Ask G

Ask G: Are there biodegradable plastics?

Plastic can have a big impact on the environment, so are there green alternatives?

A recent article on the amount of plastic floating in the doldrums of the Atlantic and Pacific Oceans had me making a New Year's resolution to limit my use of plastic-wrapped goods. Do you have information on the products which use recycled plastic or bioplastic?
—— Jenny, SA

Plastic rubbish

Credit: iStockphoto

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The huge floating patch of debris in the North Pacific Gyre - also known as the 'great pacific garbage patch', the 'plastic soup' or the 'pacific trash vortex' - has been getting a bit of press lately.

It's the result of ocean currents, litter, flotsam and jetsam, and the durability of plastic.

If you litter plastic bags, chip packets and other rubbish then you're potentially contributing to similar floating rubbish dumps.

The concern is more about the materials used to make plastic film and their degradability.

Green is not always black and white, and plastics are a case in point. They're complex materials with complex environmental impacts.

Plastic can be made from petroleum-based virgin plastic, recycled plastic or plant-derived 'bioplastics'. Some products use a blend of bioplastics and petrochemical plastics.

Many people assume that all bioplastics are biodegradable and, conversely, that all petrochemical plastics are not biodegradable.

The reality is more complicated. For starters, degradability is not one clearly defined simple product feature - plastics can be 'degradable', 'biodegradable', 'photodegradable' and/or 'oxodegradable'.

Degradability also depends on where the plastic ends up, be it land, landfill or aquatic environments. The Plastics and Chemicals Industries Association (PACIA) is working with the Australian Government to clear up some of the confusion surrounding plastics and degradability.

What to look for
There's currently no simple eco-label for plastics.

But in this age of green consumerism, product manufacturers are eager to brag about whatever eco-credentials they may have, so they are likely to state "made with recycled content" if they are.

Look for specific statements about what the plastics are made from and under what conditions, as well as their type of degradability.

Note that there is an Australian standard for biodegradable plastics (AS 4736-2006) and a similar European standard (EN 13432) that may be mentioned in statements about biodegradability.

Plant-derived alternatives to petrochemical products are not without their environmental issues. They're still an investment of energy, water and agricultural resources.

A key principle for becoming more sustainable is to avoid unnecessary consumption, so your New Year's resolution to limit or reduce your use of plastic wrap is right on target.

A reusable lunch box is an alternative to disposable cling wrap.