The environmental issues associated with plastic shopping bags have featured in the news in the last couple of months, following the apparent success of the plastic bag tax in Ireland in reducing the number of plastic shopping bags that are used in that country. While this approach has also been suggested for addressing the problem in Australia, the government will examine a number of options before deciding on a management plan. In the meantime, the best thing we can do for the environment is simply reuse, or better yet, refuse a plastic bag when we go shopping. Easy!
Plastic shopping bags have a surprisingly significant environmental impact for something so seemingly innocuous. As well as being an eyesore (next time you are outside, have a look around - you'll be amazed at the number of plastic bags littering our streets and waterways), plastic shopping bags kill large numbers of wildlife each year. In the water, plastic bags can be mistaken for jellyfish by wildlife. This makes plastic bag pollution in marine environments particularly dangerous, as birds, whales, seals and turtles ingest the bags then die from intestinal blockages. Disturbingly, it is claimed that plastic bags are the most common man-made item seen by sailors at sea.
The biggest problem with plastic bags is that they do not readily break down in the environment, with estimates for the time it takes them to decompose ranging from 20 to 1000 years. One of the disquieting facts stemming from this is that plastic bags can become serial killers. Once an animal that had ingested a plastic bag dies, it decays at a much faster rate than the bag. Once the animal has decomposed, the bag is released back into the environment more or less intact, ready to be eaten by another misguided organism. The incredibly slow rate of decay of plastic bags also means that each bag we use compounds the problem, because the bags simply accumulate.
Plastic bags also clog drains and waterways, threatening not only natural environments but also urban ones. In fact, plastic bags in drains were identified as major factors in the severe flooding in Bangladesh in 1988 and 1998. This has resulted in a ban on plastic bags being imposed there early in 2002.
On top of the significant environmental costs, widespread use of plastic bags is also costly in terms of dollars and cents. Apart from the price of the bags themselves, which is four to six cents each, a great deal of money goes into collecting the bags (ie cleaning up!) once they've been discarded.
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.
Alternatives:-
There are a range of alternatives to plastic bags. Some retailers save the cardboard cartons that stock is packaged in, so customers can use them to pack their groceries. Others may offer paper bags. Some major supermarket chains have string or calico bags available for sale at a very small price. These bags can be kept in the car and used again and again. The advantage of calico bags is that they are stronger than the plastic bags, and also much easier to carry. It takes a little thought to get used to bringing your own bags, but it is an easy habit to fall into and it is such a relief not to have to pack the groceries away, and then find room to pack away the plastic bags as well!
There are of course situations where you can't beat a plastic shopping bag, such as when buying meat or "messy" items. Thankfully, technology is catching up with the need for a replacement for polythene bags. It was recently reported that supermarkets in Australia will introduce biodegradable bags made from tapioca starch in April 2003. These bags will look and feel like polythene bags but will decompose in three months.
So next time you go shopping, hold your head up proudly as you reuse or refuse a plastic bag. You may not be in a rubber dinghy chasing a whaling boat or pursuing ivory poachers, but you have made a contribution to the future of the planet.
No comments:
Post a Comment