Organochlorine contamination in bird's eggs from the Danube Delta

In this study we report the levels of organochlorine compounds in eggs of a quatic birds from the Danube Delta, a major European wetland. The eggs were collected in 1997 and belonged to the following species: the mallard (Anas platyrhynchos), the greylag goose (Anser anser), the mute swan (Cygnus olo r), the coot (Fulica atra), the glossy ibis (Plegadis falcinellus), the spo onbill (Platalea leucorodia), the little egret (Egretta garzetta), the nigh t heron (Nycticorax nycticorax), the grey heron (Ardea cinerea), the great white egret (Egretta alba), the red-necked grebe (Podiceps griseus), the Da lmatian pelican (Pelecanus crispus), the Pygmy cormorant (Phalacrocorax pyg maeus) and the common cormorant (Phalacrocorax carbo). Dichlorodiphenyltric hloroethane (DDT) levels were higher in eggs of the little egret, the great white egret, the cormorant and the Pygmy cormorant with respect to the oth er species (48,399, 13,613, 12,400 and 10,417 ng/g dry wt., respectively). Hexachlorobenzene (HCB) levels were lower than 1393 ng/g dry wt. in all spe cies while polychlorinated biphenyl (PCB) concentrations in the Pygmy cormo rant (2565 ng/g dry wt.) were higher than in the other species. The toxicit y evaluation was based on 2,3,7,8-TCDD toxic equivalent factors (TEF) and n on-ortho PCB congeners contributed much more than mono-ortho PCBs in most o f species. A further aim of this study was to evaluate the possible differe nces of organochlorine levels in bird eggs collected in the same area in 19 82 and in 1997; generally speaking the levels detected in the latter period were lower than those detected in the earlier one. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.