KATU: PSU researchers studying microplastics in coastal shellfish
Author: By Orion Ludlow, KATU News
Posted: September 29, 2017

Watch the original story on KATU

Would you like a side of plastic trash with your locally grown oysters?

You may be getting one whether you want it or not, and a team of researchers from Portland State University wants to find out for sure.

They're testing shellfish from the Oregon coast to see just how much microplastic -- plastic pieces smaller than 5 millimeters -- is ending up inside the guts of these bivalves.

"We are looking at two species. One open-coast species, so razor clams that live in sandy beaches, and then one estuarine species," says Dr. Elise Granek, an environmental sciences professor at PSU. The estuarine species: the Pacific oyster. "That gives us more spatial coverage along the coast.”

Britta Baechler, one of Dr. Granek's master's students, is conducting the study. Oregon Sea Grant is funding the research.

To make sure they were getting a comprehensive sampling of the entire Oregon coast, the researchers visited at least nine spots to collect Pacific razor clams. Baechler dug up clams from Clatsop Beach, near the mouth of the Columbia River, all the way to near Gold Beach and the state's southern border. They also bought Pacific Oysters grown in several different estuaries.

Then comes the lab work. The team shucks the shellfish and puts them in a potassium hydroxide solution that's strong enough to dissolve the flesh, but not so strong that it affects anything else.

"Any organic material is going to be dissolved by those tissues," explains Dr. Granek. "So fibers, like cotton fibers from cotton clothes, will be dissolved because they’re organic fibers. But things like my fleece that releases little particles when I wash it? It is not gonna dissolve."

What's left behind is a watery solution. Researchers then use microscopes to search that solution to see what's left behind. They're looking for plastic particles. And if plastics are ending up inside filter-feeders like clams and oysters, it's a bad sign.

"Microplastics have certain chemicals and chemical compounds in them that can be endocrine disrupting," says Dr. Granek. That means plastics could disrupt basic biological processes inside the shellfish, including reproduction.

And that's not the only risk. Microplastics might attract environmental contaminants and concentrate them on the plastics' surfaces. Then, as animals ingest those tiny plastic particles, they’re taking in a higher concentration of other pollution than they would otherwise be taking in by filtering the water for food.

Research into plastic contamination in seafood and other sea creatures is just starting to pick up. One of the first studies into microplastics in deep-sea creatures was recently published by a team out of Scotland. Those researchers found microplastics in sea stars and sea snails more than a mile beneath the surface of the Atlantic Ocean. Other researchers just finished a study similar to the one the PSU researchers are doing, except on Vancouver Island, Canada. That study found microplastics in both clams and oysters.

Dr. Granek doesn't know how Oregon samples will compare, or if local concentrations will be higher than the Canadian findings. After all, with 300 samples to test, the PSU research team won't be ready to release its findings until early next year. But Dr. Granek says, preliminarily, they have found microplastics in some specimens.

"At this point, all I can say is that, yes, we are finding microplastics," she says. "But we don't have enough samples processed yet to be able to speak to what the concentrations are, or how spatially diverse the presence is yet."

Watch a video of researchers in action