@Article{Silva+Bonotto2015,
author="Silva, M. L. da
and Bonotto, D. M.",
title="Uranium isotopes in groundwater occurring at Amazonas State, Brazil",
journal="Applied Radiation and Isotopes",
year="2015",
volume="97",
pages="24--33",
optkeywords="Amazon area",
optkeywords="Dissolved uranium",
optkeywords="Groundwater",
optkeywords="Tube wells",
optkeywords="U/U activity ratio",
abstract="This paper reports the behavior of the dissolved U-isotopes 238U and 234U in groundwater providing from 15 cities in Amazonas State, Brazil. The isotope dilution technique accompanied by alpha spectrometry were utilized for acquiring the U content and 234U/238U activity ratio (AR) data, 0.01--1.4{\textmu}gL-1 and 1.0--3.5, respectively. These results suggest that the water is circulating in a reducing environment and leaching strata containing minerals with low uranium concentration. A tendency to increasing ARs values following the groundwater flow direction is identified in Manaus city. The AR also increases according to the SW--NE directions: Uarini{\textrightarrow}Tef{\'e}; Manacapuru{\textrightarrow}Manaus; Presidente Figueiredo{\textrightarrow}S{\~a}o Sebasti{\~a}o do Uatum{\~a}; and Boa Vista do Ramos{\textrightarrow}Parintins. Such trends are possibly related to several factors, among them the increasing acid character of the waters. The waters analyzed are used for human consumption and the highest dissolved U content is much lower than the maximum established by the World Health Organization. Therefore, in view of this radiological parameter they can be used for drinking purposes.",
optnote="exported from refbase (http://www.uhydro.de/base/show.php?record=140), last updated on Fri, 26 Jan 2024 13:19:04 +0100",
issn="0969-8043",
opturl="https://www.sciencedirect.com/science/article/pii/S096980431400431X"
}