The CESER Project: Summary of Results |
Contract No: FI4P-CT95-0021 |
Title: CESER
- Countermeasures:
Environmental and Socio-Economic Responses, A Long-Term Evaluation. |
Introduction
Accidental releases of radioactivity into the environment have the potential to cause widespread and long-term contamination of agricultural land. Although in the most severe case, food production and collection of wild foods may need to cease, in many circumstances it is possible through appropriate mitigation to allow farming to continue. The difficulty lies in designing countermeasure strategies that will deliver the required reduction in radiation dose in the most efficient, acceptable, cost-effective and technically feasible way. In the past this process of optimisation has typically neglected potential impacts on the environment and agricultural productivity, with their associated economic implications. Equally the acceptability of different remediation options to consumers has received only limited attention. However, long-term use of countermeasures may increase the risk of environmental, social and wider economic impacts. The optimal remediation strategy should therefore seek to balance these impacts against the costs and benefits of dose reduction. This has been addressed in the CESER project. Objectives
A generic methodology for the assessment of environmental and socio-economic side-effects of countermeasures was developed (see Figure 1) and successfully applied in realistic case study scenarios for Austria, Finland and Scotland. Generic criteria were selected to characterise the most significant side-effects on water, air, soil and landscape quality, biodiversity and agricultural productivity. To provide quantitative estimates of these side-effects, a combination of mathematical simulation modelling, calculations, experimentation, contingent valuation, landscape structure analysis and expert judgement was applied. A formal selection procedure was used to identify the countermeasure to be included in the impact quantification. Individual and combined countermeasures against radiostrontium and radiocaesium were allocated to farm types, based on radiological effectiveness under different radionuclide deposition scenarios and applicability to specific production systems and environments. Some food products, i.e. chicken, eggs and pork were found to be less vulnerable to radiocaesium contamination than generally accepted. This is also likely to apply to radiostrontium, but for Sr transfer estimates are less well documented. Figure 1. Overview of the CESER methodology for assessing environmental and socio-economic side-effects of countermeasures. The feeding of caesium-binders such as AFCF (ammonium ferric cyanoferrate) to animals has no known negative effects on animal health. However, experiments showed that in peat soils ferric cyanoferrate-bound radiocaesium in animal manure can migrate more rapidly than caesium chloride. This effect was not seen in sandy and loamy soils. When exposed to light, AFCF partially degrades producing toxic hydrocyanide gas, but concentrations under field conditions when animal manure is spread are unlikely to exceed occupational exposure limits. Despite these side-effects, AFCF is seen as the most cost-effective countermeasure for Cs in animal production systems. No equally effective method for radiostrontium exists. To reduce both Cs and Sr transfer effectively, changes in the feeding regime are most suitable. In dairy cows these changes have to be made during the whole year and negative environmental side-effects may occur where concentrate feeding is increased, particularly if this involves greater production of cereals on the farm. In meat production dietary changes, such as feeding of clean roughage and /or concentrate, are not likely to have significant environmental impacts when they only affect the last part of the fattening period. After application of soil-based countermeasures such as liming and ploughing, the increased mineralisation of soil organic matter can lead to greater leaching of nitrate and in sandy and some peaty soils the leaching of fulvic acid-bound nutrients, radionuclides and heavy metals is likely to be enhanced. Geochemical speciation modelling indicates that liming and application of potassium fertiliser may also imbalance ionic ratios in soil solution thereby interfering with plant nutrition and uptake of toxic metals. Experiments with mycorrhiza showed that potassium application had no effect on mycorrhizal infection of host plants but depressed the calcium uptake in mycrrhizal and non-mycorrhizal plants. These results indicate that soils on which liming and K application are most effective are also most likely to show significant side-effects, although some of these may be mitigated through simultaneous application of other nutrients together with K. Model simulations for arable land show that skim and bury ploughing has no major side-effects provided a good vegetation cover is subsequently established to minimise erosion. Deep ploughing in comparison leads to more significant changes. Depending on the nature of the subsoil long-term rates of soil erosion may increase or decrease, while in general phosphorus losses to water bodies and thus the risk of eutrophication will decrease. This is likely to be accompanied by lower crop yields due to poor soil structure, lower organic matter content and lower nutrient supplies. Measures taken to subsequently ameliorate the soil could increase the risk of water pollution. Given the potential side-effects of deep ploughing, skim and bury ploughing is the preferred technique for burying contamination provided the specialised equipment is available since implementation costs for both methods are similar . Modelling results also demonstrate that changes in land use can seriously increase soil erosion when permanent grassland is converted to arable production, e.g. when grass in the animal diet is partly replaced with cereal feed. Inputs of phosphorus and nitrogen to water bodies may also increase depending on the intensity of the original grassland production and the mode of fertilisation. Increased feeding of concentrates to dairy cows is likely to increase nitrogen inputs to soils, however, if this concentrate is imported negative side-effects are offset by lower grass production within a catchment. In areas dominated by dairy production, increased feeding of concentrate will increase ammonia emissions from cows with potential negative effects on local ecosystems. Impacts of emissions can be reduced by increased manure storage capacity and other abatement measures. National emissions would only rise significantly if feeding countermeasures were applied to a large proportion of all dairy cows. Changes in biodiversity, assessed via landscape and habitat structure, were predicted to be negative when the countermeasures made the landscape more monotonous e.g. large scale afforestation or intensive cultivation of pastures. A more varied mosaic of land uses, e.g. through the introduction of barley and fallow into a grass-dominated landscape, would most likely increase biodiversity. Quantitative estimates of environmental impacts were scaled up to catchment, regional or national level by applying GIS techniques. Impact maps were used to identify areas of high and low impact risk while catchment inventories were used to illustrate the net effects of selected countermeasure scenarios. Suitability maps were used to show the geographical distribution of areas suitable and unsuitable for a particular countermeasure. For all countermeasures, calculation methods for on-farm costs and benefits were devised and incorporated into the non-spatial decision support system (CeserDSS). Environmental costs of countermeasures have for the first time been quantified, as follows: a) Contingent Valuation, used to value changes in landscape quality following afforestation and pasture improvement, showed clear differences in people's Willingness to Pay depending on the type of landscape; b) Transferable environmental costs in the literature were identified for soil erosion and nutrient transport to water. To quantify the benefits of countermeasures to society the avoided loss of product output was chosen, measured via people's willingness to pay for 'clean' food compared to food from areas where countermeasures have been applied. This method was adopted in preference to the avoided cost of illness as a result of the averted dose. The selected approach was tested in a consumer survey. The consumer survey in Norway and Scotland showed that the Chernobyl accident still has a negative impact on consumption levels of certain foods. Despite Government actions to limit contamination and assurances to consumers, people are still concerned about these foods and their perceived risk is higher than the expertsí calculated risk. Consumers prefer to buy 'clean' food from non-contaminated areas compared to areas where countermeasures have been implemented, and are willing to pay higher prices. Scottish consumers were willing to pay on average a premium of 31% and 62% above the 'normal price' for lamb and milk, respectively, while Norwegian consumers were willing to pay 46% more for lamb. Information provided by Government authorities and experts was most trusted and food labelling was the most preferred way of conveying information. In a future fallout situation the impact of consumer attitudes on market demand will depend on whether it is possible to reduce their perceived risk by improving information and communication. If not, Governments and food retailers must take into account the consumersí 'overestimated' perceived risk to limit costs. Three consumer strategies for decision-makers are proposed in the report. Two computer based decision support systems have been developed to provide formal procedures for selecting, evaluating and comparing countermeasures. To accommodate the different requirements of decision-making at local compared to regional and national level, two types of DSS have been designed: 1) the CeserDSS, a very user-friendly non-spatial assessment tool for a single area/farm using Windows-based software; and 2) the Spatial DSS, a more generic and technically sophisticated assessment tool for larger, heterogeneous areas using a GIS. Both systems have been developed for Scottish agriculture to demonstrate the benefits of a country specific countermeasure evaluation. The countermeasure selection process ensures suitability for local or regional agricultural and environmental conditions whilst providing a tool for judging environmental and agricultural side-effects and calculating on-farm costs and benefits. The incorporation of a Multicriteria Decision Making technique gives the user the opportunity to influence the assessment criteria and generate compromise alternatives. The final outcome is a set of countermeasure suitability rankings or suitability maps, with which remediation strategies can be optimised. Implications
Co-ordinator: Dr. C. A. Salt (University of Stirling, UK) Partners: Dr. H. Solheim Hansen
(Nord-Trøndelag College, Norway), Dr. G. Kirchner (University of
Bremen, Germany), Dr. H. Lettner, (University of Salzburg, Austria), Dr.
S. Rekolainen (Finnish Environment Institute, Finland).
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