Monday, December 1, 2014

Plastic not fantastic...much

Last week I was surprised to learn that there is a difference between “bio-degradable” plastic bags and “degradable” ones. And here I was cheering on the shift to degradable plastic bags.

According to, the word “degradable” just means that something breaks down. Technically, all plastic is degradable plastic.  You can break it with a hammer. You can grind it into a fine powder.  This all counts as “breaking down” the plastic, and therefore (technically) “degrading” the plastic.

This creates a little bit of confusion, because some plastics will add chemicals that will make the plastic break down faster under certain conditions. For example, you can add an additive to normal, petroleum-based plastic that will make it become brittle and crumble in sunlight: this is referred to as making “photodegradable” plastic. Other additives can be put into plastic that will make plastic break down by oxidation: this is referred to as making “oxo-degradable plastic.”

These methods will make the bulk of the plastic appear to disappear; however, the small pieces (or even find “sand”) that is produced by this effect is still small pieces of plastic.  Nothing has changed. Over a matter of years, it is possible for the pieces to become small enough to be assimilated by microorganisms, but there is still a lot of research that needs to be done to verify how long this might take.  In the meantime, they are just very small pieces of plastic.

So be cautious when you see a plastic product that advertises that it is “degradable” but not “biodegradable” or “compostable,” because this is nothing special.  The plastic material does not “return to the earth” in any real way. It just gets really, really small.

Biodegradable plastic on the other hand, is not just degradable, but it also means something more: it means that it can be broken down by the metabolism by micro-organisms.  When a plastic is biodegradable, it can be digested, so that the carbon atoms in the chains of the polymer are broken apart and can actually participate in the creation of other organic molecules.  They can be processed by, and become part of, organic living things. This returns them to nature in a very real sense: they become part of the carbon cycle of the ecology of the earth.

Only bioplastics will biodegrade within any reasonable timescale.  Petroleum-based plastic that simply breaks down into a fine sand or small pieces still cannot be digested by microorganisms. Perhaps over the time-span of many years, the pieces may get so small that they can be digested by microorganisms. This is currently the focus of a great deal of research and debate, as different groups try to establish how quickly oxo-degradable plastics can be reduced to a form where they are actually biodegradable.

It is also important to note that even some plastics that are made from renewable resources are processed in a way that makes them non-biodegradable.  They are still “degradable” but they do not return to the earth, and cannot be processed by microorganisms. That is why the difference between biodegradable plastics, and non-biodegradable plastics, is so important.

I also happened to find out about a third type of plastic - Compostable Plastic.  When something is compostable, it means that it biodegrades, but it also means something more: it will degrade within a certain amount of time, under certain conditions.  For many types of bioplastic, it’s possible to say that it will break down “eventually”, but if you seal it in an air-tight room, it could take thousands of years.

The standards organizations that regulate materials have come up with a series of tests and benchmarks, saying that if a biodegradable plastic will completely biodegrade fast enough in a certain type of environment, then it can be labelled “compostable.” 

So these three terms aren’t really different “classes” of plastic, in the sense of being separate sets. They are subsets of one another: all compostable plastics are biodegradable, and all biodegradable plastics are degradable.  But be wary of people who make claims about the “degradability” of their product: because not all degradable plastics are biodegradable, or compostable.

As I go for my Stand-Up-Paddle sessions in Laucala Bay I come across so many discarded plastic bags on the beach and in the ocean. Because they are “degradable,” it is very hard to scoop the plastic out of the water. Instead it disintegrates in your hands, before your very eyes, leaving you with the knowledge that it will now end up in the stomach of a fish and then enter the web of life in the ocean.

With all that we are doing to our planet, the disrespectful way we are treating creation, can we take a moment to make educated, careful and positive decisions to take just one simple step, which will begin to restore the balance of nature – take your own bags for shopping (especially the recycled kind).   And find out, if the plastic that is being used is truly “bio-plastic”. If it is not.. perhaps you can educate others on the importance of knowing the difference.

“Simplicity, Serenity, Spontaneity”


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