Persistent organochlorine contaminants in liver and fat of birds of prey from Greece

The concentrations of persistent organic pollutants, such as DDT and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), cyclodienes (Cycls), and polychlorinated biphenyls (PCBs), were measured in livers and subcutaneous fat tissues of six Accipitridae and four Falconidae bird species from different areas in Greece. This is the first report of persistent organochlorine (OC) pollutants in birds of prey tissues presented for Greece and the Eastern Mediterranean region. Accumulation patterns of OCs found in birds suggested that the predominant contaminants were p,p'-dichlorodiphenyldichloro-1,1-ethylene (DDE) and PCBs, whereas Cycls and HCHs occurred at low concentrations only. Concentration values of p,p'-DDE ranged from nondetected to 19,518.72 ng/g wet wt in livers and from nondetected to 2679.19 ng/g wet wt in fat. Total PCB levels ranged from 1.01 to 7419.43 ng/g and from 3.25 to 490.10 ng/g wet weight for liver and fat samples, respectively. Higher-chlorinated PCBs such as 118, 138, 153, and 180 predominated in both the liver and subcutaneous fat samples, a pattern comparable to that observed in birds from other European countries. No significant differences in mean concentrations of OCs are detected between species. Hepatic concentrations were in general higher than the fat concentrations showing depleted fat stores in most birds. Concentration ranges were also found in lower or similar levels to those reported for birds in other regions. Variation of OCs levels in bird tissues could be due to different causes of death, with a subsequent effect on body lipid levels, and different feeding and migration habits. The liver PCB levels reported in this study are below the concentrations currently believed to exert mortality or ecotoxicological effects. On the contrary, in some cases p,p'-DDE concentrations were higher than the reported effect values for birds of the same families and could be associated with sublethal effects.