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Title: Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain

Abstract

The levels and distribution of natural radionuclides in groundwaters from the unconfined Almonte-Marismas aquifer, upon which Donana National Park is located, have been analysed. Most sampled points were multiple piezometers trying to study the vertical distribution of the hydrogeochemical characteristics in the aquifer. Temperature, pH, electrical conductivity, dissolved oxygen and redox potential were determined in the field. A large number of parameters, physico-chemical properties, major and minor ions, trace elements and natural radionuclides (U-isotopes, Th-isotopes, Ra-isotopes and {sup 210}Po), were also analysed. In the southern zone, where aeolian sands crop out, water composition is of the sodium chloride type, and the lower U-isotopes concentrations have been obtained. As water circulates through the aquifer, bicarbonate and calcium concentrations increase slightly, and higher radionuclides concentrations were measured. Finally, we have demonstrated that {sup 234}U/{sup 238}U activity ratios can be used as markers of the type of groundwater and bedrock, as it has been the case for old waters with marine origin confined by a marsh in the south-east part of aquifer.

Authors:
; ;  [1];  [2]
  1. Department of Applied Physics, University of Huelva, Campus de El Carmen, 21071-Huelva (Spain)
  2. Department of Applied Physics II, University of Sevilla, ETSA Arquitectura, 41012-Sevilla (Spain)
Publication Date:
OSTI Identifier:
21152444
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1034; Journal Issue: 1; Conference: NRE-VIII: 8. International symposium on the natural radiation environment, Buzios, RJ (Brazil), 7-12 Oct 2007; Other Information: DOI: 10.1063/1.2991212; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ACID CARBONATES; AQUIFERS; CALCIUM; CHEMICAL PROPERTIES; DISSOLVED GASES; ELECTRIC CONDUCTIVITY; GROUND WATER; HYDROLOGY; OXYGEN; PH VALUE; POLONIUM 210; RADIOACTIVITY; RADIUM ISOTOPES; REDOX POTENTIAL; SPAIN; THORIUM ISOTOPES; TRACE AMOUNTS; URANIUM 234; URANIUM 238

Citation Formats

Bolivar, J. P., Olias, M., Gonzalez-Garcia, F., and Garcia-Tenorio, R. Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain. United States: N. p., 2008. Web. doi:10.1063/1.2991212.
Bolivar, J. P., Olias, M., Gonzalez-Garcia, F., & Garcia-Tenorio, R. Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain. United States. doi:10.1063/1.2991212.
Bolivar, J. P., Olias, M., Gonzalez-Garcia, F., and Garcia-Tenorio, R. Thu . "Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain". United States. doi:10.1063/1.2991212.
@article{osti_21152444,
title = {Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain},
author = {Bolivar, J. P. and Olias, M. and Gonzalez-Garcia, F. and Garcia-Tenorio, R.},
abstractNote = {The levels and distribution of natural radionuclides in groundwaters from the unconfined Almonte-Marismas aquifer, upon which Donana National Park is located, have been analysed. Most sampled points were multiple piezometers trying to study the vertical distribution of the hydrogeochemical characteristics in the aquifer. Temperature, pH, electrical conductivity, dissolved oxygen and redox potential were determined in the field. A large number of parameters, physico-chemical properties, major and minor ions, trace elements and natural radionuclides (U-isotopes, Th-isotopes, Ra-isotopes and {sup 210}Po), were also analysed. In the southern zone, where aeolian sands crop out, water composition is of the sodium chloride type, and the lower U-isotopes concentrations have been obtained. As water circulates through the aquifer, bicarbonate and calcium concentrations increase slightly, and higher radionuclides concentrations were measured. Finally, we have demonstrated that {sup 234}U/{sup 238}U activity ratios can be used as markers of the type of groundwater and bedrock, as it has been the case for old waters with marine origin confined by a marsh in the south-east part of aquifer.},
doi = {10.1063/1.2991212},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1034,
place = {United States},
year = {Thu Aug 07 00:00:00 EDT 2008},
month = {Thu Aug 07 00:00:00 EDT 2008}
}
  • In order to assess the utility of uranium isotopes as fluid phase earthquake precursors, uranium concentrations and /sup 234/U//sup 238/U activity ratios have been monitored on a monthly or bimonthly basis in water from 24 wells and springs associated with Southern California fault zones. Uranium concentrations vary from 0.002 ppb at Indian Canyon Springs on the San Jacinto fault to 8.3 ppb at Lake Hughes well on the San Andreas fault in the Palmdale area. /sup 234/U//sup 238/U activity ratios vary from 0.88 at Agua Caliente Springs on the Elsinore fault to 5.4 at Niland Slab well on the Sanmore » Andreas fault in the Imperial Valley. There was one large earthquake in the study area during 1979, the 15 October 1979 M = 6.6 Imperial Valley earthquake. Correlated with this event, uranium concentrations varied by a factor of more than 60 and activity ratios by a factor of 3 at the Niland Slab site, about 70 km from the epicenter. At the other sites monitored, uranium concentrations varied in time, but with no apparent pattern, while uranium activity ratios remained essentially constant throughout the monitoring period.« less
  • During the summer of 1975, 464 water samples from 149 locations in South Park, Colorado, were taken for the Los Alamos Scientific Laboratory in order to test the field sampling and analytical methodologies proposed for the NURE Hydrogeochemical and Stream Sediment Reconnaissance for uranium in the Rocky Mountain states and Alaska. The study showed, in the South Park area, that the analytical results do not vary significantly between samples which were untreated, filtered and acidified, filtered only, or acidified only. Furthermore, the analytical methods of fluorometry and delayed-neutron counting, as developed at the LASL for the reconnaissance work, provide fast,more » adequately precise, and complementary procedures for analyzing a broad range of uranium in natural waters. The data generated using this methodology does appear to identify uraniferous areas, and when applied using sound geochemical, geological, and hydrological principles, should prove a valuable tool in reconnaissance surveying to delineate new districts or areas of interest for uranium exploration.« less
  • The existence of 11 organochlorine compounds and five heavy metals in the liver and muscle of 57 members of 10 species of mammals, all from Donana National Park (Spain), has been investigated. Five organochlorine compounds have been found and the five heavy metals were present in the samples. The biomagnification of organochlorines is shown. The detected concentrations for each trophic rank seem not to influence unfavourably on the population stability of the species. The rabbit is proposed as a monitor species for future studies in pollution at Donana National Park.
  • The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15 monitoring wells. U(VI) concentrations decreased in as little as 9 days after acetate injection was initiated, and within 50 days uranium had declined below the prescribed treatment level of 0.18 _M in some of the monitoring wells. Analysis of 16Smore » ribosomal DNA (rDNA) sequences and phospholipid fatty acid profiles demonstrated that the initial loss of uranium from the groundwater was associated with an enrichment of Geobacter species in the treatment zone. Fe(II) in the groundwater also increased during this period, suggesting that U(VI) reduction was coincident with Fe(III) reduction. As the acetate injection continued over 50 days there was a loss of sulfate from the groundwater and an accumulation of sulfide and the composition of the microbial community changed. Organisms with 16S rDNA sequences most closely related to those of sulfate reducers became predominant, and Geobacter species became a minor component of the community. This apparent switch from Fe(III) reduction to sulfate reduction as the terminal electron accepting process for the oxidation of the injected acetate was associated with an increase in uranium concentration in the groundwater. These results demonstrate that in situ bioremediation of uranium-contaminated groundwater is feasible but suggest that the strategy should be optimized to better maintain long-term activity of Geobacter species.« less