1. Environmental Engineer, Ecosystems Research Div., National Exposure Research Laboratory (NERL), U.S. Environmental Protection Agency, 960 College Station Rd., Athens, GA 30605 (corresponding author).
2. Research Engineer, Networks, Water Treatment and Water Quality Research Unit, Cemagref, 50 Ave. de Verdun—Gazinet, 33612 Cestas, France.
3. Associate Professor, Dept. of Civil, Construction, and Environmental Engineering, North Carolina State Univ., Raleigh, NC 27695-7908.