Microplastics: The Silent Siege on Planet and People

The maxim “what is good for people must be good for the planet” reflects the interdependence of human health and environmental integrity. Yet, this balance is under grave threat from an invisible but pervasive pollutant - microplastics. Once regarded primarily as an environmental nuisance, microplastics are now recognized as a growing public health concern, with mounting evidence linking them to systemic biological harm.

Microplastics, defined as plastic particles less than 5 millimeters in size, have been found across ecosystems and throughout the human body. They have been detected in the air we breathe, the water we drink, the food we eat, and in nearly all marine species tested, including 98.9% of seafood samples in a recent U.S. study. The average person is estimated to consume or inhale between 78,000 and 211,000 microplastic particles annually.

More alarmingly, microplastics are now routinely found in human tissues, including the lungs, liver, bloodstream, lower limb joints, and even the brain, where concentrations are rising and raising concerns about neurological risks.

Recent studies have detected microplastics in human breast milk, raising concerns about potential health implications for infants. A 2022 study conducted in Rome analyzed breast milk samples from 34 healthy mothers one week postpartum and found microplastics in 75% of the samples. The detected polymers included polyethylene, polypropylene, and polyvinyl chloride, commonly used in packaging materials. Another study published in the Journal of Clinical Medicine in 2024 reported the presence of microplastics in breast milk and suggested a possible association with alterations in the milk's bacterial microbiota.

Although the full spectrum of health impacts is still being understood, emerging research indicates that microplastic accumulation may elevate the risk of cardiovascular events, including heart attacks and strokes, due to their ability to induce inflammation, oxidative stress, and vascular dysfunction. The World Economic Forum’s Global Risks Report 2025 ranks pollution including microplastic contamination among the top 10 global threats, calling for urgent, coordinated global action.

Eating, Drinking, Breathing Plastic

Microplastics exist in various forms - primary microplastics like microbeads, glitter, and nurdles are intentionally manufactured, while secondary microplastics result from the degradation of larger plastic waste. Even more concerning are nanoplastics, ultra-fine particles now detected in remote regions like the Alps, originating from sources such as vehicle tyre wear.

Microplastics, due to their minute size, often bypass conventional water filtration systems and enter the human body through multiple environmental and dietary pathways. These particles have been found in marine and freshwater systems, where they are ingested by organisms such as fish and shellfish, ultimately transferring to humans via seafood consumption - one study estimates an annual intake of approximately 11,000 microplastic particles through seafood alone. Similarly, microplastics have been detected in drinking water and bottled beverages, with bottled water consumers potentially ingesting up to 90,000 additional particles annually. Terrestrial contamination is also significant; the use of plastic mulch and other polymers in agriculture has led to the uptake of microplastics by crops, resulting in their presence in fruits and vegetables. Food processing and packaging further contribute to contamination, with mechanical degradation of plastic materials during manufacturing and storage releasing microplastics, particularly into highly processed foods.

Moreover, airborne microplastics, transported through atmospheric currents and deposited even in remote regions, can settle on food surfaces or be inhaled directly, adding to cumulative human exposure.

The Human Health Implications of Microplastic Exposure

Once inhaled or ingested, microplastics may translocate across epithelial barriers and enter systemic circulation, distributing to major organs such as the liver, spleen, colon, and even the brain.

Experimental studies using cells, organoids, and animal models reveal a wide spectrum of biological disruptions caused by microplastic exposure. In vitro experiments have shown that polystyrene and polyethylene microplastics can induce oxidative stress, membrane damage, and DNA fragmentation in human cell lines. Human organoid models, including airway, liver, intestinal, and neural tissues—have demonstrated functional impairments such as disrupted lipid metabolism, inflammatory responses, and impaired neurodevelopment.

For instance, exposure to polystyrene in liver organoids led to hepatotoxicity and upregulation of stress biomarkers, while forebrain organoids showed compromised viability and altered neural differentiation following prolonged exposure.

Epidemiological evidence, though still limited, points to plausible links between microplastic exposure and chronic disease outcomes. Studies have detected higher microplastic concentrations in the feces of patients with inflammatory bowel disease and in liver tissues of individuals with cirrhosis. Particles have also been found in arterial thrombi, suggesting a role in cardiovascular pathologies. Alarmingly, microplastics have been identified in placental tissue, breastmilk, and infant feces, with exposure levels in infants estimated to be up to ten times higher than in adults, raising profound concerns about developmental toxicity and intergenerational health effects.

Protecting planetary and public health from plastic

Recognized by World Economic Forum as a critical environmental and public health threat, plastic pollution demands swift and coordinated global action to urgently meet Sustainable Development Goal 14.

Key policy interventions include the U.S. Microbead-Free Waters Act (2015), the EU's 2023 ban on loose plastic glitter, and the 2022 UN agreement signed by 175 nations to end plastic pollution. Innovations such as a microplastic-collecting robot fish from Sichuan University and an 87% effective magnet-based extraction technique underscore scientific progress. Hydrogel adsorbents that bind and photodegrade microplastics under UV light, achieving up to 95% efficiency, and cotton-chitin-based sponges derived from squid bone that can remove 99.9% of microplastics from water. In wastewater treatment, membrane bioreactor (MBR) systems combining biological processing and filtration are increasingly employed to trap microplastic residues.

Complementary initiatives like the EPA’s Trash-Free Waters program, Operation CleanSweep, and the Global Plastic Innovation Network are accelerating solutions, including Wasser’s 95% microplastic removal system and biodegradable alternatives like Orgro Fibre’s sapling bags.

Additionally, enhancing public health awareness regarding microplastic contamination is imperative for nurturing informed behavioral change and reducing individual exposure. Disseminating evidence-based knowledge on sources, health risks, and preventive strategies can catalyze community engagement and support for systemic interventions aimed at mitigating microplastic-related hazards.

Final thoughts

Microplastics have emerged as a formidable and omnipresent threat not only to environmental integrity but also to human health, infiltrating every ecosystem and accumulating in vital organs, including the brain and placenta. Mounting scientific and epidemiological evidence links these particles to systemic toxicity, inflammation, and chronic disease, underscoring their potential for intergenerational harm. As nations, researchers, and industries mobilize through legislative action, technological innovations, and global partnerships, it is imperative to integrate robust public health awareness and sustainable practices into the global response. Protecting planetary and public health from microplastic contamination is no longer optional, it is a critical imperative demanding urgent, coordinated, and transformative action.