1. Pacific Northwest National Laboratory, Richland, Washington 99352, United States
2. Department of Land, Air and Water Resources, University of California, Davis, California 95616-8627, United States
3. Agricultural and Environmental Chemistry Graduate Group, University of California, Davis, California 95616-5270, United States
4. Department of Environmental Toxicology, University of California, Davis, California 95616-5270, United States