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Title: Enhancement of uranium 234 in springwaters of Aguas da Prata, Sao Paulo, Brazil

Abstract

In this study, the effect of combined chemical etch and leach processes on the generation of enhanced activity ratios (ARs) was investigated for mineral water samples from several spring of Aguas de Prata. Aguas de Prata is an important tourist site in Sao Paulo State, Brazil, located at the western edge of the Pocos de Caldas alkaline complex. Results show that active uranium dissolution is occurring in the springwaters. Enhanced Uranium 234/Uranium 238 activity ratios for dissolved U are explained in terms of combined chemical etch and leach processes responsible for the bulk dissolution of rock matrix rather than by alpha recoil effects. Several direct correlations support the effectiveness of etch/leach mechanisms, for example, between AR and total dissolved solids, ionic strength, carbon dioxide partial pressure, traditional index of base exchange, and new index of base exchange. A higher AR value is found to be directly related to a higher value of dissolution rate and a higher value of Radon 222 content is found to be related to a higher value of specific surface area. These relationships explain a good inverse logarithmic correlation between AR and Radon 22 content of the studied waters.

Authors:
 [1]
  1. (Universidade Estadual Paulista, Sao Paulo (Brazil))
Publication Date:
OSTI Identifier:
5474160
Resource Type:
Journal Article
Journal Name:
Water Resources Research; (United States)
Additional Journal Information:
Journal Volume: 29:7; Journal ID: ISSN 0043-1397
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; MINERAL SPRINGS; RADIOACTIVITY; RADON 222; RADIOECOLOGICAL CONCENTRATION; URANIUM; ACTIVITY LEVELS; DISSOLUTION; CORRELATIONS; ETCHING; LEACHING; SPECIFIC SURFACE AREA; ACTINIDES; ALPHA DECAY RADIOISOTOPES; DAYS LIVING RADIOISOTOPES; ECOLOGICAL CONCENTRATION; ELEMENTS; EVEN-EVEN NUCLEI; HEAVY NUCLEI; ISOTOPES; METALS; NUCLEI; PHYSICAL PROPERTIES; RADIOISOTOPES; RADON ISOTOPES; SEPARATION PROCESSES; SURFACE FINISHING; WATER SPRINGS; 540330* - Environment, Aquatic- Radioactive Materials Monitoring & Transport- (1990-); 540230 - Environment, Terrestrial- Radioactive Materials Monitoring & Transport- (1990-)

Citation Formats

Bonotto, D.M. Enhancement of uranium 234 in springwaters of Aguas da Prata, Sao Paulo, Brazil. United States: N. p., 1993. Web. doi:10.1029/93WR00607.
Bonotto, D.M. Enhancement of uranium 234 in springwaters of Aguas da Prata, Sao Paulo, Brazil. United States. doi:10.1029/93WR00607.
Bonotto, D.M. Thu . "Enhancement of uranium 234 in springwaters of Aguas da Prata, Sao Paulo, Brazil". United States. doi:10.1029/93WR00607.
@article{osti_5474160,
title = {Enhancement of uranium 234 in springwaters of Aguas da Prata, Sao Paulo, Brazil},
author = {Bonotto, D.M.},
abstractNote = {In this study, the effect of combined chemical etch and leach processes on the generation of enhanced activity ratios (ARs) was investigated for mineral water samples from several spring of Aguas de Prata. Aguas de Prata is an important tourist site in Sao Paulo State, Brazil, located at the western edge of the Pocos de Caldas alkaline complex. Results show that active uranium dissolution is occurring in the springwaters. Enhanced Uranium 234/Uranium 238 activity ratios for dissolved U are explained in terms of combined chemical etch and leach processes responsible for the bulk dissolution of rock matrix rather than by alpha recoil effects. Several direct correlations support the effectiveness of etch/leach mechanisms, for example, between AR and total dissolved solids, ionic strength, carbon dioxide partial pressure, traditional index of base exchange, and new index of base exchange. A higher AR value is found to be directly related to a higher value of dissolution rate and a higher value of Radon 222 content is found to be related to a higher value of specific surface area. These relationships explain a good inverse logarithmic correlation between AR and Radon 22 content of the studied waters.},
doi = {10.1029/93WR00607},
journal = {Water Resources Research; (United States)},
issn = {0043-1397},
number = ,
volume = 29:7,
place = {United States},
year = {1993},
month = {7}
}