1. Associate Professor, Dept. of Civil and Environmental Engineering, Temple Univ., Philadelphia, PA, 19122. E-mail: boufadel@temple.edu
2. Postdoctoral Fellow, Dept. of Civil and Environmental Engineering, Temple Univ., Philadelphia, PA, 19122. E-mail: hailong@graduate.hku.hk
3. Herman Schneider Professor, Dept. of Civil and Environmental Engineering, Univ. of Cincinnati, Cincinnati, OH.
4. Microbiologist, U.S. Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati, OH.