PORTLAND, Ore. (AP) — A Portland State University study found tiny pieces of plastic in the vast majority of razor clams and oysters sampled along the Oregon coast and noted that the primary source of contamination was from fibers used in synthetic textiles.
Those microscopic fibers can be shed by yoga pants, fleeces and other active wear made of synthetic textiles during a wash — up to 700,000 per load of laundry, according to the study, which was reported on Tuesday in The Oregonian/OregonLive. These fibers are in the wastewater from laundry machines that eventually winds up in the ocean, although some of the tiny plastic fibers could also come from derelict fishing gear, the newspaper said.
The shellfish in question were plucked from 15 sites, from Clatsop in the north to Gold Beach near the California border, in both the spring and summer of 2017. Of the roughly 300 shellfish analyzed, all but two contained at least some microplastics, Elise Granek, a PSU professor of environmental science and management, said.
The study was published in the journal Limnology and Oceanography Letters.
"Whether it was a fairly urban site or a rural site, estuary or open-coast beach, both species had microplastics," she said. "Although we think of the Oregon coast as a much more pristine coastline compared to California, Puget Sound or the Eastern Seaboard, when we are talking about microplastics, we're still seeing that human footprint on even our more pristine coastline."
Study authors found an average of 11 pieces of microplastic in each specimen, with the foreign materials primarily consisting of microfibers as they go through washing machine cycles.
The fishing industry and oyster framers have often been scapegoated in the past for microplastic pollution, but Granek said there was no clear scientific consensus on the source of the fibers.
"It's not because people aren't managing our fisheries well or are being unclean in their practices," she said. "We're all using plastics on a daily basis. We are all the source of contamination in our seafood."
"Microplastics are not just in our seafood," she said. "We know that they are in our beer, in our salt, in our drinking water."
The impact of microplastics on shellfish health is another area where further research is needed. Some studies have shown that the presence of these foreign microfibers could impede growth or reproduction in shellfish.