Organochlorine pesticide residue concentrations and accumulation patterns in waterbirds and in their prey at Lake Kerkini, a Ramsar wetland, Greece

Abstract

The levels of 16 organochlorine pesticides (OCPs) were measured in egg samples of the great cormorant, great-crested grebe, grey heron, little egret, black-crowned night heron and in their prey being bleak, roach, pumpkinseed, goldfish and frogs from Lake Kerkini, NE Greece. Concentrations of most OCPs differed among most bird and prey species. DDTs predominated in all species, contributing to about 80% of the total OCPs in most sample types. Moving up the food chain, the relative contribution of ∑DDTs increased whereas of ∑HCHs and ∑Cycls (cyclodienes) decreased. Regarding trophic transfer, all OCPs exhibited bioconcentration but, in contrast, compounds such as A-HCH, endrin, heptachlor, heptachlor hepoxide, ·-, ‚-endosulfan and endosulfan sulfate showed low or no biomagnification. No correlations were found between either bioaccumulation (BAF) or biomagnification factors (BMF) and lipid content of biota. Nevertheless, there was a significant relationship between logK ow (the octanol-water partition coefficient) and BAF of all OCPs. OCP bioaccumulation patterns at Lake Kerkini are probably governed by the chemical properties of compounds and their metabolic ways in biota. The levels of OCPs were too low to have adverse biological effects to the waterbirds. The great cormorant, pumpkinseed and Rana frogs are suggested as the most suitable bioindicators for monitoring OCPs at Lake Kerkini due to the highest concentrations of most compounds and showing the greatest bioaccumulative properties.