Little Egrets (Egretta garzetta) and trace-metal contamination in wetlands of China.

摘要: The rapidly developing Asian countries may face threatening environmental contamination, that however remains largely unassessed. We studied persistent trace elements in three wetlands, Poyang Lake, relatively unpolluted, and Tai Pearl River Delta, selected as hotspots of pollution Central China. adopted indicator the Little Egret, a widespread colonial waterbird, during 1999 2000 we collected analysed same samples for parallel study conducted Pakistan, e.g. eggs, body feathers chicks, prey spontaneously regurgitated by sediments at areas most used foraging egrets. levels trace-metals our were similar, or within range, those found few other studies East Asia, with exceptions. concentrations various below threshold affect survival reproduction birds, even highest relative to background, i.e. Se Hg do not pose toxic hazards. In sediments, lower than critical assumed contaminated soil, except alarming high As Poyang. These results confirm expectation, was uncontaminated, while polluted. Although metal concentration differed significantly among areas, these differences minor consistent samples. bioaccumulation ratios from through prey, feather egg, previous findings Pakistan. Only exhibited bioaccumulation, Zn had low accumulation, no accumulation. This reasserts predators such egrets, be more sensitive indicators contamination subject whereas organisms food chain are better elements.