Study casts doubt on biodegradable plastic
A study has found polylactic acid (PLA), a so-called biodegradable plastic, does not biodegrade quickly in the marine environment, even after a year underwater.
The experiment by Parley science advisor Dr Sarah-Jeanne Royer and colleagues of the UC San Diego Scripps Institution of Oceanography compared PLA with other plastics and natural fibres in the ocean.
The analyses were complemented by bio-reactor tests.
Results showed that polylactic acid does not degrade in the marine environment for over 428 days.
This was also observed for the oil-based polypropylene and polyethylene terephthalate, including their portions in cellulose/oil-based plastic blend textiles.
In contrast, natural and regenerated cellulose fibers undergo complete biodegradation within approximately 35 days.
Dr Royer said: “The results on polylactic acid stress that compostability does not imply environmental degradation and that appropriate disposal management is crucial also for compostable plastics. Referring to compostable plastics as biodegradable plastics is misleading as it may convey the perception of a material that degrades in the environment.
“Advances in disposable textiles should consider the environmental impact during their full life cycle, and the existence of environmentally degradable disposal should not represent an alibi for perpetuating destructive throw-away behaviours."
