Trace elements in little egrets and flamingos of Camargue, France

Trace elements (Cd, Cu, Hg, Pb, Se, Zn) were measured in nine organs (liver, kidney, breast muscle, lungs, breastbone, stomach, gizzard, spleen, feathers) of several specimens of Greater Flamingos (Phaenicopterus ruber (Pallas] and Little Egrets (Egretta garzetta (L.] from the Camargue, in the Rhône river delta. In both species, individual fluctuations of Cd, Hg, Pb, and Se levels were important in all organs, whereas Zn and Cu, essential metals, exhibited only moderate variations. The organotropism of trace elements supports the hypothesis that major routes of contamination would be both nutritional and aerial for flamingos, and prevailingly alimentary for egrets. In both species we found the highest levels in liver and kidney, with the exception of lead, the highest levels of which were found in breastbone and feathers. Our study indicates that trace element concentrations in flamingos and egrets are higher than or equivalent to those reported in the literature for birds living in polluted areas. Because the Camargue is a unique area in western Europe it would be of interest to develop more studies to evaluate the impact of surrounding human activities on this Biosphere Reserve.