1. Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268, United States
2. Office of Research and Development, National Risk Management Research Laboratory, Water Supply Water Resources Division, U.S. EPA, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268, United States
3. Office of Research and Development, National Risk Management Research Laboratory, Land Remediation and Pollution Control Division, U.S. EPA, 26 West Martin Luther King Drive, Cincinnati, Ohio 45268, United States