Ecological and Health Risk Assessments of Major Persistent Toxic Substances (PTS) in Deep Bay Area, in Relation to Their Removal Efficiency in Yuen Long and Shek Wu Hui Sewage Treatment Works

Mai Po Marshes have been facing increasing contamination in recent years, because of the discharge of domestic sewage, livestock wastewater, industrial effluent and agrochemicals into Deep Bay from the Pearl River, Shenzhen River and Shan Pui River. This may affect the migratory birds due to consuming organisms which may contain high levels of persistent toxic substances (PTS). We hypothesize that Yuen Long Sewage Treatment Work and Shek Wu Hui Sewage Treatment Work have different removal efficiencies for different PTS, and some of the PTS (As, Hg, Cd, Pb, Zn, Cu, DDT, PBDEs, PAHs and erythromycin) will find their ways into the Ramsar site and may impose adverse effects on biota, migratory birds and humans. Major objectives of this study are as the following: (1) To assess the removal efficiencies of PTS in different stages of Yuen Long and Shek Wu Hui STWs, and (2) To evaluate their concentrations and spatial distributions around the Ramsar site (by means of different bioassay tests ), and to conduct human health risk assessments (based on the studied PTS contained in shrimps- and fish)

Funding Source: HKSAR Govt - Others^