The chemical characteristics of ground water near Fairbanks, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

Professional Paper 1615
By: , and 

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Abstract

Major- and trace-element abundances, and Sr and Pb isotopic compositions, of ground waters in and near Fairbanks, Alaska, were determined to characterize their chemical characteristics and to assess the factors controlling variations in dissolved arsenic concentrations. Collected samples show majorelement (Ca>Mg>Na>K) and strontium and lead isotopic compositions characteristic of waters that have interacted with lithologies comprising the Fairbanks Schist. Dissolved arsenic concentrations are not highly correlated with the abundances of other major and trace elements in these waters; however, waters with high arsenic concentrations (5.4 to 450 parts per billion) tend to have relatively high concentrations of antimony (as much as 1.7 ppb). The correlation between arsenic and antimony suggests that both elements were derived from the oxidation of hypogene sulfide minerals (arsenopyrite) that originally formed within the Fairbanks Schist during hydrothermal activity associated with the emplacement of Cretaceous granitic rocks. Variations in measured arsenic concentrations are due, in part, to the variations in the original abundance of upgradient sulfide minerals from a given well or spring. However, speciation studies on the ground water containing the highest concentration of arsenic in this study (450 ppb) demonstrate that the arsenic occurs primarily in its reduced form (As(III)). In agreement with previous studies, we conclude that relatively reducing ground waters have the highest potential for high arsenic concentrations due to greater mobility of As(III) relative to its oxidized counterpart (As(V)). In light of this conclusion, additional studies are being undertaken to determine how seasonal variations in ground-water redox affect arsenic mobility

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Publication type Report
Publication Subtype USGS Numbered Series
Title The chemical characteristics of ground water near Fairbanks, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
Series title Professional Paper
Series number 1615
DOI 10.3133/70180667
Year Published 2000
Language English
Publisher U.S. Geological Survey
Publisher location Denver, CO
Contributing office(s) Central Mineral and Environmental Resources Science Center
Description 12 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Geologic studies in Alaska by the U.S. Geological Survey, 1998 (Professional Paper 1615)
First page 167
Last page 178
Country United States
State Alaska
City Fairbanks
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