Evidence of oil spill 2 years ago in birds

Researchers say they have found traces of pollutants from the BP oil rig disaster in the Gulf of Mexico two years ago in the eggs of Minnesota birds.

In examining pelican eggs in the largest lakeside colony of American white pelicans in North America, scientists have discovered traces of petroleum compounds, as well as remnants of Corexit, a chemical used to break up the oil spill.

The birds migrate back to Minnesota after spending the winter in the Gulf, with young pelicans usually spending a year in the warmer climates, Minnesota Public Radio reported.

Mark Clark, an ecologist at North Dakota State University, studies pelican eggs, and is helping the state Department of Natural Resources look for contaminants that could cause birth defects in developing pelican embryos.

"Even if they're present in small amounts, they may have a large impact on the development," Clark said. "Any contaminant that makes its way into the bird could be bad, but it could be especially bad if it gets into the egg because that's where the developing embryo and chick starts. And when things go wrong at that stage, there's usually no recovery."

Clark said the research on how petroleum affects developing bird embryos is scant, meaning scientists are unsure of what will happen when the pelican eggs hatch.

The Environmental Protection Agency has said Corexit contains carcinogens as well as endocrine-disruptors, which Clark said could interfere with growth hormones at play during an embryo's development. Nearly 80 percent of the eggs tested so far contain Corexit, while 90 percent contained petroleum compounds.