A DISCUSSION OF DISSOLVED METALS IN HALIFAX HARBOUR (1989 VS 2002) WITH A COMPARISON TO A RECENT STUDY FROM SYDNEY HARBOUR

During the last few years, there has been a great deal of interest in efforts to address the "clean up" of Halifax harbour and to determine the impact of decades of steel operations on Sydney harbour. A comprehensive set of water chemistry surveys of Halifax harbour were conducted in 1989 to address the concerns of a study which described elevated levels of metal in surface sediments from locations thought out the harbour. The water chemistry study concluded the levels of dissolved metals (Zn, Cd, Cu, Pb, Ni, Hg) in the harbour were generally only 2-3 fold above levels found on the Scotian Shelf and similar to those in other less polluted harbours. During April and October of 2002, water chemistry surveys were again conducted to obtain a more recent chemical "snapshot" of the harbour. The data from these surveys will be compared to the earlier data set and used to illustrate any changes in spatial distributions or oceanographic and chemical relationships. The levels of total mercury and methyl mercury determined from the recent surveys and data collected from several runoff (rivers) sites that impact the harbour will be described. Finally, the levels of dissolved metals from Halifax harbour will be compared to a recent Sydney harbour survey to compare levels of dissolved metals from two harbours known for their long history of sewage and industrial input.