Microplastics: A new public health menace

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Dr. Farrukh A. Chishtie

Microplastics are fast becoming a dangerous public health threat. This comprehensive cover story provides essential information and action items to safeguard your health.

Plastic is woven into daily life in Pakistan. It wraps our groceries, carries our drinking water, lines takeaway meals, covers schoolbooks, and shows up in the thin bags that drift along streets and waterways. We notice plastic when it blocks a drain, burns in a rubbish pile, or gathers at the edge of a river. What we rarely notice is what happens next, when plastic does not disappear but slowly breaks apart into pieces so small that they can travel through air, water, and food.

Scientists call these fragments microplastics. In simple terms, microplastics are plastic particles smaller than 5 millimetres. Some are produced small on purpose, and others form when larger plastics break down under sunlight, heat, friction, and weathering. Once plastics fragment, they spread far more easily than bottles and bags ever could, drifting in dust, mixing into soil, moving through drains and rivers, and reaching the sea. This is why microplastics are now discussed not only as litter, but as a new kind of exposure.

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That word matters. Exposure means something that reaches bodies, not only beaches.

Over the last few years, researchers around the world have reported microplastics in places that make public health professionals pause. Reports have described plastic particles in human blood, lungs, and placenta, suggesting that what is in the environment can enter biological systems. At the same time, scientists have urged caution because measuring microplastics in human tissues is technically difficult, and contamination during sampling and analysis can lead to false signals if strict controls are not used. In January 2026, several experts speaking to The Guardian warned that some high profile “microplastics in the body” findings may be vulnerable to contamination or methodological limits and called for stronger standardization and quality controls across laboratories.

Even with these cautions, two major medical studies have intensified concern and helped move microplastics from an environmental headline into a public health conversation.

In 2024, Raffaele Marfella and colleagues reported in the New England Journal of Medicine that microplastics and nanoplastics were detected in carotid artery plaques removed during surgery, and that patients with detected particles had a higher risk of major cardiovascular events during follow up. The study did not claim that plastics alone caused heart attacks or strokes, but it raised a serious warning that plastic particles may be present in the very tissues involved in cardiovascular disease.

In 2025, A. J. Nihart and colleagues published a study in Nature Medicine reporting microplastics and nanoplastics in human brain tissue, with polyethylene as the dominant polymer, and with evidence suggesting higher concentrations in more recent samples. The authors were careful to note that the findings were associative and did not prove causation. Still, the idea that plastic fragments can be detected in organs central to life and cognition is difficult to ignore.

For Pakistan, this issue deserves attention because the pathways that generate microplastics are all around us. Waste segregation is limited in many areas, open dumping and burning still occur, wastewater treatment and sludge handling are uneven, and plastic packaging is widely used for food and water. When plastic waste is handled poorly, the environment becomes an efficient distribution system for particles that are hard to see and hard to remove.

This cover story will do three things. First, it will explain what microplastics are and where they come from, in language that fits everyday Pakistani life. Second, it will summarize what science currently knows about exposure routes and biological mechanisms, and also what remains uncertain so readers can judge alarming headlines wisely. Third, it will outline what can be done at household, city, industry, and policy levels, because microplastic exposure is not an inevitable price of modern life.

Microplastics are easy to dismiss because they are small. Public health history teaches a consistent lesson: when an exposure is widespread, even moderate risks can become a major burden. The time to take microplastics seriously is before harm becomes routine, not after.

Microplastics: Where do they come from?

If microplastics have become a public health concern, the first question is practical. Where do they actually come from, and why are they now everywhere?

Scientists generally describe two broad origins. The first is plastic that is manufactured small from the start. These are often called primary microplastics. The second, and often larger source, is plastic that begins as bottles, bags, packaging, tyres, and textiles, then breaks down over time into smaller pieces. These are often called secondary microplastics. In a widely cited scientific definition, microplastics are particles under 5 millimetres, but what makes them threatening is not only their size. It is their ability to travel, persist, and accumulate.

The most important point for readers in Pakistan is that most microplastics are not floating out at sea. Many are produced on land and move through ordinary urban systems.

One of the largest sources comes from the friction of transport. Every time vehicles move, tyres wear down. International research has repeatedly identified tyre and road wear as a major contributor to microplastic pollution in cities. The particles are released onto roads, then lifted into the air as dust or washed into drains during rain. In Pakistan, where traffic density is high in many cities and street sweeping and stormwater management are inconsistent, this pathway becomes even more significant. The dust does not only settle on roads. It settles on food stalls, windowsills, school playgrounds, and inside homes.

Another major source is synthetic textiles. Modern clothing often contains polyester, nylon, acrylic, and blended fabrics. When these materials are washed, they shed microfibres that travel into wastewater. Studies in multiple countries have shown that ordinary laundry can release large numbers of microfibres. Where wastewater treatment is limited or filtration is weak, these fibres can pass into rivers or be captured in sludge that later enters soils. In Pakistan, this matters not only because of household clothing, but also because textiles and garment production are major economic sectors. Occupational exposure and industrial discharge can intensify local contamination unless controls are strengthened.

Packaging waste is the source most people recognise. Food wrappers, sachets, bottles, shopping bags, and takeaway containers are designed for short use but persist for decades. Under sunlight and heat, they slowly become brittle. They fragment into smaller pieces, especially where waste is openly dumped, burned, or scattered. A plastic bag that tears in the wind does not vanish. It becomes smaller and smaller, moving into soil, waterways, and air.

Paints and coatings add another less visible stream. Road markings, marine paints, building paints, and protective coatings can shed particles through weathering. Construction activity can increase these particles in urban dust. In fast-growing Pakistani cities, where construction and roadworks are constant, this source is likely underestimated simply because it is rarely measured.

Industrial plastic pellets are another concern. They are small raw beads used to manufacture plastic goods. In countries where pellet loss prevention is enforced, spills are contained. Where enforcement is weaker, pellets can leak during transport and handling, then wash into waterways and break down further. This is not usually visible to the public, but it is a classic example of how a small upstream control can prevent a large downstream problem.

Then there is the link many people do not realise. Wastewater is not just dirty water, it is a transport highway for particles. Even in countries with good treatment, wastewater plants are not designed primarily as microplastics removal systems. They can capture some particles, but not all. In settings where treatment is partial or absent, the pathway is even more direct. Wastewater carries microplastics into rivers. Rivers carry them into deltas and coastal waters. Sludge captures a portion and may then spread particles into soils when used in land application.

This is why microplastics are now detected across ecosystems. They are not a single pollutant. They are the byproduct of a modern plastic economy moving through transport, clothing, packaging, construction, and waste systems.

For Pakistan, this creates a particular vulnerability. Plastic consumption is high, recycling is uneven, waste segregation is limited, and municipal capacity varies drastically from one city to another. Open burning is still practiced in many places, and while burning destroys some plastic, it also produces toxic fumes and leaves residues. Meanwhile, flooding and heavy rains, which are becoming more disruptive, can carry scattered waste from streets and dumps into canals and rivers in a matter of hours. The result is a cycle where plastic fragments build up through repeated stress, not through one dramatic event.

In the next pages, we will move from sources to exposure. Once microplastics are in the environment, how do they actually enter the body through food, drinking water, and air, and who is most at risk in Pakistan?

How microplastics enter the human body

Microplastics become a public health issue when they move from the environment into the body. For most people, exposure happens quietly and repeatedly through three main routes: ingestion, inhalation, and, to a smaller extent, skin contact.

Ingestion through water and food

Drinking water can contain microplastic particles, particularly where sources are contaminated and filtration is limited. Food can also carry particles. Seafood is often highlighted because rivers and coastal dumping deliver plastic pollution into marine ecosystems, and small particles can move through food chains. Studies in different countries have also reported microplastics in items such as salt and some crops, especially where irrigation and soils are affected by polluted water and poor waste handling. In Pakistan, exposure through ingestion can vary widely because people rely on municipal supply, tanker water, bottled water, and home filtration systems of very uneven quality.

Inhalation through dust and air

Inhalation is often underestimated. Microplastics and microfibres can become part of airborne dust, particularly in dense cities with heavy traffic, construction, and open waste. Once particles are airborne, they can be breathed in and deposited in the respiratory tract. This route is especially relevant for people who spend long hours outdoors in traffic corridors and markets, and for workers in textile production, waste collection, recycling, and informal dumping areas where airborne plastic dust may be higher than in typical residential settings.

Skin contact and everyday handling

Skin contact is generally considered a less dominant route than swallowing or breathing, but it still matters because plastics are handled constantly. Some personal care products and household items can contain or shed small particles. While skin is a protective barrier, prolonged contact and micro-abrasions can increase concern when combined with other exposure routes.

Who is at higher risk in Pakistan

Exposure is not equal. Children may receive higher exposure relative to body weight because they play close to the ground where dust settles and often put objects in their mouths. Pregnant women and infants deserve attention because early development is sensitive to inflammatory and chemical stressors. Urban residents living near high-traffic roads, construction zones, and open waste sites may inhale more contaminated dust. Industrial and informal-sector workers who handle plastics, textiles, and waste may face higher exposures through both inhalation and contact.

The key idea to remember

Microplastics should be treated as a public health equity issue. Exposure is shaped by infrastructure, occupation, and neighbourhood conditions, not only by personal choices. Next, we will explain what scientists think happens after microplastics enter the body, and why the smallest particles raise the most concern.

What happens inside the body

Once microplastics enter the body, the central question is not only whether they are present, but what they do. Scientists are still building the full picture, yet several biological pathways appear repeatedly across laboratory and emerging human evidence.

Inflammation and oxidative stress

One major concern is inflammation. When the body encounters foreign particles, immune responses can activate. Researchers have described microplastics as capable of triggering inflammatory signalling and producing reactive oxygen species, which can lead to oxidative stress. Oxidative stress is important because it can damage cells and tissues over time and may contribute to chronic disease processes.

Immune disruption and microvascular injury

Inflammation does not always remain local. Microplastics may contribute to broader immune changes, including altered immune regulation. Another concern is microvascular injury, meaning effects on the smallest blood vessels that supply organs. These pathways matter because long-term, low-level injury is how many chronic health burdens develop, especially when combined with other stressors such as air pollution, poor nutrition, and infections.

Endocrine disruption and chemical additives

Plastics are not chemically neutral. Many contain additives that give plastics flexibility, durability, colour, or flame resistance. Scientists have raised concern that some additives can interfere with hormonal systems, especially with repeated exposure. Microplastics can also act as carriers. Their surfaces can adsorb pollutants such as persistent organic pollutants and heavy metals, creating a combined exposure that is not just a particle problem but a chemical mixture problem.

Why size changes risk

Size strongly shapes what microplastics can do. Larger microplastics may pass through the gut and be excreted, although not always. Smaller particles, including nanoplastics, raise greater concern because they may cross biological barriers more easily and reach deeper tissues. This is why recent studies have focused not only on microplastics, but also on nanoplastics, which can be more biologically mobile.

What science can say responsibly

It is important to be accurate and balanced. Scientists have identified plausible mechanisms that explain how microplastics could contribute to harm, and recent medical studies have shown that plastic particles can be detected in human tissues. However, researchers are still working to establish clear dose thresholds, long-term causality, and how microplastics interact with other major risks such as smog, toxic metals, and infectious disease burdens.

Next, we will summarize the most high-impact human evidence that has intensified concern globally, and what it does and does not prove for public health policy.

The human evidence that changed the conversation

For years, microplastics were discussed mainly as an environmental threat to oceans, fish, and wildlife. That began to shift when researchers started reporting plastic particles in human tissues. The public debate changed further when two major medical studies, published in leading journals, connected microplastics and nanoplastics to organs and diseases that people immediately recognize as life changing.

A 2024 cardiovascular warning

In 2024, a research team led by Raffaele Marfella reported in the New England Journal of Medicine that microplastics and nanoplastics were detected in carotid artery plaques removed during surgery. The same study reported that patients with detected particles experienced a higher risk of major cardiovascular events during follow up. The authors were careful about interpretation. The findings do not prove that microplastics alone cause heart attacks or strokes. But they do raise concern that plastic particles may be present in the tissues involved in atherosclerosis, and that their presence may be linked with worse outcomes.

A 2025 brain bioaccumulation alarm

In 2025, researchers including A. J. Nihart published in Nature Medicine that microplastics and nanoplastics were detected in decedent human brain tissue, with polyethylene reported as the dominant polymer. The study also suggested higher concentrations in more recent samples, a detail that has drawn serious attention because it implies rising exposure over time. Again, the authors did not claim that the particles directly caused neurological disease. But the idea that plastic fragments can be detected in the brain has intensified concern and strengthened calls for precautionary public health action.

What these studies do and do not prove

These findings matter because they move beyond theory. They show that microplastics and nanoplastics can be present in human tissues involved in major disease pathways. Yet responsible public health messaging must also state limits. These studies cannot, on their own, define a safe exposure threshold, identify which sources drive the highest risk, or separate microplastics from other co-exposures such as air pollution, metals, and industrial chemicals. They also highlight why detection methods and contamination controls must be rigorous and standardized across laboratories.

Why this matters for Pakistan

Pakistan carries a heavy burden of cardiovascular disease, alongside widespread exposure to air pollution and inconsistent access to clean water. Even without definitive causality, the logic of prevention is clear. If plastic particles are reaching the bloodstream, arteries, and brain in measurable ways, reducing environmental microplastics becomes a rational public health strategy, not a luxury. Next, we will explain what microplastics may do across different body systems, and why the same exposure can look different in children, pregnant women, and high-risk workers.

Health impacts across the body

Microplastics are being studied across multiple organ systems because exposure happens through food, water, and air, and because the smallest particles can potentially travel beyond the gut and lungs. The evidence is still evolving, but several health domains repeatedly appear in scientific reviews and laboratory findings, and they align with the biological pathways discussed earlier such as inflammation, oxidative stress, immune disruption, and endocrine effects.

Digestive and metabolic concerns

The gut is a first contact site for swallowed particles. Researchers have raised concern that microplastics may irritate the gut lining, alter the gut microbiome, and contribute to inflammatory signalling. This matters because gut inflammation is linked with broader metabolic consequences and may worsen vulnerability in people already dealing with malnutrition, diabetes, or recurrent infections.

Respiratory concerns

Airborne microplastics and microfibres can be inhaled and deposited in the respiratory tract. Scientists have discussed the potential for chronic irritation and inflammatory responses, particularly for workers in textiles, plastics manufacturing, waste handling, and recycling. In Pakistan’s urban context, where smog and dust are already a respiratory burden, added particle exposure may compound risk.

Reproductive and developmental concerns

Researchers have raised concerns that microplastics and plastic additives may interfere with hormonal signalling, and that early life stages may be more sensitive to inflammatory and chemical stressors. The presence of plastic particles in placental tissue, reported in international studies, has intensified calls to treat this as a precautionary maternal and child health issue.

Neurological and immune concerns

The major brain bioaccumulation report described earlier has elevated neurological concern, especially regarding the smallest particles. Immune modulation is another recurring theme, since persistent foreign particles can influence immune signalling and chronic inflammation, potentially shaping vulnerability to other diseases.

All in all, in Pakistan, microplastics should be treated as a risk multiplier, interacting with existing burdens such as air pollution, unsafe water, heat stress, and chemical exposures, rather than as a single isolated hazard.

Moving from measurement to action: what Pakistan can do now

Microplastics science is advancing quickly, but measurement challenges can confuse the public and create room for sensational headlines. Instead of letting uncertainty paralyze action, Pakistan can treat measurement as part of the solution. Better monitoring makes policy smarter, enforcement stronger, and public messaging more trustworthy. The key is to shift from “Can we measure it perfectly?” to “Can we reduce exposure now while measurement improves?”

Why measurement still matters for solutions

Detection is not simple. To identify microplastics, laboratories must separate particles from complex samples such as water, soil, seafood, blood, or tissue, then confirm polymers using specialized techniques. Results can differ depending on methods used, the smallest particle size detectable, and the strictness of contamination controls. This variability is exactly why authorities should not rely on single headlines or isolated studies when making decisions. Instead, they should build a national monitoring approach that is consistent, transparent, and repeated over time.

Contamination risk is also real because microplastics are everywhere, including in laboratory air and equipment. If a lab does not follow strict controls, it can accidentally measure “microplastics in the lab” rather than “microplastics in the sample.” Rather than undermining the case for action, this is a reason to strengthen standards and invest in credible capacity. Nanoplastics raise the hardest questions because the smallest particles are the most difficult to measure and the most biologically concerning. Many laboratories cannot reliably detect nanoplastics at scale, which means current studies may underestimate true exposure. This is why Pakistan should plan solutions that reduce plastics at source, instead of waiting for perfect detection of the smallest particles.

When reading microplastics claims in the media, the most useful questions are practical: What sample was tested? How was the polymer confirmed? What sizes were detectable? What contamination controls were used? What does the study actually claim? Detection in a tissue is an important warning signal, but it is not automatically proof of disease causation. A mature public response can hold both truths at once: evidence is serious, and science is still refining thresholds.

A national solution pathway for authorities

Microplastics are a structural exposure problem. Individuals can reduce personal exposure, but real risk reduction depends on governance, industry accountability, and stronger municipal systems.

Authorities can move immediately on five fronts

First, Pakistan needs a basic national microplastics monitoring and reporting program. This should focus on drinking-water sources, major rivers and drains, wastewater effluent and sludge, coastal seafood zones, and urban air dust hotspots. The purpose is not academic perfection; it is to identify exposure hotspots, track trends, and guide enforcement. Results should be published in clear public dashboards, because transparency builds trust and creates pressure for sustained action.

Second, local governments must tackle the upstream driver: unmanaged plastic waste. Waste segregation at source, reliable collection, and controlled disposal are non-negotiable because open dumping and scattered waste become fragment factories under sun, friction, and floods. Reducing open burning is equally critical, not only because it fragments plastics and spreads residues, but because it creates additional toxic inhalation exposures. Authorities should treat burning as both an environmental and a direct health hazard, and enforce it accordingly.

Third, wastewater and stormwater systems need targeted upgrades. Even where treatment exists, most plants were not designed as microplastics removal systems. Priorities should include practical filtration improvements, maintenance that reduces leakages, and clear rules for sludge handling so captured microplastics do not simply shift from water into soil. Stormwater management is equally important in Pakistan’s climate reality. Heavy rains and flooding can transport large volumes of plastic waste into rivers within hours. Drain cleaning, trash traps, and improved waste collection before monsoon periods are not cosmetic measures. They are microplastics prevention.

Fourth, Pakistan must formalize industry responsibilities. Textile and garment production should adopt microfiber control and better effluent filtration because microfibers are a major pathway. Plastic manufacturers and transporters should prevent pellet losses through containment and handling standards. Packaging and consumer goods producers should be required to contribute to cleanup and recovery through extended producer responsibility, so the financial burden does not sit entirely on cities and low-income communities.

Fifth, policy must reduce unnecessary plastic production and use. Authorities can prioritize restrictions on the most avoidable single-use items, reform procurement so public institutions do not normalize disposable plastic and incentivize safer alternatives that are locally viable. Regulation must be paired with enforcement, otherwise it becomes performative. The goal is simple: less plastic entering the environment means fewer particles in air, water, and food.

What individuals can do without being blamed

Individuals should not be treated as the main solution to a structural problem, but individual steps still matter, especially when they shift social norms and reduce household-level exposure. Use fewer single-use plastics where feasible, especially for hot food and beverages. Avoid heating food in plastic containers and reduce storage of oily or acidic foods in plastic, because heat and certain food types can increase chemical migration. Choose reusable bottles and containers when possible. Where affordable, prefer natural fibers more often, because synthetic clothing sheds microfibers across repeated washing. Simple household habits also matter for waste: separate plastics for collection if services exist, reduce littering, and support local efforts that keep plastic out of drains before rain events.

A practical “action standard” for Pakistan

Pakistan does not need to wait for perfect evidence before acting. A precautionary approach is justified because exposure is widespread, biological plausibility is strong, and recent high-impact human studies have intensified concern. The most reliable public health strategy remains reducing plastic at source, improving waste and water systems, and making industry pay its fair share of prevention and cleanup.

Measurement should be treated as a tool for accountability, not a reason for delay. If authorities commit to transparent monitoring and enforceable action, Pakistan can reduce microplastics in the environment and, over time, reduce the particles reaching human bodies.