Magnetic susceptibility and distribution of heavy metals in sea-floor sediments of Hong Kong

We have conducted magnetic susceptibility measurements on twenty-four vibrocores obtained from an, area located off the coast of Lantau Island in Hong Kong. High values of magnetic susceptibility were detected in the top sections of most of the cores. The processes that led to the enrichment of magnetic particles in the uppermost layer of the sediments could have been anthropogenic or geological. Statistical correlation between magnetic susceptibility and heavy metal concentration, especially for Pb, Zn, and Cu as well as the spatial distribution pattern of the magnetic susceptibility values, have argued for an anthropogenic origin. The present study suggests that magnetic susceptibility is potentially useful as an indicator for contamination of seabed sediment and may provide us with a fast, inexpensive, and non-destructive means of detecting and mapping contaminated sediments.