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Geochemical Processes in Subsurface Systems
Research Advisor: Richard T. Wilkin, Ph.D.
(580)436-8874
Research Advisor: Robert Ford, Ph.D.
(580)436-8872
When solutes are introduced into groundwater systems or into surface waters,
complex physicochemical reactions occur between the dissolved solutes and
native solid materials. Knowledge of these complex interfacial reactions is
required to assess the impact of such inputs on water quality in aquatic and
terrestrial ecosystems. Assessments of water quality and efforts to restore
contaminated waters depend strongly on a fundamental understanding of geochemical
processes involving reactions with mineral surfaces and substrates. Such processes
include weathering reactions that contribute dissolved chemicals, sorption
that removes aqueous species, and electron transfer mechanisms that establish
redox conditions. Knowledge of the geochemical behavior and cycling of major
elements, trace elements, and nutrients in terrestrial ecosystems is necessary
for understanding and predicting the consequences of deliberate or accidental
anthropogenic additions of these substances to the environment.
Specific goals of this program include (1) determining the mechanism and rates
of chemical and electron transfer between mineral substrates and soils, surface-water,
and groundwater environments; (2) determining the nature and extent of temporal
changes in mineral surfaces during weathering and contaminant introduction, and
assessing the impact of these changes on subsequent transport and fate of inorganic
species; and (3) assessing risk posed by the weathering of toxic materials contained
in natural geologic materials and plan mitigation, and cleanup under technical
and geologic constraints. Current work has focused on the mobilization or arsenic
from landfills and other waste sites. Anthropogenic additions of organic compounds
and their subsequent natural degradation have altered the geochemistry of the
natural subsurface system in such a manner that releases significant arsenic
contained in the natural geologic materials to the dissolved phase.