CZ9626456 The ratios P1 = U2/U1, and P2= LJ4/U3, and the differences R1=U2-U1, and R2=U4-U3 should be calculated. A modified [2] decision making procedure has been developed, by which it is possible to assess whether the increase of the dose rate in a measuring site is due to: a) presence of a radioactive cloud in the measuring site, b) surface contamination of the terrain in the measuring site, c) detection of gamma radiation emitted from the surroundings of the measuring site, d) a some combination of a), b), and c). References 1. Stubna, M., Pokorny, V., Kusovska, Z., Duranova, T.: Posudenie velikosti pasma pre planovanie opatreni na ochranu obyvatelstva v pripade radiacnaj havarie JE Dukovany, Vyzkumna zprava VUJE 14/91, Trnava, 1991, 96p. 2. Guidance on Off-site Emergency Radiation Measurement Systems, Phase 1 - Airborne Release, Report FEMA-2, Rev. 1/July 1987, Washington, D.C. DETERMINATION OF THE CORRECTION ON ACTUAL NEUTRON SPECTRA IN NPP FOR PERSONAL DOSIMETRY J. Zeman SMI Bratislava ***** DEVELOPMENT OF INCIDENCE OF CANCER MORBIDITY AROUND NUCLEAR POWER STATIONS AT JASLOVSKE BOHUNICE WITHIN 20 YEARS M. LetkovidovA, J. Korec, V. Pnkazsky, Z. Smejkal Specialized Healing Institute TaRCH, Nitra-Zobor Research Institute of Nuclear Power Stations, Trnava District Hygienic Station, Poprad University Pardubice, Radioisotopic Laboratory of Department of Inorganic Technology Introduction The aim of the work is to evaluate the effect of nuclear power stations at Jaslovske Bohunice upon the development of pernicious tumours in the population around the power stations. As a base of comparison was taken the Trnava district where the power stations are situated approximately in its center. As comparative regions were selected the Levice district where the situation analysis is at the same time the starting situation of comparison after 20 years of potential functioning of nuclear power station at Mochovce. The Nitra district which is situated between Trnava and Levice is similar in composition and numbers of population as well as in its predominant fields of labour. Materials and Methods As starting materials were used data of National oncological register, available at the National Oncological Institute in Bratislava, as well as data from the Register of specific lung diseases at Vysne Hagy, and demographic data from the Department of demography of the Slovak Institute of Statistics at Bratislava. The data of oncological incidence were coming from 1968 up to 1989, all calculations were made with relative numbers referring to 100 000 inhabitants. The trend of incidence was followed separately for men and women in 63 oncological diagnoses in all the three districts. The 1968 state was taken as a base. We evaluated the trends in individual districts, and for rough evaluation the trends of overall incidence of pernicoustumours in Bratislava and in Slovakia. Other epidemiological parameters were followed as well such as: potentially lost years in the followed region, average death age, life expectancy at birth. 116 The following statistical methods were mainly used: descriptive statistics, multiple Kruskal-Wallis test, distribution analysis, trend analysis, regression analysis, cluster analysis. Some results are published using a problem-oriented map. Results In the Trnava district 60 % of the population are living within 20 km distance from the nuclear power stations. If the power stations have effect upon the increase in malignant tumours this should be evident also in changes in district numbers. In analysis of pernicious morbidity trends in Bratislava and in Slovak average only an exponential could be used as function. In Trnava, with occasional minor per annum oscillations the overall incidence keeps the level of starting 1968 year, even only 99 % of its value. In case of selected districts (Trnava-Levice-Nitra) there are highly conclusive differences (on the conclusive evidence level p < 0.01 in both men and women). The difference is caused by a very high incidence in the Levice district where there are 95 % of all cases above the occurrence level in the Trnava and Nitra districts. However, there are differences in numbers of occurrence of individual tumuor types. It can be assumed that those differences are provoked by something which is characteristic of the given locality - in conclusive differences there is increased, or reduced, occurrence in all years and in both sexes proportionally. Tumor types, in which, in agreement with preceding studies, the expected dependence with the increase of their occurrence in areas burdened with low radiation do not occur in the Trnava region in increased numbers, on the contrary in Trnava skin tumours are statistically conclusively less frequent than in the two other districts. The same applies to tumours of digestive organs. As the life expectancy is concerned, the Trnava district has been among the best in Slovakia for very long space of time. Conclusion The Trnava district has not shown any increase of malign tumours in men (99 % of the starting value) and one of the lowest increases in women (116 %). To compare, the average increase in Slovakia has been 139 % in men, and 129 % in women in the followed years. This conclusion is in correspondence with the results of studies accomplished as grant at the National Cancer Institute at Bethesda, USA where to the letter is described the protective effect of the nuclear, industry upon the environment as cancer diseases are concerned. We assume that in case of Trnava this effect may be aided by the act that vast regions around the nuclear power stations are supplied with waste heat by means of pipelines which has stopped using solid fuel and thus polluting the countryside with waste. Posters SELECTIVE LEACHING OF SOIL COLLECTED FROM DUDVAH RIVERSIDE NEAR NPP JASLOVSKE BOHUNICE ft Poiiak, D. Dr&bova', R. Filgas Centre of Radiation Hygiene, National institute of Public Health, Prague Specific forms of occurrence of radionuclides determine migration ability of these contaminants in environment. Bottom sediments are natural deposits for most radionuclides. Natural or artificial (bottom dredging) transport of sediments is a significant way of transfer of these radionuclides in and out the hydrosphere. Interactions of radionuclides with soil and rocks are important from the point of view of their inclusion in to food chain and their transport in ground water. At some places alluvia of discharge water canal Manivier contain great amounts of radionuclides which have entered soil as a result of removal of sediments contaminated by effluents from NPP Jaslovske Bohunice. The study aimed at determination of the forms of some radionuclides in the riverside and at assessment of releasibility of these radionuclides into hydrosphere. Applicable steps of sequential selective leaching as described by Tessier were used in the study. 117.