Introduction to Microplastics

By Brooke Kelly (Environmental Scientist, Reditus Consulting)

Man-made. Persistent. Mobile. Toxic. These terms are often attributed to our most concerning pollutants – those which demand funding, incite international outrage, and spur the development of legislation, guidelines and cleanup criteria. Microplastics encompass all these characteristics, and more. Yet they are not currently regulated and are often not assessed at contaminated sites.

What are microplastics?

Plastics are synthetic materials made up of polymers, which are made by linking together hundreds or thousands of organic subunits (monomers) via strong covalent chemical bonds. A Belgian chemist, Leo Baekeland, pioneered the first fully synthetic plastic in 1907. He beat his Scottish rival, Sir James Swinburne, to the patent office by one day.[1] Plastic production boomed in the 1950s, and has been increasing ever since, with global plastic production expected to exceed 460 million metric tons in 2024.[2]  Plastics have rapidly become an essential and versatile product for the modern age, with a plethora of properties, chemical compositions, and applications. Plastic waste management consists of three main channels including application to landfills, incineration and recycling.

Microplastics, as the name implies, are small plastic items. They are generally defined as any plastic item measured between 5mm – 1µm (the length of a pencil eraser to the width of a spider’s web).[3] However, the definition of microplastics is not consistent between organisations, making it difficult for comparative analysis between studies.

Depending on their origin, microplastics can be defined into two categories: primary or secondary microplastics. Primary microplastics are small, manufactured plastic items, such as microbeads used as exfoliants in beauty products and virgin resin pellets (termed ‘nurdles’). Secondary microplastics are the result of degradation of larger plastic items. The degradation of plastic items into microplastics may be physical, biological or chemical:

• Physical abrasion may fragment plastic due to atmospheric agents such as wave and wind action, or abrasion of plastic against a hard substrate such as sand or rock.
• Photodegradation, or light-induced polymer degradation, includes the physical and chemical changes caused by irradiation of polymers with ultraviolet or visible light. Additionally, photo-oxidative degradation may occur in the presence of oxygen.
• Biological degradation occurs when the hydrophobic surface of plastic promotes microbial colonisation and biofilm formation, leading to the colonisation of plastic debris by hydrocarbon-degrading bacteria that perform active hydrolysis of the hydrocarbon polymer.

As a microplastic continues to degrade, the degradation products are termed nanoplastics, defined as any plastic item <1µm. Microplastics measured below 10µm are inhalable (particles that can be breathed into the nose or mouth), and all nanoplastics are respirable (particles that once inhaled, can penetrate beyond the terminal bronchioles into the gas-exchange region of the lungs).  

Where are microplastics found?

Everywhere. Microplastics are ubiquitous in the environment, being reported in, and transported between, terrestrial, estuarine, coastal and marine environments, and on all continents. It is estimated that there are 171 trillion microplastics accumulated on the oceans’ surfaces.[4]

Microplastics are so prevalent in the environment that some literature has unofficially termed the current geological epoch the ‘Plasticene’, which is marked stratigraphically in the depositional record by a new and increasing layer of plastic.

Due to their physical properties (small particle size and weight), microplastics are highly mobile. They are transported via wind and ocean currents and have been detected in the ice and snow of several remote highland environments such as the French Pyrenees, indicating substantial geographical dispersion.[5] 80% of plastic polymers are less dense than seawater and therefore float at the surface of the water column, allowing plastic to be transported vast distances.[6] Due to the longevity of plastics and their persistence in the environment, microplastic contamination of the environment will be an ongoing and increasing environmental pollution issue into the future. 

How do they enter the Environment?

Microplastic contamination of the environment may be caused by:

• Wastewater discharge – though shedding of microfibres from domestic and commercial washings of synthetic textiles.
• Surface water and stormwater runoff – from road marking paint and tyre wear fragments.
• Minor pollution events – via purposeful or accidental littering.
• Major pollution events – via spillage from virgin resin pellet transportation.
• Agricultural application – via plastic compost and mulching and application of biosolids which contain microplastics, such as wastewater and sewage discharge.

Figure 1. Sources, sinks and transport mechanisms of environmental microplastics.[7]

Toxicity Potential

Microplastics themselves are a physical pollutant, but they can also act as a source, sink and accumulator of contaminants:

• Source: Plastics are often manufactured to contain toxic stabilisers and plasticisers that may leach from the polymer matrix to the environment or a biological receptor.
• Sink: Microplastics are particularly good at adsorbing environmental contaminants due to their high specific surface area, ubiquitous nature and strong hydrophobicity.  Various toxic substances have been proven to be readily adsorbed by microplastics such as persistent organic pollutants (POP), heavy metals, pesticides, polycyclic aromatic hydrocarbons (PAH), antibiotics, and other potentially toxic contaminants.
• Accumulator: Biomagnification occurs when concentrations of contaminants become progressively higher for each trophic level. Biomagnficiation of contaminants adhered to microplastics has been proven in the marine and terrestrial environment.

The toxic potential of plastics has sparked a call for the most harmful polymers to be classified as hazardous wastes rather than solid wastes in Europe, USA and Australia.

Microplastics can also act as a vector for biota. In particular, the persistence, buoyancy and variety of chemical composition of marine microplastics facilitates colonisation by microorganisms. An ecosystem able to exist on the surface of plastic is termed a plastisphere. Once attached to a microplastic, biota can be readily transported around the world and between environments, contributing to the dispersion of potentially invasive species. From a human viewpoint, the surface of microplastics is a suitable substrate for biofilm-forming pathogenic bacteria and viruses and can also act as a platform for the propagation of microorganisms. For example, plastics can be a carrier of the coronavirus (SARS-CoV-2) which can remain active on polypropylene (PP) microplastics for 3-7 days and spread to humans via airborne distribution.[8]

Exposure, uptake and ecotoxic impacts to biota

Humans

Human uptake of microplastics can occur through ingestion, inhalation and dermal contact. Microplastics have been reported in human blood, semen, breastmilk, liver, spleen, lung, hair, hands, skin, saliva and faeces. Microplastics were even reported in placenta samples, suggesting that microplastics are transferred from a mother to an unborn foetus. The detection of microplastics in blood revealed that microplastics are being transported throughout the body via circulation. Exposure to microplastics may inhibit cell growth and cause inflammatory responses, oxidative stress, apoptosis, metabolic homeostasis, changes in cell morphology, and alterations in gut microbiota.

• Inhalation is the primary pathway to humans, with an estimated inhalation rate of 26-130 microplastics per day.[9] A common source of airborne microplastics is synthetic fibres shed from clothing and textiles. Once inhaled, the elimination of accumulated microplastics in the lungs is difficult due to the polymeric structures and fibrous morphologies of microplastics that can cause lung inflammation.
• Ingestion of microplastics has been proven in humans, with one study reporting a minimum of 20 microplastics detected per 10 grams of adult stool.[10] They have been detected in food and drinks consumed daily including bottled water, beer, milk, soft drinks, canned food, honey, molluscs, bivalves, fish, sugar and salt. The annual human ingestion of microplastics is estimated to be more than 40,000 particles.[11]
• Dermal uptake is limited to nanoplastics, as the human dermal barrier inhibits the absorption of particles >100nm. Dermal absorption is most likely to occur through skin exposure to microbeads in personal care products. However, nanoplastics <40nm also have the potential to penetrate into epidermal cells around hair follicles. Recently, microplastics were identified in commercial over-the-counter eyedrops, posing a risk to the ocular surface. Nanoplastics that are internalised via a transdermal route will pass sublayers of epidermis before reaching the dermis and being transported through the human body via the circulatory system. 
• Translocation occurs when microplastics cross the epithelial layers of the skin, lungs and gastrointestinal tract to other body organs and tissues. The phenomenon of microplastic translocation has been demonstrated experimentally in various species. Field studies of wild-caught species report microplastics in various tissues spanning the entire microplastic size classification range, i.e. 1μm – 5000μm.[12] The mechanisms by which larger microplastics >130μm translocate are not understood but may possibly be facilitated by the abrasion and perforation of tissues and/or induction of the inflammatory response.

The potential toxicity effects of microplastic uptake in humans varies significantly. Dermal uptake of microplastics by humans is associated with the absorption of released monomers or organic plasticizers like phthalates and bisphenols, which are endocrine disruptors. When metal-contaminated microplastics enter the human body, the release of these metals into the digestive tract may occur, as has been simulated for microplastics contaminated with Cr (III) and Cr (VI).[13] While the toxicity of metals in humans depends on many factors, including dose and level of exposure, age, sex, and genetics, high concentrations of metals can cause cell and tissue damage as well as estrogenic reactions.

Fauna

Ingestion of microplastics has been reported for all feeding strategies (i.e. predation, grazing, filter-feeding etc.), at all trophic levels and is increasing over time. Methods of ingestion include:

• Direct ingestion which may occur accidentally through indiscriminate feeding strategies, particularly in suspension filter-feeding species such as zooplankton and humpback whales, or through the misidentification of microplastics for food based on visual or olfactory cues, e.g. a sea turtle misidentifying a plastic bag for a jellyfish.
• Indirect ingestion occurs through trophic transfer when contaminated prey is consumed by a predator. Microplastics may enter and exit an organism’s gastrointestinal tract and repeatedly become bioavailable. 

The physical obstruction of microplastic ingestion has been proven to cause a plethora of physical impacts to biota, e.g. ingestion may cause reduced feeding due to a false feeling of satiation, or gut obstruction that may lead to decreased energy reserves and starvation. Once ingested, there is the potential for microplastics to accumulate, which may cause fatality or several other biological impacts that reduce fitness, e.g. damaging intestinal function and/or reproductive potential. Plastic ingestion can affect trophic interactions and assemblages, impacting population and species diversity.

Microplastics <10µm may be adsorbed into organs of the body via translocation. It has been demonstrated in a species of muscle that after consumption, microplastics can accumulate in the gastrointestinal tract, and then be translocated to the circulatory system to remain in an individual for over 48 days.[14]

The proven ecotoxicimpacts of microplastic uptake in fauna includes nerve damage, endocrine system damage, immune system damage, inflammatory effects, various metabolic disorders, offspring defects, and oxidative stress. Due to the potential for bioaccumulation and biomagnification of adsorbed contaminants via trophic transfer, species of a higher trophic order are expected to be more susceptible to the toxicological impacts of ingestion.

Flora

Microplastics are bioavailable to fauna due to their extensive use in agricultural production and their ubiquitous presence in the environment. In flora, microplastics are small enough to cross the physical barriers of intact plant tissue, which has been reported for grains of major human consumption including wheat and lettuce.[15] Of course, nanoplastics are more prone to penetrating the plant cell wall due to their smaller size. Microplastic uptake by flora may occur through:

• Soil application which involves the absorption of microplastics through root hairs. Then, transpiration pull transports microplastics from the root to the stem, and from the stem to shoots, reaching nectar, lead, fruits and pollen.
• Foliar application involves microplastics entering a plant through leaf stomata, where they are transported to other plant parts via apoplastic pathways. Due to the size exclusion limits of leaf cuticle (~0.2–2nm), the stomatal pathway is generally applicable to the absorption of nanoplastics.

The bioavailability of microplastics to flora depend on the specific characteristics of the plant or organism, and soil properties such as particle size, particle density, abundance/co-occurrence and chemical characteristics.

Owing to high rates of plant leaf capture, terrestrial plants may act as a potential sink of microplastics and may play an important role in the fate of airborne microplastics.

Information on the ecotoxic impacts of microplastics to flora is currently very scarce. Known impacts include the prevention of proper absorption of nutrients and water by plant roots impacting plant growth, reduced biomass production, genotoxicity and oxidative damage, short-term and transitory effects on germination rates and root development, immobilisation of photosynthesis process, and impacts to microbial activities at the soil level.

What does this mean for the CLM industry?

Soil

Microplastic pollution of surface soil and subsoil is well documented.

• Abundance: Microplastic pollution of soil is well documented. In Sydney, the abundance of microplastics in soils of an industrial area averaged over 4,000mg/kg, with a range between 300-67,500 microplastics/kg.[16] Arable soils report the highest concentrations of microplastic pollution,[17] and may alone store more microplastics than oceanic basins.[18]
• Sources: Direct sources of microplastics in soils include wastewater and sewage sludge, organic fertilisers, plastic mulches, landfills, dumping, composting and atmospheric deposition.
• Transportation in soil: The main transportation methods of microplastics between soil layers is caused by water flow such as rain or irrigation, agricultural practices like tillage and ploughing and bioturbation by soil organisms (vertical movement of soil organisms creates micropores in the soil, which promotes the transportation of microplastics by leaching). Soil organisms can also contribute to the distribution of microplastics through casting, burrowing, ingestion, egestion, and microplastic adhesion to their exterior.
• Toxicity: Research has confirmed that contaminants sorbed to microplastics can be transported from the microplastic into soils and can leach to subsoils. This has been proven of pesticides, polybrominated diphenyl ethers (PBDE), endocrine-disrupting chemicals (EDC), PAHs, phthalates, pesticides and bisphenol-A (BPA).[19]
• Impacts: The accumulation of microplastics may impact soil microenvironments by:
  • Altering soil structure such as increasing soil porosity and water-holding capacity, decreasing soil bulk density, and decreasing the structural integrity of soil.
  • Altering soil physicochemical characteristics including porosity, enzymatic activities, microbial activities, plant growth, soil aggregation and yield.
  • Impacting organic matter including nutrient mobility and availability, moisture diffusion, crop development and growth, reducing seed germination, slowing down the development of roots during germination and hindering the sowing and growth of plants.
  • Stimulating enzymatic activity to activate organic carbon, nitrogen and phosphorus pools and increasing dissolved organic carbon levels.

Groundwater

Microplastics can travel considerable distances and infiltrate aquifers, leading to accumulation in subsurface environments. Potential sources of microplastics in groundwater may include urban infrastructure, agricultural soils, septic effluent, bioturbation by soil invertebrates and surface water / soil permeation. Globally, microplastic concentrations range between 0 – 6,832 particles/L.[20] Microplastics identified commonly in groundwater include PP and PE, with their prevalence likely due to their extensive use in agricultural areas for mulch, greenhouse films, shade nets, and fertilizer bags.

Air

Due to their small size and weight, microplastics are readily transported in the air. Microplastics are ubiquitous in indoor dust around the world, and inhalation is a major exposure route in humans. Atmospheric precipitation of plastic in urban areas of Paris was reported at approximately 2–35 particles m⁻² days⁻¹.[21] Air mass trajectory analysis showed that microplastic atmospheric transportation can be up to 95km, potentially reaching remote and sparsely populated areas.[22] Indeed, microplastic detection in soils from remote and unsettled areas have been reported.[23]

Sediments

Although most microplastics possess low density (i.e. high buoyancy), the majority of aquatic microplastics eventually sink through the water column due to weathering, biofouling and aggregation processes, meaning that sediments are often a sink for microplastics. In the marine environment, hydrophobic organic contaminants are shown to have greater affinity for a range of plastics including PE, PP and PVC, compared with natural sediments.[24] This sorption is so significant that PE is used as a sorbent to detect persistent, bioaccumulative and toxic chemicals (PBT) in aquatic environments, and the sorption of PBTs to plastics has been recommended as a global monitoring tool for oceanic PBT concentrations worldwide.

Figure 2. The Transportation of microplastics between environments.[25]

Summary

Microplastics are ubiquitous in the environment and have been reported in Australian soils, groundwater, air, sediments and landfills. In addition to being a physical contaminant, microplastics can readily adsorb other contaminants from environmental media. These contaminants, as well as any plasticisers inherent in the microplastics, can leach from microplastics and become bioavailable to humans, fauna and flora. Microplastics can facilitate biomagnification of these contaminants, making them increasingly more harmful to receptors as they progress through the food chain. Microplastics are therefore a vector of contamination: adsorbing, transporting, and introducing contaminants into environments. And yet, microplastics are not typically assessed in soil, water or air, have no risk-based assessment criteria, and are not currently regulated at a state or federal level in Australia.

Want to learn more about Microplastics and other Emerging Contaminants? Join our Symposium in Melbourne 19 & 20 August 2026 – CLICK HERE TO LEARN MORE

Reference List

1. The Institution of Engineering and Technology (2024) Archives biographies: Sir James Swinburne PART FRS.
2. International Union for Conservation of Nature (2024) Issues brief – plastic production. May 2024.  
3. Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) (2015) Sources, fate and effects of microplastics in the marine environment: a global assessment. In: Kershaw, P. (ed.).
4. Plastic Soup Foundation (2023) It is estimated that 171 trillion microplastic particles float in the ocean, published 24 March 2023, https://www.plasticsoupfoundation.org/en/.
5. Allen, S., Allen, D., Phoenix, V.R., Roux, G.L., Jiménez, P.D., Simonneau, A., Binet, S. and Galop, D. (2019) Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nature Geoscience, vol. 12, pp. 339–344.
6. Andrady, A. L. (2011) Microplastics in the marine environment. Marine Pollution Bulletin. vol. 62, pp. 1596-605.
7. European Environment Agency (2022) Microplastics from textiles: towards a circular economy for textiles in Europe, 10 February 2022.
8. Doremalen, N., Bushmaker, T., Morris, D.H., Holbrook, M.G., Gamble, A., Williamson, B.N., Tamin, A., Harcourt, J.L., Thornburg, N.J. and Gerber, S.I. (2020) Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1, The New England Journal of Medicine, vol. 382, pp. 1564-1567.
9. Prata, J.C. (2018) Airborne microplastics: Consequences to human health? Environmental Pollution, vol. 234, pp. 115–126.
10. Schwabl, P., Koppel, S., Konigshofer, P., Bucsics, T., Trauner, M., Reiberger, T. Liebmann, B. (2019) Detection of Various Microplastics in Human Stool: A Prospective Case Series. Annals of Internal Medicine, vol. 171(7).
11. Cox, K.D., Covernton, G.A., Davies, H.L., Dower, J.F., Juanes, F. and Duda, S.E. (2019) Human Consumption of Microplastics. Environmental Science & Technology, vol. 53.
12. Merrill, G.B., Hermabessiere, L., Rochman, C.M. and Nowacek, D.P. (2023) Microplastics in marine mammal blubber, melon, & other tissues: Evidence of translocation. Environmental Pollution, vol. 335,
13. Liao, Y. and Yang, J. (2020) Microplastic serves as a potential vector for Cr in an in-vitro human digestive model. Science of the Total Environment, vol. 703.
14. Browne, M.A., Dissanayake, A., Galloway, T.S., Lowe, D.M. and Thompson, R.C. (2008) Ingested Microscopic Plastic Translocates to the Circulatory System of the Mussel, Mytilus edulis (L.). Environmental Science & Technology, vol. 42, pp. 5026-5031.
15. Ziani, K., Ioniță-Mîndrican, C.B., Mititelu, M., Neacșu, S.M., Negrei, C., Moroșan, E., Drăgănescu, D. and Preda, O.T. (2023) Microplastics: A Real Global Threat for Environment and Food Safety: A State of the Art Review. Nutrients, vol. 15(3).
16. Fuller, S. and Gautam, A. (2016) A procedure for measuring microplastics using pressurized fluid extraction. Environmental Science & Technology, vol. 50(11).
17. Ramos, L., Berenstein, G., Hughes, E.A., Zalts, A. and Montserrat, J.M. (2015) Polyethylene film incorporation into the horticultural soil of small peri urban production units in Argentina. Science of the Total Environment, vol. 523, pp. 74-81.
18. Nizzetto, L., Futter, M. and Langaas, S. (2016) Are agricultural soils dumps for microplastics of urban origin? Environmental Science & Technology, vol. 50(18), pp. 10777-10779. 
19. Azeem, I., Adeel, M., Ahmad, M.A., Shakoor, N., Jiangcuo, G.D., Azeem, K., Ishfaq, M., Shakoor, A., Ayaz, M., Xu, M. and Rui, Y. (2021) Uptake and Accumulation of Nano/Microplastics in Plants: A Critical Review. Nanomaterials (Basel), vol. 11(11).
20. Lee, J. Y., Cha, J., Ha, K., and Viaroli, S. (2024). Microplastic pollution in groundwater: a systematic review. Environmental Pollutants and Bioavailability, vol. 36(1). 
21. Dris R., Gasperi J., Saad M., Mirande C. and Tassin B. (2016) Synthetic fibers in atmospheric fallout: A source of microplastics in the environment? Marine Pollution Bulletin, vol. 104, pp. 290–293.
22. Allen S., Allen D., Phoenix V., Le Roux G., Jiménez P.D., Simonneau A., Binet S. and Galop D. (2019) Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nature Geoscience, vol. 12, pp. 339–344.
23. Scheurer M. and Bigalke M. (2018) Microplastics in Swiss Floodplain Soils. Environmental Science & Technology, vol. 52, pp. 3591–3598.
24. Teuten, E.L., Rowland, S.J., Galloway, T.S. and Thompson, R.C. (2007) Potential for plastics to transport hydrophobic contaminants, Environmental Science & Technology, vol. 41(22).

Allen, D., Allen, S., Abbasi, S. et al. (2022) Microplastics and nanoplastics in the marine-atmosphere environment, Nature Reviews Earth & En

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[1] The Institution of Engineering and Technology (2024) Archives biographies: Sir James Swinburne PART FRS.

[2] International Union for Conservation of Nature (2024) Issues brief – plastic production. May 2024.  

[3] Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) (2015) Sources, fate and effects of microplastics in the marine environment: a global assessment. In: Kershaw, P. (ed.).

[4] Plastic Soup Foundation (2023) It is estimated that 171 trillion microplastic particles float in the ocean, published 24 March 2023, https://www.plasticsoupfoundation.org/en/.

[5] Allen, S., Allen, D., Phoenix, V.R., Roux, G.L., Jiménez, P.D., Simonneau, A., Binet, S. and Galop, D. (2019) Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nature Geoscience, vol. 12, pp. 339–344.

[6] Andrady, A. L. (2011) Microplastics in the marine environment. Marine Pollution Bulletin. vol. 62, pp. 1596-605.

[7] European Environment Agency (2022) Microplastics from textiles: towards a circular economy for textiles in Europe, 10 February 2022.

[8] Doremalen, N., Bushmaker, T., Morris, D.H., Holbrook, M.G., Gamble, A., Williamson, B.N., Tamin, A., Harcourt, J.L., Thornburg, N.J. and Gerber, S.I. (2020) Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1, The New England Journal of Medicine, vol. 382, pp. 1564-1567.

[9] Prata, J.C. (2018) Airborne microplastics: Consequences to human health? Environmental Pollution, vol. 234, pp. 115–126.

[10] Schwabl, P., Koppel, S., Konigshofer, P., Bucsics, T., Trauner, M., Reiberger, T. Liebmann, B. (2019) Detection of Various Microplastics in Human Stool: A Prospective Case Series. Annals of Internal Medicine, vol. 171(7).

[11] Cox, K.D., Covernton, G.A., Davies, H.L., Dower, J.F., Juanes, F. and Duda, S.E. (2019) Human Consumption of Microplastics. Environmental Science & Technology, vol. 53.

[12] Merrill, G.B., Hermabessiere, L., Rochman, C.M. and Nowacek, D.P. (2023) Microplastics in marine mammal blubber, melon, & other tissues: Evidence of translocation. Environmental Pollution, vol. 335,

[13] Liao, Y. and Yang, J. (2020) Microplastic serves as a potential vector for Cr in an in-vitro human digestive model. Science of the Total Environment, vol. 703.

[14] Browne, M.A., Dissanayake, A., Galloway, T.S., Lowe, D.M. and Thompson, R.C. (2008) Ingested Microscopic Plastic Translocates to the Circulatory System of the Mussel, Mytilus edulis (L.). Environmental Science & Technology, vol. 42, pp. 5026-5031.

[15] Ziani, K., Ioniță-Mîndrican, C.B., Mititelu, M., Neacșu, S.M., Negrei, C., Moroșan, E., Drăgănescu, D. and Preda, O.T. (2023) Microplastics: A Real Global Threat for Environment and Food Safety: A State of the Art Review. Nutrients, vol. 15(3).

[16] Fuller, S. and Gautam, A. (2016) A procedure for measuring microplastics using pressurized fluid extraction. Environmental Science & Technology, vol. 50(11).

[17] Ramos, L., Berenstein, G., Hughes, E.A., Zalts, A. and Montserrat, J.M. (2015) Polyethylene film incorporation into the horticultural soil of small peri urban production units in Argentina. Science of the Total Environment, vol. 523, pp. 74-81.

[18] Nizzetto, L., Futter, M. and Langaas, S. (2016) Are agricultural soils dumps for microplastics of urban origin? Environmental Science & Technology, vol. 50(18), pp. 10777-10779. 

[19] Azeem, I., Adeel, M., Ahmad, M.A., Shakoor, N., Jiangcuo, G.D., Azeem, K., Ishfaq, M., Shakoor, A., Ayaz, M., Xu, M. and Rui, Y. (2021) Uptake and Accumulation of Nano/Microplastics in Plants: A Critical Review. Nanomaterials (Basel), vol. 11(11).

[20] Lee, J. Y., Cha, J., Ha, K., and Viaroli, S. (2024). Microplastic pollution in groundwater: a systematic review. Environmental Pollutants and Bioavailability, vol. 36(1). 

[21] Dris R., Gasperi J., Saad M., Mirande C. and Tassin B. (2016) Synthetic fibers in atmospheric fallout: A source of microplastics in the environment? Marine Pollution Bulletin, vol. 104, pp. 290–293.

[22] Allen S., Allen D., Phoenix V., Le Roux G., Jiménez P.D., Simonneau A., Binet S. and Galop D. (2019) Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nature Geoscience, vol. 12, pp. 339–344.

[23] Scheurer M. and Bigalke M. (2018) Microplastics in Swiss Floodplain Soils. Environmental Science & Technology, vol. 52, pp. 3591–3598.

[24] Teuten, E.L., Rowland, S.J., Galloway, T.S. and Thompson, R.C. (2007) Potential for plastics to transport hydrophobic contaminants, Environmental Science & Technology, vol. 41(22).

[25] Allen, D., Allen, S., Abbasi, S. et al. (2022) Microplastics and nanoplastics in the marine-atmosphere environment, Nature Reviews Earth & Environment, vol. 3, pp. 393–405.