1. Nicholas School of the Environment; Duke University; Durham; North Carolina; USA
2. US Environmental Protection Agency, Office of Research and Development; National Health and Environmental Effects Research Laboratory-Atlantic Ecology Division; Narragansett; Rhode Island; USA
3. Department of Civil and Environmental Engineering; Duke University; Durham; North Carolina; USA
4. Department of Environmental Health Sciences, Arnold School of Public Health; University of South Carolina; Columbia; South Carolina; USA