Position Papers
Standards
The French Standards organisation, AFNOR, published in July 2007 a Standard for oxo-biodegradable plastics in agriculture.1
A draft standard2 capable of measuring oxo-biodegradation has also been published by the British Standards Institution in 2007.
Oxo-biodegradable plastic can be tested according to American Standard ASTM D6954-04 for Plastics that Degrade in the Environment by a Combination of Oxidation and Biodegradation.
European standard EN 134323 applies only to plastic packaging, and was written before oxo-biodegradable plastics became popular. It is not appropriate for testing oxo-biodegradable plastics because it is based on measuring the emission of carbon dioxide during degradation. Hydro-biodegradable plastic is compliant with EN 13432, precisely because it emits CO2 (a greenhouse gas) at a high rate.
If a leaf were subjected to the CO2 emission tests included in EN13432 it would not be considered biodegradable or compostable!
Another perversity of EN 13432 is that it requires almost complete conversion of the carbon in the plastic to CO2, thus depriving the resulting compost of carbon, which is needed for plant growth, and wasting it by emission to atmosphere.
EN 13432, does not however require that plastics biodegrade during and after composting within any particular time-scale. Paragraph 5 of EN 13432 says: "It is important to recognise that it is not necessary that biodegradation of packaging material or packaging be fully completed by the end of biological treatment in technical plants but that it can subsequently be completed during the use of the compost produced"
This is of course consistent with the behaviour of nature's waste products such as twigs, leaves and straw, which take years to biodegrade fully. It would be impossible to produce compost if these natural products had to be converted to carbon dioxide, during composting.
Also, conversion of organic materials to CO2 at a rapid rate during the composting process is not "recovery" as required4 by the European Directive on Packaging and Packaging Waste (94/62/EC as amended), and should not be part of a standard for composting. Nature's lignocellulosic wastes do not behave in this way, and if they did the products would have little value as soil improvers and fertilisers, having lost most of their carbon.
The Directive does NOT require that when a packaging product is marketed as "degradable" or "compostable" conformity with the Directive must be assessed by reference to EN13432. In the first place although the Directive5 provides that conformity with its essential requirements may be presumed if EN 13432 is complied with, it does not exclude proof of conformity by other evidence, such as a report from a reputable testing institution. Indeed Annex Z of EN13432 itself says that it provides only one means of conforming with the essential requirements. Secondly, EN 13432 does not apply at all to applications other than composting of packaging.
Packaging made from oxo-biodegradable plastic complies with para. 3(a), (b) and (d) of Annex II of the European Parliament and Council Directive 94/62/EC (as amended) on Packaging and Packaging Waste. This Annex specifies the essential requirements for the composition and the reusable and recoverable, including recyclable, nature of packaging.6
Oxo-biodegradable plastic satisfies para. 3(a) because it can be recycled. It satisfies para. 3(b) because it can be incinerated. It satisfies para. 3(d) because it is capable of undergoing physical, chemical, thermal or biological decomposition such that most of the finished compost ultimately decomposes into carbon dioxide, biomass and water.
1. XP T 54-980-1
2. BS 8472
]3. and its US equivalent ASTM 6400. There are also other national equivalents eg in Australia.
4. Annex II para. 3
5. Article 9(2)
6. Para. 1 of EN13432 itself makes it clear that it does not apply to packaging waste which may end up in the environment through uncontrolled means, ie as litter.