Ecological Risk Assessment of Environmental Contaminants for

Waterbirds have traditionally served as sentinels for monitoring environmental hazards due to their ability to integrate contaminant levels from a broad range of areas, and consequently reflect the pollutant hazards to wildlife as well as human health. In this study, eggs of Little Egrets, LE (Egretta garzetta), Black-crowned Night Herons, NH (Nycticorax nycticorax) and Bridled Terns, BT (Sterna anaethetus) were collected from northwestern and northeastern parts of Hong Kong (Fig. 1), and were analyzed for congener-specific PCBs, organochlorine (OC) pesticides and various metals and metalloids. The likelihood of potential hazards of these toxic contaminants was then evaluated against corresponding reference values from the literature. Concentrations of ΣCHLs,ΣDDTs, and ΣPCBs in eggs of LE, collected from northwestern parts of Hong Kong were the highest (P < 0.05) among the three species, whereas concentrations in eggs of NH and BT were comparable to each other (Fig. 1)