Brought together by ocean gyres, this “plastic soup” contains six times (by weight - and rising fast) more micro-plastics than zooplankton. Eighty per cent of this waste was discarded on land and entered the ocean through stormwater drains, rivers and beaches. Nations around the Pacific: North America, Mexico, China and even Australia, all contribute to this deadly cocktail away from the spotlight.

Deadly, because plastic bags kill; and not only from being mistaken as jellyfish or other food items by large animals like turtles and seabirds. Even when plastics are broken down into little pieces by photo-degradation, they continue to kill as they resemble planktonic foods – tiny plants and animals that live in the water column and form the basis of many food webs.

More alarmingly, research has shown that small plastic pieces, also termed nurdles or “mermaid tears”, act like sponges, absorbing pollutants and other harmful substances. When consumed by living organisms and passed along the food chain, the pollutants become “biomagnified” and can reach dangerously high concentrations, a particular risk if / when their host fishes find their way onto our dinner plates.

So, as a mother, marine biologist and environmentalist, I championed Federal Environment Minister Peter Garrett’s April call to phase-out free plastic shopping bags by the end of the year, if necessary with legislation. Unfortunately his call was rejected by all except South Australia. I was especially disappointed by Premier Anna Bligh’s comment: “Ultimately, Queensland wants to see the complete phase-out and ban of non-biodegradable plastic bags, but this will only be possible if a suitable alternative is found…”

Anna, the alternatives are here already, and not limited to “engineering” or “business innovations”. Durable, reusable bags are certainly a great help, “weaning” shoppers off the conventional plastics bags. There are many other constructive steps that each one of us can take. More specifically, for those who have been relying on free plastic bags in their day-to-day kitchen waste disposal at home (and therefore arguing against the phase-out of plastic bags), consider the following: 1) Choose products with little or no packaging, so you reduce the amount of waste and production costs in terms of energy and natural resources; 2) Start composting, so you recycle most of your food and garden waste from the kitchen; even better, keep a few chooks if you have a fair sized backyard; 3) For food scraps that you don’t want to compost (e.g. meat), keep in the freezer till the day before refuse collection, so you avoid odour;

4) Line your kitchen bin with old paper (rather than plastic bags) which can be used to wrap up your garbage before putting into the kerbside bin; 5) Use “biodegradable” plastic bags sparingly and dispose of them correctly to avoid contamination in the recycling stream.

However, the mass replacement of free plastic bags by free, so-called “biodegradable” ones is not a solution for many reasons. There is a wide range of “biodegradable” plastics (e.g. thermoplastic starch, PCAL, PBS, modified PET, etc.), often as blends of renewable materials with petroleum-based products. Yet there are no standards and tests for biodegradable plastics nationally, although they do exist internationally.

The rate and degree of breakdown of plastics vary hugely depending on the constituent polymer and external conditions such as temperature and available oxygen. Degradation is generally minimal in sealed landfills because of the lack of water and oxygen. Breakdown in the marine environment is likely to be slow as well, due to the cooler temperatures. Other adverse environmental risks include pollution in waterways due to increased levels of organic matter, contamination from degradation by-products (e.g. plastic residuals, additives and modifiers such as plasticisers, fillers, catalysts, dyes and pigments). 

Most importantly, I fear that the push for cheap “biodegradable” plastic bags will add to the insatiable demand on our ever-dwindling energy and natural resources, for the sake of pure convenience. I am convinced that continued reliance on “disposables”, the habit of “use once and throw” is not a solution to our environmental problems.

And finally, before you put this in the ‘too hard’ basket, most likely made of, yes you guessed it, plastic, remember that this is a problem that will not go away without our concerted collective effort. Do we really want to simply pass this problem along to our kids and the coming generations? Please think about it.

For more information, check these out: http://www.algalita.org/pelagic_plastic_mov.html http://www.environment.gov.au/settlements/publications/waste/degradables/biodegradable/exec-summary.html http://www.abc.net.au/science/features/indestructibles/ http://science.howstuffworks.com/great-pacific-garbage-patch.htm http://www.greenpeace.org/international/news/trashing-our-oceans/ocean_pollution_animation

Catherine Cheung Education Officer Noosa Integrated Catchment Association