Polychlorinated biphenyls in house dust and yard soil near a Superfund site

Polychlorinated biphenyls (PCBs) were measured in house dust and yard soil at 34 homes surrounding New Bedford Harbor during dredging of highly contaminated harbor sediments. PCBs can volatilize from sediments and seawater and subsequently deposit on surrounding soil, resulting in potential exposures for nearby residents. House dust was collected from carpet, while yard soil was collected from the main entryway to evaluate whether PCBs might be tracked indoors. All samples were analyzed for 65 PCB congeners to evaluate the relative importance of the harbor and indoor sources for human exposure. PCB concentrations (260-23 000 ng/g) in house dust were about 10 times higher than yard soil concentrations (15-1800 ng/g), although similar congener patterns were detected in these two media. Yard soil concentrations in neighborhoods closest to the harbor were significantly higher than those in comparison neighborhoods (23-1800 ng/g and 15-290 ng/g, respectively), while house dust concentrations did not differ significantly between these two locales (320-23 000 ng/g and 260-3600 ng/g, respectively). PCB concentrations in house dust were correlated with those in indoor air, but house dust and yard soil concentrations were not correlated, suggesting that track-in may not be the only source of PCBs in house dust.