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13.08.2021 - Ausgabe: 4/2021

Microplastics in the environment – they are everywhere and their impacts are still hard to assess

An interview with Dr. Martin Löder, University of Bayreuth

© Dr. Martin Löder

The problem of ocean litter and the very slow biodegradation of plastics in the environment has been known for several decades now. In the meantime, the problem has taken on a new dimension. Small to tiny plastic particles - microplastics as they are termed - have now been detected in many places. Scientists and researchers have addressed this issue to investigate the extent of microplastic pollution, its impacts and possible measures to tackle it. 

Scientist Dr. Martin Löder has been doing research on the topic of microplastics for more than ten years – currently at the Chair of Animal Ecology I of Prof. Dr Christian Laforsch at the University of Bayreuth. He has investigated different aspects of the problem in over 30 projects and he is a member of the DFG Collaborative Research Centre 1357 "Microplastics" at the University of Bayreuth.  S+L asked him about the current state of affairs on the issue of microplastics, the environmental impacts and what options there might be to further reduce or prevent microplastic pollution in the future.


Sports & Leisure Facilities (S+L): Dr. Löder, thank you for taking the time to talk to me.  The issue of microplastics has been under discussion for some time now. What do you consider the most serious implications of microplastic pollution? 

Dr. Martin Löder: My pleasure. This is not an easy question to answer. Large-scale production of plastics began in the mid-1950s, and since then microplastics have also been produced and gets into the environment. This is a gradual process and at first glance you don't see any serious environmental impacts, because these changes are also a gradual process. There are many factors at play and the impacts have yet to be observed. However, our research shows that microplastics are everywhere, even today. Microplastics can be found in every environmental sample. For example, a researcher from our faculty analysed Microplastic pollution of the atmosphere at various locations in the Weser catchment area and found that around 230 t of microplastic particles are released through deposition from the air to the earth's surface of the catchment area alone every year. 

However, as I have already pointed out, there are currently no serious impacts of microplastic pollution visible in the environment; extensive research is still underway. It is important to know that there are many different kinds of microplastics. It is a group of substances with many different variants, all of which have different ingrediants and properties. Laboratory tests, however, have already revealed possible impacts on animal organisms in the environment. Moreover, research into the impacts on plant life is only just beginning. 

In "hotspots", i.e. places with a high occurrence of microplastics, immediate impacts could soon manifest themselves. For instance, the physical properties of the soil could be altered due to a high plastic level. It would then lose its ability to retain water, among other things. 


S+L: What will be the future impacts if the present level of microplastic pollution in the environment remains unchanged, or even increases? 

Dr. Martin Löder: We have to bear in mind that even if we were to reduce all microplastic pollution to zero right now, the number of microplastic particles would still continue to increase due to the degradation of the plastic already present in the environment. 

There is growing evidence of environmental impacts, which can already be verified in the laboratory. Theoretically there are different impact factors: physical hazards for organisms that ingest microplastics – they then get a false sense of satiety, for example, and starve to death. Or they get injured or significantly weakened. Then there are potential chemical hazards caused by various additives in the plastics. These can be plasticizers, for example, or endocrine active substances. Each composition of a plastic can have different impact on the environment. Furthermore, we know that plastics can accumulate various hazardous substances, such as heavy metals or persistent organic pollutants, on their surface. This means that an organism that ingests microplastics will then also ingest these hazardous substances and there is a potential risk of transmission. However, the issue of pollutants is the subject of controversial scientific debate. In addition, there is for example the influence of UV radiation on the ageing of the plastic and much more. All these factors make this too complex an issue to be able to say conclusively whether there will be adverse impacts or not. While there are many indications, a lot of research is still needed to gain comprehensive insights. 

Laboratory research, however, has already shown that various animals respond negatively to certain microplastics in the environment. And there will be more of these interactions between organisms and microplastics in the future. Even though, of course, high concentrations of plastics were used in the laboratory, we are noticing that there are already individual hotspots in the environment that have concentrations similar to those in the laboratory. However, as research into plastics has only been going on for less than 100 years, the long-term impacts of microplastic pollution cannot be predicted with any certainty, as I have already said. Scientists are still debating how long it exactly takes for individual plastics to biodegrade. 

But even though efforts are already underway to minimize the amount of plastic in the environment – if we do not manage to drastically curb emissions, we will always produce more microplastics than are degraded. As a result, we will inevitably be getting closer to "laboratory conditions". 


S+L: Even though there is no doubt that any plastic harms the environment, what do you think is the bigger problem: macroplastics (just think of the Great Pacific Garbage Patch, also known as the Pacific trash vortex) or microplastics?  

Dr. Martin Löder: Macroplastics are in fact nothing other than young microplastics that means you can't actually separate the two from each other. In the environment, this macroscopic waste breaks down into smaller fragments when exposed to UV radiation or other influences. For instance, a plastic bag measuring 30 x 30 cm can break down into millions of tiny microplastic particles. This is exactly why the "garbage patches" in the Pacific Ocean are actually not "islands" of trash, but offshore accumulation zones, having some of the highest concentrations of plastic in the sea. Contrary to popular belief, however, these are not solid patches of plastic waste or places that can be walked on, but rather accumulations of plastic particles that gradually degrade into microplastics. You can no longer see them afterwards, but they are present in all the oceans of the world. Therefore, differentiating between macroplastics and microplastics is simply pointless.


S+L: Do you see any possibility of developing equivalent plastics on a large scale in the coming years that are environmentally friendly and readily biodegradable? Or are there already promising solutions to tackle the microplastic pollution?

Dr. Martin Löder: Plastic-degrading microorganisms could have a pivotal role to play in the future. For example, there is a bacterium that is able to break down PET – however, only at a very slow rate.

Biodegradable plastics could also be a solution wherever a durable material is not wanted. Some compostable plastics that are already available today, however, do not meet the expectations in some cases. These are neither fully compostable in the private compost and also often not completely degraded after industrial composting. For this reason, some organic bags for compost collection that are already on the market have already been banned again by various disposal companies. Nevertheless, we might well be able to develop truly compostable plastics on the basis of these developments. It is also important to identify plastic properties that have a harmful effect and to develop new materials without these properties.


S+L: Do you believe that a ban on microplastics or severe restrictions on the industry, as planned by the EU in the medium term, are the ideal way to curb this problem? Or would it perhaps be more sensible to focus more on promoting the development of eco-friendly plastics or microplastic filters or systems for large-scale water purification from microplastics? Or do you perhaps see any other measures that would make a difference in the medium term? 

Dr. Martin Löder: Plastics are part of our everyday lives, and despite the significance of research findings, we should not demonise them in principle. Plastics are critical to modern life. Take, for example, medical or computer technology – it would be almost impossible for us to go about our daily lives without plastics because there is no other group of materials as variable as plastics. A fundamental ban would therefore not be expedient. Instead, the properties of plastics should be improved, for example their degradability, and, of course, unnecessary emissions and pollution should be prevented.

There are, of course, some ways to avoid high levels of microplastic pollution in the future. In my lectures, I always point out that every single one of us can make a positive difference by acting responsibly and becoming more environmentally conscious. If you always dispose of your waste properly and do not litter, you are doing your part to prevent microplastics. Another problem that can be avoided quite easily is over-packaging. Many everyday consumer products are wrapped in several layers of plastic by the industry. This is an area where both consumers and industry can significantly cut down on plastics. In general, packaging should be rethought. If a shrink-wrapped steak lasts a few weeks, why does its wrapping have to last 50 years or more for example? 

Overall, one will have to take a multi-pronged approach to solving this problem. Wastewater treatment plants, which also release not inconsiderable amounts of microplastics into the environment, could, for example, be equipped with an additional filter. Moreover, the aforementioned development of truly biodegradable plastics is certainly also essential. It would definitely also be helpful to have the industry’s self-commitment to take back and recycle plastics in certain fields. Companies could certainly also use this as part of their public relations and marketing strategy in the future.

S+L: Dr Löder, thank you for this insightful interview.


The interview was conducted by Tobias Thierjung (Sports & Leisure Facilities) 


Collaborative Research Centre (SFB) 1357 “Microplastics” at the University of Bayreuth 

The widespread microplastic pollution of the environment as well as the associated potential risks for ecosystems and ultimately for our health have been the focus of much public and scientific attention recently.

When the Collaborative Research Centre “Microplastics” was launched in January 2019, research was primarily focused on the development of suitable monitoring methods, the quantitative assessment of environmental contamination as well as the identification of relevant emission pathways and limited to initial approaches aimed at curbing emissions. Ecotoxicological issues were mostly investigated using virgin plastics. However, all these approaches have so far failed to provide a fundamental understanding of the physical, chemical and biological processes that microplastics undergo in the environment. The interdisciplinary approach of the Collaborative Research Centre “Microplastics” at the University of Bayreuth, which is funded by the German Research Foundation, crosses exactly these traditional academic boundaries and combines them in order to address the scientific complexity of this issue. 

Based on model systems for plastics, organisms and environmental compartments, SFB 1357 aims to gain a fundamental understanding of those processes and mechanisms. How do the physical and chemical properties of plastics affect the biological impact of microplastics on our ecosystems? How are microplastic particles transported between soils, waters and air? How long does it take for microplastics to be generated from plastic materials and to decompose? 

These findings will for the first time provide a scientifically sound basis for assessing the environmental risks of microplastics generated from existing bulk plastics. They also provide an important basis for the development of new eco-friendly plastics in terms of sustainable polymer chemistry.

These new plastics should, among other things, be able to decompose faster by using catalysts and structural modifications, and will help to avoid or reduce microplastic pollution. 

Further information: https://www.sfb-mikroplastik.uni-bayreuth.de/en/ 

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