| Summary: | Persistent organic pollutants (POPs) constitute a chemically diverse group of lipophilic substances that may accumulate in living organisms, often with harmful effects. To some extent these substances may be expelled via the liver functions. The preen gland is an organ in most birds that produces a lipid-based secrete which is applied to the bird's feathers by preening. The preen gland may thus be an alternative way for birds to excrete POPs. Furthermore, if the preen oil applied to the feathers contain POPs, traceable amounts of the pollutants might be left on the feathers. Sampling of feathers may therefore be a non-destructive alternative for monitoring POPs in birds. During the breeding season 2009, 24 black-legged kittiwakes Rissa tridactyla were sampled in a colony near Ny-Ålesund, Svalbard in order to analyse feather, liver and preen gland samples for POPs. In addition liver and preen gland samples from 12 kittiwakes were analysed for lipid class composition. Kittiwake feathers were found to be contaminated by POPs and the POP profiles in feather and preen gland were found to be more similar than the feather and liver profiles. This indicates a transfer of POPs from the preen gland to the feathers. High levels of contaminants were measured in the preen gland. This creates a basis for the kittiwake to excrete POPs through the preen gland. Similar to liver, the POP concentrations in the preen gland increased from the incubation- to the chick rearing period. This could give the kittiwake an even greater opportunity to excrete POPs in energy demanding periods where POPs are most concentrated. However, a trend for lower feather contamination in chick rearing- compared to incubation period, may indicate lower preen oil production and thereby no increase in the excretion of POPs in energy demanding periods. Despite a very different lipid composition in liver and preen gland samples, only small magnitude differences appeared in the POP profiles and there seem to be no severe restrictions to which POPs could ...
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