Microplastics: Tiny Particles, Massive Impact - Understanding the Source, Implications, and Mitigation of a Global Crisis

Introduction

As we go about our daily lives, it's easy to forget that our actions have consequences beyond our lifetimes. But the threat of microplastic pollution is a stark reminder that our choices today will shape the world that our children and grandchildren inherit. Every year, billions of tons of plastic waste enter our oceans, breaking into tiny particles and contaminating our water and food. This pollution harms marine life and poses a severe threat to human health. It's difficult to give an exact number, but studies estimate that millions of marine birds, fish, and other marine life die yearly because of plastic pollution. Plastic ingestion can cause various issues in marine life, including suffocation, entanglement, and ingesting harmful chemicals.

The discovery of ‘plasticosis’ in seabirds is just one example of how plastic pollution impacts our wildlife. The fact that birds are ingesting so much plastic that it's causing a new disease to emerge is a clear sign that we must take urgent action to address this issue. It's heartbreaking to think of the suffering these animals are going through due to our plastic consumption, and it's up to us to make changes to reduce the harm we're causing.

 While reducing our plastic consumption and adequately disposing of plastic waste is crucial, it's also important to recognize that even if we stopped producing plastic today, we could not undo the damage we have already done to the planet. The microplastics that have already entered our oceans and food chains will continue to persist for hundreds, if not thousands, of years, causing harm to marine life and humans alike. Recent studies have shown that microplastics have intruded into humans' saphenous veins due to consuming contaminated food and water. These tiny particles can cause damage to the circulatory and immune systems, and studies have linked microplastics to cancer, infertility, and other diseases.

We must ask ourselves: If we don't act now to curb this pollution, what kind of planet will we be leaving for future generations? Will it be a world where our bodies are contaminated with tiny particles of plastic that can cause serious harm? Will our descendants inherit a polluted, depleted earth we failed to protect? The time for action is now - we owe it to our posterity to protect the only home we have. By reducing our plastic consumption, properly disposing of plastic waste, and supporting efforts to clean up our oceans, we can help ensure that our children and grandchildren inherit a healthy, vibrant planet.

Microplastics have become ubiquitous, infiltrating every corner of our planet and posing a significant threat to our health and the environment. We need to act fast to address this problem, which starts with education and awareness. By understanding microplastics' health impacts and ecological hazards, we can begin to take steps toward mitigation and prevention. It's not just up to individuals – policymakers, the private sector, and other stakeholders must also play a role in finding solutions. This article aims to raise awareness about the growing problem of microplastic pollution and encourage action to reduce its negative impacts.

The scale of the Problem

Let us understand the magnitude of the plastic problem at our table. According to a recent study, the total global production of all polymers, synthetic fibers, and additives from 1950 to 2015 was approximately 8300 million tonnes of plastic. Of this, 30% (2500 million tonnes) of primary plastics were still being used as of 2015, while 55% (4600 million tonnes) went straight to landfills or were discarded. Incineration accounted for 8% (700 million tonnes), and only 6% (500 million tonnes) of plastic was recycled. Among the recycled plastic, 100 million tonnes were still in use, 100 million tonnes were burned, and 300 million tonnes were discarded or sent to landfills. Notably, only 9% of the 5800 million tonnes of primary plastic no longer in use since 1950 has been recycled.

How much of this plastic is in our ocean? In 2015, a study published in Science estimated that in 2010, anywhere from 4.8 to 12.7 million metric tons of plastic waste were discharged into the ocean. A recent estimate suggested that yearly plastic waste entering the sea may have increased to 29 million metric tons. It is also estimated that there are currently between 100 and 150 million metric tons of plastic waste in the ocean. According to Vegter et al. (2014), the United Nations Ocean Conference in 2017 projected that by 2050, the weight of plastics in the oceans could surpass that of fish. Plastic pollution permeates every inch of the sea – from microplastics in the food chain to plastic water bottles floating on the surface. However, the Great Pacific Garbage Patch is one of the most famous examples. This monolith of ocean pollution comprises all kinds of marine debris and contains 1.8 trillion pieces of plastic, covering an area twice the size of Texas. Research has shown that microplastics have now reached the Arctic, threatening wildlife and the ecosystem in this pristine region.

How does it get there?

Various sources, such as improper disposal, stormwater runoff, industrial activities, sewage treatment plants, and beachgoers, contribute to plastic pollution in the ocean. Improper disposal includes littering, leaving garbage on the beach, and not properly disposing of plastic waste, leading to its eventual entry into rivers, streams, and the ocean. During rainfall, water carries plastic debris from roads and other surfaces into a storm drain that empties directly into the sea. A significant amount of plastic waste comes from the world's rivers, which serve as direct conduits of trash into lakes and the ocean. According to a study, nearly 80% of global annual riverine plastic emissions into the sea come from 1,000 rivers. The amount of plastic that enters these rivers ranges between 0.8 and 2.7 million tonnes per year, with small urban rivers being the most polluting. Daily-use products such as wet wipes, cotton buds, sanitary products, and microfibers released during clothes washing also end up in waterways. Marine species consume them, eventually making their way up the food chain. Industries such as manufacturing, shipping, and fishing can also contribute to plastic pollution in the ocean through discarded fishing gear and plastic pellets used in manufacturing processes. Beachgoers who bring plastic items, such as water bottles, food packaging, and plastic bags, can also contribute to plastic pollution if not correctly disposed of. Most plastic in our oceans originates from land-based sources, with 50% to 60% transported to the sea via rivers or coastlines. The remaining 40% to 50% comes from marine sources, including abandoned vessels, fishing nets, lines, and ropes.

Microplastics in the Ocean: Sources and Quantities

Microplastics are tiny fragments of plastic debris that measure between 0.001 and 5mm in size and, in some cases, even less than 0.001mm (nanoplastics). These microplastics are likely the most abundant plastic debris in the ocean and are formed through various routes. Some are produced intentionally, such as microbeads in personal care products or plastic pellets. In contrast, others are unintentionally created due to wear and tear from products like tire abrasion or synthetic textile washing. A third formation route is the fragmentation of plastic litter into smaller particles. Estimating and measuring the quantities of microplastics released into the environment is difficult due to the many primary and secondary sources and the need for standardized sampling and measurement methods. However, research suggests that at least 14 million tonnes of microplastics have accumulated on the world's ocean floor, and approximately 1.5 million tonnes of microplastics enter the oceans each year. The influence of sunlight, wind, waves and other factors causes the plastic to degrade into microplastics. Thus, microplastics encompass a very heterogeneous particle assemblage that varies in size, shape, and chemical composition, among other properties. Monitoring and controlling microplastic sources is essential to reduce these tiny particles' impact on the marine ecosystem. It's critical to note that the plastic litter you can see on the ocean's surface, such as whole bottles and plastic bags, only represents 1% of the total plastic in the ocean. The other 99% are microplastic fragments far below the surface. A good analogy would be to compare microplastics in the ocean to sprinkles on a cupcake, except they're spread out over a vast area and can't be cleaned up with a simple swipe of a finger.

Microplastics: Properties, Forms, and Potential Hazards

Microplastics are present in various shapes, sizes, and chemical compositions. Manufacturers use different polymer types to represent each microplastic shape to produce plastics with specific properties such as flexibility, roughness, resistance, and durability. Fibers, films, foams, and fragments are the most common microplastic forms. They usually consist of eight types of polymers: PES, PA, PP, LDPE (polyethylene), PET, PU, PS, and PC.

These microplastics can act as vehicles for chemicals, including those intentionally added during manufacturing and environmental contaminants absorbed onto their surface during use and permanence in the environment. Some harmful microplastic chemicals include styrene, toxic metals, phthalates, BPA, PCB, and PAHs. Research studies have also suggested that aquatic microplastics may carry biofilm-associated opportunistic bacterial pathogens and antibiotic-resistance genes that may interact with gut microbiota. Furthermore, the possibility that microplastics can act as carriers of other potential pathogens, such as fungi and viruses, deserves attention.

Another potentially hazardous property of microplastics is the presence of an eco- or biocorona, which refers to biomolecules and other substances on the surface of the plastic particle that may influence particle uptake, fate, and effects. The composition of the eco- or biocorona is determined by the physicochemical properties of the microplastic and complex particle interactions with the environment (natural matter, biomolecules, chemical contaminants, and microorganisms) and the human body (adsorbed lipids and proteins).

Concerns and Impacts of Microplastic Pollution

Chronic exposure to microplastics is a part of contemporary life, and its environmental and health impacts are uncertain. Microplastics are ingested by many living organisms, from plankton, fish, and large mammals in marine environments to land animals and humans. Microplastics can be consumed through water, soil, and even airborne particles, both indoors and outdoors. They have been found in human foods and beverages such as seafood, drinking water, beer, salt, and sugar.

Microplastic Ingestion by aquatic life and its Implications

Numerous animals that humans consume as food, such as fish (like Atlantic cod, Atlantic horse mackerel, European pilchard, red mullet, and European sea bass), bivalves (like mussels and oysters), and crustaceans (like brown shrimp), have been observed to ingest microplastics. The ingestion of microplastic can happen because microplastics are often mistaken for prey. Once ingested, microplastics can be absorbed, distributed throughout the circulatory system, and enter different tissues and cells, potentially leading to harmful effects. In addition, plastic debris has been found in seafood intended for human consumption and in fish and shellfish sold in markets. Barboza et al.'s recent review revealed that out of the 25 species contributing significantly to global sea fishing, 11 species contained microplastics. The authors calculated that consumers in European countries with high shellfish consumption could ingest up to 11,000 microplastic particles (ranging in size from 5-1000 μm) annually. In China, a study on commercial bivalves reported an average of 2 to 11 microplastic items (ranging in size from 5-5000 μm) per gram and 4 to 57 items per individual bivalve. While microplastics in fish's gastrointestinal tract do not provide direct evidence of human exposure, seafood species consumed whole (such as mollusks, crustaceans, and small or juvenile fish) pose a more significant threat to seafood contamination than gutted fish or peeled shrimp. However, a recent study has found microplastics in the muscles of fish consumed by humans, which is a significant concern.

In addition to human health concerns, some organisms investigated are keystone species* in their ecosystems. Recent studies suggest that micro- and nano-sized plastics can transfer within different food webs, leading to concerns about the bioaccumulation and biomagnification of microplastics, increasing the risks and toxic effects mainly for top predators. An increase in the abundance of microplastics in the marine environment will also affect its bioavailability because the chance of organisms encountering microplastics is enhanced. The top predator population may decrease over time, resulting in potentially adverse consequences for environmental health, biodiversity conservation, ecosystem services, and human food security due to reduced availability. Thus, microplastic pollution can have a cascading effect on the entire food chain, from tiny organisms to apex predators, potentially threatening the health of whole ecosystems.

*(A keystone species is a species that has a disproportionately large impact on its ecosystem relative to its abundance. Keystone species play a critical role in maintaining their ecosystem's structure, function, and diversity. They often have a complex network of ecological interactions with other species. Their removal or decline can lead to significant changes in the ecosystem, including the loss of different species and a reduction in ecosystem services.)

Marine birds are facing a grave threat from plastic pollution in our oceans. The early 1960s saw the publication of the first photograph of a marine bird with much plastic in its stomach. This photograph, which depicted a Northern Fulmar with a stomach full of plastic debris, was taken by a biologist named Eric Hosking in the North Sea. The image was a significant milestone in documenting plastic pollution in marine wildlife. However, recently Chris Jordan's photographs of albatross chicks with plastic-filled stomachs have been widely circulated and have played an essential role in raising public awareness about the devastating impact of plastic pollution on marine birds. A study by an Australian group published a week ago has found that all 30 flesh-footed shearwaters examined on Lord Howe Island had scar tissue inside their stomach lining caused by ingesting large amounts of plastic. This new plastic-induced disease, known as "plasticosis," has raised concerns among scientists about the impact of plastics on human tissue and calls for further research into this pollutant. The study's findings are particularly concerning as it's estimated that around 1200 other marine species also ingest plastic and may suffer similar symptoms.

The Impacts on Human Health

In addition to seafood, microplastics have been reported in other food products, such as sea salt. Sea salts contain about 50–280 microplastics/kg particles made of PET, PUR, PP, PE, PMMA, PA, and PVC. Another study estimated that table salts contain about 550–681 particles/kg, mostly PET, PE, and cellophane particles. When humans ingest microplastics, most of these particles (over 90%) are eliminated through the excretory system via feces. The amount of microplastics retained or cleared from the body depends on their size, shape, polymer type, and added chemicals. Several factors, including the nature of the toxic chemical, exposure characteristics, individual susceptibility, and the effectiveness of hazard controls, influence the adverse effects of exposure to microplastics. Although researchers understand how toxicants are distributed and stored in the human body, the physical effects of accumulated microplastics still need to be fully understood. However, early studies suggest that microplastics can lead to several potentially concerning impacts, such as an increased inflammatory response, size-related toxicity of plastic particles, transfer of adsorbed chemical pollutants, and gut microbiome disruption. In a preliminary investigation, the toxic effects of polyethylene (PE) beads were examined using blood samples taken from two healthy individuals. The PE beads had sizes ranging from 10 to 45 μm and were exposed to blood for 48 hours at concentrations of 25 to 500 μg/mL. The results showed that exposure to these PE beads increased genomic instability, which was demonstrated by an elevated level of micronucleation, nucleoplasmic bridge formation, and nuclear bud formation in human peripheral blood lymphocytes.

Numerous recent studies have documented microplastics in various parts of the human body, including stool, blood, cadaver lung, placenta, and colon. In a study conducted in multiple countries, microplastics were found in the placentas of women, raising concerns about potential impacts on fetal health. A study published in the previous month investigated the prevalence of microplastics in the saphenous vein, one of the major veins in the legs, of patients undergoing heart bypass surgery. The study's findings were surprising, with the number of microplastics in the saphenous vein exceeding previously reported levels in the colon and lungs, indicating that microplastics may be more pervasive in the human body than previously thought.

In conclusion, the widespread presence of microplastics in various food products, including seafood and salt, highlights the urgent need for greater awareness and regulation of plastic pollution. While the human body can eliminate a significant proportion of ingested microplastics, the potential adverse effects of these particles on human health are still not fully understood. Preliminary research suggests that microplastics may have various concerning impacts, such as inflammation, toxicity, pollutant transfer, and gut microbiome disruption. The recent study on the prevalence of microplastics in the saphenous vein of heart bypass surgery patients suggests that microplastics may be more pervasive in the human body than previously thought. These findings underscore the importance of continued research and action to mitigate the environmental and health impacts of plastic pollution.

Mitigation and Prevention Strategies

Microplastics are a global problem that requires international cooperation and policy solutions to address it effectively. There is a growing call for reducing plastic waste, increasing recycling, and promoting alternative materials. It's important to provide readers with information on the latest research and technology that can help mitigate the negative impacts of microplastics, including innovations in waste management, alternative materials to plastic, and other strategies. The role of individuals, policymakers, and industry is crucial in reducing plastic waste and addressing microplastic pollution. The mitigation can be achieved through individual actions, policy changes, and industry practices prioritizing environmental sustainability. Highlighting current international efforts, such as the United Nations' Clean Seas campaign, can help raise awareness and encourage action.

Raising public awareness about microplastics is crucial to tackling this global issue. Education campaigns, community events, and social media can all be practical tools for increasing awareness and promoting behaviour change. By informing the public about the negative impacts of microplastics and providing practical solutions, individuals can be empowered to make more sustainable choices and take action to reduce their plastic footprint. Engaging diverse audiences, including children, young adults, and marginalized communities, is crucial to ensure that everyone is informed and motivated to participate in efforts to address microplastic pollution. By implementing potential solutions at the local, national, and international levels, we can work towards reducing microplastic pollution's prevalence and negative impacts.

What can we do as individuals?

Microplastic pollution is a complex issue that requires collective action at different levels, from individuals to industries and governments. As an individual, here are some steps you can take to reduce the amount of microplastic pollution:

1. Reduce your use of single-use plastics: Single-use plastics significantly contribute to microplastic pollution. You can reduce your use of single-use plastics by carrying a reusable water bottle, using a reusable shopping bag, and avoiding products with excessive packaging.
2. Dispose of plastics properly: Recycle or dispose of them in the appropriate trash bin. Avoid littering, as plastic waste can quickly enter the environment and eventually break into microplastics.
3. Choose natural fibers: Synthetic fibers like polyester, nylon, and acrylic are significant sources of microplastic pollution. When buying clothes, choose natural fibers like cotton, wool, or silk, or look for clothes made from recycled plastic.
4. Use natural cleaning products: Many cleaning products contain microplastics that can end up in waterways. Switch to natural cleaning products that don't have plastic microbeads.
5. Support organizations fighting plastic pollution: Many organizations are working to fight plastic pollution and raise awareness about the issue. You can support these organizations by donating or volunteering your time.

Remember that every little action counts, and even small changes in your daily habits can help reduce the amount of microplastic pollution in the environment.

Selected References

1.      Rotchell, J. M., Jenner, L. C., Chapman, E., Bennett, R. T., Bolanle, I. O., Loubani, M., Sadofsky, L., & Palmer, T. M. (2023). Detection of microplastics in human saphenous vein tissue using μFTIR: A pilot study. PLOS ONE, 18(2), e0280594.

2.      Barboza, L. G. A., Dick Vethaak, A., Lavorante, B. R. B. O., Lundebye, A.-K., & Guilhermino, L. (2018). Marine microplastic debris: An emerging issue for food security, food safety and human health. Marine Pollution Bulletin, 133, 336–348.

3.      Yuan, Z., Nag, R., & Cummins, E. (2022). Human health concerns regarding microplastics in the aquatic environment - From marine to food systems. Science of The Total Environment, 823, 153730.

4.      An, L., Liu, Q., Deng, Y., Wu, W., Gao, Y., & Ling, W. (2020). Sources of Microplastic in the Environment. In Handbook of Environmental Chemistry (Vol. 95, pp. 143–159). Springer Science and Business Media Deutschland GmbH.

5.      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.

6.      Andrady, A. L. (2011). Microplastics in the marine environment. Marine Pollution Bulletin, 62(8), 1596–1605.

7.      Lim, X. (2021). Microplastics are everywhere — but are they harmful? Nature, 593(7857), 22–25.

8.      Geyer, R., Jambeck, J. R., & Law, K. L. (2017). Production, use, and fate of all plastics ever made. Science Advances, 3(7).

9.      Vethaak, A. D., & Legler, J. (2021). Microplastics and human health. Science, 371(6530), 672–674.