The toxic legacy of plastic bags

Ian Kiernan, ABC News 25 Jan 08;

At the heart of arguments against introducing a ban on the damaging common plastic shopping bag lies a stubborn refusal to consider anything other than the economic costs of keeping them.

Plastic bags are cheap to make and cheap for shops to buy. We have become used to the convenience of them and think they make our lives somehow easier.

But our easy addiction to plastic bags is destroying our environment, killing our marine life and birds, and is so pervasive and persistent that it is entering the food chain.

How can those who assess plastic bags simply on their economic merits ignore the impacts of the waste left behind? How can any of us afford not to?

In the half dozen decades since plastic became a regular part of our lives and plastic bags a common sight, the natural environment has become full to bursting with plastic rubbish.

Plastic doesn't go away - it breaks down into smaller and smaller pieces but it never actually dissolves or disappears completely. Much of it ends up in our oceans.

In the middle of the Pacific Ocean, near Hawaii, lies a floating garbage patch twice the size of Britain. It is a place where the water is filled with six times as much plastic as plankton. This plastic-plankton soup is entering the food chain and heading for our dinner plates.

Plastic bags are mistaken as food and consumed by a wide range of marine species, especially those that consume jellyfish or squid, which resemble plastic bags when floating in the water column.

There have been international studies done on the impact of plastic on marine life and birds but unfortunately the statistics on the dead and maimed are often only estimates as it is almost impossible to track where all plastic bags end up and observe what happens to every whale, dolphin and turtle that swallows them.

Stomach-churning

What scientists do have are the contents of marine mammals' stomachs when they wash up dead on our coastlines.

A total of 177 marine species are known to ingest plastic litter. Ingestion of litter such as plastic bags can cause physical damage to the oesophagus, mechanical blockage of the digestive system, and a false sensation of feeling full. This can lead to infections, starvation and death.

In August 2000, an autopsy of an eight-metre bryde's whale beached at Trinity Bay near Cairns revealed a tightly compacted ball of plastic debris in the animal's stomach. The contents included 33 different items made up mainly of plastic bags, as well as noodle packages.

In total there was nearly six square metres of plastic in the whale's stomach.

Sea turtles are especially affected by the presence of plastic debris. They ingest different types of floating objects including condoms, balloons and fishing line, as if they were food.

In 1998, an autopsy carried out on the body of a juvenile green turtle found washed up on Lennox Head Beach in northern NSW revealed a complete bowel blockage caused by a piece of black plastic the size of an open palm.

Above the blockage food putrified and slowly poisoned the animal to death.

The Federal Government's own Threatened Species Scientific Committee has found plastic bags and other marine debris are a direct threat to 20 marine species, including the loggerhead turtle, southern right whale, blue whale and tristan albatross. It has listed plastic bags as a Key Threatening Process under the Environment Protection and Biodiversity Conservation Act 1999.

Public support

Eighteen years of Clean Up Australia Day has clearly demonstrated the impact plastic bags are having on the environment.

A survey of the rubbish collected is done each year and plastic bags are among the most common plastic items found on Clean Up Australia Day year after year.

More than half of the tens of thousands of plastic bags collected on Clean Up Australia Day are found on beaches, waterfront areas, in rivers and creeks.

Two national opinion polls in a row have shown overwhelming public support for a ban on plastic bags in Australia and a growing number of communities are introducing their own bans.

The only harm involved in a ban on plastic bags is not doing it.

Introducing a levy on plastic bags has now been shown to not work. In Ireland, a levy produced a dramatic initial decrease but we now know that people simply became used to paying the levy, which led to an increase in plastic bag use by one third in just two years.

There are alternatives to the common single-use plastic bag and the most encouraging progress is being made with biodegradable bags, often made from cornstarch.

But of course you could just not use a plastic bag at all - just as using a plastic bag is a habit, so too would not using one become.

Ian Kiernan AO is chairman of Clean Up Australia and Clean Up the World.