Microplastics are tiny fragments of plastic pollution that invade the human body on a daily basis, with individuals unknowingly ingesting them through various means – from eating and drinking to simply breathing. Shockingly, studies estimate that the average person inhales an equivalent of a credit card’s worth of plastic every week, the health implications of which remain largely unknown. Recent research in 2022 discovered microplastics lurking in the deepest recesses of the human lung, marking a significant turning point in our understanding of the impact of plastic pollution on human health.
Scientists around the world are scrambling to unravel the mysteries surrounding the fate of these plastic pollutants once they enter our bodies. Researchers at the University of Technology Sydney (UTS) have made significant strides in tracking the passage of plastic through the respiratory system. Their latest study builds upon previous research efforts by comprehensively mapping how air and particles flow through the entire respiratory tract, from the nasal cavity down to the 13th generation of the bronchial tree.
The UTS study considers three different breathing rates – slow, medium, and fast – as well as three distinct sizes of plastic fragments: large microplastics, microplastics, and nanoplastics. Their findings reveal a delicate interplay between gravity, which pulls plastics onto surfaces, and wind, which propels them along the airways. Interestingly, the study shows that at a normal breathing rate, microplastics in the air can cover up to half the surface area of the nasal cavity.
At slower breathing rates, medium-sized pollutants tend to accumulate in the upper airway, including areas like the nasal cavity, voice box, and the junction between the windpipe and the throat. Conversely, smaller particles are more evenly distributed throughout the upper and lower respiratory tract. The research team notes that larger microplastics exhibit a propensity for rapid deposition in the upper airways, while smaller nanoplastics are more likely to escape or penetrate deeper into the lung.
The implications of microplastic pollution on human health are alarming. Notably, the smaller the plastic fragment, the higher the likelihood of it reaching deep into the lung, potentially infiltrating critical regions like the alveolar sacs where gas exchange occurs. Moreover, it’s not just degraded plastic products that pose a threat; everyday items like toothpaste, which contain tiny plastic fragments, also contribute to the problem.
Experimental evidence indicates that inhaling these minuscule plastics can trigger inflammation, oxidative stress, lung tissue damage, and even systemic dysfunction in the respiratory tract. While most research on the health effects of microplastics has been limited to animal models and cell studies, recent findings among surgery patients suggest a link between plastic exposure and heightened risks of heart attack, stroke, or death.
In light of these findings, further exploration of the associations between plastic pollutants and cardiac health is imperative. Mechanical engineer Suvash Saha from UTS emphasizes the urgent need for toxicologists to fully comprehend the trajectory and impact of plastic particles once they enter the human body. Ultimately, safeguarding human health requires a thorough understanding of how these ubiquitous microplastics operate in our bodies and what consequences they may entail.
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