Exposure to polychlorinated biphenyls in residential indoor air and outdoor air near a Superfund site

Polychlorinated biphenyl(PCB) concentrations were measured in indoor and outdoor air at 34 homes surrounding New Bedford Harbor during dredging of highly contaminated harbor sediments. PCB volatilization from harbor sediments and water leads to inhalation exposure far nearby residents. On each sampling day, 24 h indoor and outdoor air samples were collected simultaneously and analyzed for 65 PCB congeners to evaluate the relative importance of the harbor and indoor sources for human inhalation exposure. Outdoor air concentrations were higher in neighborhoods closest to the harbor (0.4-53 ng/m(3)) relative to comparison neighborhoods (0.1-8.2 ng/m(3)) and contained slightly greater proportions of volatile PCB congeners. Outdoor air concentrations near the harbor are some of the highest measured in recent years. indoor air concentrations in homes near the most contaminated part of the harbor (7.9-61 ng/m(3)) were slightly higher than concentrations in homes distant from this area (5.2-51 ng/m(3)). In all neighborhoods, indoor concentrations exceed corresponding outdoor concentrations (mean ratio = 32), suggesting the importance of indoor PCB sources even near a highly contaminated waste site.