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(112) Risk assessment of metals and trace organics to birds in a Hong Kong Ramsar site. Wong, Bryan1, Minh, Tu2, Tanabe, Shinsuke2, Lam, Paul1, 1 2 ABSTRACT- In Hong Kong, the Mai Po Marshes encompass 172 ha of mangroves and 209 ha of tidal shrimp ponds and fish ponds, and lie within the 535 km2 catchment of Deep Bay. The Mai Po and Inner Deep Bay area is of regional and global conservation significance, and was listed as a Wetland of International Importance under the Ramsar Convention in 1995. The area receives a rich supply of pollutant-laden sediments from nearby streams and the Pearl River in mainland China. To assess the effect of environmental pollution to the long-term ecological sustainability of the site, an initial ecological risk assessment was undertaken based on concentrations of heavy metals and persistent organic pollutants in sediment samples collected from the area. A food chain analysis of exposures and risks to wetland-dependent birds was also performed with herons and egrets as the main target species. Samples of common food items for the birds, including crabs, mudskippers, shrimps and fish, were collected and analyzed for metals (Cr, Zn, Cd, Mn, Fe, Cu, Pb, Hg) and trace organics (PAHs, PCBs, petroleum hydrocarbons and chlorinated pesticides). This paper provides the means to (a) integrate the information from the risk assessment with existing ecological and ecotoxicological data in the area; and (b) establish a framework for the formulation of a long-term monitoring strategy for the Ramsar site. Key words: Ecological risk assessment, wetland |
