Twenty-eight sediment grab samples from the western bank of the Detroit River and three of its tributaries were chemically analyzed. Sampling sites were chosen to find worst-case conditions. High levels of conventional pollutants and metals were found throughout most of the study area. Hydrophobic organic contaminants found in a wide range of concentrations included: polynuclear aromatic hydrocarbons, polychlorinated biphenyls, various pesticides, and volatile organic compounds. Contaminant distributions suggest recent inputs from local sources. Highest contaminant levels were found in the Rouge River, the northern Trenton Channel and Conners Creek in the Belle Isle Area. The City of Detroit Wastewater Treatment Plant, combined sewer overflows, local steel and chemical industry and oil refineries are implicated as likely sources. Several contaminants including volatile organics, PCBs and hexachlorobenzene, seem to have major upstream sources, perhaps in Lake St. Clair or the St. Clair River.