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.
