Environmental impacts of inadvertently generated PCBs along the Penobscot River

The presence of polychlorinated biphenyls (PCBs) in river water, sediment, and fish: white sucker (Catostomus commersonii) and smallmouth bass (Micropterus dolomieu) was assessed along the Penobscot River (Maine, U.S.) to determine trends in concentrations of PCBs, specifically PCBs that were likely inadvertently generated. The Penobscot Indian Nation's Department of Natural Resources (PINDNR) collected and shipped river water, sediment, and fish from three locations downstream from former pulp and paper facilities. Samples were analyzed for all PCB congeners (209). Of particular interest were inadvertently generated PCBs (iPCBs) associated with pigments (20) as these are not manufactured. Concentrations of sum-PCB congeners (across all locations) in river water ranged between 696 pg/L to 1,020 pg/L, between 1660 pg/g to 21,700 pg/g in sediment, between 17,800 pg/g wet weight (ww) to 129,000 pg/g ww in white suckers, and between 17,000 to 117,000 pg/g ww in smallmouth bass. All samples contained measurable levels of iPCBs, regardless of site. Statistically significant (p < 0.05) differences in PCB concentrations between fish species across all sites were observed for several pigment colors suggestive of species-dependent bioaccumulation. The highest PCB concentrations were found in fish from East Millinocket, regardless of species. The widespread presence of iPCBs associated with pigments in the area suggests that pulp and paper mills along the Penobscot River may have contributed to iPCBs detected in the environment.