolimit exposure to electromagnetic fields in the extremely low frequency range. However,the flux density threshold at which MP occurs, as well as the dose and frequency responsesof the phenomenon, are not clearly experimentally established. The 50–60 Hz threshold isextrapolated from data in the lower frequency range. The objective of this paper is toprovide a descriptive anecdotal report of MP from 8 individuals exposed to 50 mT MF at 20,50 and 60 Hz. They describe variations of flickering light perceptions in the visualfield, matching the description by D’Arsonval (1896). This preliminary testing introduces a new experimental protocol, which willtest the threshold for MP and other associated neurophysiological responses in humans.

Accumulation of transuranic element 241Am by photoassimilating organs and its distribution in fractions of the biomass of aquatic plant Elodea canadensis have been investigated in laboratory batch experiments. Americium was taken up by apical shoots of Elodea from water. Of the activity accumulated by the shoots, up to 80% of 241Am was detected in the leaves and 20% in the stems. Americium concentration in apical leaves was several times higher than in distal leaves. Of the 241Am activity concentrated in the shoots, 95% was bound to cell walls, membranes and organelles and 5% of the radionuclide was dissolved in cytoplasm. Less than 1% of americium accumulated in the biomass was found in the lipid extract; up to 10% of americium was bound to proteins and carbohydrates; the major part of the radionuclide (about 90%) was registered in the cell wall fraction that mainly contained cellulose-like polysaccharides. Biomass treatment with hydrochloric acid resulted in desorption of about 70% of americium, mostly from the polysaccharides.

La surveillance de la radioactivité d'origine naturelle et artificielle du Tage est effectuée depuis 1975 ; en effet, bien qu'il n'y ait pas d'installations nucléaires dans le secteur portugais du fleuve, il faut tenir compte de celles qui existent en amont, en Espagne. Une étude radioécologique du fleuve a également été conduite (Contrat (CCE) n° BI6-B-198-P) entre la mi 1986 et 1989. Un bref exposé des principales caractéristiques de l'eau, des sédiments et du matériel biologique (hydrophytes et poissons) est présenté et les données sur la radioactivité artificielle concernant les années 1981 à 1989 sont analysées. Une hausse de la radioactivité artificielle a été détectée en 1987 et en 1989 dans l'eau ainsi que dans les sédiments, les hydrophytes et les poissons en 1988 ; les raisons de cette augmentation sont discutées. Les sédiments semblent constituer le compartiment préférentiel de rétention du 137Cs.

Genomic and proteomic techniques provide the opportunity to investigate plant response to ionising radiation in unprecedented detail. Understanding plant molecular responses to ionising radiation might be useful for radioprotection but also for understanding plant stress responses. This is because radioactivity was a primordial stressor to cells and many stress responses are highly conserved through evolution. DNA microarrays for Arabidopsis plants exposed to 40 µGy h-1 through a hydroponic solution revealed that, after 14 days, there are changes in gene expression primarily in roots. The genes that change are not associated with DNA repair, and correlations with responses to other stressors in public databases suggest that there are elements of plant stress response being activated. The number of genes and their fold changes are lower than those reported for many other stressors but have particular overlaps with oxidative stress responses. Proteomic analyses form similar experiments are ongoing but similarly show no change of abundance in proteins associated with DNA repair and more changes in roots than shoots at these exposures.

The separate contributions of all source regions to organ doses from 131I and 123I administered to the bodywere calculated using voxelized reference phantoms. The photon and electron components oforgan doses were also evaluated for each source region. The MCNPX Monte Carlo particletransport code was utilized for dose calculations. All organs and tissues of male andfemale phantoms were taken into account as source regions with their correspondingcumulated activities. The results showed that cumulated activities assigned to sourceregions and inter-organ distances were two factors that strongly affected the contributionof each source to the organ dose. The major contribution of the dose to the main sourceregions arose from self-irradiation of electrons, while for nearby organs it was due tophotons emitted by the main source organs. In addition, self-irradiation plays animportant role in the dose delivered to most target organs for lower thyroid uptakes.

To document the tritium uptake following chronic atmospheric exposure, potted lettuces (Lactuca sativa L.) were cultivated outdoors in the vicinity of a nuclear facility. During two sets of experiments performed in spring and autumn, the plants were continually exposed to low tritium levels throughout growth. These experiments factored in meteorological data, tritium monitoring in air (HT and HTO) and analysis of Tissue Free Water Tritium (TFWT) and Organically-Bound Tritium (OBT) in biological material. The global conversion rate of HTO to OBT in plants averaged 0.16% ⋅ h-1 over the growing period, but marked variations were observed during growth. In particular, a significant increase appeared at the exponential growth stage. Consequently, the usual predictive models (for cases of accidental or chronic exposure to tritium) should factor in the conversion rate according to the biological stage. Moreover, as plant growth is closely correlated to total energy received, meteorological parameters (temperature, light intensity) may be considered reliable indicators of growth.

Natural radionuclide concentrations in soil samples collected within and around crude oilflow and gas compression stations in the Niger Delta, Nigeria, were determined usinggamma-ray spectroscopy. The mean activity concentrations of 40K,238U and 232Th varied from 30.1 ± 3.0 to 59.0 ± 17.1, BDL to 8.8 ±2.3 and 7.9 ± 3.7 to 10.9 ± 1.9 Bq.kg-1, respectively. The 40K,238U and 232Th contents of the soil samples are very low comparedwith the world average for natural background area. The absorbed dose rate and effectivedose ranged from 6.9 to 11.1 nGy.h-1 and 8.5 to 13.6 μSv.y-1,respectively. The annual gonadal dose equivalent rate ranged from 48.9 to 77.5μSv.y-1, which is lower than the world average of 0.30 mSv.y-1.The radium equivalent activity and the external hazard index of the soil samples werebelow the recommended limits of 370 Bq.kg-1 and unity, respectively. Theresults obtained reveal that there is no significant radiation hazard due to naturalradionuclides of the soil samples in the studied areas.

Beach Sand Mining (BSM) is a profitable industry earning a sizable income for the countryby way of foreign exchange. The Indian coast is rich in rare earths such as ilmenite,rutile, leucoxene, zircon, garnet and sillimanite, and is invariably associated withradioactive monazite. Due to the nature of the separation processes involved and themanual handling, workers in these factories are continuously being exposed to suspendedparticles containing naturally occurring radioactive materials. An attempt was made toestimate DNA damage using a chromosome aberration assay to monitor radiation effects inworkers of BSM industries in India. The study group comprised 27 BSM workers and 20controls. Percentage yields of dicentrics, acentric fragments and chromatid breaksobserved in the control group were 0.058 ± 0.017, 0.073 ± 0.03 and 0.22 ± 0.112,respectively. Percentage yields of dicentrics + centric rings, acentric fragments andchromatid breaks observed in the BSM group were 0.029 ± 0.01 (P value 0.19), 0.24 ± 0.06(P value 0.006) and 0.455 ± 0.06 (P value 0.0004), respectively. Elevated levels offragments and chromatid aberrations are suggestive of low-dose radiation effects and alsochemically-induced DNA damage.

The results of the low-level performance of an anti-Compton device are presented. The anti-coincidence action of the NaI detectors lowers the total background of the HPGe detector integrated on the energy range 30 keV to 2730 keV by a factor 8.1 and suppresses the continuum above 300 keV by a factor larger than 10. Qualitative and quantitative results on environmental samples are described to illustrate the improvement of uncertainties determination and the significant reduction of detection limits. This provides ever more accurate and precise data on natural and anthropogenic radionuclides often used as tracers for environmental studies.

In the mid-long-term after a nuclear accident, the contamination of drinking water sources, fish and other aquatic foodstuffs, irrigation supplies and people's exposure during recreational activities may create considerable public concern, even though dose assessment may in certain situations indicate lesser importance than for other sources, as clearly experienced in the aftermath of accidents like Chernobyl. The MOIRA system is designed to allow for a reliable assessment of the long-term evolution of the radiological situation and of possible alternative rehabilitation strategies, including an objective evaluation of their social, economic and ecological impacts in a rational and comprehensive manner. MOIRA also features a decision analysis methodology, making use of multi-attribute analysis, which can take into account the preferences and needs of different types of stakeholders. A decision-making exercise regarding such problems, in which MOIRA has been be used as a decision support tool, was organised in Spain involving the organizations responsible for emergency management and the affected services, as well as local and regional stakeholders and several international observers. The system resulted very helpful in assessing the overall situation and the alternative management strategies and also facilitated the interaction between agencies which reached a better common understanding of all related issues.

99Tc and 79Se, two long-lived radionuclides, are supposed to be highly mobile in soils, because of their anionic forms. Their behaviours in the soil are often considered only from a physico-chemical point of view, although the microorganisms can affect either directly or indirectly their speciation. This study demonstrates the role of the microbial compartment in the retention of Se and Tc in soil by comparing experiments with soils constrained to different microbiological status (sterile / raw / amended). Kd coefficients for Se and Tc were determined in batch experiments, whereas transport of Se and Tc was investigated through column leaching experiments. Kd for Se was enhanced for the raw soil without amendment compared to the value obtained for the sterilised soil. The retention of Se was higher again in the amended soil. Besides, a biofilm, which can directly retain Se, was obtained at the entrance of the amended soil column. This effect was less obvious for Tc in batch experiments, but was revealed by leaching experiments where a high quantity of Tc was retained in the amended soil columns. These results give strong evidence that microorganisms are responsible for a greater retention of Se and Tc in soil.

In 1986–2009 the dynamics of the radionuclide contamination of the Pripyat inlet ánd Perstok Lake and their biota as well as the set of biological test criteria reflecting impact of ionizing radiation on pulmonate mollusk Lymnaea stagnalis from these reservoirs have been investigated. The γ-activity of biota after the highest level in 1987 (up to 1100 kBq kg−1 wet mass) quickly decreasing. In 2005–2008 the activities of biota in the Pripyat inlet dropped to the natural level, but in the Perstok Lake they remained a rather high – up to 4000 Bq kg−1. Alongside the increase of activity of transuranium α-isotope 241Ám in bottom sediments of the Perstok Lake has been observed since 2006. In the L. stagnalis population in the Perstok Lake the obvious negative effect of chronic impact of radiation was noted. The share of cells with the micronuclei has considerably grown there if compared with the mollusks from the Pripyat inlet. The negative effects mentioned above did not influenced seriously on the viability on organism and populations levels. So, the embryonic mortality in both populations is low and they are capable to maintain sufficient level of reproduction despite the chronic radioactive impact.