Tiny plastics, big problem. What we know about microplastic impacts - Fidra (2024)

Fromthe highest mountain ranges¹ to the deepest marine ecosystems on the planet²plastics are everywhere.Fidra’s ownresearch intonurdle distribution shows that plastic pellets have been found on the shorelines of almost every continent in theworld³.

When we started the Great Nurdle Huntwealreadyknew that nurdles were found in the stomachs of seabirds, andthat they could be associated with harmful chemicals– plenty toshowusthatthese pellets didn’t belong in the oceans!Sincethen,researchintomicroplastic pollutionhas rapidly advanced.Sowhat has changed in our understanding of microplasticsand their impactsinrecent yearsand should wecontinue tobeworriedabout them?

Impactsof microplastics on marineecosystems

Astudyhasestimated that79% ofall plastic ever produced has ended up in landfill or theenvironment,oceansareconsideredplastic’s final sink.All plastic that enters the ocean will break up and eventually become microplastics.It is predicted that microplasticsnow make up94% of the1.8 trillion particles that make up the Great Pacific Garbage Patch⁴and other recentresearchhas shownthere is 14 million metric tons of microplastics on the ocean floor (35 times more plastic than that found on the surface)⁵.Due to their small size microplastics can be easily ingested bya range ofmarine animalswithfish andseabirdsconfusingplastic withfood⁶.

Eating Plastic

Ingesting microplastics pose several threats to marine animals. Microplastics can build up in digestion tracks leading some animals to not eat enough real food with proper nutritional value to survive. This has been shown in species of fish⁷, babyturtles⁸and has been particularlydamaging toseabirds,with one study showing thatmicroplasticscanalso directly enterthe liversofseabirdscausingharm⁹.

Microplastics can cause abrasions tointernaltissuesof animals when they ingest them,whichcanlead tobacteria buildingupcausingfurtherharm to animals.Worryingly thishas been shownto happen inimportantkeystone species(certain species that are critical to the survival of the other species in an ecosystem¹⁰)suchasredcoralthat support vital and fragile tropical reef ecosystems¹¹.

Chemical Contaminants

Another concern with microplastics that scientists are only just beginning to understand is the negative effects from chemicals associated with plastic. Microplastics acquire chemicals in three ways – firstly most plastic is made of fossil fuels which can contain harmful contaminants, secondly chemical additives are used to give plastic colour or to make the plastic “bendy”.

For example, rubber crumb from artificial football pitchesis a type of microplastic that has been found toleach outheavy metals, endocrine disrupters (substances that interfere with how our hormones functione.g.,phthalates) and carcinogens (e.g.,PAHs) into the surrounding environment.Arecent studyfound197 chemicals out of 306 identified in a sample of rubber crumbmetthe carcinogenicity criteria¹².

Thirdly, plastics have been shown to adsorb chemical contaminants once in the environment, including persistent organic pollutants (POPs) and metals. We‘ve known about this effect on nurdles, but research in the last few years shows that the ability to absorb contaminants increased as microplastic particles get smaller, and as they become weathered with age¹³.

Whetherthese chemicals are absorbed into the bodyof animalsand cause harmdepends on how long they stay in theanimalfor.Nevertheless, several studies are starting to showproofof absorption of these chemicals into animal tissue and associated negative impacts. For example,a study showedseabassthatwere fed food containing contaminants of microplastics accumulatedthe contaminants intheir tissues in highconcentrations after fortydays¹⁴. Other studies have shown chemicals from tyre rubber can be deadly to salmon ¹⁵and cause harm to other marine animals such as mussels¹⁶.

Spreading disease and invasive species

As well as transporting harmful chemicals throughout the world’s oceans, microplastics can also act as a vector for biological contaminants. For example, studies have shown that harmful species of algae have been found to colonise microplastics¹⁷. A recent study in Scotland also demonstated that nurdles at five public beaches had been colonised by E.coli¹⁸. This poses a great risk of microplastics being an ideal vector to transport invasive microorganisms far and wide and is another reminded of the importance of hygiene when handling nurdles and other marine litter.

Are microplastics harming humans?

Due toplastics widespreadprevalence and potentialtoxicity,there are increasing concerns around human health impacts.Studies have recently predictedhumans could be ingesting up to 52,000 microplastic particles every yearthrough contaminated foodand these estimates increase to 121,000particleswhen inhalation of microplastics isconsidered^{19, 20, 21}.

Up until now, it has been estimated that the quantity of microplastics consumed by humans has been too little to cause significant harm.However,scientists are becoming increasingly concerned about nano plastics (plasticsless than1μmin size,equivalent to the size of a typicalbacterium)and theirpotential to enter human cellsdisturbing cellular activity.

This has been shown in a recent study which exposed lungcellstopolystyrenemicroand nanoplasticsat concentrations ranging from that experienced by residents of urban areas,tothe higherconcentrations workers at industrial manufacturing sites may experience. The cells were found to display major

changes and multiple nanoplastics were found to enter the cells²².Overall, research showsmicroplastics do not endanger short-term health except at high concentrations like that of workers in industrial settings.However, recentstudies suggest long term exposure to microplasticinhalation hassignificant potentialtoharm humans.

Why we must actnow

Microplastics are threatening whole ecosystems and are becoming of increasing concern for human health. Plastic production is increasing, a recent study predicts the amount of plastic ending up in our oceans is to triple by 2040 to 23-37 million metric tons per year²³. Additionally, current estimates of marine microplastic concentrations are predicted to be vastly underestimated²⁴.Wemust act now to reduce the amount of microplastics entering the environment. There aremanyways we can cut down onmicroplastic pollution and you can be part of the solution.Why not start by taking part in one ofFidra’sprojectstacklemicroplasticpollution?

• Join theGreatGlobalNurdle hunt this Octoberto trackplastic pellet pollutionand hold industry to account. Find out more about this by heading to:www.nurdlehunt.org.uk
• Tackle microplastic pollution from artificial football pitches in your local area. Find out more about this problem and resources to use at: www.fidra.org.uk/artificial-pitches

References

1. Napper, Imogen E., et al. 2020. Reaching new heights in plastic pollution—preliminary findings of microplastics on Mount Everest. One Earth 3.5: 621-630.
2. Jamieson, Alan J., et al. 2019. Microplastics and synthetic particles ingested by deep-sea amphipods in six of the deepest marine ecosystems on Earth. Royal Society open science 6.2.: 180667.
3. Fidra, 2019. The Great Nurdle Hunt. [Online] Available at: https://www.nurdlehunt.org.uk/nurdle-finds.html (Accessed 8th April 2021).
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5. Barrett, J., Chase, Z., Zhang, J., Holl, M. M. B., Willis, K., Williams, A., … & Wilcox, C. (2020). Microplastic Pollution in Deep-Sea Sediments From the Great Australian Bight. Frontiers in Marine Science, 7, 808.
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8. Eastman, C. B., Farrell, J. A., Whitmore, L., Rollinson Ramia, D. R., Thomas, R. S., Prine, J., … & Duffy, D. J. (2020). Plastic ingestion in post-hatchling sea turtles: assessing a major threat in Florida near shore waters. Frontiers in Marine Science, 7, 693.
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10. https://www.nationalgeographic.org/encyclopedia/keystone-species/
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12. Perkins, AN, Inayat-Hussain, SH, Deziel, NC, et al. Evaluation of potential carcinogenicity of organic chemicals in synthetic turf crumb rubber. Environ Res 2019; 169: 163–172.
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14. Granby, K., Rainieri, S., Rasmussen, R. R., Kotterman, M. J., Sloth, J. J., Cederberg, T. L., … & Larsen, B. K. (2018). The influence of microplastics and halogenated contaminants in feed on toxico*kinetics and gene expression in European seabass (Dicentrarchus labrax). Environmental research, 164, 430-443.
15. Tian, Z., Zhao, H., Peter, K. T., Gonzalez, M., Wetzel, J., Wu, C., … & Kolodziej, E. P. (2021). A ubiquitous tire rubber–derived chemical induces acute mortality in coho salmon. Science, 371(6525), 185-189.
16. Capolupo, Marco, et al. 2021. The sub-lethal impact of plastic and tire rubber leachates on the Mediterranean mussel Mytilus galloprovincialis. Environmental Pollution: 117081.
17. Casabianca, S., Capellacci, S., Giacobbe, M. G., Dell’Aversano, C., Tartaglione, L., Varriale, F., … & Penna, A. (2019). Plastic-associated harmful microalgal assemblages in marine environment. Environmental Pollution, 244, 617-626.
18. Rodrigues, A., Oliver, D. M., McCarron, A., & Quilliam, R. S. (2019). Colonisation of plastic pellets (nurdles) by E. coli at public bathing beaches. Marine pollution bulletin, 139, 376-380.
19. Cox, K. D., Covernton, G. A., Davies, H. L., Dower, J. F., Juanes, F., & Dudas, S. E. (2019). Human consumption of microplastics. Environmental science & technology, 53(12), 7068-7074.
20. Gasperi, J., Wright, S. L., Dris, R., Collard, F., Mandin, C., Guerrouache, M., … & Tassin, B. (2018). Microplastics in air: are we breathing it in?. Current Opinion in Environmental Science & Health, 1, 1-5.
21. Smith, M.; Love, D.C.; Rochman, C.M.; Neff, R.A. (2018). Microplastics in Seafood and the Implications for Human Health. Curr. Environ. Health Rep.5, 375–386.
22. Goodman, K. E., Hare, J. T., Khamis, Z. I., Hua, T., & Sang, Q. X. A. (2021). Exposure of Human Lung Cells to Polystyrene Microplastics Significantly Retards Cell Proliferation and Triggers Morphological Changes. Chemical Research in Toxicology, 34(4), 1069-1081.
23. The Pew Charitable Trusts, 2020. Breaking the Plastic Wave, A comprehensive assessment of pathways towards stopping ocean plastic pollution. Available: breakingtheplasticwave_mainreport.pdf (pewtrusts.org). (accessed 8th April 2021).
24. Lindeque, Penelope K., et al. 2020. Are we underestimating microplastic abundance in the marine environment? A comparison of microplastic capture with nets of different mesh-size. Environmental Pollution 265: 114721.

Tags: marine litter, microplastics, nurdles, plastic pollution, rubber crumb