Bolsas plasticas

A report on the production of carrier bags made from recycled rather than virgin polythene concluded that the use of recycled plastic resulted in the following environmental benefits:
* reduction of energy consumption by two-thirds
* production of only a third of the sulphur dioxide and half of the nitrous oxide
* reduction of water usage by nearly 90%
* reduction of carbondioxide generation by two-and-a-half times
A different study concluded that 1.8 tonnes of oil are saved for every tonne of recycled polythene produced.
In addition, plastics manufacture requires other resources such as land and water and produces waste and emissions. The overall environmental impact varies according to the type of plastic and the production method employed.
Plastics productionalso involves the use of potentially harmful chemicals, which are added as stabilisers or colorants. Many of these have not undergone environmental risk assessment and their impact on human health and the environment is currently uncertain. An example of this is phthalates, which are used in the manufacture of PVC. PVC has in the past been used in toys for young children and there has been concernthat phthalates may be released when these toys are sucked (come into contact with saliva). Risk assessments of the effects of phthalates on the environment are currently being carried out.
The disposal of plastics products also contributes significantly to their environmental impact. Because most plastics are non-degradable, they take a long time to break down, possibly up to hundreds of years -although no-one knows for certain as plastics haven't existed for long enough - when they are landfilled. With more and more plastics products, particularly plastics packaging, being disposed of soon after their purchase, the landfill space required by plastics waste is a growing concern.
Plastic waste, such as plastic bags, often becomes litter. For example, nearly 57% of litter found on beachesin 2003 was plastic.
How’s, what’s and where’s of recycling plastic
Plastics are used in a wide range of applications and some plastics items, such as food packaging, become waste only a short time after purchase. Other plastic items lend themselves to be reused many times over.
Reusing plastic is preferable to recycling as it uses less energy and fewer resources. Long life, multi-tripplastics packaging has become more widespread in recent years, replacing less durable and single-trip alternatives, so reducing waste. For example, the major supermarkets have increased their use of returnable plastic crates for transport and display purposes four-fold from 8.5 million in 1992 to an estimated 35.8 million in 2002. They usually last up to 20 years and can be recycled at the end of theiruseful life.
According to a 2001 Environment Agency report, 80% of post-consumer plastic waste is sent to landfill, 8% is incinerated and only 7% is recycled. In addition to reducing the amount of plastics waste requiring disposal, recycling plastic can have several other advantages:
* Conservation of non-renewable fossil fuels - Plastic production uses 8% of the world's oil production, 4% asfeedstock and 4% during manufacture.
* Reduced consumption of energy.
* Reduced amounts of solid waste going to landfill.
* Reduced emissions of carbon-dioxide (CO2), nitrogen-oxide (NO) and sulphur-dioxide (SO2).
Plastic process scrap recycling
Currently most plastic recycling in the UK is of 'process scrap' from industry, i.e. polymers left over from the production of plastics.This is relatively simple and economical to recycle, as there is a regular and reliable source and the material is relatively uncontaminated. Process scrap represents some 250,000 tonnes of the plastic waste arisings in the UK and approximately 95% of this is recycled. This is usually described as reprocessing rather than recycling.
Post-use plastic recycling
Post-use plastic can be described...