There is a growing amount of plastic floating around in the world's oceans, posing threats to animal life, human health and environmental balance.
But how much plastic is out there? It's a hard question to answer because there is no one standardized way to document all the bits of floss, fishing line and food containers drifting in the waves.
Looking into the bellies of birds might be one solution to quantifying the problem, suggests a new study in the Pacific Northwest. In the waters there, plastic pollution is becoming as common as in the highly polluted North Sea.
For the study, scientists cut open the stomachs of 67 northern fulmars, a type of seabird, which had died and been beached on the coasts of British Columbia, Washington and Oregon. Fulmars are particularly good for this kind of study because they eat only in the water, they eat over a wide migratory range, and their tastes are not discriminating, making them prone to swallowing plastic if it’s there.
Nearly 93 percent of the birds harbored plastic in their stomachs, the research team reported in the journal Marine Pollution Bulletin. And each bird contained an average of nearly 37 pieces of plastic. One bird had 454 pieces in its stomach.
Ninety-six percent of the plastic came from everyday consumer objects, including twine, rope, fishing line, Styrofoam, bottle caps and candy wrappers. The other 4 percent were industrial pellets.
On average, each bird had about 0.4 grams (0.01 ounces) of plastic in its body, accounting for about 5 percent of its body mass. That would be like a human swallowing the equivalent of 10 quarters, said Stephanie Avery-Gomm, a graduate student in zoology at the University of British Columbia.
Compared to previous studies of fulmars in the Northwest, the new work suggests that the birds there are consuming 34 percent more plastic than they did 40 years ago. And they are eating nearly 100 times more of it. A much greater proportion now is coming from commercial products instead of industrial ones.
Levels of plastic in the Pacific Northwest's fulmars were on par with what similar studies have found in the highly polluted and industrialized regions of the North Sea.
"Like the canary in the coal mine, northern fulmars are sentinels of plastic pollution in our oceans," Avery-Gomm said in a press release. "Their stomach content provides a 'snapshot' sample of plastic pollution from a large area of the northern Pacific Ocean."
The new findings, Avery-Gomm said, warrant further monitoring to track the problem.
Photo: A northern fulmar; credit: Ashok Khosla, www.seabirds.com