1. DuPont Central Research and Development, Environmental Biotechnology, GBC-301, P.O. Box 6101, Newark, DE 19714-6101
2. Department of Biology, University of Cincinnati, Cincinnati, OH 45221
3. Department of Soil and Environmental Sciences, University of California, Riverside, CA 92521
4. The Institute of Wildlife and Environmental Toxicology, Department of Environmental Toxicology, Clemson University, Pendleton, SC 29670