The Utility of Magnetic Properties as a Proxy for Mapping Contamination in Hamilton Harbour Sediment

Rapid, non-destructive, magnetic-property measurements are useful as a proxy for contamination in sediment, and as an indicator of disturbed sediments. Magnetic-property measurements on sub-samples from sediment cores taken from Hamilton Harbour define a boundary marked by a sharp increase in magnetic mineral content. At this boundary magnetic susceptibility (κ) increases by at least one order of magnitude. Confirmation that this represents the base of the industrial sediment is provided by concomitant increases in both polycyclic aromatic hydrocarbon (PAH) and trace metal content. Detailed correlation of these horizons allows for the distinction between undisturbed and disturbed sediments. A consequence of this work is the potential use of completely non-destructive measurements of κ as a tool for mapping the distribution of contaminated sediments in Hamilton Harbour.