PCBs, TEQs and plasma retinol in grey heron ( Ardea cinerea) hatchlings from two rookeries in Norway

Abstract

Fish-eating birds are particularly subject to accumulation of persistent organic pollutants, and polychlorinated biphenyls (PCBs) have been shown to constitute a major hazard for this group of birds. Grey heron ( Ardea cinerea) hatchlings from two rookeries were applied as sentinel species to study PCB burdens in coastal ecosystems in mid Norway and north Norway, and plasma retinol and dioxin-equivalencies (∑TEQ) were applied to assess toxic effects of the PCB-burdens. The results show that grey herons appear to be amongst the fish-eating birds in Norway that are accumulating PCBs to the largest extent. There were no differences in ∑PCB or ∑TEQ in the yolk of grey heron hatchlings from the two rookeries and, accordingly, none in plasma retinol concentrations either. Furthermore, plasma retinol concentrations could not be related to ∑PCB or ∑TEQ. Thus, it seems that exposure levels are below the threshold for gross retinoid-related effects in grey heron hatchlings. There are also indications that the grey heron could be relatively insensitive to retinoid-related effects of PCBs. In the hatchlings with the highest pollutant levels, ∑TEQs were in the lower range of levels that have been associated with reduced hatching success in other fish-eating bird species.