Abstract
In the present study, we examined organs of 145 white-tailed eagles (Haliaeetus albicilla) from Germany and 5 specimen from Austria, as well as 62 northern goshawks (Accipiter gentilis) from different regions of Germany for their organ concentrations of chlorinated pesticides, polychlorinated biphenyls (PCB) and potentially toxic heavy metals. We proved a significant decline of DDT concentrations in livers of 127 white-tailed eagles (WTE) collected between 1990 and 2001. Considering the final ban of DDT in the former German Democratic Republic (GDR) in 1988, the decline of DDT concentrations in organs of WTE and the improved reproduction and the population increase in northern Germany in recent years are discussed. The concentrations for gamma-hexachlorocyclohexane, PCB 28 and PCB 52 were negligible. The penta-, hexa-, heptachlorinated biphenyls (PCB 118, PCB 138, PCB 153, PCB 180) accumulate in hepatic and adipose tissue, respectively. Interpretation of these organ concentrations was difficult, because individual body condition revealed a strongly negative relationship with hepatic contaminant concentrations. During catabolic metabolism the stored body fat is metabolized and the lipophilic organochlorines (OC) are mobilized and distributed through the blood stream to highly metabolic active organs, e.g. the liver. Therefore birds with decreasing fat deposits had elevated concentrations of the OC in the liver. One adult WTE, found dead in the year 1979, had hepatic concentrations for DDT that were assumed for a lethal intoxication. However, we proved that WTE are at high risk for metal toxicosis. Twenty-eight percent (28%) out of 57 free-ranging WTE from Germany and Austria had elevated lead concentrations in their liver, indicating lethal lead exposure. Birds of prey are exposed to lead ammunition through foraging of shot-crippled and therefore handicapped prey, e.g. waterfowl, and scavenging of shot game or gut piles. We measured mercury concentrations in organs, which were far below the concentrations reported in studies conducted during the period when mercury compounds were used as seed dressings. The concentrations for cadmium were in general two up to ten magnitudes higher in kidneys than in liver tissue. All cadmium concentrations were considered to be harmless for birds. One out of 62 examined goshawks was diagnosed for lethal lead poisoning. Two further goshawks had lead concentrations in their organs, which were indicative for acute lead exposure. Goshawks from Berlin and Brandenburg had significantly higher hepatic concentrations for DDT than birds from Lower Saxony. These higher DDT concentrations in goshawks from regions of the former GDR were assumed to result from application of DDT in the years 1983 and 1984 in Brandenburg and the overall late ban of DDT in these regions. Furthermore, we discuss the manufacturing of DDT in Berlin during the past as a local source for the extraordinary high DDT concentrations in some "urban" goshawks from Berlin. Highly contaminated feral pigeons as main prey were suspected as vectors for these high levels of chlorinated contaminants in the livers of goshawks in Berlin. Similar to the WTE we proved a strong relationship between individual body condition and organ concentrations for the OCs. Beside the three goshawks with high lead concentrations, all other metal concentrations in organs were harmless and in the range of background contaminations. The organ distributions for cadmium is similar to those described for the WTE. |
