What Do Those Recycling Symbols and Codes Mean?

iStock.com/ChrisSteer
iStock.com/ChrisSteer

Earth Day is here again, serving as an annual reminder of the need to reduce, reuse, and recycle our way to a better planet.

When it comes to the last part of that familiar three-”R” mantra, most people know enough to separate certain items from the rest of their garbage, but much of our modern recycling routine remains a mystery. From the recycling symbol itself to what those numbers on plastic containers actually mean, there's a lot you can learn from your trash before it becomes someone else's treasure.

An International Symbol With An Earthy Origin

The universal recycling symbol—three folded arrows that form a triangle, with the head of one arrow pointing to the tail of the next—was created in 1970 by University of Southern California student Gary Anderson as part of a contest tied to the very first Earth Day. Each arrow of the design represents one of the steps in the recycling process: collecting the recyclable goods after use, breaking them down and reforming them, and then packaging new products in the containers.

Originally designed as an inverted triangle, the symbol was later rotated to the pyramid-like orientation commonly used now.

The Number Game

The American Society of Plastics Industry first began using numbers inside the recycling symbols on plastic containers in 1988 as a way to assist with sorting them. The "Resin Identification Code" uses seven numbers to identify the type of synthetic material used to manufacture the container, with the higher numbers representing less commonly used plastics.

Here's a primer on each of the codes:

1. Polyethylene Terephthalate (PETE/PET)
Usually accompanied by the letters "PETE" or "PET," this resin is generally used for soda bottles and other containers for edible and non-edible goods. When it's not being used to manufacture containers, you might recognize it by another name: polyester. (Yes, it's the stuff that insulates your jackets.) It's also one of the most widely accepted forms of plastic in curbside recycling programs, though the amount of useable material available for new products after breaking down this plastic is relatively small.

2. High Density Polyethylene (HDPE)
The second most widely used resin for plastic bottles, HDPE is a stiff, strong material with a high resistance to chemicals, which has made it the go-to plastic for food items like milk and juice, as well as household cleaners and trash bags. It's also easy to break down in the recycling process and easy to reform, making it one of the most efficient consumer plastics. Most curbside recycling programs have no problem with accepting products made from this plastic.

3. Polyvinyl Chloride (PVC)
First discovered in the 19th century, PVC is commonly used in building materials today—especially pipes and plumbing material—due to its strength and chemical resistance (although it's occasionally used for some household products). It has a nasty habit of releasing highly carcinogenic toxins into the atmosphere when it's burned, so recycling is a significantly less appealing option for PVC disposal, and it's usually not accepted by curbside recycling programs.

4. Low Density Polyethylene (LDPE)
This plastic is becoming more common today, especially for manufacturing squeeze bottles and grocery bags. Plastics made from LDPE are usually very strong, and they're regularly used as sealants because of this quality. While they weren't included in curbside recycling programs at first, plastics made from LDPE are now becoming more commonly accepted.

5. Polypropylene (PP)
Regarded as one of the “safest” plastics produced today, PP is generally used for squeezable bottles, bottle caps, and straws. Along with LDPE, it's also used for food-storage containers that can be reused over time. It has an extremely high melting point, so it's one of the best consumer plastics for items that will be exposed to heat. Like LDPE, it's becoming more common for curbside recycling programs to accept items made from this plastic.

6. Polystyrene (PS)
More commonly known as styrofoam, this type of plastic is not only notoriously difficult to recycle, but it's also been shown to leach dangerous toxins over time into anything packaged in it—and even greater amounts of toxins when it's burned. This is the resin usually found in disposable serving trays, egg cartons, and cups, and it's rarely accept by curbside recycling programs due to the danger it poses and the difficulty of recycling it. Basically, this is the worst of the bunch.

7. Everything Else
There are countless other plastics, but very few of them are easily recycled in curbside programs, making this category the catch-all for everything that could conceivably be broken down and reformed, but might be better off reused or reformed in some way that doesn't require a chemical process. This category encompasses everything from bulletproof material to those large water jugs on office coolers, and is rarely included in curbside recycling programs.

Safety In Numbers

For anyone wondering which plastics are safe to reuse in their current form, it's widely accepted that HDPE (2), LDPE (4), and PE (5) can be reused multiple times for edible items, as they're generally resistant to chemicals, haven't been shown to degrade, and don't leach dangerous substances into their contents.

This story first ran in 2013.

New Time-Lapse Shows the Threat Meltwater Lakes Pose to Greenland’s Glaciers

Sean Gallup/Getty Images
Sean Gallup/Getty Images

A historic amount of ice has disappeared from Greenland's glaciers in recent years. During this summer's heat wave in Europe, which scientists linked to climate change, the Greenland ice sheet melted at a rate of up to billions of tons of ice per day. The phenomenon was part of a trend: The previous summer, the Arctic sea ice near northern Greenland broke up for the first time ever. Now, newly published time-lapse footage illuminates another aspect of the dire situation.

As Live Science reports, a British team of scientists captured this video of the Store Glacier in western Greenland on July 7, 2018. It shows a lake of meltwater on the ice rapidly draining in a span of hours. When cracks form on glaciers in the summer, they fill up with water, creating massive, temporary lakes. These meltwater lakes become a problem when the water drains deep into the glacier, where it can damage the base and dislodge ice chunks into the ocean. Melting ice that drifts out to sea is one of the driving forces behind rising sea levels.

In a paper published this month in the journal Proceedings of the National Academy of Sciences, the researchers report that the lake captured in the video flushed more than 1.26 billion gallons of water—the equivalent of 2000 Olympic-size swimming pools, notes Live Science—toward Store Glacier's base even without fully draining. This shows that meltwater lakes that don't drain completely should still be treated as serious threats to ice sheets.

You can check out the complete time-lapse from their study below.

[h/t Live Science]

10 Simple Ways to Waste Less This Holiday Season

iStock.com/Allkindza
iStock.com/Allkindza

According to Washington University in St. Louis, “Americans throw away 25 percent more trash during the Thanksgiving to New Year’s holiday season than any other time of year. This extra garbage amounts to 25 million tons of trash.” Here are a few everyday ideas for reducing waste.

1. Use reusable bags when shopping.


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Before you hit the mall or begin shopping for your holiday groceries, remember to bring along a reusable bag or three. Plastic bags are petroleum-based products and—let's face it—few of us use them more than once, and many end up in our oceans. Make bringing a bag a habit.

2. Send Christmas cards judiciously.


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According to Washington University, the “2.65 billion Christmas cards sold each year in the U.S. could fill a football field 10 [stories] high.” Of course, your grandmother will be delighted to receive a handwritten note—and so may plenty of your friends—so feel free to mail away! But be honest with yourself: If there’s anybody on your list who is probably going to toss your thoughtful note into the trash five minutes later, just send them a digital greeting.

3. Buy light strands that are wired in parallel.

Red and white lights on a Christmas tree.
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Few things are more annoying than watching the whole strand of Christmas lights go dark just because of one cruddy bulb. According to the EPA, strands that are wired in parallel will still work if a bulb bursts, “so you won’t be throwing away ‘bad’ strands.” And if you’re the type of person who worries constantly about whether you turned the lights off, put your displays on a timer: It saves energy, money, and worry.

4. Skip the Secret Santa if you don’t know the people well.

A wrapped present on a desk with a tag that reads "Secret Santa."
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We don’t want to sound like Scrooges here. A gift exchange with your colleagues or acquaintances can be a delightful way to get to know people better. But let’s be real: If you don’t already know the people well, chances are you’ll give—and receive—something that will be thrown away within days. It’s OK to just say no.

5. Quit guessing (and stop other people from guessing about you).

A blank piece of paper labeled "gift list" surrounded by an iPad and candy.
MichellePatrickPhotographyLLC/iStock via Getty Images Plus

Here’s a tip: If you need a second or third opinion on a gift—"Do you think so-and-so would like this?"—don’t buy it. We all love planning a thoughtful surprise, but few things are as wasteful as buying somebody something they don’t want or need. Be forward and ask people what they’d like. And give helpful suggestions when people are shopping for you.

6. Buy experiences instead of things.

The legs and feet of a man and woman taking a dance class.
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Tickets to a concert or game, dance lessons, a reservation at a hotel, and other experiential gifts don’t require wrapping or packing peanuts. Besides, many people insist that they find experiences more meaningful than physical objects (and there are even some scientific studies that back that observation up).

7. Stop wrapping gifts.

A big teddy bear peeking out from behind a wall.
Simona Balconi/iStock via Getty Images Plus

Hide them instead! If you have small children, one of the most fun (or evil) things you can do is create a scavenger hunt. (This also works on adults who have refused to grow up.) Searching for gifts in mundane-yet-unexpected places like a pillowcase, a cookie tin, or in the pocket of a coat buried deep in the attic closet can be more surprising and fun than unwrapping them.

8. If you choose to wrap, use recyclable wrapping paper.

A woman holding a present wrapped in brown paper.
Kikovic/iStock via Getty Images Plus

Every year, millions of pounds of wrapping paper end up in the trash. “Some wrapping paper is recyclable—but it has to be not metallic, textured, or have glitter or ribbon on it,” Tim Donnelly writes in a great guide at Lifehacker. If you do buy recyclable paper, make sure to use it correctly and remove all the tape before recycling it. In fact, why not just skip the tape entirely and bundle the present the old-fashioned way with some string or ribbons (which you’re reusing, right)?

9. Make your own wrapping paper.

Wrapped presents, including one that's wrapped in newspaper.
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If you’re the creative type, gifts wrapped in old catalogs, newspapers, butcher paper, magazines, and other paper products lying around the house can actually look quite handsome. According to one oft-cited statistic, “If every family in the U.S. reused just 2 feet of holiday ribbon, the 38,000 miles of ribbon saved could tie a bow around the entire planet."

10. Don’t pop that bubble wrap.

Bubble wrap on a blue background.
Xiuxia Huang/iStock via Getty Images Plus

We know. This one is nearly impossible—but resist the urge to pop any bubble wrap you receive. Save whatever packaging you get to be used later. (That includes those pesky packing peanuts!)

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