Microplastics and Nanoplastics: Hard to See, Harder to Stop

Dr. Prithu Mukhopadhyay, Editor-in-Chief of the Journal of Vinyl and Additive Technology, shares insights on microplastics and their impact.

Polymers (plastics) have indisputable benefits as a material. We see, touch, and carry plastic items every day. Their macromolecular architecture and ability to generate shapes as needed make plastics versatile. Now, the bad news: Plastics are in water, air, and the human body, including the brain, everywhere. If one is unfamiliar with the basics of microplastics (MPs), the constant barrage of news about MPs and nano-plastics (NPs) can be overwhelming.

You can also read: Microplastics and Nanoplastics: What Science Tells Us About Their Effects.

When news about micro- and nano-plastics (MNPs) is shared without proper understanding, it can lead to divided opinions. People involved in the plastics industry will have a different opinion from those who are not. The paradox of this divide is that plastic developers and formulators are aware of the risks associated with MNPs if released. In contrast, health-conscious individuals are less likely to understand real risks, overlooking the benefits of plastic. The question is: How do we separate the wheat from the chaff?

From Background to Breakthroughs: Why All the Attention Now?

Microplastics (MPs), nanoplastics (NPs), or collectively micro- and nanoplastics (MNPs), have existed since the birth of plastics as materials. Visible or not, these tiny particles are now ubiquitous, detected from the summit of Mount Everest to Antarctic snow [1], and from tap water to bottled water.

“Microplastics” was first coined in 2004 in the landmark paper Lost at Sea: Where Is All the Plastic? [2]. At the time, researchers noted that the potential transfer of toxic substances from plastics into the food chain remained unproven. Two decades later, science has advanced: MNPs have been found to enter the human body easily through breathing, drinking, and eating, bringing the issue squarely into public and scientific focus [3].

Significantly, any polymer, including fluoropolymers (PFAS) and elastomers, can degrade into MNPs [4]. For instance, fluoropolymer coatings used in commercial bakeries or non-stick cookware release fluoropolymer particles during cleaning [3]. Similarly, researchers established that an antioxidant additive in tire treads, 6PPD-quinone, contributed to the deaths of coho salmon returning to spawn in Pacific Northwest streams [5]. These findings reinforced how diverse sources contribute to the MNP problem and why concern has intensified.

Microplastics in the Human Body: From Placenta to Arteries

Research findings over the past few years have provided compelling evidence of MNPs in human tissues. In 2021, Italian scientists reported the first detection of microplastics in human placentas [6].

In 2024, a multicenter observational study involving 257 patients, published in the New England Journal of Medicine, found that patients with carotid artery plaque containing MNPs had a significantly higher risk of myocardial infarction, stroke, or death compared with those without MNP presence [7]. Such findings link MNPs not only to biological presence but also to potential clinical outcomes.

The implications are complex. Plastics are not uniform—different polymeric materials exhibit a broad spectrum of toxicity. Some may pose risks, while others may not. This complexity underscores the challenge in drawing universal conclusions and highlights the need for careful, material-specific study.

Emerging Evidence: Brain Accumulation and Everyday Exposure

The latest studies continue to expand the scope of concern. In February 2025, researchers at the University of New Mexico reported in Nature Medicine that MNPs were present in the liver, kidneys, and brain, with brain tissues containing 7–30 times higher concentrations than the other organs. Notably, brain samples from dementia cases exhibited even greater accumulation [8].

You can also read: Detecting Microplastics in the Human Brain.

Other surprising sources are also emerging. At the American Chemical Society’s Spring 2025 meeting, UCLA researchers presented findings that chewing gum can shed MPs directly into saliva [9]. These findings suggest that human exposure is not only environmental but can also occur through seemingly harmless daily habits.

Taken together, these findings emphasize why microplastics and nanoplastics dominate current scientific and industry discussions. Concerns about human health are not sudden or unexpected but rather the result of growing, consistent evidence over two decades. The proof, as the saying goes, is in the pudding.

Can One Distinguish Between Micro- and Nano-Plastics?

Scientists classify MPs into two sources: primary and secondary. Manufacturers produce primary MPs as microbeads for products such as paints, abrasives, and cosmetics, although regulations now restrict their use in cosmetics.

Plastics, however, inevitably age, which causes them to decompose and fragment. Mechanical agitation, exposure to heat, UV, ozone, moisture, or contact with chemicals such as chlorine can damage plastics and break them into smaller pieces. For example, repeated dishwashing or microwaving of a plastic container produces rough patches on the surface—evidence of fragmentation [3].

Studies have shown that these smaller plastic particles, often invisible to the naked eye, are secondary MPs. Scientists define MPs as particles smaller than 5 mm. With continued degradation, these fragments may shrink further into nanoscale particles, less than 1 μm in diameter, which are referred to as nanoplastics (NPs) [10]. A single microplastic can generate trillions of NPs, and that scale of breakdown remains a central challenge.

MNPs Identification Challenges

The difficulties in identifying and/or quantifying MNPs stem from their variety and heterogeneity. Chemical compositions (additives, pigments, or non-pigmented), particle size, and shapes (morphology) make it challenging to characterize them. Then there is the effect of the environment, often dynamic, such as air, water, effluents, tissues, and so on, where these particles are found. Many studies report data based on laboratory-produced MNPs, which are not equivalent to the naturally found MNPs.

You can also read: Advancing Microplastics Characterization with FT-IR Microscopy.

Conventional single-particle chemical imaging techniques (FTIR, SEM, AFM, Raman) have problems with sensitivity, specificity, and throughput to analyze real-life MNP samples. Novel methods like SRS microscopy are emerging [11]. Interlaboratory comparison is necessary for method improvement and harmonization [12]. This will aid in the separation of MNPs and the development of effective membranes based on particle sizes, shapes, and the release of additives. Without standardized methods and procedures, determining MNP types and quantities will be difficult. Works, however, have been initiated, and results are being reported.

In Conclusion

• A direct relationship between MNPs and health is yet to be established. Many observational studies have shown that the effects of MNPs in living organisms, as well as humans, are detrimental.
• Researchers need to develop accurate (reproducible), cost-effective, and standardized methods to determine the presence of MNPs in any system. Then, meaningful mitigating policies can be created.
• More realistic research is needed on how to mitigate the presence of micro- and nano-plastics for human health and the environment. Collaborations across geographic regions are necessary to pool knowledge in MNPs and expertise in instrument handling.
• While effective plastic waste management strategies are crucial, the separation and identification of MNPs are equally important. Safety, sustainability, and circularity of plastics need to consider their fate as MNPs.
• An opportunity for the plastic industries to work closely with academia for the safety of public health, essentially the customers.

Regardless of one’s opinion about plastics, micro- and nano-plastics (MNPs) are here to stay for now.

References

[1] A. L. Kelly et al., “First evidence of microplastics in Antarctic snow; Microplastics in Antarctica – A plastic legacy in the Antarctic snow?,” Science of the Total Environment, 2022.

[2] R. C. Thompson et al., “Lost at Sea: Where Is All the Plastic?,” Science, 2004.

[3] M. F. Fadare et al., “Release of Micro- and Nanosized Particles from Plastic Articles during Mechanical Dishwashing,” Environmental Science & Technology, 2020.

[4] J. Henry et al., “Are Fluoropolymers Really of Low Concern for Human and Environmental Health and Separate from Other PFAS?,” Integrated Environmental Assessment and Management, 2021.

[5] J. N. Tian et al., “A ubiquitous tire rubber–derived chemical induces acute mortality in coho salmon,” Science, vol. 371, no. 6525, pp. 185–189, 2021.

[6] A. Ragusa et al., “Plasticenta: First evidence of microplastics in human placenta,” Environment International, vol. 146, 2021.

[7] L. Marfella et al., “Microplastics and Nanoplastics in Atheromas and Cardiovascular Events,” New England Journal of Medicine, vol. 390, no. 6, pp. 574–583, Feb. 2024.

[8] A. Brahney et al., “Bioaccumulation of microplastics in decedent human brains,” Nature Medicine, Feb. 2025.

[9] American Chemical Society, “Chewing gum can shed microplastics into saliva, pilot study finds,” ACS Spring Meeting, Mar. 2025.

[10] M. Gigault et al., “Nanoplastics are neither microplastics nor engineered nanoparticles,” Nature Nanotechnology, vol. 16, pp. 501–507, 2021.

[11] H. Chen et al., “Rapid single-particle chemical imaging of nanoplastics by SRS microscopy,” Nature Communications, vol. 13, 2022.

[12] K. Primpke et al., “Interlaboratory Comparison Reveals State of the Art in Microplastic Detection and Quantification Methods,” Analytical Chemistry, vol. 92, no. 24, pp. 14877–14885, 2020.

Written by Dr. Prithu Mukhopadhyay, Editor-in-Chief of the Journal of Vinyl and Additive Technology

Edited for online by MSc. Juliana Montoya