October 15, 2019

Why “Green” Plastics Aren’t Any Better

Manufacturers are catching on that people don’t really want single-use plastics. To offer an “eco-friendly” option they developed bioplastics, compostable plastics, and biodegradable plastics.

But what do these terms mean? Are they any better than regular plastic? Or are they a more expensive, newer version of the same old plastic?

What is Bioplastic?

Bioplastics are plastics made from plants or other biological material, unlike regular plastic which is made from petroleum (i.e. oil).

The two most common types are:

PLA (polylactic acid) made from starchy sugars
PHA (polyhydroxyalkanoate) made from microorganisms

Don’t worry, there won’t be a chemistry quiz later. PLA is used in food packaging and PHA is used in medical devices, like sutures.

Bioplastics can break down over time. Thus, they are advertised as a greener alternative, unlike petroleum-derived plastics which will never fully break down. Even with this ability, PLA only breaks down in high temperatures and can take up to 6 months to fully degrade.

What Does Biodegradable Mean?

Biodegradable means a material that can break down using living organisms such as bacteria, algae, or fungi. Unlike composting, there is no time limit to the process and items that leave toxic residues can be added.

What About Compostable?

Compostable means a material that can break down into carbon dioxide, water, and plant (or animal) material through a naturally occurring process. Because compost is used to return nutrients back into the soil, items that can leave toxic residues should not be added to compost. Generally, there is a time limit to the composting process dictated by how long it takes fibrous materials to fully break down.

The confusing part is, some bioplastics are not biodegradable or compostable. Biodegradable does not mean it is compostable. And to top it off, nearly none of these items are actually composted in curbside pickup programs because they take too long to break down. Also, they add no nutrients, and thus no value, to the compost. So, if it looks like plastic, it gets picked out and throw into the landfill.

When compostable plastics go to the landfill, they do not break down there either. Compostable plastics need air, heat, sunlight, and moisture to break down. In a landfill, trash is continually compressed and essentially entombed. Without exposure to air, heat, and other elements, compostable plastics are preserved.

Compostable plastics also can’t go into recycling. Since it is structurally different from regular plastics, it’s considered a contaminant and weakens the integrity of the recycled plastic material.

In a marine environment, biodegradable and compostable plastics have the same problem as regular plastics. They break down into smaller and smaller pieces and get absorbed or eaten by sea animals.

The 5 Gyres Institute sampled several compostable, biodegradable, “green” plastics, buried some in their backyard, and sank others to see what would happen. Sure enough, nearly every item did not fully breakdown during a duration in which they should have.

Sunken Compostables Test Crate – photo by @5gyres

As shown below, even paper cups, which have a plastic lining, leave plastic behind.

Compostable Cold & Hot Cups Breaking Down – photo from 5 Gyres BAN List 2.0

What About BPA?

What is BPA? Bisphenol A, BPA, is a chemical used to harden plastics. It coats the inside of food and beverage cans, is embedded in thermal printed receipts, and used in medical devices.

If BPA stayed within the plastic, then I wouldn’t be writing about it. Unfortunately, BPA leaches from the plastic and into whatever it contacts. We think of plastic as inert surfaces but in reality, plastic acts as a sponge, soaking in and spilling out chemicals it comes in contact with. The more acidic or fatty the substance it contacts, the more BPA it pulls out.

One study showed that people who touched a thermally printed receipt after using hand sanitizer absorbed 10 times more BPA than someone who used no hand sanitizer.

Because the structure of BPA is similar to hormones like estrogen, scientists believe it can disrupt normal hormone function. BPA has also been linked to cancer, brain development issues, heart problems, and etc. Although we absorb small amounts, the cumulative effect of years of small exposures is still unknown.

Are “Green” Plastics Any Better?

Back to “green” plastics, biodegradable, bioplastics, and compostable plastics are not necessarily BPA-free. What’s marketed as an eco-friendlier and safer alternative to regular plastics ends up not really being any safer or eco-friendly. Adding a picture of a green leaf does not make it safe for humans or the Earth.

So, the point is, just like the composting facilities, if it looks like plastic, just avoid it. Regular plastics, bioplastics, and whatever new green plastic they come up with next will not degrade in a cold marine environment or airless landfill–they will continue to persist in and cause damage to the environment. So, choose reusable options.

Finally, if you have the purchasing power at your office. DO NOT buy compostable plastics thinking you’re making your office greener. The best options are to provide reusable utensils, or don’t provide anything at all and encourage employees to bring their own.