Is PLA packaging harmful to the environment?

Bioplastic: it takes a long time to break down

Environmental pollution from plastic waste is currently on everyone's lips - whether it is rubbish islands in the oceans or microplastics in the fields. Since it is not possible to do without plastic packaging everywhere, more and more biodegradable plastics are now being produced, which are supposed to have less impact on the environment. But their use is also controversial: Although biodegradability helps in the fight against long-term littering of the environment, it could at the same time lead to an even more careless handling of packaging waste and careless throw-away behavior, which would pollute the environment even more.

The Federal Environment Agency has therefore commissioned an expert opinion in which materials, products and standards of biodegradability are described and the recycling of the relevant waste in five member states of the EU is comparatively presented. Scientific publications on the topic were also evaluated. The result: Even biodegradable materials remain in the environment for several months to years. The 150-page manuscript was created by three researchers from the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT in Oberhausen together with three experts from BiPRO GmbH in Munich and is available online as a free download.

Microorganisms break down plastic

According to the report, the share of bioplastics in global plastics production is now 1.3% - and the trend is rising. According to the definition, a plastic is biodegradable if it is decomposed into carbon dioxide, water, mineral salts and biomass by microorganisms under the supply of oxygen, or if it can be converted into carbon dioxide, methane, mineral salts and biomass without the supply of oxygen. It should be noted that not all bio-based plastics are biodegradable and at the same time not all biodegradable plastics are bio-based.

Dismantling can take up to two years

The biodegradation of polymers takes place in two stages: The first, rate-limiting step is hydrolysis of the polymer chains into smaller fragments. These are mostly water-soluble and can be taken up by cells and broken down further. As the report shows, the polymers need at least six weeks to almost two years for their degradation, depending on the temperatures, the oxygen supply and whether they are degraded in the soil or in fresh or sea water.