In a Landfill, How Long Does Trash Really Last?

We’ve all been there—at the beach, empty beer bottle in hand, a trash can, but no recycling bin in sight. So we dump the bottle in the normal trash, perhaps feeling guilty we weren’t able to recycle it, perhaps not. Most likely, we rapidly forget about it—out of sight, out of mind, and onto the next beer.

The bottle, like the rest of our trash, may slip easily from our hands and minds, but it doesn’t leave our collective refuse piles so quickly. Landfills, which are lined with clay and plastic, layered with soil, and capped, are not extremely hospitable when it comes to microbial degradation. The three necessary components for decomposition—sunlight, moisture, oxygen—are hard to come by in a landfill; items are more likely to mummify than to break down.

But how long do things last? These rough estimates, compiled from U.S. National Park Service, United States Composting Council, New Hampshire Department of Environmental Sciences, and the New York City government, give an idea of how long our consumables remain after we’ve kissed them goodbye.

Glass Bottle—One Million Years
Okay, we don’t really know whether a glass bottle takes a million years, two million years, or a million years and one day to degrade since no one has been monitoring them for that long. But suffice it to say, when a glass bottle isn’t recycled, it sticks around for a really, really long time. Glass is primarily of composed of silica—the same material as sand—and doesn’t break down even under the harshest environments. Given the relatively inert conditions of a landfill, it’s likely the bottle of beer our forefathers sipped is still at large.

Plastic Bags—Unknown, Possibly 500+ Years
Plastic bags also have a hard time decomposing; estimates range from ten to twenty years when exposed to air to 500–1,000 years in a landfill. Since microbes don’t recognize polyethylene—the major component of plastic bags—as food, breakdown rates by this means in landfills is virtually nil. Though plastic bags can photodegrade, sunlight in landfills is scarce. Made with petroleum and rarely recycled, many cities have banned them in order to curb consumption and prevent their long-lasting presence in litter (e.g., the Great Pacific Garbage Patch—an island you don’t want to visit).

Plastic Beverage Bottles—Unknown, Possible 500+ years
Bottles face the same problem as plastic bags. Most soda and water bottles are composed of polyethylene terephthalate (PET), a petroleum-based product that tends to last a long time in a landfill. Even newer bottles that claim to be biodegradable or photodegradable may take much longer than advertised. According to the Air and Waste Association, biodegradable plastics made with the addition of starch may just simply disintegrate into smaller non-degradable pieces: they don’t break down; they break up.

Aluminum Can—Eighty to 200 Years
According to the Container Recycling Institute, we sent 55 billion aluminum cans to the landfills in 2004, an amount that has increased by 760 percent since 1972.

Cigarette Butt—One to Five Years
The Ocean Conservancy found that during coastal cleanups, cigarette filters and butts were the number one source of litter. While certainly they’re better off in a landfill than underfoot at the shore, their composition makes them particularly resistant to breakdown both in nature and in a landfill. Though the filters look like cotton, almost all are made of cellulose acetate, which is slow to degrade.

Newspaper—Two to Four Weeks or Longer
Paper, including newspaper, seems like one of those items that although recyclable, would also break down quite nicely when mixed in a landfill. Theoretically it can, but because microbial decomposition is so stifled in landfills, paper takes much longer to decompose there than under normal conditions. Or so discovered William Rathje, a professor of archeology at the University of Arizona, who started the Garbage Project—digging through landfills to find clues about consumer behavior. While there, his team found legible newspapers more than fifteen years old, indicating decomposition in landfills doesn’t occur as it would in a compost heap. They also discovered that newspapers made up the largest single item by weight and volume in the landfills studied.

Apple Core—One to Two Months or Longer
If tossed in a composting bin or outside, an apple core might take weeks or months to break down. However, the Garbage Project discovered easily identifiable food and yard waste that were years old. They estimate that food in landfills does degrade, but at a very slow rate—about 50 percent every twenty years. Even yard waste, by definition biodegradable, was found intact years later.

So what does it all matter if stuff stays in landfills indefinitely? Limited space, for one thing—finding a suitable spot for a landfill can be difficult, especially since they are a classic case of NIMBY (Not in My Backyard). Though they can be covered and made into something else—both John F. Kennedy and La Guardia Airports were built on landfills—the process is long and fairly expensive. Perhaps most importantly, reducing the amount of stuff we consume, reusing what we already have, and of course, recycling, doesn’t just mean less trash, it also means less primary resources—oil, trees, water, etc.—that have to be used in the first place. But while most of us are familiar with recycling programs, the EPA estimates that the bulk of our garbage is made up of items that can be recycled or composted—40 percent of it is paper, 17 percent is yard waste, 8 percent is plastics, and 7 percent is food waste. Seems like something ain’t working. Perhaps to be truly effective, recycling won’t just mean more places to put your beer bottles, it’ll mean making the trash can the alternative, rather than the norm.

Original here