Transcription
As over 80% of the mushrooms are cultivated via the bag cultivation method significant amount of plastic waste is produced within the industry every year. With the advent of biodegradable plastics and, more recently, oxo-degradable plastic, the hope to reduce the environmental impact by using them is huge.
But what are biodegradable plastics and oxo-degradable plastics?
And are they the answer to our problem?
Let us find out.
To deal with waste in general, countries started years ago to introduce a recycling system based on recycling codes to identify the material from which an item is made to facilitate the recycling process. The code, for example, for Polyethylen is 04, and for Polypropylen is 05.
While the first sorting starts at our home, the second sorting is made by hand and later by Near-IR laser combined with an air nozzle within the recycling facilities. The current system is, therefore, designed for the conventional types of plastic.
But what about biodegradable plastics?
On the one side, we have conventional plastics which are fossil-based and are not biodegradable. On the other side of the spectrum, we find bio-based plastics which are also not biodegradable. But there are fossil-based plastics which are biodegradable like PCL or PBAT and bio-based plastics which are biodegradable like PLA or PHA.
Besides, we have to distinguish between biodegradable and compostable. Biodegradable means that the material disintegrates and is decomposed by micro-organisms into elements found in nature, given enough time. But the length of the biodegradation process is highly dependent on environmental parameters such as humidity and temperature. Meaning this process relies on an oxygen-rich environment or aerobic conditions.
While all compostable plastics are biodegradable, only a tiny set of biodegradables are compostable and within the compostable world, we have to distinguish between industrial settings and home compostable. Meaning, to compost certain types of plastic, we have to maintain the right temperature and humidity for a certain period without oxygen or anaerobic conditions.
That means that biodegradable and bio-based plastics have to be designed, tested, and certified for a specific disintegration process. As otherwise, each of the processes gets contaminated.
As in both processes, biodegradation and composting, time is the crucial part. Scientists developed new kinds of plastic called oxo-degradable plastic. These plastics are conventional plastics that include additives to accelerate the fragmentation of the material into tiny pieces triggered by UV radiation or heat exposure.
Given these two sets of parameters, UV radiation and heat, we understand that oxo-degradable plastics are a unique type of plastics. And they do not belong in your compost.
More importantly, while many studies could show that oxo-degradable plastics disintegrates faster than conventional plastic, the final product of oxo-degradable plastics is microplastics and, therefore, solve only one part of the puzzle.
Given this situation, the European Commission stated in its report that while oxo-degradable plastic disintegrates faster into smaller fragments, the question “is however whether in uncontrolled conditions in the open environment, in landfills or in the marine environment, the plastic fragments will undergo full biodegradation within a reasonable time-frame.”
And furthermore, “If this is not the case, oxo-degradable plastic will contribute to the microplastics release in the (marine) environment while misleading consumers. As recent research shows, microplastics released in the marine environment get into the food chain and end up being consumed by humans.”
The European Commission continues that “for none of these environments, a full biodegradation process has been documented. Most experiments were carried out over a too short time span to demonstrate full biodegradation, and the results of measurements of molecular weight reduction in the initial stage of fragmentation were extrapolated following certain models.
Therefore, no conclusive evidence is currently available to confirm that the fragmentation is sufficiently rapid and leads to a reduced molecular weight that allows subsequent biodegradation taking place within a reasonable time-frame.”
Besides, “The evidence also suggests that oxo-degradable plastic is not suitable for any form of composting or anaerobic digestion.”
Which led to the final conclusion that “In the absence of conclusive evidence of a beneficial effect on the environment and indeed indications to the contrary, given the related misleading claims to consumers and risks of resulting littering behavior, EU wide measures should be considered. Therefore, in the context of the European plastics strategy, a process to restrict the use of oxo-plastics in the EU will be started.”
But the EU is not the only country that has its problem with oxo-degradable plastics.
The parliament of New Zealand stated in a publication that oxo-degradable plastics cannot be processed in New Zealand.
This brings me back to our current recycling system. The idea of “a circular economy retains the value of products and materials in the economy as much as possible. Although biodegradable and compostable plastics are technically recyclable, they are currently not recycled back into the plastic material. Instead, they are treated as an impurity in the recycling of conventional plastics when collected together.
Increasing market shares in future could aggravate the situation but could also make the recycling of certain biodegradable or compostable plastics economically viable.”
We, therefore, need “a labeling system needs to avoid confusing consumers.” Awareness-raising campaigns and clear communication with consumers will improve their understanding of the labels used on plastics and ensure their correct disposal.”
But did you know that by producing bioplastics, you are competing with food production?
It is estimated that, for example, 1kg PLA needs 1.6 kg fermented sugar feedstock. While other bioplastics can require 2.5 to 3 times more sugar feedstock. Meaning, producing bioplastic will reduce the amount of food available.
On the other hand, a life cycle analysis of PLA showed that the production of PLA fixates 1.833 kg CO2 per kg PLA out of the atmosphere.
As you can see, there are way more things to consider about biodegradable and oxo-degradable plastics than just reducing the use of conventional plastics by resort to them.
How do you think now about those types of bio-plastics?
Do you agree or disagree with my findings?
Let me know down in the comment section.
Talk to you in the next video.
Sources
[2] https://de.wikipedia.org/wiki/Recycling-Code
[4] https://commons.wikimedia.org/wiki/File:Biokunststoffe_Final.svg, https://upload.wikimedia.org/wikipedia/commons/c/c5/Biokunststoffe_Final.svg, Ple210, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
[5] Wei, Ren, Zimmermann, Wolfgang, Microbial enzymes for the recycling of recalcitrant petroleum-based plastics: how far are we?, Microbial Biotechnology, 10, 6, 1751-7915, https://doi.org/10.1111/1751-7915.12710, https://creativecommons.org/licenses/by/4.0/
[6], [7] M. Goss, Z. Li and M. S. McLachlan, Environ. Sci.: Processes Impacts, 2020, 22, 1006, A simple field-based biodegradation test shows pH to be an inadequately controlled parameter in laboratory biodegradation testing, DOI: 10.1039/C9EM00491B, https://creativecommons.org/licenses/by/3.0/
[9] https://www.chesapeakebay.net/news/blog/photo_essay_microplastics_in_the_chesapeake_bay
[10] Xochitl, Q.-P.; María del Consuelo, H.-B.; María del Consuelo, M.-S.; Rosa María, E.-V.; Alethia, V.-M. Degradation of Plastics in Simulated Landfill Conditions. Polymers 2021, 13, 1014. https://doi.org/10.3390/polym13071014, https://www.mdpi.com/2073-4360/13/7/1014, https://creativecommons.org/licenses/by/4.0/
[11] Noreen L. Thomas, Jane Clarke, Andrew R. McLauchlin, and Stuart G. Patrick, Proceedings of the Institution of Civil Engineers – Waste and Resource Management 2012 165:3, 133-140 https://www.icevirtuallibrary.com/doi/10.1680/warm.11.00014, https://creativecommons.org/licenses/by-nc-nd/2.5/
[12] https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A52018DC0035
[13] https://www.pce.parliament.nz/publications/biodegradable-and-compostable-plastics-in-the-environment
[14] Morão, A., de Bie, F. Life Cycle Impact Assessment of Polylactic Acid (PLA) Produced from Sugarcane in Thailand. J Polym Environ 27, 2523–2539 (2019). https://doi.org/10.1007/s10924-019-01525-9, https://doi.org/10.1007/s10924-019-01525-9
