PCBs and organochlorine pesticide residues in eggs of Audouin's gull (Larus audouinii) in the north-eastern Mediterranean

Levels of eight PCB congeners (IUPAC 8, 20, 28, 52, 101, 118, 138, 180) and 13 organochlorine pesticides (alpha -BHC, beta -BHC, lindane ( gamma -BHC) , heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, 2,4 ' -DDT, 2,4 ' -DDD, 4,4 ' -DDT, 4,4 ' -DDD, 4,4 ' -DDE) were measured in unhatched Aud ouin gull eggs from Aegean Sea (northeastern Mediterranean) colonies in 199 7 and 1998, Levels of more persistent congeners 138, 180 and in some coloni es 118, predominated among PCBs, Between years significant differences were found in the levels of a variety of contaminants in the same regional colo nies (Lipsos, Agathonisi, and Fourni) attributable to temporal changes in d iet. Within years differences were limited (1997: PCB congeners 52, 118, 18 0, heptachlor and 4,4 ' -DDD; 1998: PCB congener 8 and heptachlor epoxide) which in combination with cluster analysis suggest a temporal rather than s patial pattern of pollution in the Aegean Sea. Maximum median levels of fiv e PCB congeners, total PCBs and eight organochlorine pesticides were found in the Agathonisi and Fourni colonies suggesting an elevated nearby polluti on probably from the polluted Menderez River. Levels of all contaminants we re too low to have any adverse reproductive effects on the Audouin's gull o f the Aegean colonies. (C) 2001 Elsevier Science Ltd, All rights reserved.