Degradable plastics may not be as environmentally friendly as producers believe, finds research by Loughborough University backed by the Department for Environment, Food and Rural Affairs.
Producers of oxo-degradable plastics regularly tout it as being a solution to the plastic bag litter problem, claiming the plastic is 100% degradable or biodegradable. But Defras report asserts that because it can take two to five years in the open environment to break down, it will still appear as litter until it starts to degrade.
The report also found that the oxo-degradable polyethylene (PE) bags have the same effect on greenhouse gas emissions and the depletion of resources as conventional single-use PE bags.
Assessing the Environmental Impacts of Oxo-degradable Plastics Across Their Life Cycle states that the bags are not suitable for composting because a plastic must biodegrade within six months. Material left over once the plastics begin to degrade could also adversely affect the quality and saleability of the compost, a problem concerning many composters. This could cause confusion among consumers who believe them to be compostable and may lead to contamination in the composting stream.
Plastic recyclers fears that if oxo-degradable plastics enter the recycling stream it will render the product more susceptible to degradation were also confirmed. It recommended that such plastics be kept out of mainstream plastics recycling processes.
Defras environment minister Dan Norris said: The research published today clearly shows that consumers risk being confused by some claims made about oxo-degradable plastics. We hope this research will discourage manufacturers and retailers from claiming these materials are better for the environment than conventional plastic.
Following the research, retailer The Co-operative has decided to stop purchasing carrier bags with the oxo-biodegradable additive.
Oxo-biodegradable plastics producer Symphony Environmental refuted the reports assessment that marketing claims which are typically applied to such materials are potentially misleading.
In a statement it said: It should be obvious that plastic which self-destructs at the end of its useful life, leaving no harmful residues, is better for the environment than normal or recycled plastic, which can lie or float around for decades.