Proposal Objectives: The primary objective of this U.S.-Hungary cooperative research project between Dr. Gerald Ward and Dr. James Johnson of Colorado State University and their Hungarian colleague, Dr. Pal Kralovanszky, of the Technical University of Budapest is to design a model to simulate the transfer of radionuclides through the animal food- chain to humans. Samples collected in Hungary will be analyzed for radiocesium originating from the Chernobyl accident to enable comparison of data from world wide fallout in the 1960's with fallout from a nuclear reactor accident. Relevance of Proposal to Program Objectives: This biotic systems project fulfills the program objective of advancing scientific knowledge by enabling experts in the United States and Eastern Europe to combine complementary talents, pool resources, and share research data and facilities in areas of strong mutual interest and competence. Access to a new data set from such a unique event presents many scientific opportunities for analysis using state-of-the-art methods. Merit: The proposal ranks in the Excellent/Very Good category. Its technical merit therefore warrants NSF support. The U.S. and Hungarian researchers are well regarded and the rationale for international cooperation, in terms of anticipated mutual scientific benifits, is clearly articulated. This cooperation should yield significant, more accurate research results, specifically useful in estimating and characterizing food-chain contamination to be expected from a nuclear reactor accident. Interrelated Projects: None. Funding: The requested budget covers the incremental costs to the U.S. of international cooperation associated with the research, in accordance with program guidelines.