1. National Research Council, U.S. Environmental Protection Agency, National Exposure Research Laboratory, Ecosystems Research Division, Athens, GA 30605-2700.
2. Department of Civil Engineering, University of Virginia, Charlottesville, VA 22904-4742.
3. Corresponding author: School of Engineering & Applied Science, University of Virginia, 351 McCormick Road, Thorton Hall, P.O. Box 400742, Charlottesville, VA 22904-4742. Phone: 434-982-2951; Fax: 434-924-7991; E-mail: jas9e@virginia.edu.
4. Biomin Inc., Ferndale, MI 48220.