31 Aug 2018 - In a world that can seem overwhelmed by potentially eternal plastic waste, are biodegradables the ultimate solution? Probably not. But it’s complicated. The industry is still debating what “biodegradable” actually means. And some plastics made of fossil fuels will biodegrade, while some plant-based “bioplastics” won’t.
Biodegradable plastics have been around since the late 1980s. They initially were marketed with the implied promise that they’d somehow disappear once they were disposed of, just as leaves on the forest floor are decomposed by fungi and soil microbes. It hasn’t quite worked out that way.
Biodegradables don’t live up to their promise, for example, in the dark, oxygen-free environment of a commercial landfill or in the cool waters of the ocean, if they should end up there. You can’t throw them in your backyard compost either. To break down, they require the 130-degree heat of an industrial composter. Many industrial composters accept only plastics that meet certain standards, ensuring they will leave no fragments behind that can harm the environment or human health. And if you throw some biodegradables in with recyclables, you might ruin the latter, creating a mix that can no longer be relied on to make durable new plastic.
In 2015 the United Nations Environment Programme wrote off biodegradables as an unrealistic solution that will neither reduce the amount of plastic flowing into the oceans nor prevent potential chemical or physical harm to marine life. It concluded that the label “biodegradable” may actually encourage littering.
Some engineers are looking for ways around these obstacles. Jenna Jambeck and her colleagues at the University of Georgia’s New Materials Institute are using polymers synthesized by microbes to make packaging they hope will compost readily and biodegrade in the ocean. Corn chip bags are their first target.
Polymateria, a British firm, is taking a different approach, developing chemical additives to help biodegrade any plastic—bio based or synthetic—more quickly. The firm aims to be the “Tesla” of biodegradable plastics; CEO Niall Dunne says the goal is a product that will “harmonize plastics with the biosphere.”
It’s a tall order. Even the best biodegradable product won’t magically disappear. A plastic container robust enough to carry a gallon of milk can’t decompose like paper. A flowerpot, one of Polymateria’s experimental products, could take up to two years to dissolve if tossed in a ditch, Dunne concedes. Biodegradables, some critics say, don’t address the fundamental problem: our throwaway culture.
“What is it that we are promoting?” asks Ramani Narayan, a Michigan State University chemical engineering professor. “Throw it away, and eventually it will go away?” The more responsible approach, he says, is a “circular economy” model, in which everything is reused or recycled and “any ‘leakage’ into the environment, whether biodegradable or not, is not acceptable.”
Norway has shown how far the recycling of plastic bottles—a big part of beach trash—can go. It now recovers 97 percent of them. Its trick: deposits as high as 2.5 kroner (32 cents) and machines, found at most supermarkets, that ingest bottles and spit out refunds.
But recycling can go only so far. Part of the solution, many say, must be to use less disposable plastic in the first place. The “zero waste” movement, which dates to the mid-1990s, is gaining favor. Hundreds of communities worldwide are embracing it—including the downtrodden industrial town of Roubaix, France, where the success of a citizens’ campaign shows that zero waste is more than an affectation of wealthy liberals.
On the contrary, the idea seems to have a cross-cutting, almost spiritual appeal. In the U.K., the Church of England asked its flock to give up plastic packaging and disposables for Lent this year. Conservative Prime Minister Theresa May called for supermarkets to set up plastic-free aisles, where food is sold in bulk. She’s also considering a tax on single-use plastics such as take-out containers. It’s all part of her government’s campaign to rid the country of plastic waste within 25 years.
China is providing motivation. For nearly three decades it has bought about half the world’s recyclable plastic. But this year it called a halt to most scrap imports. Recyclables are now piling up in the countries that generated them. “That pushes the question upstream,” Jambeck says. “We hope it will push towards more circular management.”
Six Things You Can Do (and Feel No Pain)
1. Give up plastic bags. Take your own reusable ones to the store. A trillion plastic shopping bags are used worldwide every year, and 100 billion in the United States alone—that’s almost one per American per day. The average Dane, in contrast, goes through four single-use bags per year. Denmark passed the first bag tax in 1993.
2. Skip straws. Unless you have medical needs, and even then you could use paper ones. Americans toss 500 million plastic straws every day, or about 1.5 per person.
3. Pass up plastic bottles. Invest in a refillable water bottle. Some come with filters if you’re worried about water quality. A handful of cities, including Bundanoon, Australia, and San Francisco, have banned or partially banned bottled water. But around the world, nearly a million plastic beverage bottles are sold every minute.
4. Avoid plastic packaging. Buy bar soap instead of liquid. Buy in bulk. Avoid produce sheathed in plastic. And while you’re at it, give up plastic plates and cups. The French are (partially) banning the stuff.
5. Recycle what you can. Even in rich countries, recycling rates are low. Globally, 18 percent of all plastic is recycled. Europe manages 30 percent, China 25—the United States only 9.
6. Don’t litter. The Ocean Conservancy has run beach cleanups for 30 years. Of the top 10 types of trash they find, the only nonplastic item is glass bottles. Worldwide, 73 percent of beach litter is plastic: cigarette butts (the filters), bottles and caps, food wrappers, grocery bags, polystyrene containers. In 2016 the conservancy collected 9,200 tons of trash in 112 countries—around a thousandth of what enters the ocean each year.