FUTURE PLANS The study described here will continue. Future soil and microorganisms~artificial rumen joint studies have been designed with the following objectives: 1. To compare the biological availability of biologically incorporated plutonium with nonbiological plutonium. 2. To determine whether biological organic binding protects plutonium from being removed from solution by competing chemical reactions, such as adsorption, formation of insoluble salts, or polymerization. 3. To determine the effects of soil microbiological activity on the solubility of plutonium-238, plutonium-239, and americium-241 in contaminated soil in an artificial rumen and simulated abomasal and intestinal fluids. 4. To compare the in vitro behavior of plutonium-238, plutonium-239, and americium-241 in soil contaminated with nuclear debris. ACKNOWLEDGMENTS The author wishes to thank the following personnel of the Environmental Monitoring and Support Laboratory-Las Vegas: K. R. Giles, J. T. Titus, and D. D. Smith for making rumen contents available; K. W. Brown for assistance pertaining to desert vegetation; and D. C. Beauch and J. S. Coogan for radiation safety support. 135