Throw a polyester sweater in the washing machine and it’ll come out nice and clean, but also not quite its whole self. As it rinses, millions of synthetic fibers will shake loose and wash out with the waste water, which then flows to a treatment plant. Each year, a single facility might pump 21 billion of these microfibers out to sea, where they swirl in currents, settle in sediments, and end up as fish food, with untold ecological consequences.
Everywhere scientists look in the world’s oceans, they’re finding microfibers, technically a subcategory of microplastics, which are defined as particles less than 5 millimeters long. And now, after making four expeditions across the Arctic Ocean, a team of scientists is reporting just how badly even these remote waters have been tainted. Sampling as deep as 1,000 meters, they found an average of 40 microplastic particles per cubic meter of water, 92 percent of which were microfibers. Nearly three-quarters of these were polyester, strong evidence that humanity’s addiction to synthetic clothing is corrupting Earth’s oceans.
“It simply illustrates just how contaminated our planet has become with synthetic polymers,” says Peter Ross, an ocean pollution scientist and marine pollution adviser at Ocean Wise Conservation Association, a conservation NGO, and lead author on a new paper in Nature Communications describing the findings.
Ross and his fellow researchers from the Department of Fisheries and Oceans Canada took care not to sample surface waters, which tend to accumulate buoyant styrofoam and lost fishing gear. For this reason, that water is not a proper representative sample of the plastic pollution that lurks in the sea. Instead, they had to collect water from a few meters beneath the surface, and—conveniently enough—their research vessels had intakes ports situated on the bottom of their hulls. The scientists also took samples up and down the water column, as deep as 1,015 meters, from six stations in the Beaufort Sea above Alaska.
They had to be sure, though, that they weren’t mistaking natural particles for synthetic ones, so they employed a forensic technique called Fourier transform infrared spectrometry, or FTIR. An instrument bombards the particles with an infrared beam, exciting certain molecules in the sample, and analyzing the infrared signature reflected back at the detector. In this way, the scientists could not only confirm whether a particle was synthetic, but could also determine what kind of plastic it was. “Even our trained technicians in our group would often mistake these mystery particles for plastic when they are in fact something natural,” says Ross. “So the FTIR is very important to confirm that the mystery particle is plastic or not.”
Particles confirmed, the team measured their lengths and diameters, which matched the known dimensions of synthetic fibers. Nearly 75 percent of the fibers were polyester, a common material in synthetic clothing, and they came in a range of colors too. “The alignment is striking,” says Ross. “All of this really does line up our concerns around the prospects of a significant role for textiles and laundry in contaminating the world’s oceans.”
Because the team had data from four expeditions that wandered all over the Arctic, they could compare their samples from the eastern region (above the Atlantic Ocean) to the western region (above Alaska and the Yukon). They found three times more particles in the east compared to the west. The fibers were also 50 percent longer in the east and their infrared signature more closely resembled that of virgin polyester—indicators that these fibers were newer. “As fibers move into the Arctic or into the environment, they get weathered, they get older over time,” Ross says. “The infrared signature changes with sunlight, with chemical processes, with bacterial decomposition.”