226
Frontiers in Contaminant Speciation and Reactivity in Terrestrial Environments:
The Role of Synchrotron Radiation
Donald L. Sparks (Department of Plant and Soil Sciences University of Delaware)
Environmental quality and sustainability is a concern
worldwide. Contamination of soils and waters with
metals, oxyanions, radionuclides, nutrients, and
organic chemicals is the focus of research in a variety
of fields including soil and environmental sciences and
engineering. Ideally, one wants to understand
environmentally important reactions and processes in
natural systems at multiple scales to accurately predict
the fate, transport, toxicity, and bioavailability of
contaminants. In the past, most studies were conducted
at larger scales such as the field and macroscopic scales.
However, in the past decade, there have been major
advances in the development and use of state-of-the-art
in-situ analytical techniques that enable one to study an
array of important reactions and processes at the
molecular scale. In fact, a new interdisciplinary science
has evolved based on the use of molecular scale
approaches- molecular environmental science.
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To delineate reaction mechanisms of contaminant
reactions on soil minerals and in soils, it is advisable to
couple macroscopic investigations with molecular scale
studies. In recent years, synchrotron-based, in-situ
micro-focused X-ray absorption and fluorescence
spectroscopic techniques, infrared spectroscopy, and
microtomography have significantly advanced research
frontiers in the soil and environmental sciences.
Applications of these techniques to assess metal and
metalloid sorption/release, natural attenuation processes,
speciation
of metal(loid)s
in
heterogeneous
soilslbiosolids/plants, and mineral/microbe/contaminant
reactions will be addressed. Future research needs and
directions will also be assessed.
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