Applications of Magnetic Susceptibility Measurements to the Monitoring of Heavy Metal Contamination in the Marine Sediment of Hong Kong

Principal Investigator:
Ng, Sai Leung

Co-investigator(s):
Chan, Lung Sang

Summary:
Heavy metal contamination of marine sediments due to industrial and human activities have received much attention in recent years. Conventional approaches heavily rely on the analyses of heavy metal concentration and forms (speciation) and bio-toxic studies, which are often expensive and require laborious work. Since heavy metal concentrations and forms greatly vary with place and time and their toxic impacts vary among different biota, to acquire sufficient data for assessing the state of the heavy metal contamination in Hong Kong waters would be a wearisome assignment, if not an impossible task.

The researchers' previous study of seabed sediments in Hong Kong has revealed a strong correlation between magnetic susceptibility and heavy metal contents. Supplementary experimental studies have shown that the sediments posses stable and consistent magnetic properties suitable to be used for the intended study. These results pose a notion that magnetic properties can be potentially developed as an alternative means of assessing heavy metal contamination in Hong Kong.

This study attempts to develop the technique of using magnetic properties as a heavy metal indicator by detailed study of the magnetic properties, heavy metal concentrations and forms of the sediments, and the relationship between them. The technique so developed, which is rapid, cheaper and non-destructive, is believed to be an effective tool in environmental management and impact assessment.