Production of plastic bags
Plastic bags are made from ethylene, a gas that is produced as a by-product of oil, gas and coal production. Ethylene is made into polymers (chains of ethylene molecules) called polyethylene. This substance, also known as polyethene or polythene, is made into pellets which are used by plastic manufacturers to produce a range of items, including plastic bags.
You have probably noticed that there are two types of plastic shopping bags - the lighter, filmy bags you get from supermarkets and other food outlets, and the heavier bags you get from other retail outlets, like clothing stores. The supermarket bags are made from high density polyethylene (HDPE), while the thicker bags are made from low density polyethylene (LDPE). Unlike HDPE, LDPE can not be recycled.
While plastic bags may not be the most high tech application of plastics technology, it is certainly one of the most prevalent. According to Clean Up Australia, Australians use in excess of 6 billion plastic bags per year. If tied together these bags would form a chain that is long enough to go around the world 37 times. More than half of these bags (3.6 billion) are made from HDPE.
Management of plastic bag usage
With this number of plastic bags in circulation, it is of little surprise that plastic bags are a significant pollutant. On Clean Up Australia Day in 2002 nearly half a million plastic bags were collected.
Different countries have adopted a range of approaches to discourage the use of plastic bags in an attempt to cut down on the number of bags finding their way into the environment. In South Africa for instance, where an estimated eight billion plastic bags are used annually, the government has implemented new regulations that will see only thicker, more durable plastic bags produced. As well as making them more suitable for reuse, it is hoped that the extra cost associated with their production and supply will prevent retailers giving the higher quality bags away, making their use a more expensive option for consumers.
The use of plastic bags is being discouraged in other countries such as Singapore and Taiwan, while the tax imposed on the use of plastic shopping bags in Ireland has resulted in the use of plastic shopping bags being reduced by 90% in just six months. Prior to the 15 euro cent per bag tax, it was estimated that 1.2 million plastic shopping bags were being handed out in Ireland per year. The money raised from the tax will be used to fund environmental initiatives.
We'll have to wait and see if any of these measures will be adopted in Australia to address the problem here. In September 2002 federal Independent MP Peter Andren and Greens Senator Bob Brown introduced private member's bills into parliament that would put a 25 cent levy on plastic shopping bags, and direct the funds raised to an education program publicising the environmental costs of plastic bags in Australia. This bill was not passed, with the Minister for the Environment and Heritage Dr David Kemp preferring to explore voluntary options for plastic bag control, before imposing another tax on the Australian public.
One of the key voluntary options currently being trialed is the National Packaging Covenant, a self-regulatory agreement between government and industries in the packaging chain that was established in 1999. Over the five year period of the agreement, signatories will aim to minimise the environmental impacts of consumer packaging waste and develop sustainable recycling collection systems. To date there are over 500 signatories to the covenant, representing government, industry and business interests.
While Canberra decides on a national plan of action to reduce the problem of plastic bag pollution, it's easy to put a household action plan in place. http://www.abc.net.au/science/features/bags/default.htm
 |
No comments:
Post a Comment