Release of uranium decay-series nuclides from Florida phosphate rock
Studies are being conducted on Florida phosphate rock to help understand the release of natural decay-series radionuclides into associated groundwaters. The authors have analyzed all isotopes with half-lives longer than a few days in samples of both weathered and unweathered phosphate rock previously separated into seven size classes. Samples which have been subjected to intense weathering display higher specific activities than relatively fresh materials with the highest activities in weathered samples occurring in the <63 ..mu..m size class. When normalized to mass, the most significant fraction of the activity of the weathered samples is in the finest size fraction. Activities in the fresher materials, on the other hand, are concentrated in the intermediate size classes. In bulk samples of the weathered materials, there is significant disequilibrium in the uranium decay series chain except for /sup 210/Pb//sup 226/Ra which is close to unity. Unweathered samples show exactly the reverse behavior. This is probably a result of /sup 222/Rn diffusion and subsequent adsorption onto fine particles. Mass balance calculations of total activities by summation of the activities measured within each individual size class produce lower results compared to those actually measured in bulk samples of the phosphatic materials. This apparent loss may be due either to loss of very fine-grained, high-activity particles or actual solution of these radionuclides into the deionized water used during the wet seiving process.
- Research Organization:
- Florida State Univ., Tallahassee (USA)
- OSTI ID:
- 6651580
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
FLORIDA
PHOSPHATE ROCKS
GROUND WATER
RADIONUCLIDE MIGRATION
RADIONUCLIDE KINETICS
AQUIFERS
DYNAMIC FUNCTION STUDIES
URANIUM ISOTOPES
WEATHERING
ACTINIDE ISOTOPES
ENVIRONMENTAL TRANSPORT
FEDERAL REGION IV
HYDROGEN COMPOUNDS
ISOTOPES
MASS TRANSFER
NORTH AMERICA
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
USA
WATER
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)
520300 - Environment
Aquatic- Radioactive Materials Monitoring & Transport- (1989)