55. Stevenson, F. J. 1972. "Role and Function of Humus in Soil With Emphasis on Adsorption of Herbicides and Chelation of Micronutrients." PLUTONIUM ASSOCIATION IN SOILS Biosetence 22:643-650. 56. Stokley Jr., J. R., and F. L. Moore. 1967. "New Separation Method for Americium Based on Liquid-Liquid Extraction Behavior of Americium 57. Thomas, C. W., and R. W. Perkins. 1974. "“Transuranium Elements in the Atmosphere." BNWL-1881. Battelle Pacific Northwest Laboratories. pp. 181-1103. 58. Wallace, A. 1972a. “Increased Uptake of 74!am by Plants Caused by the Chelating Agent DTPA." Health Phys. 22:559-562. 59. Wallace, A. (V)." Anal. Chem, 39:994-997, 1972b. Tsuneo Tamura "Effect of Soil pH and Chelating Agent (DIPA) on Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge, Tennessee ABSTRACT Uptake by and Distribution of 2"!am in Plant Parts of Bush Beans." Rad. Bot. 12::433-435. 60. Wood, R. A., H. Nishita, M. Hamilton, and S, Wakakuwa. 1976. "The Determination of 238py and ¢42cm in Aqueous Soi] Extracts." UCLA 12-1047. University of California, Los Angeles. 61. Yanir, E., M. Givon, and Y. Marcus. of Americium in Phosphate Solutions." 51369-372. 1969. “Higher Oxidation States Inorg. Nucl. Chem. Letters This paper reviews che association of plutonium in the soils and sediments of several contaminated environmental samples. The plutonium-matrix association based on selected chemical treatments is reviewed. The association of plutonium with the soil particle sizes is reviewed and a soil plutonium index is derived for several contaminated sites to permit comparison of the potential transfer to man via the inhalation pathway. The soil plutonium index accounts for the fraction of the total activity in the resuspendible sizes, the relative concentration of the activity on the soil particle, and the potential lung deposition upon inhalation. The derived soil plutonium indices for four sites range from 0.52 to 1.26 from the least to the most severely contaminated site. The order of increasing site severity is the Nevada Test Site (0.52), Oak Ridge National Laboratory (0.69), Mound Laboratory (1.18), and Rocky Flats (1.26). Limitations of the soil factor are discussed. INTRODUCTION Piutonium is an element of mixed blessing. On the one hand, it is a valuable potential energy resource; on the other, its radiological properties make it a potentially hazardous element if mismanaged or mishandled. Its future potential will be determined, in part by understanding the properties, behavior, and fate of this radioelement after dispersal in the biosphere, The papers in this symposium volume provide information on the many environmental aspects of plutonium which are being investigated. As the information base and understanding regarding the various reactions of plutonium grow, sound decisions can then be made of the role of plutonium in mankind's future. 96 97