TABLE OF CONTENTS VOLUME I PAGE PREFACE vii SMALL ANIMAL STUDIES Ecological Studies of Small Mammals in a Nuclear Site on Nevada Test Site. W. G. Bradley and K. S. Moor. 1 Overview of the EPA Bioenvironmental Research Program-~NAEG Research. E. W. Bretthauer. 15 LARGE ANIMAL STUDIES Metabolism of Americium-241 in Dairy Animals. W. W. Sutton, R. G. Patzer, A. A. Mullen, P. B. Hahn, and G. D. Potter. 19 The Solubility of Americium-241 in In Vitro Bovine Ruminal Gastrointestinal Fluids and Predicted Tissue Retention and Milk Secretion of Field-Ingested Americium-241. J. Barth. Area 13 Grazing Studies--Additional Data. D. D. Smith. 45 59 MICROORGANISM STUDIES Microbial Contributions to Plutonium Bioavailability and Transport in the Environment. F. 4. F. Au and W. F. Beckert. 95 PLANT-SOIL STUDIES Plant Uptake of Pu and Am Through Roots in Nevada Test Site Soils. E. M. Rommey, A. Wallace, and J. E. Kinnear. 109