Sustainable End-of-Life Options for Plastics in New Zealand

4.2.4 Cons
• The cost of deriving raw materials/processing and handling.
• Most degradable plastics are organic, so to decompose, biodegradable and compostable plastics
require the right environment. Lack of oxygen, nitrogen and in some cases sunlight, may cause
serious odour and insect problems, and/or leach harmful chemicals. These types of repercussion
suggest degradable materials are unsuitable for landfill disposal.
• There is high risk of contamination of recyclable non-degradable plastics if product-handling is not
controlled properly.
• Currently there is no requirement for degradable plastic products in New Zealand to be labelled
under a standard system (international standards exist: for example, the European Norm, EN
13432:2000, defines four characteristics a material must display in order to be described as
‘compostable’); or regulation for specifying the degree of degradability. Standards that are used
are mainly ASTM (American Society for Testing Materials) standards for manufacturing degradable
plastics.
• The collection and sorting infrastructure is not in place throughout New Zealand.
4.2.5 Measure of Degradability
The most important factor concerning degradable plastic materials is the level of degradability they
can reach over a specified time period. All plastics have the ability to degrade when put in the right
environment. The variables that cause degradation include temperature, humidity, pressure and
chemicals. Some plastics partially degrade, e.g. bio/hydro/photo-degradable materials, and break
down into small fragments of plastic. Others, such as 100% compostable plastics, completely
decompose.
• Key questions to ask about the safety of plastics degradation are:
• Where will the product be used/reside
•Will there be any potential effects on the environment
•Will hazardous chemicals be formed once the polymer chains in the molecular structure of the
material break
4.2.6 Developments in NZ
Although still a small proportion of the market, there are currently a number of developments in the
plastics industry involving the use of degradable materials. Large plastic-production companies such
as Vertex-Pacific, Elldex and Huhtamaki are investigating innovative materials and are manufacturing
degradable products.
An example of an event that helped introduce compostable plastics products to the NZ public, was
when Vertex manufactured water cups from PLA to be used for the Auckland Round the Bays annual
‘fun run’ event in March 2005. They then worked with the Waitakere City Organic centre and Perry
Environmental to compost the material. For more information, visit:
http://www.plastics.org.nz/_attachments/round-the-bays-2005.doc.
Alternative End-of- Life Options
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