A linked chain of 1D river model RIVTOX and 3D estuary model THREETOX was used to assess impact of the previous and potential releases from the nuclear installations in the basins of Ob' and Yenisey rivers on radioactive contamination of the rivers and the Kara Sea. The RIVTOX includes the model of river hydraulics, suspended sediment and radionuclide transport in river channels. THREETOX includes a set of sub-models: a hydrodynamics sub-model, ice dynamics-thermodynamics sub-model, suspended sediment transport and radionuclide transport sub-models. The radionuclide transport model simulates processes in the water, suspended sediments and in bottom sediments. The simulations of the flux of 90Sr and 137Cs through the Ob' River and estuary from activities at the Mayak Production Association for the period 1949-1994 and through the Yenisey River and estuary from activities at the Mining, Chemical Combine for the period 1959-1994 were carried out. Based on scenarios, simulations have been performed in order to assess the potential risk of contamination from existing and potential sources of radionuclides into the Kara Sea through the Ob' and Yenisey rivers.

Two types of plants (lettuce and radish) were contaminated by dry deposition of radioactive aerosols (137Cs, 85Sr, 133Ba and 123mTe). Due to the rain efficiency in decreasing radiological contamination of crops, a rain scenario was applied on the two types of plants. These experiments aimed at improving the prediction of the consequences on agricultural products of a nuclear accident occurring on a PWR, and at improving the understanding of the different processes occurring between contamination and harvest. For a plant species at a given stage of its growth cycle, the interception of the four radionuclides was found to be identical and varied from 68% for radish to 75% (at the middle of ripeness stage) or 78% (at the mature plant stage). Using a conceptual model, the predominance between the two processes - washing-off the leaves and absorption through the leaves cuticles allowing translocation - was evidenced. For Cs, Sr and Ba, for both the lettuce and the radish, washing-off on the foliar cover was the most significant during the first rain. The absorption process inside the plant became dominant only from the third rain event. Tellurium had a particular behaviour: it was non-mobile and stayed put on the leaves. The values of the washing-off and absorption coefficients were estimated. The global transfer factor values were dependant on both the radionuclides and the plant species; nevertheless, a higher value was obtained for cesium, regardless of the plant and the rainfall (from 0.06 m2.kg$_{\scriptsize\textrm{fresh}}$-1 for radish to 0.1 m2.kg$_{\scriptsize\textrm{fresh}}$-1 for a whole lettuce).

Contaminations of the terrestrial gastropods Helix aspersa maxima by direct deposition or labelled food ingestion of 137Cs, 85Sr, 133Ba and 123mTe were carried out under laboratory conditions. The aim of this study was to compare the two contamination pathways: direct and trophic, in terms of individual mortality and radionuclide uptake, depuration and tissular distribution. A first group of 30 snails (2-years old) was exposed to radioactive aerosols during a twenty-hour period. These aerosols were assumed to be representative of those that would be released during a nuclear accident occurring in a PWR. A second group of 40 snails (same age) was submitted to an ingestion of food contaminated by the same aerosols, twice-a-week for 10 days (flour at a feeding rate of about 0.2g). During the 21 day-observation period, a comparison between the two groups and the reference group (not contaminated by radionuclides) was performed. No significant difference between the three groups was observed in the growth or in the mortality. One day after deposition, cesium was the most bioavailable element, distributed rather homogeneously through the whole body (from 13 to 28% of the total Cs in organs other than the digestive system and the muscle, respectively). Strontium accumulated in the shell (about 70%). Barium was found in the muscle (20%) and the shell (65%). Tellurium was mainly present in the shell (70%) and in the digestive system (20%). After a few days, this element was mostly present in the faeces. As regards contamination by ingestion, it was mainly accumulated in the digestive system.

The need to increase the predictive power of risk assessment for large tritium releases implies a process level aproach for model development. Tritium transfer for atmosphere to plant and the conversion in organically bound tritium depend strongly on plant characteristics, season, and meteorological conditions. In order to cope with this large variability and to avoid also, expensive calibration experiments, we developped a model using knowledge of plant physiology, agrometeorology, soil sciences, hydrology, and climatology. The transfer of tritiated water to plant is modelled with resistance approach including sparce canopy. The canopy resistance is modelled using Jarvis-Calvet approach modified in order to directly use the canopy photosynthesis rate. The crop growth model WOFOST is used for photosynthesis rate both for canopy resistence and formation of organically bound tritium, also. Using this formalism, the tritium transfer parameters are directely linked to known processes and parameters from agricultural sciences. The model predictions for tritium in wheat are closed to a factor two to experimental data without any calibration. The model also is tested for rice and soybean and can be applied for various plants and environmental conditions. For sparce canopy the model uses coupled equations between soil and plants.

Aerosol dry deposition onto agricultural and forest areas is investigated. Its estimation is still uncertain, particularly for rough surfaces and sub-micronic aerosols. In fact models used in radiological risk or air quality assessment studies are highly empirical and fail to reproduce the results of the most recent measurement campaigns. Therefore a theoretical framework, based on a mechanistic description, has been developed. The proposed approach consists in two steps. First, interaction between aerosols and foliar surface is formulated by using a set of parameters, which are defined on the local scale of one foliar element. In the second step, the collective effect of the foliage is taken into account through statistical distribution of these parameters. The model integrates the three main factors governing aerosol dry deposition. These are local aerodynamic characteristics of the flow within the canopy, aerosol mechanisms governing the deposition, and canopy structural and morphological properties. Physical processes considered in the study are inertial impaction, gravitational settling and Brownian diffusion. The canopy characteristics considered are spatial distribution, orientation and micro-structure of foliar surfaces. The applicability of the model is demonstrated on an existing measurement campaign.

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 Radiological Protection Institute of Ireland (RPII) monitors airborne radioactivity concentrations at ten stations throughout Ireland, of which nine are equipped with low volume particulate samplers and one, in Dublin, with a high volume particulate sampler. The low volume particulate samples are assessed for total beta activity. In the period 1998-2003 the total beta activity concentrations observed have been consistently low, ranging between 0.03 and 1.33 mBq m-3 with a mean over all sampling sites of 0.26 ± 0.15 mBq m-3 (n = 2361). High volume particulate samples have been assessed for caesium-137 and beryllium-7. A mean caesium-137 activity concentration of 2.3 ± 2.2 mBq m-3 (n = 26) was observed in samples taken since 1993 while the mean beryllium-7 activity concentration over this period was 3.0 ± 1.6 mBq m-3 (n = 42). In addition, air sampled at the RPII's laboratory in Dublin, is monitored for krypton-85, a radioactive noble gas, released into the environment primarily as a result of the reprocessing of nuclear fuel at installations such as Sellafield in the UK and Cogema La Hague in France. Analysis of the krypton-85 monitoring data, along with additional backward air trajectory modelling, demonstrate the influence of the reprocessing plants on the krypton-85 concentrations in Ireland. 


In terrestrial ecosystems, soil is the main interface between atmosphere, hydrosphere, lithosphere and biosphere. Its interactions with carbon cycle are primordial. Information about carbon 14 dynamics in soils is quite dispersed and an up-to-date status is therefore presented in this paper. Carbon 14 dynamics in soils are governed by physical processes (soil structure, soil aggregation, soil erosion) chemical processes (sequestration by soil components either mineral or organic), and soil biological processes (soil microbes, soil fauna, soil biochemistry). The relative importance of such processes varied remarkably among the various biomes (tropical forest, temperate forest, boreal forest, tropical savannah, temperate pastures, deserts, tundra, marshlands, agro ecosystems) encountered in the terrestrial ecosphere. Moreover, application for a simplified modelling of carbon 14 dynamics in soils is proposed. 


The dry deposition to several leafy vegetables (endive, head lettuce, red oak leaf lettuce, spinach) was studied. Particles with attached 134Cs were used for testing the particulate deposition, gaseous elemental 131I was the tracer for gas deposition. The particle deposition was the highest for rough and structured leafs as red oak leaf lettuce has, but as well for spinach with many open stomata. The stomatal uptake seamed to be the most important process for gas deposition, the deposition to spinach was for Radioiodine the highest as compared to all other species. The lowest deposition was always found to the closed heads of head lettuce. The difference in deposition to the various species was up to a factor 9.

Model predictions of solute transport in a wetland were compared with tracer experimental data to illustrate that the number of compartments in a compartmental model should be selected according to certain rules to accurately describe the transport process. If the input pulse is short, the model structure affects the output significantly. The temporal moments of the residence time distribution was obtained from a general solution of the compartmental model in the Laplace domain derived with an arbitrary inflow pollutograph. The variance of the residence time can be used as a useful tool to analyse the effect of model structure and long-term inflow pollutograph on the response of the model predictions.


Temporal changes in radionuclide transfer factors were evaluated in forage fishes over a 40- to 50-year period. In general, 90Sr, 60Co and 137Cs transfer factors fairly consistent over time, as indicated by strong correlations between measured and estimated values. This conclusion was further strengthened by comparing radionuclide transfer factors measured in Perch Lake biota relative to those reported for other Canadian Shield lakes, since similar values were found. Despite these similarities, however, within-lake differences of up to an order of magnitude were observed for a given species collected in a given year, suggesting that within lakes, there may be factors influencing biota exposure to radionuclides and/or bioavailability. 


Earthworms and their growth media were analyzed for 33 elements, including radionuclide related elements such as Cs, Sr and U, in order to obtain basic information on the transfer parameters of the elements. The earthworms analyzed were Eisenia foetida fed in the laboratory by using cotton linters or leaf litter. The concentrations and transfer factors (TFs) of the elements were determined. Relatively high TFs were observed for Na, Mg, P, K, Ca, Co, Ni, Cu, Zn, Rb, Mo and Cd. The TFs for Al, Sc, Ti, Y, Nb and lanthanide elements were low. The TFs of alkaline elements, K, Rb and Cs, decrease with atomic number. The TFs of Cs were 0.16 for both media. Multi-element analyses could provide much information on the concentration and transfer of elements for earthworms which are one candidate reference organism for environmental radiation protection studies.

More than 200 data sets from the literature of measured time series of activity concentrations and transfer factors concerning: (1) soil, green plants, mushrooms, and game in forests and (2) water, particulate matter, and fish in rivers, reservoirs and lakes in Europe have been analyzed. We used a sum of up to 3 exponential functions to evaluate ecological half-times (T$_{\scriptsize\textrm{eco}}$). In fresh water systems we fitted lognormal distributions of T$_{\scriptsize\textrm{eco}}$ for 137Cs (e.g. in the water of 32 European lakes, T$_{\scriptsize\textrm{eco}1}$ = (0.3*2.2$^{\pm 1}$) years and T$_{\scriptsize\textrm{eco}2}$ = (5.7*3.9$^{\pm 1}$) years as geometric mean value and standard deviation). Pronounced seasonal variations were observed in suspended matter of Lake Lugano, reflecting the bio-mass cycle of this lake. In forests, ecological half-times for 137Cs can also be fitted by a lognormal distribution. For Central Europe T$_{\scriptsize\textrm{eco}}\:<$ 12 years. Extraordinarily high 137Cs activity concentrations were observed recently in wild boar in Germany. For Eastern Europe the physical half-time is dominant and in some components of the ecosystem the activity concentration is still increasing. 


One of the most serious problems occurring during coal extraction in Upper Silesia in Poland is caused by waters with very high salinity. These waters often contain also high concentrations of natural radionuclides, mainly 226Ra from uranium series and 228Ra from thorium series. At least 70% of the total amount of radium carried by this waters remains nowadays in underground galleries as radioactive deposits. But, during the period of the most extensive coal extraction up to 225 MBq of 226Ra and 400 MBq of 228Ra were released daily into surface along with the other mine effluents. As a result of discharge of radium-bearing waters into settling ponds and later into rivers a significant increase of radium concentration in bottom sediments has been observed. Sometimes there is also a contamination of river beds, soils and biota. The paper describes results of investigation of waters and sediments with enhanced natural radioactivity, that occur in settling ponds, where mine waters have been dumped. Measurements of different factors of radiological hazard were made, such as radium content in the soil from ponds' banks, variations of gamma radiation background and radon exhalation. Additionally radium transfer to vegetation that had transgressed into the ponds has been calculated.

A comparative assessment of physiological and cygotenetical parameters in Lymnaea stagnalis populations from Perstok lake and the inlet of Pripyat river with the highest in Belarus and moderate levels of radioactive contamination have been carried out. In 2004 f γ-activity of snails from river and lake amounted to 39.2 and 567.8 Bq kg-1, respectively, and β-activity - to 123.4 and 7055 Bq kg-1 respectively. Snails from the lake were characterized by the increase of the cells with cytogenetic damages (micronuclei) and by the decrease of cells with interphase death and proportion of young cells in hemolymph. It indicates the unfavourable environmental conditions in the lake due to increased level of radioactive contamination. Nevertheless, the embryonic mortality in the progeny of the snails from lake was lower and the average population radioresistance of snails much higher than that in the river indicating intensification of the radioadaptation processes in populations from the lake.

This work aimed at treating the new database on cesium-137 and strontium-90 transfer by wash-off collected by IRSN in the framework of the Franco-German Initiative for Chernobyl. It focused on the 71 runoff plot (from 1 to 400 m2) experiments conducted under artificial rainfalls in the Chernobyl district between 1986 and 1998. These data, mostly still unpublished, provide a quantification of wash-off at the rainfall scale, still rare for radionuclides. Normalized entrainment coefficients by liquid and solid wash-off were calculated for each experiment. In average, the liquid entrainment coefficient was 10-5 mm-1 for cesium, and 10-3.8 mm-1 for strontium. The solid entrainment coefficient was 10-41 m2g-1 for cesium and 10-4.3 m2g-1 for strontium. These trends and values were found consistent with reported values in the literature. For assessment purposes, the extrapolation of these coefficients to wider areas and to other sites would need their physical interpretation.

The organic carbon accumulation rate in mangrove ecosystem was reported to be important sink of carbon as well as that in boreal peat accumulation. For the estimation of 10 years scale organic carbon accumulation rates at mangrove plantation coastal area, the 210Pb is expected to be suitable for decades scale estimation by its half-life, though it has possibility of bio-/physical- turbation effect in applying 210Pb chronology, especially in Asian mangrove ecosystem where the anthropogenic physical turbation by coastal fishery is vigorous. We studied the organic carbon and 210Pb accumulation rates in subtropical mangrove coastal ecosystems in Japan, Vietnam and Thailand to remove the effect of bio- anthropogenic turbation on organic carbon accumulation. We finally concluded that 210Pb was applicable to estimate organic carbon accumulation rates in these ecosystems. The measured organic carbon accumulation rates using 210Pb in mangrove coastal ecosystems of Japan, Vietnam and Thailand were $0.22 - 6.0$ t-C ha-1 y-1.

Methodologies have been developed to allow impacts of ionising radiation on marine ecosystems to be evaluated within selected geographical settings. The stages in the assessment require initial information about unit concentrations of radionuclides in reference media to be collated. Activity concentrations for reference groups of flora and fauna and for representatives of these groups are then derived using an equilibrium concentration factor approach. Following this, dose-rates can be calculated using relevant dose conversion factors. Impacts on the environment are evaluated by comparison with dose-rates at which selected biological effects are known to occur and the natural radiation background. This paper focuses mainly on the transfer part of the assessment drawing attention to gaps in information that have been identified through review and providing an outline of methods that may be used to fill these gaps. Biokinetic models parameterised using allometric relationships have shown their utility in this respect. Initial work looking into the application of such models has met with some success with model predictions comparing favourably with the few empirical data available. Further work will be needed to validate the models for a large range of radionuclides and to consider uncertainty in model estimates through probabilistic analyses.

An extensive diagenetic study carried out on a sediment core collected in the Cumbrian mud patch off the Sellafield nuclear reprocessing plant, is presented. Sequential leaching data, using a thoroughly validated protocol specifically designed to prevent any resorption of the released plutonium in the course of the extraction, demonstrate that a significant proportion of the plutonium is loosely bound to sites that readily exchange with seawater, oxidise upon oxygenated water contact (reactive sulphides) or easily dissolve upon changes in pH. Such a result contradicts many previous sequential extraction studies which have reported that little of the plutonium in Irish Sea sediments is in a readily available form. The profile of dissolved plutonium in pore waters indicates an active uptake process at depth, probably linked to sulphide (Acid Volatile Sulphide) precipitation. These reactive sulphides are liable to act as source of plutonium to the overlying water if they are brought close the interface by bioturbation or in contact with oxygenated seawater by burrowing activity.

An aluminum processing plant, which is located at the Antikyra Bay, at the northern margin of Corinth Gulf, is producing a high radioactive contamination in the marine environment, due to the discharge of bauxitic red mud tailings. The levels and the distribution of 238U, 232Th, 226Ra, 40K and 137Cs in marine sediments of the area have been determined. The results indicate that the seafloor of Antikyra bay and the basin of Gulf of Corinth are highly contaminated with 238U, 232Th and 226Ra. On the contrary, the red mud tailings induce depletion to the 40K and 137Cs concentrations in the area.