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 contam inated harbor sediments. PCBs can volatilize from sediments and seawater an d subsequently deposit on surrounding soil, resulting in potential exposure s for nearby residents. House dust was collected from carpet, while yard so il was collected from the main entryway to evaluate whether PCBs might be t racked 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 hi gher than yard soil concentrations (15-1800 ng/g), although similar congene r patterns were detected in these two media. Yard soil concentrations in ne ighborhoods closest to the harbor were significantly higher than those in c omparison neighborhoods (23-1800 ng/g and 15-290 ng/g, respectively), while house dust concentrations did not differ significantly between these two l ocales (320-23 000 ng/g and 260-3600 ng/g, respectively). PCB concentration s in house dust were correlated with those in indoor air, but house dust an d yard soil concentrations were not correlated, suggesting that track-in ma y not be the only source of PCBs in house dust.