PLA showed no measurable biodegradation after 428 days submerged in seawater, while cellulose-based fabrics degraded in roughly 30 days. The authors state directly that calling compostable plastics 'biodegradable' is misleading, because it implies a material that breaks down in the environment when PLA does not.
Researchers at Scripps Institution of Oceanography submerged PLA, cellulose-based and blended textiles in natural seawater off the Scripps Memorial Pier and tracked them for 428 days, alongside closed-respirometry mineralisation testing. Natural cellulose fabrics broke down within about a month; the PLA samples did not.
