Is plastic ever really biodegradable

Why is this important? The plastic pollution highlighted by the Blue Planet TV Program is plastic that was not recycled or incinerated or put in landfill. If it had been it would not be in the oceans. It’s litter. The same applies to litter in Britain. I believe that the only solution it to make sure that packaging is fully biodegradable. But that leads to problem of what to we mean by biodegradable. There is a lot of Greenwash in this area.

Let’s start with a definition.

Biodegradable: capable of being broken down especially into innocuous products by the action of living things such as microorganisms[1]

The problem is that capable does not mean it will breakdown. To quote Jacqueline McGlade, chief scientist at the UN Environment Programme. “It’s well-intentioned but wrong. A lot of plastics labelled biodegradable, like shopping bags, will only break down in temperatures of 50C and that is not the ocean. They are also not buoyant, so they’re going to sink, so they’re not going to be exposed to UV and break down”[2]

If they need to get to 50oC that will also not happen in the British countryside, not even this Year.

Is compostable an alternative term? Again, this may only work at temperatures above ambient. So, I think compostable can be as misleading as biodegradable.

So, what is the alternative. The best solution is to eliminate single use packaging. But this is utopian. So what alternatives are there.

For some uses paper bags are a good solution. Where paper bags do not work there are alternatives which claim to work but the question I ask is do they breakdown in the environment be that the ocean or the countryside, or even the city.   These alternatives include cellophane and “plastic” made from corn or potato starch.

Searching the web finds lots of products but are they really the solution. I do not know. The term “Home Compostable” look promising but I fear it could become greenwash.

Greenpeace have a useful video here on plastic packaging.

For the more technically minded one informative link is The truth about bioplastics by Renee Cho, Earth Institute, Columbia University  from Phys.org

Ian Caldwell