The development of atomic industry and nuclear power engineering was accompanied by radiation incidents and catastrophes, some of these being rather large and resulting in radioactive contamination of the environment. Among the most important radiation accidents which have affected expanded areas are: the accident in the USSR in the South Urals with the formation of the East Urals Radioactive Trace in 1957, the accident in Sellafield, the United Kingdom in 1957, and the catastrophe at the Chernobyl NPP in 1986. The resulting radioactive traces – Emergency Radioactive Zones (ERZ) – have become the test sites for large-scale long-term radioecological investigations. The unique natural peculiarities of ERZs (wide variations in the environmental conditions – soil, plant-animal life, climatic factors, etc.) considering a wide range of man-made radionuclides (primarily biologically important 90Sr, 131I and 137Cs) released into the environment have made it possible to quantify the parameters of radionuclide migration via a large number of trophic chains in different natural environments (terrestrial, aquatic and other ecosystems). Information has been collected on radiation and post-radiation effects in various biota representatives in a wide range of doses and dose rates (especially at the population and ecosystem levels). Different countermeasures have been developed and applied on large territories for reducing exposure of the ERZ population and for remediation of the affected areas.

In-situ and ex-situ measurements of environmental radioactivity were made on the iThemba LABS (iTL) grounds in South Africa. The MEDUSA and HPGe detector systems were used to make in-situ and ex-situ measurements, respectively. The MEDUSA was mounted ~0.5 m above the ground on a 4 × 4 vehicle to traverse [at ~2m∙s-1] the accessible portions of the iTL grounds. Spatial data (via a GPS receiver) were acquired every 1 s, and γ-ray spectra every 2 s. MEDUSA count rate maps were produced to show the spatial distribution of radioactivity on the grounds. The HPGe was used to measure the radioactivity in soil (and also in some grass) samples collected at particular spots on the iTL grounds. The sampled spots include six identified high activity spots (“hot spots”) and two “calibration spots”. The activity concentrations were determined for both the natural and anthropogenic radionuclides. The absorbed and effective doses (from external γ-ray irradiation) were also determined for the natural and anthropogenic radionuclides. The maximum effective dose to humans on the iTL grounds as a result of external exposure to natural and anthropogenic radionuclides was found to be well below the regulatory 1 mSv per year per member of public.

Sewage sludge has predominantly organic composition and can improve soil characteristics, such as fertility and erosion resistance. Therefore, its application as an amendment for agriculture is an adequate alternative for its final disposal. However, there is a lack of information concerning soil enrichment with radionuclides in long-term experiments in tropical areas. Thus, the objective of this study was to determine the impact of soil biosolid amendment on the concentration of 210Pb, 226Ra, 228Ra, U, Th, and other elements in maize grown in a Brazilian Ferralsol. The results obtained showed that radionuclide concentrations in maize grains were not significantly influenced by either the applied biosolid doses, or biosolid origin, or the interaction of these two factors.

Since the Goiânia Accident in 1987, the Environmental Impact Assessment Service of the Institute of Radioprotection and Dosimetry started developing studies aiming to improve response for nuclear and radiological accidents. In 1993 radioecological studies for determining transfer factors adequate to main types of agricultural soils and crops cultivated in Brazil. While the studies proceeded, it was felt that mechanisms involved in soil-plant processes should be better understood. Sequential extraction was seen as an important tool to understand radionuclide behavior in the soil-plant system. After 15 years studying different types of tropical soils and several radionuclides, such as 137Cs, 90Sr and 60Co, it could be seen the relevance of site specific data to be used for environmental impact assessments and to the decision making process after an accidental contamination, and that these assessments need to be based on the knowledge of environmental processes governing the long term behavior of radionuclides at a specific type of environment.

Environmental radioactivity in Greenland and the Faroe Islands was investigated from samples collected in 2004 of seawater, seaweed, marine fish, seal, whale, lake water, freshwater fish and total diet. Anthropogenic radionuclides in Greenland and the Faroe Islands are present due to long-range transport by air and water mainly due to fallout from nuclear weapons testing, from the Chernobyl accident and discharges from European reprocessing facilities, Sellafield in the UK and La Hague in France. Concentrations of anthropogenic radionuclides in environment and food are low, however, and present insignificant health risks to humans. Naturally occurring radionuclides are present in the environment and human food and dominate the radiation dose from ingestion. Even in case of landlocked Arctic char from South Greenland showing elevated concentrations of anthropogenic 137Cs, the radiation doses to man from ingestion derive mainly from the presence of the naturally occurring radionuclide 210Po. Samples of total diet from Uummannaq indicate that annual radiation doses by ingestion could approach 1 mSv from 210Po possibly due to a high proportion of seal flesh and liver in the diet.

In 2003–2005 we investigated current contamination of small birds in Chornobyl zone, as vertebrates with the largest diversity and biomass, and inherent season migrations. A whole-body live counting method was used to analyze 90Sr and 137Cs in the birds. Total number and biomass of small birds was estimated using 1) data of birds population density in different kinds of biogeocenosis, 2) ratio of biogeocenosises area at the zone, 3) data of biomass of species. We used GIS application, an electronic map of the Chernobyl zone contamination and 90Sr and 137Cs transfer factor “soil–bird” to calculate average contamination of birds at any location regardless they had been caught there or hadn't. According to our assessment total number of small birds by the end of breeding season in 2004 amount to at least 5.14 million individuals, total biomass – 134 tons, total stock of radionuclides – 74.7 MBq 90Sr and 55 MBq 137Cs. All these birds can export no more 80% of their initial contamination outside the zone. Together with total avian flow yearly passed through the region (2600 km2) they export up to 2.47 GBq 137Cs and 3.70 GBq 90Sr.

Radiocarbon (C-14) is potentially important in radioactive waste. Because the carbon transfer through the biosphere is principally different from the transfer of other radionuclides, using an empiric soil-to-plant transfer coefficient (also called soil/plant concentration ratio) in the same way as with other nuclides is inappropriate and can lead to wrong results in biosphere assessment models. C-14 concentrations and fluxes in the biosphere are strongly influenced by the concentrations and fluxes of stable carbon. We developed a new process-based model of the soil to plant transfer of C-14 for the use in the safety assessments of radioactive waste repositories. The model describes the steady-state nuclide abundance in the plants due to the fluxes of water and solid matter within the biosphere system. To study the model sensitivity to parameter variations, parameter variations were studied. We found that the carbon cycle plant => soil => canopy determines the uptake of C-14 by crops. The major parameters are the plant productivity (yield) and the exchange rate of carbon between the air within the canopy and the general atmosphere. The quantification of this exchange rate of carbon is, however, a major open issue.

Protecting the environment and the public from radioactive hazard is a top priority for all companies operating in the nuclear domain. In order to quantify dose impact on members of the public due to annual discharges of its nuclear installations, AREVA developed the COMODORE code in collaboration with Institute of Radiation Protection and Nuclear Safety (IRSN).

COMODORE is a synthesis of 3 softwares validated by IRSN (ACADIE, COTRAM and AQUAREJ). ACADIE is a code elaborated by IRSN and the Treatment Business Unit of AREVA synthesizing the works of the GRNC (Nord-Cotentin Radioecology Group) created by the French government to deal with the estimation of exposure levels to ionizing radiation and associated risks of leukemia for populations in the Nord-Cotentin. COMODORE is a version of ACADIE designed to be adaptable to any other AREVA site. Thus, the operators of the south east of France (Pierrelatte, Marcoule and Romans sites) carried out the adaptation of COMODORE for theirs specificities (for instance, uranium in the terrestrial model).

At the moment, COMODORE is used in routine by the AREVA operators to assess the annual dosimetric impact and is also being adapted with SGN to model the radiological impact of uranium ore treatment residues repositories.

Soil-grass-milk is one of the main food chains leading radioactivity in man in Finland. From 1963 onwards dairy and farm milk and from 1972 deposition have been regularly collected at several sites in Northern Finland; some grass and AIV-silage samples have been taken simultaneously. 137Cs and 90Sr have been analysed by the Radiation and Nuclear Safety Authority (STUK) in the Regional Laboratory in Northern Finland. In this study the activity concentrations and decrease rates of 90Sr and 137Cs were studied in the years following the atmospheric nuclear weapon testings and after the Chernobyl accident in 1986 until 2008. Also the transfer factors were calculated and the ecological half-lives were estimated in the study. The concentrations of 90Sr and 137Cs were highest in the beginning of 1960 due to the nuclear weapon tests. The radioactive fallout in Finnish Lapland from the Chernobyl accident in April 1986 was low. The increase of the 137Cs concentrations in milk was found out in July 1986 and it decreased rapidly after summer 1987. There was no increase of 90Sr concentrations in milk and in deposition after Chernobyl fallout.

Large amount of produced water, containing elevated levels of radionuclides (mainly 226Ra and 228Ra), is discharged to the sea~in connection with oil and gas production on the Norwegian continental shelf. The main objective of this project has been to establish radiological safe discharge limits for radium associated with other components in produced water. We present a summary of the methodology developed and the overall results obtained. Our results show that presence of added chemicals like scale inhibitors in the produced water have a marked influence on the speciation of radium, i.e. formation of radium and barium sulphates when produced water is mixed with seawater. Radium's behaviour in the sea has been modelled using the DREAM model. Also, we have showed that the bioavailability of radium may be increased due to presence of scale inhibitors. Juvenile cod has been exposed to radium through food and from water. The uptake in different organs, i.e. skin, gills, liver, blood, and kidneys, show large variability, but is modest in all organs.

The UK Government has said that energy companies can invest in new nuclear power stations. As part of this, the safety, security and environmental regulators (the Nuclear Directorate of the Health and Safety Executive and the Environment Agency in England and Wales) are engaged in a process known as generic design assessment (GDA) that was proposed by UK Government to improve the process of consulting on and approving new nuclear power stations. The GDA process is expected to take about 3½ years to complete. From an environmental perspective, the Environment Agency is interested in assessing whether the proposed reactor designs represent the 'best available techniques' (BAT) with regard to environmental discharges. This paper describes a project that has been assessing BAT for radioactive discharges for analogues (i.e. the previous generation) of four reactor designs on which assessment work started in 2007. Where possible data on environmental discharges has been collated for individual radionuclides for a number of reactor analogues and the discharge performance has been normalized with respect to thermal and electrical outputs to allow trends in the data to be determined. Where possible, explanations for any trends have been identified.

Assessment tools and frameworks have been developed that allow environmental assessments to be conducted and which can be used to demonstrate whether non-human species are protected from the impact of exposure to ionising radiation released under regulation. Frameworks are often tiered, increasing in the level of complexity, input data requirements and need for expert involvement as the assessment moves to successively higher tiers. These are, conceptually, similar to assessment approaches available for chemical risk assessment. What criteria (e.g. numeric benchmarks) should be used, and how these should be defined, are currently under debate, but it is likely that use will be made of approaches developed for setting assessment criteria for chemicals. However it will be necessary to ensure that any assessment criteria developed are fit for use in a regulatory context. This paper reviews the similarities and differences between regulation of, and assessment methods for, chemicals and radioactive substances and presents recommendations regarding how components of chemicals risk assessment may be adopted for radioactive substances.

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.

A grid model was developed to combine small-scale grid resolution and long-term predictions of radionuclide dispersion in shallow seas. A predictor-corrector algorithm ensures an unconditional stability of the model. Four modules calculate the concentration of suspended sediments, the dispersion of radionuclides in the marine environment, and the doses to members of the public and marine biota. The model was applied to the dispersion of liquid effluent in the Irish Sea from the Sellafield nuclear reprocessing plant, Cumbria (UK). The concentration factors and partition coefficients have been calibrated for biota species and local conditions. The validation against environmental samples for twenty-two radionuclides shows a good agreement between predicted and measured values.

Using the south-western districts in the Bryansk region affected by the Chernobyl accident as an example, the dynamics has been estimated of 137Cs transfer factors to plants and effects of countermeasures on the accumulation of this radionuclide by farm products. A significant decline with time in TF 137Cs to plants is shown. Over the 20 years after the radioactive fallout this decline varies from 7 to 85 times for different plants, being maximum in the early years. The 137Cs accumulation by plants is greatly influenced by the soil properties. Thus, the maximum transfer of this radionuclide to plants is reported on peaty soils, somewhat lower on sandy soils and minimum on sandy loam soil. A detailed comparative analysis of data on TF 137Cs to plants grown on sandy and sandy loam soils has shown that on the former transfer is higher and varies between 1.2–4.5 times for different crops. An important role of mineral fertilizing and liming of soil has been proved in reducing 137Cs accumulation in plants. On agricultural lands that saw the increased rates of mineral fertilizing, a significant (by an average factor of 3–7) reduction in TF 137Cs was reported compared to the plots with no countermeasures.

Ecological Risk Assessment is used to evaluate the potential hazards to the environment that are attributable to emissions of pollutants from industries. There is guidance available regarding the general ecological risk assessment process including problem formulation, exposure and effect analyses, and risk characterization. In a first step, the Screening-Level Ecological Risk Assessment (SLERA) is used to evaluate whether the emissions can put the receptor ecosystems at risk or not. Concerning releases from nuclear facilities under authorization, any SLERA is a challenging task because of (1) the large number of substances, (2) the various quantities that may be emitted to the aquatic ecosystems and (3) the various environmental situations to be considered. This task must be performed for two categories of pollutants, radionuclides and chemicals, each exhibiting specificities in terms of concentration in media or dose-effect relationships. Since these relationships for radioactive substances are based on the tissue-absorbed dose in Gray, the first step is to express critical exposure values to radionuclides in a consistent way with the critical concentration used for chemicals. We describe here the screening and ranking method that was developed and an application to the electronuclear sites along the Rhône River.

During 2001–2002 we investigated current contamination of soils in several places in the Chornobyl zone. We have measured the content of alpha emitting isotopes Pu, 241Am, 154,155Eu, 90Sr, and 137Cs in layers of soil up to the depth of 30 cm. By including the two mechanisms of migration: convection and diffusion in our model, we were able to estimate the ecological and effective half-lives of self-purification processes for these layers of soil. Effective half-lives vary from 20 to 400 years dependent upon the type of soil and the isotopes.

The classic ERA method is today recognised as relevant for both chemicals and radionuclides. As uranium presents the double ecotoxicity, a unique method may then now be applied to evaluate in tandem the associated ecological risks, following the classic four steps methodology (problem formulation, effect and exposure analysis, risk characterisation [1]). The approach is developed for freshwater ecosystems receiving ore mining releases, exposed to uranium as a chemical element and as the radioactive families of its isotopes 234, 235 and 238. The structure and the function of the ecosystem are described by a conceptual model on which both the exposure and the effect analysis are based. Species Sensitivity Distributions are applied (1) to the chemotoxicity data, to estimate a Predicted-No-Effect-Concentration for uranium in water (in µg/L); (2) to radiotoxicity effect data, to estimate a Predicted No-Effect-Dose-Rate (in µGy/h). The risk is assessed at first through the risk quotient approach, a screening method involving for the radiological aspect back calculation of the water limiting concentration from the PNEDR for each isotope taken into account. When significant, the assessment is refined applying probabilistic techniques. The whole approach applicability was tested on a real case-study related to a former uranium mining site.

The paper deals with a specific aspect of a general survey, that is being carried out during last ten years in several regions of Serbia (former Yugoslavia, former Serbia and Montenegro) to assess population exposure to natural radioactivity based on geochemical and integrative pattern research approach. The originality regarding this work is related to the facts such as follows: the first identification and assessment of high areas of natural radiation in Serbia which provides insight into its regional characteristics, the interpretation of the results in terms of geological aspects, building types and human habits, the first introduction and field applicability of both (surface and volume trap) retro techniques in Serbia and assessment of doses and risks to the population in investigated high natural radiation rural communities.

In Northern Europe the use of tree biomass for production of energy is mostly based on thinning of forests, harvest residues, stumps from final cutting, bark of commercial roundwood, and organic waste of pulp industry. Results based on field experiments allow estimations of 137Cs activity removed from forests in wood fuel, and also the activity returned in ash used as a fertiliser. After one fertilisation treatment in three types of coniferous forests the activity concentration of 137Cs in wood fuel and ash was reduced to a fraction of 0.3 to 08 of activities in products from unfertilised forests. The improved tree growth and lowering activity concentrations of 137Cs in trees and understorey after fertilisation refer to reduction of human radiation exposure in Chernobyl-affected areas in the long term. Thereby radiation doses to workers handling the ash and members of the public using forests will gradually decrease faster than through radioactive decay only. A documented and traceable ash recycling history of forests is important for all users of forests.