Estimates of Human Exposure to PCBs and Associated Health Risks from Dietary Seafood

Surveys of Native Americans and Asian and Pacific Islanders (API) in the Puget Sound area have demonstrated seafood consumption rates far greater than the general population (20.1 g/person/d EPA, 1997). Mean consumption rates are 61 g/person/day for the Tulalip and Squaxin Island Tribes and 117.2 g/person/day for API. There is concern about possible health risks from seafood PCB exposure for these groups, but exposure evaluation is difficult due to inadequacies of environmental data. To identify data gaps, a ranking system based on species specificity, data quality, and location compatibility was developed to rate available seafood PCB data as matched to seafood consumed. The sensitivity of total PCB and congener specific PCB testing (for use in TCDD toxic equivalency approaches) necessary for cancer risk assessment was explored and included in the ranking scheme. For the Squaxin Tribe, appropriate total PCB data were available for 58% of seafood consumed, which is dominated by local salmon. For API, appropriate total PCB data were identified for only 4% of seafood consumed, which is dominated by commercial shellfish. Insufficient sensitivity of commercial seafood PCB analysis and lack of sufficiently sensitive PCB congener analysis are major gaps in ability to characterize PCB exposure for these groups.