PLA does not create persistent microplastics
First findings from a new meta-study conducted by HYDRA Marine Sciences on PLA in the environment found that in contrast to non-biodegradable polymers, PLA will eventually fully hydrolyze and biodegrade, meaning no persistent particles should remain and accumulate in the environment.
As long as moisture or water is available, the molecular weight and size of PLA fragments will continually decrease, passing the micrometer and nanometer range, until the polymer chains are so short that the material becomes soluble in water and fragments are not particles anymore. These soluble substances, oligomers, and lactic acid monomers are non-toxic and can be biodegraded by microorganisms into biomass, water, and CO2 . No special additives are needed for PLA to degrade via hydrolysis and subsequent biodegradation.
The PLA polymer itself is not toxic. Neat PLA and its oligomers are widely recognized as
non-toxic substances. Lactic acid, the monomer building block of PLA, is classified as Generally Recognized as Safe by the US Food and Drug Administration and EU. Many PLA grades comply with long standing global legislation for food contact requirements in the US and EU.
Additionally, specific grades of PLA have been approved and used for decades in medical applications such as sutures, tissue scaffolds, and drug administration substrates. After use in the body, these PLA polymers are absorbed and degraded by the human body.
Beyond the chemistry, the physical impact on the environment and its organisms caused by the presence of a plastic article made from or with PLA is the same as of other plastics with a similar form or shape, be it as an intact object or as micro- and nanoparticles. However, in contrast to non-biodegradable plastic, which will persist and permanently accumulate as micro- and nanoplastics in the environment, PLA in the environment will hydrolyze into molecules of ever smaller size, becoming soluble and eventually fully
biodegraded (mineralized). PLA’s non-persistency will allow the environment to recover with time, and its potential impacts can be seen as temporary
