Abstract: The safe ocean disposal of contaminated dredged sediments requires robust, ecologically relevant assessment protocols to evaluate risks to marine ecosystems and human health accurately. This presentation synthesises findings from two complementary studies commissioned by the Hong Kong government. The first study, for the Environmental Protection Department, developed and applied a practical, multi-trophic level bioassay battery for screening sediment toxicity. Tests were conducted on sediment elutriates using a suite of marine organisms: the bacteria Photobacterium phosphoreum (Microtox) and Escherichia coli (Toxi-Chromotest); the microalgae Skeletonema costatum and Dunaliella tertiolecta; the juvenile shrimp Metapenaeus ensis; and the juvenile fish Trachinotus blochii. Solid-phase testing was also performed with the Microtox assay. The second study, for the Civil Engineering and Development Department, investigated the bioaccumulation of contaminants in pelagic fish, benthic organisms, and sensitive species, including the Indo-Pacific Humpback Dolphin (Sousa chinensis) and humans, during the disposal process. Collectively, the results demonstrate that management decisions must be informed by site-specific biological response data from local and ecologically representative species. This integrated approach is crucial for developing robust disposal guidelines that safeguard marine biodiversity, fisheries resources, and public health.

Biography: Professor Wong is a Foreign Member of the Russian Academy of Sciences and a Member of the European Academy of Sciences and Arts. He served as the Editor-in-Chief of ‘Environmental Geochemistry and Health’ (Springer Nature), from 2002 to 2023. Professor Wong was the Coordinator of Central and North-East Asia of ‘Regionally Based Assessment of PTS’ and a Panel Member of ‘Chemicals Management Issues of Developing Countries and Countries with Economies in Transition’, sponsored by UNEP/GEF, 2001-2003 and 2010-2012. His research areas included ‘Environmental toxicology’, ‘Ecological restoration’, and ‘Resource recovery’. Under Environmental Science, Professor Wong is ranked 6th for 3 years, 7th for 1 year, and 8th for 2 years (career-long) globally according to the World’s Top 2% Scientists (Stanford University, 2020-2025).