Oxo-degradable plastics. Many of you have probably already heard of them. They are claimed to be biodegradable, although not everyone agrees. Currently the European Commission is considering a possible ban on oxo-degradable carrier bags. Also in France a group of MPs in the French National Assembly have called for a similar ban.
Last year, OWS performed a large desk research study for Plastics Europe on the benefits and challenges of bio- and oxo-degradable plastics. A copy of this study can be found here. Key aspect of this study was the evaluation of the validity of the existing claims on biodegradability of oxo-degradable plastics, from which it could be concluded that independent proof (or disproof) is today not (yet) available.
In his context, OWS, together with IKT-University Stuttgart, is setting up a multi-client project with the aim to find a “once and for all” (independent) answer on whether oxo-degradable plastics are biodegradable or not. To make this study as objective and neutral as possible, they are aiming at a broad participation including government agencies, consumer goods producers, NGO’s, oxo-degradable producers, bioplastic industry.
Proponents of oxo-degradable plastics argue that by breaking down the long carbon-hydrogen bonds and reducing the plastic's molecular weight, the molecules become 'wettable' and able to sustain a biofilm on the surface supporting microorganisms, which then consume the molecules and reduce the plastic into water, carbon dioxide, and reusable biomass.
However, lacking proof from independent laboratories or certification bodies that this process actually occurs, critics of these materials doubt whether complete biodegradation takes place. Experts fear that these fragments will disperse into the environment, causing further problems with microplastic waste, particularly when they are used in agricultural applications, like plastic mulch film, and incorporated into the soil at the end of life.
As ultimate biodegradability has not been demonstrated for these fragments, there is substantial risk of accumulation of persistent substances in the environment. Small plastic fragments may also ends up in water ways, thus polluting our oceans.
Fully biodegradable agricultural mulch film comply with Australian standard, AS 4736-2006, and international standards, such as EN 13432.