Comments on biodegradable plastics (besides compostable)

Biodegradation in open environments:

EUBP would like to stress that biodegradation in the open environment is not a waste management option. In order to claim a product’s biodegradability, the ambient conditions must be specified, and a timeframe for biodegradation must be set to make claims measurable and comparable. This is regulated in applicable standards. Biodegradability in the open environment (especially marine) is “desirable” only for very few, highly specific, applications. These could be applications that would be difficult to find and recover, such as firework casings, or applications intended to be used by professionals (e.g., farmers or fishermen/fisherwomen) under specific circumstances.

Therefore, we strongly advise that biodegradation should be regarded as a ‘system property’ only insofar, as it refers to the intended receiving environment. The mere eventuality that a plastic application – or small parts of it – may, in rare cases, end up in a different environment, does not justify overly burdensome biodegradation requirements. Or else, such requirements would have to apply to all other materials, too.

Biodegradation in soil without generating microplastics:

Biodegradable polymers have the advantage that they do not erode into persistent secondary microplastics upon degradation, because  natural environments habit microbes that are able to metabolise these polymers. The residence time is considerably lower for biodegradable polymers compared to conventional plastic materials. Therefore, biodegradable plastics can help in minimizing environmental impacts, while reducing the accumulation of plastic particles in different environmental habitats. I.e., industrially compostable plastics significantly reduce the amount of persistent non-biodegradable microplastics in the compost and thus a subsequent leakage into the environment. Soil-biodegradable mulch films help to stop leakage and accumulation of persistent microplastics in agricultural soils.

EUBP supports efforts to gain a better understanding of the origin and creation of microplastics and their release into and effect on the environment, to minimise environmental impacts. There is no evidence of a greater dispersion of biodegradable or compostable plastic products in the environment than any other materials (glass, paper, metal, etc.). The risk for any (plastic) material to be transferred (by wind or runoff) from one (e.g., soil) environment to another (e.g., aquatic) environment applies to all plastic materials, especially conventional non-biodegradable materials, which, however, have no chance of biodegrading in any environment.

Biodegradability vs. littering:

EUBP and its members do not support any statements that advertise bioplastics as a solution to the littering problems. Littering should never be promoted or accepted for any kind of waste, neither on land nor at sea, including all varieties of plastics. Littering is a behavioural problem and should be addressed by educational and public communication measures and be supported by clear messages on the products and packaging itself. There is no evidence that claims or labels on the biodegradability or compostability of a product would lead to or even encourage increased littering. What is more, if an overall assessment of the persistence of items that are of consequence for “littering” is to be carried out, it should incorporate a risk assessment for all materials that are found in open environment.

Use of additives:

All compostable plastic applications that are intended to be certified as compostable must pass vigorous ecotoxicity tests such as plant growth or nitrification inhibition tests. They should not include any substances that are regulated under REACH as part of the EU standard EN 13432 for industrially compostable packaging to prevent any risks to human health and the environment.

The often cited ‘Zimmerman study’*, alleging that biodegradable plastics can be similarly toxic as conventional ones, is flawed. The test methods used in the study did neither follow the standardised methods for migration testing required by the EU Regulation on Food Contact Materials on plastic materials, nor REACH. Therefore, the study by Zimmerman et. al (2020) cannot be consulted when assessing the safety of additives used in biodegradable and compostable plastics. All plastic products, including conventional plastics as well as bioplastics, contain additives, the latter of which must pass even more rigorous testing than conventional plastic products.

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Find out more about the specific benefits of biobased and compostable plastics and the shortcomings of the Commission’s Communication …

* Zimmermann et.al “Are bioplastics and plant-based materials safer than conventional plastics? In vitro toxicity and chemical composition”, Environment International 145 (2020)