Environment Canada wildlife scientists examined the eggs from four gull species from across Canada to investigate how geography, sources and dietary relationships affected the trends of highly bioaccumulative, perfluorinated sulfonate (PFSA) and carboxylate (PFCA) contaminants, and precursor compounds including several perfluorinated sulfonamides, and fluorotelomer acids and alcohols.

Glaucous-winged gull, California gull, ring-billed gull and herring gull eggs were collected in 2008 from 15 marine and freshwater colonies across Canada.

The highest PFSA and PFCA concentrations were found in urban areas in the Great Lakes and St. Lawrence River, specifically Big Chicken Island, Toronto Harbour, and Ile Deslauriers. The Sable Island colony in Atlantic Canada also had high concentrations, but generally marine sites had lower PFSA concentrations than freshwater sites.

Dietary tracers (stable nitrogen and carbon isotopes) revealed that marine, aquatic and terrestrial prey were likely sources of perfluorinated compounds (PFCs) contaminant exposure, but were specific to each colony.

Marine colonies were exposed to PFCs via marine prey, with the exception of Mandarte Island colony in Pacific British Columbia, where PFSA and PFCA exposure appeared to be via terrestrial and/or freshwater prey consumption. Stable isotope analysis of freshwater sites suggested PFCs were sourced from both aquatic and terrestrial prey consumption.

These chemicals are used in a variety of consumer products including surfactants, insecticides and fire suppressants.

Read more about the Organic Contaminants Research Laboratory, where this study was conducted.

Source: Gebbink, W.A., N. Burgess, L. Champoux, J.E. Elliott, C.E. Hebert, P. Martin, M. Wayland, D.V.C. Weseloh, L. Wilson and R.J. Letcher. 2011. Perfluoroalkyl carboxylates and sulfonates and precursors in relation to dietary source tracers in the eggs of four species of gulls (Larids) from breeding sites spanning Atlantic to Pacific Canada. Environment International 37:1175-1182.

Contact: Robert Letcher, 613-998-6696, Ecotoxicology and Wildlife Health