Trace metals in sediments of four harbours in Guam

Sediment samples were collected in May June 1997 from four harbors in Guam, with sites selected on the basis of their proximity to potential sources of contamination, and concentrations of trace metals were measured. The analytical methods employed are described. Results showed that silver concentrations were consistently below 0.2 mu g/g, and the majority of the arsenic, cadmium, chromium, and nickel concentrations were typical of relatively clean coastal environments. Localized pockets of copper contamination were found at all locations, however, except for Agat Marina, and some mercury enrichment was identified in the Agana Boat Basin inner harbor area, with the highest concentrations found locally at Apra Harbor. The highest mean lead concentration was 96.3 mu g/g, found at a site in Apra Harbor. Tributyltin and other organotin compounds were found selectively at high concentrations, as expected, and the highest zinc levels were found in Apra Harbor off Hotel Wharf.