ISSN:
1573-5117
Keywords:
sediments
;
uranium
;
radium
;
radionuclides
;
models
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Uranium mining and milling operations can contribute to environmental degradation through the increased release of naturally-occurring radionuclides. However, studies of the interactions of these radionuclides with freshwater sediments have been limited. The present study examined the vertical distribution of uranium, thorium, radium-226, polonium-210 and lead-210 in undisturbed sediment cores collected in the vicinity of mining, milling and exploration activities. Uranium levels in surface sediments ranged from 1.9 to 5650 µg g−1, Ra-226 from 〈0.1 to 480 pCi g−1 and Pb-210 from 0.8 to 931 pCi g−1 in the samples reported here, with the highest values occurring downstream of waste rock disposal areas. Concentrations usually decreased with depth, and there was little evidence of any strong effect of bioturbation on radionuclide profiles at the scale examined here. Mathematical models of uranium and radium-226 adsorption on and movement into the sediment were constructed, based on expected adsorption coefficients and estimated loading. The model predictions of radionuclide distribution with depth were qualitatively similar to those actually measured, but the predicted concentrations were generally lower than those observed, both in unaffected areas and in areas adjacent to uranium extraction activities.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00000035
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