A recent news article caught my attention; it was based on a new scientific study that found the highest ever recorded concentration of microplastics on the seafloor. They discovered up to 1.9 million plastic pieces per square metre, in the Mediterranean Sea near Italy. Personally, I was shocked by the article, how have I not heard more about this? Shouldn’t this be something we talk about more? I believe knowledge on climate related issues helps us all make more informed decisions, helps us shout louder and fight harder for what we believe in. By now I’m sure most of us are aware plastic waste is a big environmental problem and we’ve all probably seen images of wildlife being harmed by plastic packaging and pictures of the vast amounts of plastic in oceans and landfills. Those bigger pieces of plastics are called macro plastics, but what about microplastics?
I hoped to do some research and be able to answer the questions I had and to share the information I had found with you. Specifically, I wanted to know what microplastics exactly are and what their sources are. Is it harmful to the environment and in particular marine life? Who is responsible, is it due to consumption and waste by individuals or businesses and industries? And of course, if it’s harmful, what can we do about it!
Quickly, I discovered that the answers to these questions are not as easy as I (naïvely) thought. Since research into microplastics and their environmental impact has only become a topic of interest quite recently, there are different definitions and collection filters / techniques. To summarise, microplastics are defined as any type of plastic that has a size of < 5 mm or < 1 mm, depending on the paper. Many different types of plastic (PE, PP, PVC, etc.) exist which are usually made by refining petroleum. Each type has different properties, usually plastics found are not any pure type of plastic, but mixed with other substances. Microplastic shapes can be fibres, spheres, fragments, usually depending on the source and weathering. The source can be primary; manufactured microplastics, or secondary; bigger sources that have broken down (they can breakdown even further into nano plastics). Due to their different densities some float, some sink, some are consumed and move up the food chain. It’s not just in the oceans, they exist on land and in the air.
The optical microscope image of microplastics. a: Transparent fiber, b: red fiber, c: transparent sphere, d: green granule, e, f: blue hexagonal fragments, g: white granule covered with silver shiny film, h: blue granule, and i: sample of microplastics fragments with two colors.
This was a lot of information to take in and the numbers and answers I was looking for do not exist, but that does not mean that microplastics are not a problem. In fact I was alarmed to find where it was found and how far it can spread. Studies have shown they exist in waters near coasts, the middle of oceans, the bottom of seas, indoors, outdoors, near factories, in cities, on mountains in remote areas, in rainfall, in snowfall, in shellfish, in birds. This was just from the few studies I read, microplastics are truly everywhere, all over the world.
Where do they come from? Well, some plastics are manufactured at the microplastic size before entering the environment (primary sources). The main industries are cosmetics, manufacturing and clothing. These can be beads of microplastics that are added to cosmetics (branded as microbeads) or blown with air at high speeds to smooth out surfaces in manufacturing. They can also be in the form of fibres from synthetic clothing materials. The rest are from the breakdown of larger pieces of plastic products (secondary sources). The rate at which they breakdown depends on the type of plastic, what they’re mixed with and the environmental conditions they are in. In the papers I read, UV light and high temperatures seem to be the main factor in the rate of breakdown. Due to higher temperatures and more direct sunlight, plastics on land (especially on beaches) breakdown faster and plastics in the ocean take longer to break down into microplastic fragments .
Conceptual model of atmospheric microplastics in the environment.
We create them, directly or indirectly, we introduce them to the environment, intentionally or unintentionally, and they will certainly be around long after we’re all gone, so… are they harmful? To be honest, I have not found a paper that states in certain terms it is harmful, but the majority of researchers seem to think that it is most likely going to be harmful. One of the ways it can be harmful is due to its size and properties making it able to absorb toxic substances, so although most are not toxic when created, it can carry toxic substances to marine life that ingest it. In addition, certain colours of microplastics can make them look like prey to smaller marine life, and although most of them have mechanisms to excrete out sediments, they can still pose a threat to their digestive system by blocking it. It is, additionally, possible to have effects on reproductive functions, and since they can’t be digested they can accumulate. This to me is worrying, any disruption in the natural ecosystem is bound to have vast effects, even if it is in the tiniest of creatures, the effect can go all the way up the food chain. It’s also important to remember microplastics have been found globally, any disruption will not be locally contained. However, the research is still in the early stages, maybe they can just excrete it all out and we’ll be fine, but are the possible consequences worth waiting to find out?
This is an entirely human made problem, microplastics would never exist naturally and it is yet another way we have imposed ourselves and our lifestyles on the environment. The issue of (macro/micro) plastic pollution fits into the bigger picture of the climate crisis we face and every step of the life cycle of plastics, from the raw materials needed, to the manufacturing to the transportation to the breaking down, harms the environment. That’s not to say that all plastics are the enemy. The same properties that make it so harmful make them very useful in many fields. For example, in healthcare its versatility and properties make plastic much more practical than other materials. But our overconsumption of plastics is the main problem, our actions have long term effects on the environment and natural ecosystems. So next time you need to purchase something that contains plastic, the first thing you should ask yourself is do I actually need this? Then ask yourself, can I use something I already have for the same purpose? Can I find an alternative made from biodegradable materials? And if after all of these questions you come to the conclusion you still need it, think about how recyclable it is. But, at the end of the day, it doesn’t make sense to be too hard on yourself, if we lived in a world where an environmentally friendly alternative was as easy to obtain, would you still buy the polluting plastic? Probably not.
Living organisms tangled in microplastics. A sample of water collected off the coast of Hawaii shows how intertwined microplastics are in the daily lives of marine animals.
That brings us to the need for system change (you can argue that individual consumption drives system change, but that is an entirely other discussion). Decisions at the manufacturing level can have effects on the lifetime of plastics and the harm they cause to the environment. Antioxidants are sometimes added to plastics to increase durability, but since oxygen is an essential component needed for breakdown this makes these plastics much harder to breakdown. The addition of other chemicals and substances to plastics and the mixing of different types of plastics makes it much harder to recycle, the more we are able to reuse existing plastics, the less new plastics we need to create. Higher concentrations of microplastics were found near factories that manufacture plastics, so better containment measures can lead to reduced leaks to the environment. Companies and governments need to think of metrics other than maximising profits and economic growth, resources are finite and current production is destroying and deteriorating the very environment that produces those finite resources. We need to move on from the idea that infinite economic growth is possible, our relationship with the environment needs to be reassessed and sustainability needs to be a main factor moving forward.
To conclude, plastic waste is an undeniable problem and when plastics degrade to microplastics, even though we can’t see it, that doesn’t mean the problem goes away. In fact, even if as a global population we took the decision to take out all the plastics we put into the environment, the sheer amount of plastics and scale of the issue makes it impossible. We can’t ignore that our individual consumption has added to this problem, our collective lifestyles have become increasingly wasteful. Instead of investing in products that will last, we use easy and cheap plastics that will be around in the environment for exponentially longer than the time we used it for. Since plastics don’t last in a form where they can be useful forever and most are not recycled, the most effective step we can take to reduce our waste is to reduce our consumption. But let us not lose sight that we also need system change to change both the quantity and production process of plastics, even if we reduce our direct plastic consumption entirely, plastics are still going to be used in manufacturing of goods and services we use indirectly. The issue of microplastics is a global one and like many other environmental problems we currently face, it is man-made. Everyone is affected, everyone needs to take action and everyone needs to be a part of the solution.
Reduce, Reuse, Recycle. In that exact order.
Appendix (Here you can find some quotes and figures from the papers used as sources in the research of this article):
Quote from source 1: “Microplastic fibres have been identified as a particular concern for the environment, owing to their abundance and bioavailability, with research suggesting that microplastic fibres can contribute up to 91% of all plastics collected in global seawater samples (Barrows et al., 2018). Plastic production has increased rapidly since its inception, with an estimated 8.3 billion metric tonnes of virgin plastic produced to date. Approximately 4.6 billion metric tonnes of this (55%) has been produced since 2000 (Geyer et al., 2017).”
Locations where Microplastics were found in the atmosphere (and amount found) summarised from source 1, each entry is from a separate study and different studies use different collection techniques and units:
Paris, France (Average: 118 particles m−2 d−1)
Hamburg, Germany (275 particles m−2 day−1)
Tehran metropolis, Iran (88–605 items per 30 g dry dust)
Asaluyeh County, Iran (0.3–1.1 item m−3)
Dongguan, China (175–313 particles m−2 d−1)
Shanghai, China (1.42 ± 1.42 items m−3)
Yantai, China (Fibres: 115–602 items m−2 d−1, Others: 40 items m−2 d−1)
39 major cities in China (PET: 1550–120,000 mg kg−1 (indoor), 212–9020 mg kg−1 (outdoor), PC: 4.6 mg kg−1 (indoor), 2.0 mg kg−1 (outdoor))
Pyrenees mountains, Europe (249 fragments, 73 films and 44 fibres m−2 d−1)
Europe and Arctic (190–154 × 103 items L−1 European snow, 0–14.4×103 items L−1 Arctic snow)
Helsinki, Finland (700 items m−2 of melted snow (market place) 1400 (road side))
Italian Alps (74.4 items kg−1 of sediments (dry weight))
Surabaya, Indonesia (132.75–174.97 items m−3)
Nottingham, UK (0–31 fibres m−2 d−1)
West Pacific Ocean (Open Ocean) (0–1.37 items m−3 Average.: 0.06 items m−3)
Quote from this paper: “Microplastics are now acknowledged as atmospheric pollutants and particulates. Recent studies have demonstrated the existence of microplastics in the area of urban, rural and remote atmosphere and atmospheric deposition. As an atmospheric pollutant, there is significant potential for long-range transport and therefore influence on locations far from microplastic pollution sources. Among the published studies, relative abundance of atmospheric microplastics reflects a wide range of characteristics and quantities across different regions. Fibres and fragments are the most frequently identified microplastic shapes in the atmosphere. Conclusion on size distribution in these studies are difficult to draw due to the differences in targeted particle size. Because of its light-weight, durability, and other intrinsic features, atmospheric microplastics can be transported to remote areas and deposited through dry or wet deposition. Wind, snowfall, and weathering play an important role on atmospheric microplastics from sources to ocean or land surfaces.”
Locations where microplastics were studied, each number is from a separate paper and different papers use different collection techniques, filter sizes and units of measurement. Some of the numbers here are from quite old papers but this is to emphasise that microplastics are widespread (Source 8):
Coastal waters, Sweden 102 000 particles m3
Coastal Waters, California 3 particles m3
Coastal waters, New England 3 particles m3
Open ocean, North West Atlantic 67 000 particles km2
Northwest Mediterranean Sea 1 particle m2
Beach, Malta >1000 particles m2
Beach, UK 8 particles kg-1
Estuarine sediment, UK 31 particles kg-1
Subtidal sediment, UK 86 particles kg-1
Subtidal sediment, Florida 214 particles l-1
Subtidal sediment, Maine 105 particles l-1
Harbour sediment, Sweden 50 particles l-1
Industrial harbour sediment, Sweden 3320 particles l-1
Industrial coast sediment, Sweden 340 l-1
Ship-breaking yard sediment, India 89 mg kg-1
Harbour sediment, Belgium 7 mg kg-1
Continental shelf sediment, Belgium 1 mg kg-1
Beach, Belgium 1 mg kg-1
Beach, Portugal 6 particles m2
Beach, East Frisian Islands, Germany 621 particles 10 g-1
Quotes from source 2 on the effect of Microplastics on marine life and food security:
“All of the commercially important organisms studied here, where data was available, were shown to contain microplastics. The population of animals shown to ingest microplastics varied widely by species, and when normalized for weight, the number of microplastics ingested per gram wet weight decreased with increasing trophic level. We conclude that commercially important organisms towards the base of the food chain (bivalves, crustaceans and small planktivorous fishes) are more likely to be contaminated with higher concentrations of microplastics, potentially posing a greater risk to their health and having implications for perceived or actual food safety.”
“Microplastics are a risk to the health of marine organisms worldwide. As fisheries and aquaculture are critical for global food security, this has implications for food security and food safety. Microplastics present an added risk to an already stressed environment, and further research on the effects of microplastic pollution is required to be able to perform comprehensive risk assessments on the effect of microplastics on food security.”
Quotes from source 7 on the effect of Microplastics on marine life consumed by humans and estimates the dietary exposure of European consumers:
“Using the average microplastic concentration detected in this study (i.e. 0.42 particles g1 tissue; average of M. edulis and C. gigas plastic load without depuration), an annual dietary exposure can be calculated. European top consumers will ingest up to 11,000 microplastics per year, while minor mollusc consumers still have a dietary exposure of 1800 microplastics per year.”
“The presence of marine microplastics in seafood could pose a threat to food safety, however, due to the complexity of estimating microplastic toxicity, estimations of the potential risks for human health posed by microplastics in food stuffs is not (yet) possible.”
Dutch focused studies:
Older (but still relevant) studies:
By Karim Abdel Kader
member of Maastricht for Climate: www.maastrichtforclimate.nl