1. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Cincinnati, Cincinnati, OH 45221-0071 (corresponding author). E-mail: george.sorial@uc.edu
2. Senior Research Microbiologist, National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Dr., Cincinnati, OH 45268.
3. Research Associate, Dept. of Civil and Environmental Engineering, Univ. of Cincinnati, Cincinnati, OH 45221-0071.
4. President and Senior Statistician, Statking Consulting, Fairfield, OH 45014.