1. Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA
2. Oak Ridge Institute for Science and Education at the Center for Public Health and Environmental Assessment, Office of Research and Development (ORD), U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina, USA
3. Center for Public Health and Environmental Assessment, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
4. Environmental Health Services, British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada