Prompt Mapping of Radioactively Contaminated Areas

The paper presents a methodology for prompt mapping of radioactively contaminated areas. The efficiency of obtaining cartographic information is achieved by using correlation dependences between the characteristics of radioactive contamination obtained during various radiological surveys of contaminated areas. The method of spatial interpolation based on regression-kriging is used to formalize the data on radioactive contamination. This method allows combining the information resulting from direct measurements of density of territory contamination by radionuclides we are interested in with the information contained in other characteristics of radioactive contamination received at the surveyed area (for example, ER). Such an approach allows more accurate mapping of 137Cs deposition density and concentration of its activity in the root layer of soil, as well as significant reduction of the time and cost to survey the mapped area (sampling, sample preparation and measurement of samples). This, in turn, accelerates and reduces the cost for mapping of radioactively contaminated territories (fields, lands, sites). The methodology has been tested on the fields contaminated by radionuclides resulting from the Chornobyl accident in the Narodychi, Polissia and Ivanivka Districts and has proved its performance and efficiency. Comparison and analysis of the obtained maps of radioactive contamination of the territory show that in the conditions of limited amount of data on direct measurements and time limit, the use of correlation dependences between the characteristics of radioactive contamination of soil is often the only possible way to increase the information content and accuracy of the obtained cartographic information.

Radiological Modelling of Thermaikos Gulf

The radiological model of Thermaikos Gulf ecosystem has been designed based on the MOIRA-PLUS Decision Support System properly modified for the marine environment. Radioactive fallout contamination exercises have been performed for 90Sr and 137Cs radioisotopes, within the frame of environmental sensitivity analysis. The model’s performance has been calibrated, taking into account the available 137Cs deposition estimations and published experimental concentrations to the sediment, the water and the fish at the Gulf, from the time of the Chernobyl accident up to now. The radiation doses to adults – assuming that their entire food intake from the marine pathway comes from the local environment – after the first year of one instantaneous deposition of 1000 Bq/m2, were found 0.72 μSv for 137Cs and 8.8 μSv for 90Sr, respectively. The results are consistent with other models estimations in Northern Seas and NE Aegean Sea.

Natural sepiolite efficiency in reducing 137Cs transfer and deposition into meat and edible organs of broiler chickens

The objectives of the present study were to examine the level of radiocesium deposit in meat and edible organs of broiler chickens as well as to investigate efficiency of natural sepiolite in reducing 137Cs deposition in meat, liver and gizzard of alimentary contaminated broiler chickens. Broiler chickens (six weeks of age) were fed with the standard diet and each broiler was given a single oral dose of 137Cs, total activity of 3750 Bq. The broilers were divided into two groups (10 broilers per group). The group 1 was control (received only radiocesium). The broilers of the group 2, in addition to radiocesium received natural sepiolite solution (2 g sepiolite per bird). After 24 hours, all broilers, from each group, were stunned and killed. The samples of meat, (breast and legs), liver and gizzard were taken from each broiler, for gamma spectrometry determination of radiocesium activity. After 24 hours of contamination, 56 % of introduced 137Cs radioactivity was deposited in the meat (breast and legs muscles), 1 % in the liver and 2,4 % in the gizzard of broiler chickens 42 days of age. Natural sepiolite demonstrated insufficient protective action. Compared to the control group, percentage reduction (decreasing percentage) of 137Cs deposition in meat was 16%, in liver 5% and in gizzard 12%.