You are here:
BIOSURFACES AND BIOAVAILABILITY: A NANOSCALE OVERVIEW
Citation:
Bailey, G W. AND P. Sawunyama. BIOSURFACES AND BIOAVAILABILITY: A NANOSCALE OVERVIEW. Presented at Bouyoucos Conference on Molecular Level Processes Controlling Availability of Chemical Species to Plants and Animals, Chalkidiki, Greece, June 23-28, 2002.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
Environmentally, contaminant bioavailability is a key parameter in determining exposure assessment and ultimately risk assessment/risk management. Defining bioavailability requires knowledge of the contaminant spatial/temporal disposition and transportability and the thermodynamic activity of the contaminant in the system. Different chemical species of the same substance will vary in their biological availability and toxicity, and this availability and toxicity will change depending on the type of organism being considered (i.e., whether it is humans, other animals or plants). The interplay of various biogeochemical processes -- adsorption/ desorption, complexation precipitation/dissolution (including biomineralization), speciation, abiotic and biotic transformation ? defines contaminant bioavailability/activity.
At the center of the biogeochemical processes are environmental surfaces. Environmental surfaces (mineral, organic, biological, and composite) determine the physicochemical and biological properties of soils and control the chemical reactivity, fate, transport, transformation and bioavailability of nutrients and chemical contaminants in soil ecosystems. In this presentation we will examine the nature and character of biosurfaces --lignin, humics, polysaccharides, proteins, and cell walls of bacteria, fungi and algae. This will be done by scrutinizing the structure, morphology, chemical composition, chemical functionality, electronic properties, and hydrophobic/hydrophilic character of each biosurface type. Such scrutiny will be done through the "eyes" of scanning probe microscopy, spectroscopy, computational chemistry and virtual reality. Interpretation of such an examination will be couched in terms of a 3-dimensional, holistic, and dynamic perception of soil.