An independent life-cycle-assessment (LCA) has revealed that oxo-biodegradable plastic carrier bags and bread bags by UK company Symphony Environmental Technologies performed better or similarly as conventional and other bio-based bags.

The report, conducted by Intertek Group, revealed that Symphony’s oxo-biodegradable bags performed 75% better when compared to conventional bags in the litter category, while in all other categories it got similar results.

Symphony CEO Michael Laurier said plastic litter is a serious problem, which cannot be ignored by calling it a behavioural problem.

"While only 0.75% of plastic carrier bags enter the litter stream each year this amounts to over 48 million bags in the UK alone as estimated in this LCA. The LCA confirms that oxo-biodegradable plastic offers real environmental benefits," Laurier added.

Intertek looked at 11 different environmental impact categories: global warming potential, litter effects, abiotic depletion, acidification, eutrophication, ozone layer depletion, photochemical oxidation, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity and terrestrial ecotoxicity.

In ten of the 11 environmental impact categories, bio-based bags performed worst. The bags got better results than the conventional plastic bag in the litter-effects category but were inferior to Symphony’s oxo-biodegradable bag.

The impact of oxo-degradable plastics in landfill is the same as conventional plastics, with no anaerobic degradation and no emission of methane. The report further confirmed that bio-based bags emit methane in landfills.

The report concluded that bio-based plastic cannot be recycled with conventional plastic as part of a mixed, post-consumer waste stream without compromising the recycling process.

The global warming impact of conventional bags has reduced by 19% with the inclusion of 50% recycled content, the report said. This however has had a negative effect on seven of the environmental impact categories due to extra transportation, as well as the need to make bags thicker and heavier for the same strength.

The report concluded that the best way of reducing the impact of plastic carrier bags is by re-using them, minimising the transportation needed for recycling and making them oxo-biodegradable.