Plastic has been a topic of public debate for a while - and for good reason: Recent studies have shown that the yearly amount of plastic waste per capita in Germany reaches a total of 39.7kg. In Ireland, this figure is even bigger with 61.5kg per person in 2022 (Statista, 2022). Public and media attention has often focussed on plastic in the ocean (e.g. Michael, 2022). In 2014, the estimated weight of plastic elements in the North Pacific alone amounted to 96,400 tons (Statista, 2014). Figures like these, as well as campaigns by NGOs and activists, have lead to an increasing interest amongst the public. The growing attention on plastic issues has also triggered a rise in research focusing on materials with higher biodegradability (Priyadarshini et al., 2022) in search of more environmentally friendly options. This has partially led to the emergence of “bioplastics”. The materials that fall into this categorization however often vary widely in their properties regarding both their degradability and production processes. Due to the different definitions, consumer knowledge on bioplastics appears to be low according to an Australian study from 2019 (Dilkes-Hoffman et al., 2019). European researchers also have found that consumer attitudes towards bioplastics tend to be favourable, at times overestimating the biodegradability of these materials. They also often think that recycling is not as important for bio-based plastics as it is for fossil-based plastics (Zwicker, Brick, Gruter & van Harreveld, 2021).
So… what are Bioplastics?
The European Union differentiates between several different types of materials that together make up the family of bioplastics. Plastic can be considered bioplastic if it is either biobased, biodegradable or both. The term “biobased” describes a material which is at least partly produced from some form of biomass (usually corn, sugarcane, or cellulose). Biodegradation on the other hand is the process by which a material is converted into natural substances through microorganisms that are already available in the environment (European Commission, 2022).
The different categories of Bioplastics include a number of materials, such as PET, PA or PEF (European Bioplastics, 2022). PET stands for Polyethylene Terephthalate – a form of polyester that is often used for water bottles - PA stands for Polyamides which is more commonly known as nylon (WRAP, 2020), finally PEF stand for Polyethylene Furanoate and is thought by some to replace PET in the future (Rosenboom et al., 2018). One of the most often used bio-based, biodegradable materials is PLA (Polylactic Acid) (Cosate de Andrade, Souza, Cavalett & Morales; 2016).
Bio-based, biodegradable plastics include starch blends made of thermoplastic starch (TPS), as well as innovative polyester forms. They can be used for products with a shorter life-span (e.g. packaging). Not all these materials biodegrade under the same conditions. Biodegradable, fossil-based plastics are a smaller group of materials and are often combined with other plastics (PLAs or biodegradable versions), as they can improve performance for different products (European Bioplastics, 2022).
Confusion around the properties of Bioplastics
As explained, the term bioplastic can mean different things in different instances. The resulting complexity in understanding it has led to a low knowledge on and confusion around the topic amongst the public. However, the public opinion on bioplastics still tends to be positive, with 68% of people claiming they would like to see more plastic items be biodegradable (Dilkes-Hoffman, Ashworth, Laycok, Pratt & Lant, 2019). Consumers are also more willing to pay for bioplastic alternatives (Zwicker, Brick, Gruter & van Harreveld, 2021). Due to the positive associations, the market for bioplastics has constantly been growing and is predicted to continue this growth over the next years (European Bioplastics, 2018).
More bioplastics flooding the market might lead to difficulties due to their different levels of biodegradability and related waste management challenges. Napper and Thompson (2019) tested the biodegradability of 4 different types of plastic bags over a three-year period. Their results show that the degradation process is strongly influenced by the kind of material used, as well as the environment the plastic gets discharged in. They looked at biodegradable, oxo-biodegradable, compostable, and high- density polyethylene in three environments – open-air, buried in soil, and in sea water – with a laboratory control condition. While the level of deterioration differed, the researchers reported that none of the plastic bags examined showed substantial deterioration over a 3-year period. This result shows that it should be a priority to discard even biodegradable bags in accordance with waste management guidelines, as they could still end up polluting the environment for years to come.
These findings and their implications are of particular interest when looking more closely at consumer opinions. Research has shown that consumers tend to form their opinions about plastics largely due to end-of-life attributes associated with the materials (Herbes et al., 2018). Juxtaposing this finding with the apparent popularity or preference of bioplastics amongst the public (Dilkes-Hoffman, Ashworth, Laycok, Pratt & Lant; 2019) further implies that consumers may not be aware of end-of-life challenges.
Where does it go?
The reported research results therefore suggest to further focus on end-of-life characteristics of bioplastics. As with any material, where and how bioplastics are disposed plays an important part in ensuring sustainable usage and minimizing negative effects on the environment. Studies have shown that waste management plays an important role at this stage. It has also been suggested that recycling often has a better environmental profile than biodegradation (Piemonte, 2011; De Andrade, Souza, Cavalett, Morales, 2016). From a consumer perspective, sustainable waste disposal can be especially hard, because recycling practices usually differ from country to country or even state to state. In Austria specifically, the beginning of 2023 has also marked the start of a country-wide alignment of recycling practices – meaning that the waste management system in different states now operates with the same rules and consumers do not need to learn different practices when moving to a new state.
A 2016 study looked at PLAs as some of the most widely used bioplastics. Specifically, the researchers compared three different forms of PLA disposal: mechanical and chemical recycling, as well as composting. Results showed that mechanical recycling had the lowest environmental impacts, followed by chemical recycling and composting. The output of recycled polymer is mainly responsible for his outcome (Cosate de Andrade, Souza, Cavalett & Morales; 2016).
Piemonte (2011) also showed that the production of PLA and other bioplastics uses less energy and produces less GHGs emissions compared to conventional plastics, but appropriate waste disposal is still important to fully reap ecological benefits. They too came to the conclusion that mechanical recycling appears to be the best solution for the materials (Piemonte, 2011).
What can we do?
If you want to shape your plastic consumption in a more sustainable way, bioplastics can be part of that journey. However, it is important to carefully investigate which bioplastics to use and how to dispose of them according to their composition and local waste disposal and recycling practices.
From what we know up to this point, recycling seems to be the better option in general compared to composting and we therefore suggest opting for this strategy whenever possible. This is partly due to the fact that no energy has to be wasted composting or worst case burning the materials. Moreover, the energy and resources invested in the production of the initial material are invested more long-term than if the plastic would just get thrown away.
Try to go for bioplastics that are both bio-based and bio-degradable, as they tend to use less energy in their overall lifespan.
As always: If there are other options, try to not use plastic in general, and/or go for reusable rather than single-use items. When there is no way around it, using bioplastics can often be the better alternative, provided they are disposed of properly. Keep in mind that e.g. in Vienna, Bioplastic is not allowed to be disposed of in biowaste (see https://www.wenigermist.at/muellsackerl). We therefore encourage all consumers to look up the specific waste management regulations in their state or city.
List of References
Statista research department. (2022). Plastikverpackungsabfall in ausgewählten EU-Ländern je Einwohner 2020. Retrieved February 2, 2023, from de.statista.com/statistik/daten/studie/786353/umfrage/plastikverpackungsabfall-in-ausgewaehlten-eu-laendern-je-einwohner/.
Michael, C. (2022, 25. Juli). Plastic in the Depths: how pollution took over our oceans. The Guardian. www.theguardian.com/environment/2022/jul/25/plastic-in-the-depths-how-pollution-took-over-our-oceans.
Statista research department. (2014). Gewicht der Plastikteilchen in den Ozeanen. In Statista – The Statistics Portal. Retrieved February 2, 2023, from de-statista-com.uaccess.univie.ac.at/statistik/daten/studie/694775/umfrage/gewicht-der-plastikteilchen-in-den-ozeanen/.
Priyadarshini, S. R., Srinivasan Krishnamoorthy, J. A. Moses, & Anandharamakrishnan, C. (2022). Starch-Based Edible Films and Coatings. In S. Kumar, A. Mukherjee, & J. Dutta (Hrsg.), Biopolymer-Based Food Packaging: Innovations and Technology Applications (First Edition, 147-177). John Wiley & Sons Ltd.
Cosate de Andrade, M. F., Souza, P. M. S., Cavalett, O. & Morales A. R. (2016). Life Cycle Assessment of Poly(Lactic Acid) (PLA): Comparison Between Chemical Recycling, Mechanical Recycling and Composting. J. Polym. Eviron., 24, 372-384.
Dilkes-Hoffman, L; Ashworth, P.; Laycock, B.; Pratt, S. & Lant, P. (2019). Public attitudes towards bioplastics – knowledge, perception and end-of-life management. Resources, conversation and recycling, 151, 104479.
European Bioplastics. (2018, December 5). New market data: The positive trend for the bioplastics industry remains stable. Retrieved August 30, 2023, from https://www.european-bioplastics.org/new-market-data-the-positive-trend-for-the-bioplastics-industry-remains-stable/
European Bioplastics. (2022, October). What are bioplastics? [fact sheet] European bioplastics. docs.european-bioplastics.org/publications/fs/EuBP_FS_What_are_bioplastics.pdf
European Commission. (2022, November 30). Communication from the commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions: EU Policy Framework on Biobased, Biodegradable and Compostable Plastics. European Commission. environment.ec.europa.eu/system/files/2022-12/COM_2022_682_1_EN_ACT_part1_v4.pdf
Napper, I. E. & Thompson, R. C. (2019). Environmental Deterioration of Biodegradable, Oxo-biodegradable, Compostable, and Conventional Plastic Carrier Bags in the Sea, Soil, and Open-Air Over a 3-Year Period. Environ. Sci. Technol., 53, 4775-4783.
Herbes, C., Beuthner, C. & Ramme, I. (2018). Consumer attitudes towards biobased packaging – A cross-cultural comparative study. Journal of cleaner production, 194, 203-218.
Rosenboom, J. G., Hohl, D. K., Fleckenstein, P., Storti, G. & Morbidelli, M. (2018). Bottle-grade polyethylene furanoate from ring-opening polymerisation of cyclic oligomers. Nature Communications, 9 (1), 2701-2707.
Understanding plastic packaging and the language we use to describe it. (2020, 11. September). WRAP UK. preprod.wrap.org.uk/sites/default/files/2020-10/WRAP-Understanding%20plastic%20packaging%20FINAL.pdf
Zwicker, M.V.; Brick, C.; Gruter, G.J.M.; van Haareveld, F. (2021). (Not) Doing the Right Things for the Wrong Reasons: An Investigation of Consumer Attitudes, Perceptions, and Willingness to Pay for Bio-Based Plastics. Sustainability, 13, 6819.
