Granek (along with colleagues at other universities and her students) has helped advance our understanding of plastic pollution.
In a project with Oregon Public Broadcasting, one of her students helped the public radio station sample rivers around the Portland area, including tests near their headwaters in fairly remote areas. They tested sites on the Willamette, Rogue and Deschutes rivers.
“We found microplastics everywhere,” Granek says.
The amount of plastic found was lowest in the most remote areas and higher near urban centers.
“It makes sense that there was a correlation with population density, but nowhere was pristine,” Granek says.
Plenty of research has focused on the microplastics found in the guts of fish and seafood, to better understand how that may be taken up through their digestion process. But in another project, Granek and others looked at fillets from common fish found at markets.
Microplastics were found in the tissue that people actually eat, she says.
“What’s happening is, we actually find fairly long fibers even in the muscle tissue of the organisms,” Granek says. “Those long fibers are very, very thin, on the order of 20 microns in width, but they can be a millimeter in length.”
But that doesn’t mean she wants to dissuade people from eating seafood, which is a great source of healthy protein.
“It’s not like you should avoid this, because you’re getting [microplastics] from other sources,” as well, Granek says.
This summer, her lab will use a grid system to study parts of Portland. By looking for tiny plastics deposited in moss, which is abundant throughout the city, they’ll try to get a sense of some of the hot spots for plastic pollution.
Plastic particles that wear off tires are one of the most common sources of that pollution. So, the researchers expect highways and freeways to be a big source.
“We think the recycling center in north Portland is probably a source, because some gets dropped or weathered,” Granek says. “We know a number of studies have found dryer vents release microfibers … so we’re wondering if laundry facilities are higher sources.”
The most common type of microplastic found anywhere is the microfiber. They commonly shed off of plastic clothing such as polyester and nylon during the wash cycle, and while wastewater treatment plants may capture about 90 percent of those fibers, about 10 percent still escape into effluent. Even more of those microfibers may end up in the environment if biosolids captured at the treatment plant are used in agricultural fertilizing practices.
Those same microfibers are also released into the air through dryer vents. Using dryers at residential homes in Idaho and Vermont, researchers took bright pink blankets, got them wet and placed them in the dryer on low for an hour. They found the hot pink fibers in surface snow samples up to 30 feet away from the vents, with more than a thousand fibers found in some of the test spots.
Think about what that means for how many microfibers Portland or Seattle put out into the environment, Granek says. There are likely millions released into the environment every single day.
One solution governments are considering is requiring special filters on dryers to capture most of those microfibers at the source. Though the fibers may end up in landfills when those filters are disposed of and replaced, at least they won’t be released into the air.
About two-and-a-half hours southwest of Portland, other groundbreaking microplastics research is underway at Oregon State University’s Hatfield Marine Science Center, located in Newport on the Oregon Coast.
In early May, Associate Professor Susanne Brander walks through the university’s brand new microplastics lab completed during the pandemic. Brander teaches in the Fisheries, Wildlife and Conservation Sciences and Environmental and Molecular Toxicology departments, and helps mentor students whose work touches on plastic research in diverse ways.
With her for this May tour is a team of graduate students who will spend this summer researching microplastics in tiny shrimp, bioluminescent fish, animal waste and more.
The team collaborates with government agencies and universities around the country, as they have a special piece of equipment to identify the type of plastic each tiny particle is made of.
While many labs have had FTIR (Fourier-transform infrared spectroscopy) machines for years, this lab has a micro-FTIR that can analyze micro- and nanoplastics mere microns in length. (A micron is just 1/25,000 of an inch, or one-millionth of a meter.)
In the lab’s clean room, where special hoods and HEPA filters keep the area clear of as many background contaminants as possible, lab technician Emily Pedersen puts a plastic sample under what looks like a microscope. The micro-FTIR passes infrared radiation through the particles and takes several scans as a computer creates a wavelength showing how much light was absorbed or reflected.
“It reads the wavelengths that are coming back and compares it to a known library,” Pedersen says, noting that many labs helped create the library by scanning known substances into the system. “So, that’s just PETE (polyethylene terephthalate), which is a regular water bottle or packaging.”
For this demonstration, she already knew the material came from a water bottle, but when the team is running tests on various microplastics found in animal samples, the machine is key to understanding what’s there. It also helps sort out natural fibers and organic material from man-made substances.
“If you’re pulling a bunch of different fibers from a fish gut, it’s really hard to tell if they’re synthetic or not unless you chemically analyze them,” Brander says.
Brander notes that in the freezer they have samples of otter scat from Alaska they’ve been asked to test. Another student at the school has sand dune core samples waiting to be tested. Granek may send samples here as well.
In another lab on the satellite campus, first-year graduate student Olivia Boisen shows off frozen samples of myctophids that she plans to test. Also known as lanternfish, the small creatures serve as a major food source for other fish, and they are commonly picked up by accident when research teams are out collecting salmon and other sea creatures for testing.
As she holds up a jar of the sardine-sized fish, they flash silver as the light catches the organs that enable them to bioluminesce deep underwater. While they spend their days about a kilometer deep, at night they rise close to the surface to eat, Boisen says.
“This huge number of fish are doing this every night, and then they migrate back down to live out their days down there,” Boisen says. “So they’re probably this microplastic pump from the surface to midwater, which is really important to study.”
Because of their unique abundance, and the fact that many museums have preserved lanternfish in jars of ethanol over several decades, Boisen will get to see if she can track the rise in plastic production and pollution over time.
The first fully synthetic plastic was bakelite, which was first made in 1907 and soon grew popular for making phones, radios, car parts and jewelry. But it wasn’t until the 1950s and ’60s that plastic production started to take off. In recent years, production has continued to grow on an exponential scale, as the cheap material is used in more products than ever before.
Boisen theorizes that she may be able to see lower levels of plastics in the myctophids captured and preserved in the 1960s compared to those caught fresh for her this year. Those caught this year were preserved using far stricter quality control measures to avoid contamination, yet they may still have higher levels of plastic in them.
Also working with Brander are Sara Hutton, a third-year doctoral candidate, and Felix Biefel, a visiting doctoral student from Germany.
Hutton, who works in the Environmental and Molecular Toxicology Department at OSU, is studying gene expression in silverside fish that are being raised and exposed to microplastics in the lab.
Biefel is working with tiny mysid shrimp raised in the lab to study how their behavior is impacted after microplastic exposure. He’ll expose them to light and dark, as well as different temperatures.
“The nice thing about using behavior is it can be an indicator of neurotoxicity,” Hutton explains. “We’re interested in how it affects their brain. If the organism developed differently, it’s going to affect its behavior.”
Exposure experiments are essential to better understand what it means when researchers find microplastics in various species, Brander says.
“It’s great to go out and find microplastics,” Brander says. “But the only way to know if it’s dangerous is if we have lab experiments.”