The results of this RI indicate that chemical contamination in the Gowanus Canal sediments presents unacceptable ecological and human health risks, primarily due to exposure to PAHs, PCBs, and metals (barium, cadmium, copper, lead, mercury, nickel and silver). All of these contaminants are thought to have been deposited in the canal as a result of current and historical discharges to the canal. High PAH concentrations are found in coal tar waste adjacent to the three former MGP sites along the canal. PAHs and metals are the most prevalent contaminants detected in present-day CSO discharges to the canal, as well as in low volume discharges from a limited number of other outfalls. PAHs and metals are also present in various concentrations in contaminated groundwater discharging to the canal at different locations. Contaminated sites adjacent to the canal and discharges from outfalls represent ongoing sources of contamination to the canal.