Little Egrets (Egretta Garzetta) and Trace-Metal Contamination in Wetlands of China |
| |
Authors: | Y Zhang L Ruan M Fasola E Boncompagni Y Dong N Dai C Gandini E Orvini Xavier Ruiz |
| |
Institution: | (1) School of Life Sciences, Lanzhou University, Lanzohu, 730000, PR China;(2) Dipartimento Biologia Animale, Università, Piazza Botta 9, 27100 Pavia, Italy;(3) Institute of Soil Science, Chinese Academy Sciences, Nanjing, 210008, PR China;(4) Jiangxi Academy Sciences, Nanchang, Jiangxi, 330029, P.R. China;(5) Dipartimento Chimica Farmaceutica, Università, Viale Tarmelli, 27100 Pavia, Italy;(6) Dipartimento Chimica Generale, Università, Viale Taramelli, 27100 Pavia, Italy;(7) Departamento Biologia Animal, Universidad de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain |
| |
Abstract: | 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 Lake, and Pearl River
Delta, selected as hotspots of pollution in Central China. We adopted as indicator the Little Egret, a widespread colonial
waterbird, and during 1999 and 2000 we collected and analysed the same samples as for a parallel study we conducted in Pakistan,
e.g. eggs, body feathers of chicks, prey spontaneously regurgitated by the chicks, and sediments at the areas most used by
foraging egrets. The levels of trace-metals at our three study areas were similar, or within the range, of those found in
the few other studies for East Asia, with few exceptions. The concentrations of the various elements were below the threshold
that may affect the survival or reproduction of the birds, and even the highest concentrations relative to background, i.e.
Se in eggs, and Hg in feathers at Pearl Delta, do not pose toxic hazards. In sediments, the levels of trace elements were
lower than the critical levels assumed for contaminated soil, except for alarming high levels of As at Poyang. These results
do not confirm our expectation, that Poyang was relatively uncontaminated, while Tai and Pearl were polluted. Although trace
metal concentration differed significantly among the three study areas, these differences were minor and were not consistent
among elements and samples. The bioaccumulation ratios from sediments through prey, feather and egg, were consistent with
our previous findings for Pakistan. Only Hg exhibited high bioaccumulation, while Se and Zn had low accumulation, and the
other elements no accumulation. This reasserts that feathers of predators such as egrets, may be more sensitive indicators
of environmental contamination for the elements subject to bioaccumulation, whereas the sediments or the organisms low in
the food chain are better indicators for the other elements. |
| |
Keywords: | bioaccumulation China contamination Egretta garzetta trace-elements waterbirds |
本文献已被 PubMed SpringerLink 等数据库收录! |
|