Enumeration of Microbial Populations in Radioactive Environments by Epifluorescence Microscopy
Epifluorescence microscopy was utilized to enumerate halophilic bacterial populations in two studies involving inoculated, actual radioactive waste/brine mixtures and pure brine solutions. The studies include an initial set of experiments designed to elucidate potential transformations of actinide-containing wastes under salt-repository conditions, including microbially mediated changes. The first study included periodic enumeration of bacterial populations of a mixed inoculum initially added to a collection of test containers. The contents of the test containers are the different types of actual radioactive waste that could potentially be stored in nuclear waste repositories in a salt environment. The transuranic waste was generated from materials used in actinide laboratory research. The results show that cell numbers decreased with time. Sorption of the bacteria to solid surfaces in the test system is discussed as a possible mechanism for the decrease in cell numbers. The second study was designed to determine radiological and/or chemical effects of {sup 239}Pu, {sup 243}Am, {sup 237}Np, {sup 232}Th and {sup 238}U on the growth of pure and mixed anaerobic, denitrifying bacterial cultures in brine media. Pu, Am, and Np isotopes at concentrations of <=1 x 10{sup {minus}5}M, <=5 x 10{sup {minus}6}M and <=5 x 10{sup {minus}4}M respectively, and Th and U isotopes <=4 x 10{sup {minus}3}M were tested in these media. The results indicate that high actinide concentration affected both the bacterial growth rate and morphology. However, relatively minor effects from Am were observed at all tested concentrations with the pure culture.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 760108
- Report Number(s):
- LA-UR-97-253; TRN: US0004446
- Resource Relation:
- Conference: Material Research Society Meeting, Boston, MA (US), 12/02/1996--12/06/1996; Other Information: PBD: 2 Dec 1996
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BACTERIA
BRINES
GROWTH
MORPHOLOGY
POPULATION DYNAMICS
SORPTION
UNDERGROUND DISPOSAL
SALT CAVERNS
BIOLOGICAL FOULING
ALPHA-BEARING WASTES
PLUTONIUM 239
AMERICIUM 243
NEPTUNIUM 237
THORIUM 232
URANIUM 238
RADIATION EFFECTS