Reactive solute transport in an acidic stream: Experimental pH increase and simulation of controls on pH, aluminum, and iron

Environmental Science & Technology
By: , and 

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Abstract

Solute transport simulations quantitatively constrained hydrologic and geochemical hypotheses about field observations of a pH modification in an acid mine drainage stream. Carbonate chemistry, the formation of solid phases, and buffering interactions with the stream bed were important factors in explaining the behavior of pH, aluminum, and iron. The precipitation of microcrystalline gibbsite accounted for the behavior of aluminum; precipitation of Fe(OH)3 explained the general pattern of iron solubility. The dynamic experiment revealed limitations on assumptions that reactions were controlled only by equilibrium chemistry. Temporal variation in relative rates of photoreduction and oxidation influenced iron behavior. Kinetic limitations on ferrous iron oxidation and hydrous oxide precipitation and the effects of these limitations on field filtration were evident. Kinetic restraints also characterized interaction between the water column and the stream bed, including sorption and desorption of protons from iron oxides at the sediment-water interface and post-injection dissolution of the precipitated aluminum solid phase.
Publication type Article
Publication Subtype Journal Article
Title Reactive solute transport in an acidic stream: Experimental pH increase and simulation of controls on pH, aluminum, and iron
Series title Environmental Science & Technology
DOI 10.1021/es960055u
Volume 30
Issue 10
Year Published 1996
Language English
Publisher ACS
Contributing office(s) Toxic Substances Hydrology Program
Description 9 p.
First page 3016
Last page 3024
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