Preliminary delineation of natural geochemical reactions, Snake River Plain aquifer system, Idaho National Engineering Laboratory and vicinity, Idaho
The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, is conducting a study to determine the natural geochemistry of the Snake River Plain aquifer system at the Idaho National Engineering Laboratory (INEL), Idaho. As part of this study, a group of geochemical reactions that partially control the natural chemistry of ground water at the INEL were identified. Mineralogy of the aquifer matrix was determined using X-ray diffraction and thin-section analysis and theoretical stabilities of the minerals were used to identify potential solid-phase reactants and products of the reactions. The reactants and products that have an important contribution to the natural geochemistry include labradorite, olivine, pyroxene, smectite, calcite, ferric oxyhydroxide, and several silica phases. To further identify the reactions, analyses of 22 representative water samples from sites tapping the Snake River Plain aquifer system were used to determine the thermodynamic condition of the ground water relative to the minerals in the framework of the aquifer system. Principal reactions modifying the natural geochemical system include congruent dissolution of olivine, diopside, amorphous silica, and anhydrite; incongruent dissolution of labradorite with calcium montmorillonite as a residual product; precipitation of calcite and ferric oxyhydroxide; and oxidation of ferrous iron to ferric iron. Cation exchange reactions retard the downward movement of heavy, multivalent waste constituents where infiltration ponds are used for waste disposal.
- Research Organization:
- Geological Survey, Idaho Falls, ID (United States)
- Sponsoring Organization:
- Department of the Interior, Washington, DC (United States); USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC07-94ID13223
- OSTI ID:
- 572708
- Report Number(s):
- DOE/ID-22139; USGS-WRI-97-4093; ON: DE98050488; TRN: 98:004305
- Resource Relation:
- Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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