Study Examines Link Between Toxins, Eggshell Colour

August 14, 2012 - News Release

Environmental contaminants can cause birds’ eggs to change colour, offering a possible tool to estimate and monitor environmental toxins, according to a new study by a University of Guelph researcher.

Daniel Hanley, a Mitacs Elevate post-doctoral researcher in the Department of Integrative Biology, found that not only can pollutants influence the colour of herring gull eggs, but the colour of these eggshells can also predict contaminant load with 84-per-cent accuracy.

EggsPigments that give eggshells their colour are believed to be the same for all birds, says Hanley. Along with University of Windsor researcher Stéphanie Doucet, he used a spectrometer to measure the colour of Great Lakes herring gull eggs and evaluate the influence of numerous toxins, such as insecticides and industrial byproducts.

The eggs were collected over 40 years by the Canadian Wildlife Service’s Great Lakes herring gull monitoring program, one of the longest-running programs of its kind in the world.

Hanley said the research has profound implications for human health.

Despite success in reducing concentrations of persistent organic compounds in the environment, these compounds are still found in many species. If industrial and agricultural chemicals have affected eggs, they’ve probably affected humans, too, he said.

“The Great Lakes support a variety of industries and are densely populated, which is one reason why the lakes have been contaminated historically. These lakes are a way of life and are vital for the entire region.

“What we have learned about monitoring contaminants at home may help improve our monitoring efforts across the globe. This may be especially useful in regions with limited access to funding for monitoring efforts. In these regions, people’s survival is often more directly connected with the land, and subsequently they are even more vulnerable to the contaminants in their food sources.”

Measuring egg colour may offer a quick, inexpensive and non-destructive way to monitor areas of concern and evaluate potential human health risks, said Hanley.

“However, our paper has broader implications than human health alone. Our aim is to assess the quality of the entire habitat. This is really our duty as stewards of the environment.”

The paper appears in the Journal of Applied Ecology.

Hanley will present research on the Atlantic puffin diet at the North American Ornithological Conference, which runs Aug. 15 to 18 in Vancouver.

Photo courtesy of Donnell Gasbarrini, Royal Ontario Museum

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