Heavy Metal Distributions in the Waters of Sydney Harbour, Nova Scotia

Abstract

Four surveys of total Hg and dissolved Cd, Cu, Fe, Mn, Ni, Pb and Zn concentrations in Sydney Harbour waters were conducted between 1999 and 2001. Suspended particulate matter samples were analysed for Cd, Cu, Fe, Mn, Ni, Pb, Zn and 22 other metals. The measurements were made to establish environmental context for toxicological studies, provide ground-truthing data for water quality modelling, and investigate estuarine geochemistry of heavy metals in a harbour subject to significant anthropogenic input. Despite the long history of metal contamination in Sydney Harbour, metal concentrations are almost all below water quality guidelines for estuarine or marine waters. The distributions of total Hg and dissolved Cu, Fe and Mn show that freshwater inputs are important contributors of these metals to the harbour. For Cu, Fe and Mn, additional inputs to the central part of South Arm are evident from the metal vs. salinity relationships. Particulate Cd, Cr, Cu, Pb, Mn, Ag and Zn distributions also show evidence of inputs in the central part of the harbour. Sewage appears to be the major, but not sole, source for these metals.