Monitoring dissolved copper concentrations in Chesapeake Bay,U.S.A.

Dissolved copper and selected water chemistry parameters were monitored for 11 months in Chesapeake Bay, U.S.A. Dissolved copper concentrations in four recreational marinas, a large harbor, two major river systems, and a heavily used shipping canal ranged from below detectable levels to 80 g L^-1 (\-X=11.7 g L^-1). Dissolved copper was detected >91% of the time at five locations. Lowest copper concentrations were found in Potomac River, Baltimore Harbor, Pier One Marina, and C & D Canal (\-X=6–10 g L^-1; slightly higher levels of dissolved copper were found in Choptank River (\-X=12 g L^-1). Highest levels of copper were detected in Port Annapolis, Hartge, and Piney Narrows Marinas (\-X=13–18 g L^-1), with the highest values observed in the study (70 and 80 g L^-1) found in two of these marinas. Copper in the three marinas with highest dissolved copper levels could have been toxic to some of the more sensitive aquatic species. Intensive study of one marina indicated that a likely source of dissolved copper was the recreational boats housed in the marina.