G. Arapis

Reduction of soil-plant transfer factors: mechanical aspects

Abstract In order to reduce food-chain contamination after a nuclear accident, mechanical actions may be taken to remove the radionuclides, or to prevent their uptake. Some of these actions have been reviewed by a working group in the REACT workshop. The conclusions of the group are briefly reviewed using tables to summarised available methods.

RADIOLOGICAL EFFICIENCY OF AGRICULTURAL COUNTERMEASURES APPLIED IN RADIOCONTAMINATED FIELDS

Abstract Implementation of agricultural countermeasures is one of the principal methods that allow to decrease irradiation doses. Summarizing available information about countermeasures and taking into account the experience in the elimination of the nuclear accident consequences, it is demonstrated that the most widespread countermeasures after the Chernobyl accident were soil ameliorations. These methods are simple, inexpensive and effective in reducing radionuclide transfer from the soil to agricultural crops. Among the above mentioned methods, agrotechnical countermeasures were the most applicable, decreasing the contamination of plant products up to 20 times. Radical and surface improvements of natural and semi‐natural meadows were carried out on a large scale on contaminated lands. The biggest decrease of vegetation contamination was observed after the radical improvement of meadows, with and without drainage, 43 and 16 times, respectively. Other effective measures are agrochemical methods. In fact ...

Japanese quail acute exposure to methamidophos: experimental design, lethal, sub-lethal effects and cholinesterase biochemical and histochemical expression.

We exposed the Japanese quail (Coturnix coturnix japonica) to the organophosphate methamidophos using acute oral test. Mortality and sub-lethal effects were recorded in accordance to internationally accepted protocols. In addition cholinesterases were biochemically estimated in tissues of the quail: brain, liver and plasma. Furthermore, brain, liver and duodenum cryostat sections were processed for cholinesterase histochemistry using various substrates and inhibitors. Mortalities occurred mainly in the first 1-2h following application. Sub-lethal effects, such as ataxia, ruffled feathers, tremor, salivation and reduced or no reaction to external stimuli were observed. Biochemical analysis in the brain, liver and plasma indicates a strong cholinesterase dependent inhibition with respect to mortality and sub-lethal effects of the quail. The histochemical staining also indicated a strong cholinesterase inhibition in the organs examined and the analysis of the stained sections allowed for an estimation and interpretation of the intoxication effects of methamidophos, in combination with tissue morphology visible by Haematoxylin and Eosin staining. We conclude that the use of biochemistry and histochemistry for the biomarker cholinesterase, may constitute a significantly novel approach for understanding the results obtained by the acute oral test employed in order to assess the effects of methamidophos and other chemicals known to inhibit this very important nervous system enzyme.

AIR POLLUTION ASSESSMENT IN VOLOS COASTAL TOWN, GREECE

A study of air pollutants has been performed using the available data for the last ten years in the Greek costal town, Volos. Long-term air quality data is valuable and informative to understand in depth the trends that will lead to more realistic findings and conclusions, while the governmental regulatory policies have to use them, in order to reduce the emissions of primary and secondary air pollutants. The aim of this study was: a. to determine and study the daily variation patterns of O3, NO, NO2, CO and SO2 concentrations per weekday, in the Greek coastal town, Volos. To this purpose, the air pollution data collected over the last 10 years in Volos were analyzed.

Radiocapacity of Forest Ecosystems

Vast territories have been exposed to radioactive fallout from to the Chernobyl accident and require integrated assessment of the ability of ecosystems to retain and accumulate radionuclides. The fate of radionuclides in an ecosystem is determined by its capacity to retain radionuclides, defined as radiocapacity. Radiocapacity provides the absolute quantity of radionuclides that can be retained in an ecosystem without damaging its living ability. The estimation of this parameter for different types of ecosystems, allows an assessment to be made of many properties of the ecosystem, a prediction of the fate of the radionuclides and their public health impact.

FROM MOLECULE TO ECOSYSTEMS: ECOTOXICOLOGICAL APPROACHES AND PERSPECTIVES

Ecotoxicology belongs to one of the new ecological branches, which emerged as a consequence of the adverse effects of pollution on various ecosystems. These ecosystems are complex and it is difficult to fully understand all their details. Therefore, the description of ecosystems and their processes inevitably has a certain degree of uncertainty, due to their enormous complexity. Nowadays, the ecosystem as a whole, starts to be considered as a living, evolving and dynamic entity, and not simply a conglomeration of physical and biotic components. In fact, appropriate examples drawn from various species, populations, communities and ecosystems emphasise and explain the role of ecological factors and phenomena. Thus, at the level of organisms the effects and the way they adapt for example to temperature, moisture, light, photoperiod, ionising radiation, salinity, pH and toxicants, must be taken into account. At the population level, parameters such as growth, reproduction, mortality, spatial pattern, dispersal, migration and communication are important. At the community level, additional attributes such as diversity, competition, parasitism, predation, etc. are of great significance. At the ecosystem level, the concepts of trophic levels and webs, nutrient cycles, maturity, succession, niche, stability, homeostasis, etc., must also be taken into consideration.

METHODS AND TOOLS IN ECOTOXICOLOGY AND ECOLOGICAL RISK ASSESSMENT WORKING GROUP SUMMARY

Discussions regarding the role of ecotoxicology in Ecological Risk Assessment were held in an open forum.

Limitations and Perspectives of Radioecological Assessment for Soil—Plant Systems in Greece

Approaches to radiological risk assessment in Greece are insufficient. There is a need to point out some regional differences between Mediterranean region and the Northern European countries.

Behaviour of Cesium in Contaminated Soils with and without Agricultural Practices

The migration of cesium into affected agricultural soils, five years after the Chernobyl accident, is examined in this study. Samples of soil were taken from an undisturbed non-cultivated rural area in the north of Greece, where an important contamination has been detected. The migration of Cs into these soils was measured by y spectrometry. Slight movement of Cs was observed during the five year period following the accident. The agricultural practices, used in this area from 1986 up to now, have diluted the contamination into the 0—40 cm horizon and thus only low concentration of cesium in the cultivated soils was detected.