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A model is presented that dynamically estimates the radiocesium activity in herbage from readily available soil parameters. Three key properties underlying the bioavailability of radiocesium in soils were estimated in the model: the labile radiocesium distribution coefficient (k dl ), the solution K + concentration ([m K ]), and the radiocesium concentration factor (CF, Bq kg -1 plant/Bq dm -3 soil solution). These were determined as functions of the soil clay content and exchangeable K status. The effect of time on radiocesium fixation was described by two first-order decay equations. The model was initially parametrized using radiocesium uptake data from a ryegrass pot trial. Without further parameterization, the model was then tested for a wide range of soil and crop combinations using a database of published and unpublished information from a variety of sources and covering contamination time periods of 0.5-11 years. Model predictions of activity concentrations in crops were in generally good agreement with observed values.

A database of soil-to-plant transfer factors for radiocesium and radiostrontium has been compiled for arable crops from published and unpublished sources. The database is more extensive than previous compilations of data published by the International Union of Radioecologists, containing new information for Scandinavia and Greece in particular. It also contains ancillary data on important soil characteristics. The database is sub-divided into 28 soil-crop combinations, covering four soil types and seven crop groups. Statistical analyses showed that transfer factors for radiocesium could not generally be predicted as a function of climatic region, type of experiment, age of contamination, or soil characteristics. However, significant relationships accounting for more than 30% of the variability in transfer factor were identified between transfer factors for radiostrontium and soil pH/organic matter status for a few soil-crop combinations. Best estimate transfer factors for radiocesium and radiostrontium were calculated for 28 soil-crop combinations, based on their geometric means: only the edible parts were considered. To predict the likely value of future individual transfer factors, 95% confidence intervals were also derived. A comparison of best estimate transfer factors derived in this study with recommended values published by the International Union of Radioecologists in 1989 and 1992 was made for comparable soil-crop groupings. Whilst there were no significant differences between the best estimate values derived in this study and the 1992 data, radiological assessments that still use 1989 data may be unnecessarily cautious.

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A lysimeter experiment was carried out on a relatively infertile soil to examine the effect of potassium fertiliser application on the uptake of radiocaesium by spring wheat. Porous ceramic cups were used to obtain samples of soil solution. Results showed that the uptake of radiocaesium by spring wheat was reduced by the addition of potassium. However this inhibitory effect was less marked at later stages of plant growth due to factors such as the spatial variability of potassium within the soil, differences in root distribution down the soil profile and age-related demand for potassium by the plant. There was some evidence that a negative power function could be used to describe the relationship between the concentration of 137Cs in the plant and concentrations of potassium or 137Cs:K quotients in soil solution over the whole experimental period. Practical implications of potassium fertilisation in terms of reducing uptake of radiocaesium by crops are discussed.

The STRATEGY project (Sustainable Restoration and Long-Term Management of Contaminated Rural, Urban and Industrial Ecosystems) aimed to provide a holistic decision framework for the selection of optimal restoration strategies for the long-term sustainable were identified. The importance of stakeholder consultation at a local level and of ensuring that any response is site and scenario specific were emphasised. A value matrix approach was suggested as a method of addressing social and ethical issues within the decision-making process, and was designed to be compatible with both the countermeasure compendia and the decision support system. The applicability and usefulness of STRATEGY outputs for food production systems in the medium to long term is assessed.

Two handbooks have been developed in conjunction with a wide range of stakeholders that provide assistance in the management of contaminated food production systems and inhabited areas following a radiological incident. Emergency centres in Member States not involved in the development of these handbooks were invited to take part in demonstration activities to establish whether the handbooks would be useful for the purposes of contingency planning and accident management. Some eight centres took part. Emergency exercises or similar events based on scenarios involving contamination of the foodchain and inhabited areas were used. Feedback from all of the demonstrations was positive with constructive criticism given on how to improve the navigation, structure and format of the handbooks. All of the key improvements highlighted during the demonstrations were taken into account and included in version 2 of the handbooks. Two additional demonstrations took place in Denmark and Slovakia to investigate the appropriateness and applicability of a stakeholder participatory process when applying the handbooks. These stakeholders expressed their willingness to discuss the issues at stake from contamination of food production systems and inhabited areas and gave a clear commitment to continue the process.

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