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Title: Radioecological investigations of uranium mill tailings systems. Fifth technical progress report, October 1, 1983-September 30, 1984

Technical Report ·
OSTI ID:6381068

The general intent of this investigation is to quantitatively evaluate the potential release of important radionuclides from active and reclaimed uranium mill tailings and their entry into the food chain. For active mill tailings, we are trying to quantify the degree of escape and dispersal, primarily by wind, and to measure the accumulation of /sup 238/U, /sup 230/Th, /sup 226/Ra, /sup 210/Pb and /sup 210/Po by various native plants. Of particular interest are the relationships between soil and vegetation at different sites, since the chemical environment of areas impacted by mill tailings are drastically different than undisturbed natural areas. Also of great interest, is the relative importance of various mechanisms of radionuclide accumulation by plants, such as root uptake and aerial deposition, followed by some degree of foliar absorption. This investigation includes as a major component, studies relating to the final disposal of mill tailings. An experimental plot was developed in which a slab of uniform tailings was covered with various depths of earthen materials and seeded with native range vegetation. Experiments on radon flux versus overburden depth have been conducted and continuing studies are planned. The influence of overburden depth on uptake of radionuclides by native plants is also under study. Work relating to the ability of roots to penetrate tailings or to function near a soil-tailings interface is being carried out. Data on the effect of barium chloride treatment of uranium ore indicate significant reduction of the /sup 222/Rn emanation fraction in simulated mill tailings and reduced /sup 226/Ra leachability. Soil spiked by injecting radionuclides into the root zone of mature sagebrush was used to obtain data on root uptake for /sup 226/Ra, /sup 210/Pb and /sup 210/Po.

Research Organization:
Colorado State Univ., Fort Collins (USA). Dept. of Radiology and Radiation Biology
DOE Contract Number:
AC02-79EV10305
OSTI ID:
6381068
Report Number(s):
DOE/EV/10305-15; ON: DE85000005
Resource Relation:
Other Information: Portions are illegible in microfiche products
Country of Publication:
United States
Language:
English