Eastern Lake Erie and the upper Niagara River basin were sampled for polycyclic aromatic hydrocarbons (PAH) to assess their distribution and sources. Twenty-five sites were sampled using polypropylene substrates. Five areas were identified as having relatively high PAH contamination. These were Lake Erie at the mouth of Smoke Creek, the Union and Lackawanna Ship Canals, the Buffalo River, Two Mile Creek, and the Buffalo Sewer Authority. Subsequent sampling and analyses of sediments, water, and polypropylene substrates confirmed the preliminary findings. The sources of the PAH were attributed to steel manufacturing operations (Lake Erie at the mouth of Smoke Creek and Union and Lackawanna Ship Canals) and oil storage facilities (Two Mile Creek). The Buffalo Sewer Authority was sampled directly in the outfall, and the analytical results identified it as a source of PAH to the Niagara River. The Buffalo River had several PAH inputs near the South Park Bridge. In addition to the areas identified as having high PAH contamination, there was a generalize PAH contamination throughout the study area.