- Microplastics, plastic pieces smaller than 5 millimeters, have become increasingly prevalent in the natural world, and a suite of studies published in the last three years, including several from 2020, shows that they’ve contaminated not only the ocean and pristine wildernesses, but the air, our food, and even our bodies.
- Past research has indicated that 5.25 trillion plastic pieces are floating in the ocean, but a new study says that there are 2.5 to 10 times more microplastics in the ocean than previously thought, while another recent study found that microplastic “hotspots” could hold 1.9 million pieces per square meter.
- Other emerging research suggests that 136,000 tons of microplastics in the ocean are being ejected into the atmosphere each year, and blowing back onto land with the sea breeze, posing a risk to human health.
- Microplastics are also present in drinking water, and edible fruits and vegetables, according to new research, which means that humans are ingesting microplastics every day.
In 1997, Charles Moore was sailing a catamaran from Hawaii to California when he and his crew got stuck in windless waters in the North Pacific Ocean. As they motored along, searching for a breeze to fill their sails, Moore noticed that the ocean was speckled with “odd bits and flakes,” as he describes it in his book, Plastic Ocean. It was plastic: drinking bottles, fishing nets, and countless pieces of broken-down objects.
“It wasn’t an eureka moment … I didn’t come across a mountain of trash,” Moore told Mongabay. “But there was this feeling of unease that this material had got [as] far from human civilization as it possibly could.”
Moore, credited as the person who discovered what’s now known as the Great Pacific Garbage Patch, returned to the same spot two years later on a citizen science mission. When he and his crew collected water samples, they found that, along with larger “macroplastics,” the seawater was swirling with tiny plastic particles: microplastics, which are defined as anything smaller than 5 millimeters but bigger than 1 micron, which is 1/1000th of a millimeter. Microplastics can form when larger pieces of plastics break down into small particles, or when tiny, microscopic fibers detach from polyester clothing or synthetic fishing gear. Other microplastics are deliberately manufactured, such as the tiny plastic beads in exfoliating cleaners.
“That’s when we really had the eureka moment,” Moore said. “When we pulled in that first trawl, which was outside of what we thought was going to be the center [of the gyre], and found it was full of plastic. Then we realized, ‘Wow, this is a serious situation.’”
Since Moore’s discovery of the plastic-swirling gyres, there’s been a growing amount of research to try and understand the scale of the plastic pollution issue, including several studies from 2020. This new research shows that there’s actually a larger quantity of plastic in the ocean than previously thought, and that the plastic even enters the atmosphere and blows back onto land with the sea breeze. Recent studies also indicate that plastic is infiltrating our bodies through food and drinking water. The upshot is that plastic is ubiquitous in the ocean, air, food supply, and even in our own bodies. The new picture that is emerging, scientists say, is of a biosphere permeated with plastic particles right down to the very tissues of humans and other living things, with consequences both known and unknown for the lifeforms on our planet.
How much is really in the ocean?
In the past 70 years, virgin plastic production has increased 200-fold, and has grown at a rate of 4% each year since 2000, according to a 2017 study in Science Advances. Only a small portion of plastics are recycled, and about a third of all plastic waste ends up in nature, another study suggests.
While new research indicates that plastic is leaking into every part of the natural world, the ocean has long been a focal point of the plastic pollution issue. But how much is actually in the sea?
Moore says it’s “virtually impossible” to get an accurate estimate because of the ongoing production of plastic, and the tendency for plastic to break down into microplastics.
“This count is constantly increasing, and it’s increasing at a very rapid rate,” he said. “It’s a moving target.”
One commonly cited study, for which Moore acted as a co-author, estimated that there are more than 5.25 trillion plastic pieces floating in the ocean, weighing more than 250,000 tons, based on water samples and visual surveys conducted on 24 expeditions in five subtropical gyres. But even at the time of publication in 2014, Moore said he knew “that was an underestimate.”
A more recent study published this year, led by researchers at Plymouth Marine Laboratory, indicates that there’s a lot more microplastic in the ocean than we previously thought. When taking samples from the ocean, most researchers use nets with a mesh size of 333 microns, which is small enough to catch microplastics, but big enough to avoid clogging. But the team from Plymouth Marine Laboratory used much finer 100-micron nets to sample the surface waters in the Gulf of Mexico and the English Channel.
“Our nets clogged too, so we used shorter trawls and a specialized technique for removing all the plankton — microscopic plants and biota — from the sample to reveal the microplastics,” Matthew Cole, a marine ecologist at Plymouth Marine Laboratory and author of the study, told Mongabay in an email. “This process is quite time-consuming, so it’d be challenging for all samples collected to be treated this way.”
The researchers found there were 2.5 to 10 times more microplastics in their samples compared to samples that used 333-micron nets.
“If this relationship held true throughout the global ocean, we can multiply existing global microplastic concentrations ascertained using 333-micron nets, to predict that globally there are 125 trillion plastics floating in the ocean,” Cole said. “However, we know these plastics keep on degrading, and these smaller plastics would be missed by our smaller 100 micron net — so the true number will be far greater.”
Another team of researchers delved down to the seafloor in the Tyrrhenian Sea in the Mediterranean to take sediment samples. They found that microplastic accumulated at depths of 600 to 900 meters (about 2,000 to 3,000 feet), and that certain spots in the ocean, termed “microplastic hotspots,” could hold up to 1.9 million pieces per square meter — the highest level ever to be recorded on the seafloor. The results of this study were published in Science in June 2020.
“We were shocked by the sheer number of [microplastics],” Ian Kane, the study’s lead author, told Mongabay in May. “1.9 million is enormous. Previous studies have documented much smaller numbers, and … just talked about plastic fragments, but it’s fibers that are really the more insidious of the microplastics. These are the things that are more readily consumed and absorbed into organisms’ flesh.”
While these studies shine light on the fact that there’s definitely more plastic in the ocean than we think, it still doesn’t complete the picture, says Steve Allen, a microplastic expert and doctoral candidate at the University of Strathclyde in the U.K. Large quantities of microplastics still appear to be “missing” from the ocean, he said. For instance, one study suggested that 99.8% of oceanic plastic sinks below the ocean surface layer, making it difficult to detect, but Allen says this doesn’t fully explain what’s happening to all of the plastic that enters the ocean.
“We’re finding some of it,” Allen told Mongabay. “But we’re … trying to explain where the rest of it went.”
Allen and his wife, fellow scientist Deonie Allen, also from the University of Strathclyde, have been working to find their answer, or at least part of it, in an unlikely place: up in the sky.
‘Microplastics are in our air’
As the ocean churns and breaks waves, air is trapped in tiny bubbles. When those bubbles break at the sea’s surface, water rushes to fill the void, and this causes tiny, micro-sized particles, like flecks of sea salt or bacteria, to burst into the atmosphere. A new study, published in PLOS ONE, suggests that microplastics are entering the air in the same way.
“[Bubbles] act a little bit like velcro,” Deonie Allen told Mongabay. “Rather than the bubble going through the plastic soup and coming to the surface and not bringing any of the plastics with it, it actually collects [the plastic] and hangs on to it as it comes up. And when it bursts, the energy from the creation of the jet to fill the hole that’s left in the sea … is what gives it the force to eject the plastic up into the atmosphere.”
A lot of previous research on plastic pollution in the ocean has assumed that plastic remains in the seawater and sediment, or gets washed ashore. But this study takes a pioneering step to suggest that ocean plastic is entering the atmosphere through the sea breeze.
“This was just the next logical step to see whether what we’re putting into the ocean was actually going to stay there, or whether it would come back,” Steve Allen said.
To obtain the necessary data for this study, the research team collected air and sea spray samples on the French Atlantic coast, both onshore and offshore. They found that there was a high potential for ocean microplastics to be released into the air, and suggested that each year, 136,000 tons of microplastics were blowing ashore across the world, although Steve Allen said this number was “extremely conservative.”
This study specifically looked at microplastics, but the much smaller nanoplastics are likely going into air by the same means, according to the Allens. But detecting nanoplastics in the water or air can be challenging.
While this is the first study to look at the ocean as a source of atmospheric plastics, other research has examined the capacity of land-based plastics to leach into the air. One study, authored by the Allens and other researchers, found that microplastics were present in the air in the Pyrenees Mountains between France and Spain, even though the testing site was at least 90 kilometers (56 miles) from any land-based source of plastic, such as a landfill. This suggests that the wind can carry microplastics over long distances.
“We know that microplastics are in our air everywhere, from the looks of it,” Deonie Allen said.
More research needs to be done to understand the implications of atmospheric microplastics on human health, but according to the Allens, it can’t be good for us.
“Microplastics are really good at picking up the contaminants in the surrounding environment — phthalates, flame retardants, heavy metals,” Deonie Allen said. “That will get released into the body, relatively effectively.”
Enrique Ortiz, a Washington, D.C.-based ecologist and journalist who writes on the plastic pollution issue, says that this evidence should be a “wake up” call to humanity.
“The oceans are picking up the plastic that we throw in it, and that’s what we’re breathing,” Ortiz told Mongabay “And that’s the part that really … amazes me.”
“But it’s not just happening in coastal cities,” he added. “No matter where you go, [even] in the middle of the Arctic … the human imprint is already there.”
We’re not just inhaling microplastics through the air we breathe — we’re also getting it through the water we drink and the food we eat.