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Shopping Bag New Zealand |
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Plastic shopping
bags/Carrier bags are a common type of shopping bag
in several countries. They are made of polyethylene
(low-density or more "crinkly" high-density) and are
cheaper and lighter in weight than their paper
counterparts, but lack stiffness. Items shifting
within the bag can cause the bag to fall over and
spill its contents; this can be prevented by placing
rigid items in the sides of the bag to provide
support. The handles of these bags also have a
tendency to lose elasticity and break under the
weight of their contents. Plastic bags hold up
better than paper bags when wet, such as in rain.
Plastic bags are commonly reused as either garbage
bags, or can be recycled along with other plastic
containers.
Plastic bags are notorious for becoming litter. They
are known in several countries by names such as
"Witches' knickers" because of their unpleasant
tendency to blow about and cling to things in the
wind. Most do not biodegrade although increasing
numbers are made from degradable material.
UV-degradable bags are easy to design and
manufacture and manufacturers have also made
biodegradable versions, many using a TDPA additive
to speed up the breakdown of plastic into small
enough parts which can be used as food by microbes
or simply become an inert fraction in humus.
However, the environmental benefits of biodegradable
plastic bags must be balanced against the fact that
they ultimately release CO2 and/or methane (both
greenhouse gases) into the atmosphere.
Because of their light weight, steady winds can blow
them for long distances, and they can become
life-threatening for birds and marine life. It is
now generally regarded that re-using bags is the
most environmental approach. In 2002, Ireland
introduced a 'plastic bag tax' which reduced their
use by 90%. |
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