Uranium isotopes distribution in soils at the Rocky Flats Plant, Colorado
- EG&G Rocky Flats Plant, Golden, CO (United States)
Soils east of Rocky Flats Plant (RFP) near Golden, CO, are contaminated with U as a result of past waste-storage practices, accidental release of oils laden with U, and low-level airborne emissions. A spatial analysis of three U isotopes was conducted to determine the concentration and distribution pattern of U contamination. Soils were sampled from 118 plots of 1.01- or 4.05-ha by compositing 25 evenly spaced samples from the top 0.64 cm. Uranium-234 activity ranged from 25.9 to 92.8 Bq kg{sup -1}, U-235 activity ranged from 30.7 kg{sup -1} to 286 Bq kg{sup -1}. Geostatistical techniques were used to model the spatial dependency and construct isopleth maps showing U isotope distributions. Spatial correlation was not observed for U-234. This implies that U-234 is randomly distributed in the soil environment east of RFP. Uranium-235 exhibited a spotty and localized concentration pattern with no clear relationship between known burial and spill sites, and the present distribution of U-235 in the soils. Proposed wind-dispersal mechanisms were not consistent with the spatial distribution of U isotopes. Most of the observed activities of U-234 and U-235 were well within the natural range of U isotopes in soils. The lack of similarity in spatial distribution between Pu-239 + 240 and U isotopes probably resulted from the higher solubility and leachability of U isotopes compared with Pu-239 + 240 in the soil system. Although U-238 exhibited a pattern of localized spatial distribution, most of its observed activity was well within the natural range of U-238 activity in soils. 25 refs., 6 figs., 6 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 258797
- Journal Information:
- Journal of Environmental Quality, Journal Name: Journal of Environmental Quality Journal Issue: 2 Vol. 24; ISSN JEVQAA; ISSN 0047-2425
- Country of Publication:
- United States
- Language:
- English
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