Human exposure to PCBS: modeling and assessment of environmental concentrations on the Akwesasne reservation

The Mohawk Nation at Akwesasne, comprised of approximately 10,000 people, is located along the St. Lawrence River in upstate New York. The Akwesasne reservation has been contaminated by local industries, which are located on the St. Lawrence River and its tributaries, and by upstream sources on the Great Lakes. The closest known source of contamination to the reservation is General Motors (GM) Foundry, which is located less than 100 feet from the reservation's border. This facility is listed on the Environmental Protection Agency's National Priority List and the New York State's Department of Environmental Conservation's (NYSDEC) inactive hazardous waste disposal site list. Contamination to the reservation arising from discharge and secondary transport mechanisms has caused concern to the Mohawk people of Akwesasne. The characterization of the environment at Akwesasne required a historical review of existing environmental data, generation of a database, review of existing data, sampling to augment existing data, data analysis, data modeling and data generation based on a chosen model for all environmental pathways of interest. The objectives this work were to: 1) assess the quality of existing data, 2) create a database which will manage the over 6000 samples recorded taken from the local area, 3) augment the existing data with additional sampling, 4) determine the degradation or attenuation of PCBs and specific congeners in various environmental media over time, and 5) create a model that estimates environmental concentrations of PCBs retro- and pro-spectively for times that sampling had not occurred. The results of this process yielded concentrations of PCBs, congener specific and total, in several environmental medium. Modeling of environmental concentrations through a thirteen-year time period was performed for a fish, wildlife and surface soil. Other media were not modeled due to limited information or non-detectable concentrations reported in past work. Additionally, the study participants activity, consumption and residential information was considered when limiting this modeling effort. The results of this work were used to estimate environmental concentrations through time and space. The results of this work were extremely valuable when determining areas of concern and provided the basis for a detailed exposure assessment of 97 women who reside at the Reservation.