1. Environmental Specialist, Arizona Dept. of Environmental Quality, 1110 W. Washington St., Phoenix, AZ 85007 (corresponding author).
2. Manager of Environmental Engineering Research Laboratory, Dept. of Civil, Construction and Environmental Engineering, Iowa State Univ., Ames, IA 50010.
3. Professor, Dept. of Civil, Construction and Environmental Engineering, Iowa State Univ., Ames, IA 50010.
4. Postdoctoral Research Associate, Dept. of Earth and Planetary Science, Univ. of Tennessee, Knoxville, TN 37996.