A
prominent environmental scientist says we need to rethink everything about how
we make, use, and trash plastic.
By Emily J. Gertz
A new study linking microplastic pollution to low reproductive rates in Pacific oysters underscores the need to overhaul the use of petroleum-based plastics, according to a leading American ecotoxicologist.
“The reason why we study these species is because we know
they’re indicators for what is happening to us,” said environmental chemist
Sherri Mason of the State University of New York at Fredonia, whose work has
documented widespread microplastic contamination in
aquatic ecosystems. “People are ingesting microplastics when they eat shellfish
and other seafood.”
In the new study, researchers in France exposed
Pacific oysters for two months to water contaminated with microplastics smaller
than a fifth of an inch across, at a concentration that equalled the amount
found in the Great Pacific Garbage Patch.
They found that compared with oysters grown in plastic-free
water, the exposed oysters produced fewer and smaller egg cells, slower-moving
sperm, and fewer, slower-growing offspring.
“We know that filter-feeder animals, animals that filter water to catch plankton, they are particularly vulnerable to this kind of pollution,” said the study’s lead author, marine biologist Rossana Sussarellu of the French Research Institute for Exploitation of the Sea in Nantes, France. “So we can assume that other shellfish, like clams and scallops, are also at risk.”
The study adds to growing evidence that microplastic pollution
can harm animals at the bottom of the marine food chain and has entered the
human food supply.
“We have a lot of data
indicating that while the microplastics don’t immediately kill organisms, they
can pass them on to other animals,” Mason said. “As they get ingested by other
organisms, say a fish, it’s not able to move as quickly, and it’s going to be
more easily captured by a predator, and then it’s passing on all the plastics
and the toxins that are associated with those plastics to the predator.”
In 2013, researchers reported that lugworms, a burrowing animal
sometimes called the earthworm of the ocean, consumed less food and were less
energetic when they lived in sediment highly contaminated with microplastics.
Scientists found in a 2014 study that when a tiny, freshwater
crustacean called daphnia ate microplastics, 68 percent of its offspring were
malformed.
In another 2014 study, Belgian scientists reported finding
microplastics in mussels and oysters cultivated for human consumption—enough to
expose European consumers to up to 11,000 pieces of microplastic a year.
Researchers last year reported finding microplastics in sea salt
on the shelves of supermarkets across China.
The risks to human health go well beyond the potential gross-out
factor. That’s because microplastics in the environment absorb persistent
organic pollutants that can cause cancer and harm reproductive health,
including PCBs—polychlorinated biphenyls, once widely used in electrical
equipment—and PAHs, or polyaromatic hydrocarbons, which are byproducts from
burning fossil fuels.
In 2015, researchers reported finding microplastics contaminated with
phthalates, brominated flame-retardants, and other persistent pollutants in
more than 18 percent of Mediterranean bluefin, albacore, and swordfish
sampled.
“The plastics become like little poison pills,” Mason said. “As
they are ingested, all those chemicals are ingested,” and once in the moist,
warm confines of an animal’s digestive system, “those chemicals will tend to
de-sorb from the plastic and get stored in their fatty tissues.”
Last year, environmental experts at the United Nations
recommended a global ban on microbeads in personal care and cosmetic products,
citing the harm microplastic pollution is causing to marine life.
Several European nations have called for a EU-wide ban on
microbeads, including the Netherlands, which enacted a ban in 2014.
The Canadian government announced plans to ban microbeads in
July.
Mason’s own work, which has revealed that the Great Lakes are highly contaminated with
microplastics, helped spur Congress in 2015 to pass a federal ban on plastic
microbeads in toothpaste, face wash, and other consumer products. Researchers
have estimated that 8 trillion microbeads enter aquatic
ecosystems every day in the United States alone.
President Obama signed the measure into law, giving companies
nearly two years to fully phase out microbeads.
Mason called it “an incredible first step” but noted that
microbeads are not the major source of microplastic pollution.
Microplastics also form as larger pieces of plastic break down
in the environment. “A plastic bag is in use, on average, for 12 minutes, and
will be alive in the environment for 100 years,” Mason said.
A 2011 study showed that the polyester fleece and other plastic
fabrics shed microscopic plastic fibers when washed.
The researchers behind that study found plastic microfiber contamination on 18
shoreline sites across six continents.
Mason believes solving the microplastics crisis means replacing
most petroleum-based plastics with safe materials. “I think the big movement is
in finding plastics that can come from renewable resources,” she said, and
“truly biodegrade when they’re released in the environment, regardless of where
they’re released.”
“Microplastics are just so incredibly small, and so enmeshed in
the life of the ecosystems where they exist, that you can’t clean up the
plastic without destroying the ecosystem you’re trying to save,” she said.
“You’re mostly talking about letting Mother Nature do what Mother Nature does”
by breaking down contaminants in ecosystems over time.
The Earth “has been here for 4.5 billion years,” she added.
“It’s quite robust in its own way and good at taking care of itself, if we give
it the opportunity. What we have to do is lessen our impact.”
Emily
J. Gertz is an associate editor for environment and wildlife at TakePart.