1. Arizona Dept. of Environmental Quality, 1110 West Washington St., Phoenix, AZ 85007 (corresponding author).
2. Dept. of Civil, Construction, and Environmental Engineering, Iowa State Univ., IA 50010.
3. Dept. of Earth and Planetary Science, The Univ. of Tennessee/Oak Ridge National Laboratory, Knoxville, TN 37996.
4. Dept. of Civil, Construction, and Environmental Engineering, Iowa State Univ., Ames, IA 50010.