Mercury Fixation in Contaminated Sediments as a Management Option at Albany, Western Australia

Water overlying mercury contaminated sediments in Princess Royal Harbour, Albany, was found to contain up to 0.8 µg/L of mercury. Using contaminated sediments and water from Princess Royal Harbour experiments were carried out to remove the mercury from the waterbody and fix it to the sediment. Treatment with metallic iron reduced the mercury concentration of the water to less than 0.1 µg/L within 2 minutes and any potential visual pollution from the oxidation of iron was prevented by a sand overlay. The sand did not interfere with the lasting effectiveness of the iron. A field trial was conducted to test the system under wind and tidal conditions in shallow waters of Princess Royal Harbour. It was established that due to the sedimental rework, the overlay thickness would have to be increased for the shallow waters. For deeper waters (>2 m), the system is expected to give good results over sand bottoms. Seagrass covered areas are expected to yield staining problems due to ineffective sand overlay.