A comparison of PAH, PCB, and pesticide concentrations in air at two rural sites on Lake Superior.

Atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pesticides were compared at Brule River and Eagle Harbor, two rural sites on Lake Superior that are part of the Integrated Atmospheric Deposition Network (IADN). Brule River lies 40 km southwest of Duluth, MN, a small industrial city, and Eagle Harbor is in Michigan's upper peninsula, 400 km east of Brule River. Pesticide and PCB concentrations were similar at both sites. Day-by-day regression analyses of the data showed that PAH concentrations, an indication of urban contamination, were significantly higher at Brule Riverthan at Eagle Harbor. Concentration ranges for all compounds at both sites were well within global background levels, despite the differences observed between the two sites. Clearly, pollution from Duluth is influencing PAH concentrations at Brule River more than at Eagle Harbor.