Organochlorine insecticide residues in eggs of the little tern (Sterna albifrons) in the Axios Delta, Greece.

Organochlorine pesticides such as DDT were long ago banned in America and Europe but due to their persistence their metabolites are still detected in the environment. In Greece, organochlorine insecticides such as DDT were extensively used before 1972 (Albanis et al. 1994). Coastal wetlands, which are widespread in Greece, are areas where pesticides from the agricultural activities of extensive surrounding areas are transported through rivers. In wetlands of the Thermaikos Gulf wetland complex (north-eastern Greece) among 11 pesticides detected in water and sediments three organochlorines, namely BHC, lindane and 4,4'DDE (a DDT metabolite) were found (Albanis et al. 1994). These and some other organochlorines were found in heron chicks and in their food in the same area (Albanis et al. 1996). Once these compounds were detected, and it was necessary to obtain more information about their presence in the food chains and simultaneously investigate potential effects on bird species that are of interest from a conservation perspective.