Microplastics and Human Health

What are plastics
Plastics production is up from 234 million tons in 2000, reached 435 million tons in 2020, and is projected to keep increasing. Plastics are synthetic materials composed of polymers. There are natural polymers for example: rubber, silk, wool, DNA, and starch. Synthetic polymers include plastic bottles (polyethylene terephthalate), plastic bags (polyethylene), and synthetic fibers such as polyester, polyethylene, copolymers of polypropylene, and polyurethane. Plastics vary in chemical composition and often contain additives.

More than 13,000 chemicals are added to or associated with plastics. Of them, 10 groups of chemicals are identified as being of major concern to health due to their high toxicity and potential to migrate or be released from plastics. These include specific flame retardants, certain UV stabilizers, per- and polyfluoroalkyl substances (PFAS), phthalates, bisphenols, alkylphenols and alkylphenol ethoxylates, biocides, certain metals and metalloids, and polycyclic aromatic hydrocarbons.

What is the fate of plastics in the U.S.
In the United States, plastic typically follows one of several paths after it’s used—most of them not very sustainable.

Ending up in landfills is the most common outcome

• About 70–75% of plastic waste in the U.S. ends up in landfills.
• Plastic can take hundreds of years to break down, and it often just fragments into microplastics rather than fully decomposing.
• These microplastics can leach into soil and groundwater.

A small fraction are recycled

• Only about 5–10% of plastic in the U.S. is actually recycled.
• Many plastics are not economically recyclable due to:
• Mixed materials
• Food contamination
• Low market value

• Commonly recycled plastics:
• #1 (PET) – water/soda bottles
• #2 (HDPE) – milk jugs, detergent bottles

• Most other types (#3–#7) are usually discarded even if placed in recycling bins.

Incineration (waste-to-energy)

• Roughly 10–15% of plastic waste is burned.
• This reduces landfill volume but:
• Releases greenhouse gases
• Can emit toxic chemicals if not properly controlled

Exported waste

• The U.S. exports some plastic waste to other countries.
• After China banned most plastic waste imports in 2018, much of it shifted to Southeast Asia, where it is often:
• Improperly recycled
• Dumped or burned
• Some of this plastic ends up in rivers and oceans.

Environmental leakage

• Mismanaged plastic can escape into:
• Rivers and waterways
• Oceans (contributing to marine pollution)
• Over time, plastics break down into microplastics, now found in:
• Drinking water
• Food
• Human tissues and blood

Why recycling is so limited in the U.S.

• Cheap production of new (virgin) plastic
• Lack of national recycling standards
• Inconsistent local recycling rules
• Limited investment in recycling infrastructure

Microplastics (MP) are Found in Human Tissues
Plastics smaller than 5 mm are termed microplastics. They enter the body primarily through inhalation or ingestion after plastic litter in the environment degrades into smaller plastic fragments. Longitudinal studies suggest increased microplastic concentrations in the human body, with evidence of the presence of microplastics in many human tissues and organs, including the lungs, brain, blood, liver, kidneys, heart and circulatory system, spleen, colon, testes, ovarian follicular fluid, and placenta as well as in human breast milk and infants’ first stools. Inhaled particles that have a diameter of 2.5 μm or smaller can enter the alveoli of the lungs and the bloodstream and accumulate widely in the tissues. 

Many foods, beverages, and drinking water sources contain microplastics, which can enter the body upon ingestion. A 2020 study in Mexico found microplastic contamination in 57 common beverages (soft drinks, beer, cold tea, and energy drinks). Many clothing pieces, cosmetics, and other personal use products contain microplastics and use of these products may lead to increased exposure through accidental ingestion or aerosolized inhalation. A 2024 review of 38 studies investigating 2379 cosmetic and personal care products reported 16.4% contained microplastics. Face scrub was the most commonly tested product and 26.5% of the face scrubs tested contained microplastics.

Known and Potential Health Effects Associated with Microplastics
Observational studies have shown an association of microplastics with adverse health effects, although this does not prove causation. Microplastics appear to act through several overlapping toxic mechanisms, mainly driven by particle properties and the chemicals they carry.

Microplastics’ unique surface area, defined by coarse shapes and heterogeneous material, enables them to act as a vehicle for various contaminants by adsorb or absorb various pollutants on their surface. The additives such as plasticizers, flame retardants, stabilizers, and monomer residues leach from particles and can exert endocrine‑disrupting, neurotoxic, or hepatotoxic effects. Studies have shown that even a low level of microplastic exposure increases oxidative stress, cell membrane organelle damage, mitochondria damage, inflammation, immune response, and DNA damage.

Microplastics appear to act through several overlapping toxic mechanisms, mainly driven by particle properties and the chemicals they carry.

• Gastrointestinal effects: Ingested MPs can alter gut physiology, cause local oxidative stress and inflammation, impair nutrient absorption, and disturb the gut microbiome in animal models.
• Respiratory and cardiovascular effects: Inhaled MPs may induce airway inflammation, oxidative lung injury, and systemic oxidative and inflammatory responses that are implicated in cardiovascular disease.
• Reproductive and developmental effects: Experimental studies indicate impacts on fertility, embryo development, and placental function, likely via oxidative damage, endocrine disruption, and inflammation

One study found that patients with detectable microplastics had a 4.5 times higher risk of a composite of myocardial infarction, stroke, or death from any cause at 34 months of follow-up than those in whom microplastics were not detected.  A postmortem study reported that brain tissue obtained from 12 patients with dementia had higher levels of microplastics than those obtained from 52 individuals without dementia. The DNA damage observed after MP exposure suggests a potential contribution to causing cancer. It has been speculated that the recent increase in colorectal cancer among young people in the U.S. is the result of increased microplastic exposure.

Key points with regard to children’s health:
Microplastics and associated additives are increasingly linked to a range of adverse health effects in children, with the developing fetus and early life particularly vulnerable. Evidence supports potential impacts on neurodevelopment, growth, respiration, metabolism, and reproductive development, though exact doses, critical exposure windows, and which plastic components are most dangerous remain uncertain.​

• Fetal and early-life exposure occurs via placenta, amniotic fluid, cord blood, breast milk, formula, feeding equipment, toys, indoor dust, and air. This early exposure is particularly concerning because of ongoing development and immature detoxification systems.​
• The central nervous system appears especially sensitive. Animal and human data associate micro- and nanoplastic exposure with altered brain development, behavioral changes, and neurodevelopmental disorders, though study methods and exposures vary widely.​
• Beyond neurodevelopment, associations have been reported with fetal growth restriction, preterm birth, obesity, insulin resistance, asthma and other allergic diseases, and puberty timing changes. However, clear causal links and exposure thresholds are not yet defined, and findings can be inconsistent across studies.
• Mechanisms proposed include oxidative stress, inflammation, immune dysregulation, apoptosis, genotoxic effects, and endocrine disruption from plastic additives like bisphenols and phthalates. These pathways can act in concert and may be amplified in children due to developing systems.
• Weaker areas of evidence include precise dose–response relationships, the relative toxicity of different polymers and additives, and long-term outcomes into adulthood. Regulatory and policy actions are evolving as data gaps are recognized.

Practical implications for families and clinicians

• Health practitioners should take environmental histories during prenatal and pediatric visits to identify potential plastic-exposure sources (e.g., feeding bottles, heated food packaging, toys, household dust) and offer advice about practical reductions where feasible (e.g., avoid heating liquids in plastic bottles, minimize dust in homes with children prone to wheeze).​
• Public health and regulatory measures are increasingly focusing on reducing exposure to microplastics and additives, including labeling initiatives and limiting certain microplastic-containing products. Clinicians can support families by staying informed about evolving guidelines and safer material substitutes.
• A fetus or infant may encounter microplastics and additives from multiple routes (placenta, breast milk vs formula, feeding gear, toys, dust, air). Because development is rapid and sensitive, even low-level, chronic exposure could contribute to a spectrum of health outcomes later in childhood or adolescence, though more robust longitudinal data are needed to confirm causality and quantify risk.

What we know and what isn’t settled

• Known concerns: potential impacts on neurodevelopment, growth, respiratory and metabolic health, and reproductive development, with plausible mechanisms via oxidative stress, inflammation, and endocrine disruption.
• Uncertainties: exact dose thresholds, which specific polymers or additives are most harmful, critical windows of vulnerability, and long-term outcomes into adulthood. More high-quality, longitudinal pediatric studies are needed to guide precise risk assessments and policy actions.

Main polymer types in children’s environment
The microplastics most commonly found in children’s environments are polyethylene (PE) and polypropylene (PP), followed by polyester and other synthetic‑fiber polymers such as polyamide (nylon) and acrylics.

• Polyethylene (PE) and polypropylene (PP) dominate in playground sand, soil, and leaves, largely because they are the main plastics used in slides, play structures, rubber flooring, toys, and food‑packaging litter.
• Polyester and other synthetic fibers are the most abundant microplastics in indoor air and dust, shed from children’s clothing, plush toys, carpets, curtains, and upholstery.
• Polystyrene and polyurethane show up in foam‑based toys, cushions, and packaging, while polyvinyl chloride (PVC) appears in some toys, flooring, and pipes.

Where these polymers are found

• Playgrounds and parks: PE‑ and PP‑rich fragments and granules from worn‑down plastic structures, artificial‑turf infill, and litter.
• Homes and bedrooms: Polyester and nylon fibers from clothes, bedding, and stuffed animals; PE/PP fragments from packaging, bottles, and toys.
• Feeding and food: PP‑based baby bottles and food containers, plus PE‑lined packaging and bottles, can release microplastics into milk, formula, and water.

Why this matters for children
Because kids spend so much time on floors, carpets, and playgrounds, and often mouth toys and their hands, they are repeatedly exposed to PE, PP, and polyester microplastics via ingestion, inhalation, and hand‑to‑mouth transfer.

How to reduce microplastics in the environment of a baby or child formula and foods
Reducing microplastics in baby formula and foods is a smart and growing concern. While it’s impossible to eliminate exposure completely, you can significantly reduce it with practical choices at home. Reducing microplastics in a child’s environment is very doable with practical, everyday choices. Here are evidence-based steps that make the biggest difference, focusing on what children are most exposed to: food, air, water, and daily products.

 Food & Drink (highest impact)

• Avoid plastic food containers for hot food. Heat causes plastics to shed microplastics.
• Avoid plastic utensils for hot food
• Use glass, stainless steel, or ceramic for storage, lunchboxes, bottles, and plates.
• If plastic is unavoidable, choose BPA-free, polypropylene (PP) bottles and replace them when scratched or cloudy
• Skip plastic baby bottles and sippy cups if possible; choose glass or stainless steel.
• Don’t microwave or heat formula or food in plastic, even if labeled microwave-safe —heat dramatically increases microplastic release.

• Use ready-to-feed liquid formulas they tend to contain fewer microplastics than powdered formula prepared in plastic containers.

• Limit ultra-processed foods, which often contain higher microplastic contamination.
• Choose loose produce instead of plastic-wrapped fruits and vegetables.
• Rinse foods well

Water

• Use a high-quality water filter (reverse osmosis or activated carbon with ultrafiltration).
• Avoid bottled water, which contains significantly more microplastics than tap water.
• Use stainless steel or glass water bottles for school and outings.

The Home environment––Air & Dust

• Vacuum with a HEPA filter to capture microplastic fibers from dust.
• Wet-dust (mop) floors and other surfaces instead of dry dusting.
• Wash hands frequently, especially before eating.
• Ventilate rooms daily, especially bedrooms and play areas.
• Reduce synthetic carpets and rugs; choose wool or cotton where possible.
• Wash new clothes, bedding, and stuffed animals before use.
• Keep shoes at the door to reduce plastic-contaminated dust indoors.

Clothing & Textiles

• Choose natural fibers (cotton, wool, linen, bamboo) over polyester, nylon, or fleece.
• Wash synthetic clothes less often and at lower temperatures.
• Consider a microfiber-catching laundry filter or washing bag.
• Avoid fleece pajamas and blankets, which shed large amounts of microplastics.

Toys & Everyday Products

• Favor wood, silicone, rubber, or metal toys over soft plastic ones.
• Avoid cheap plastic toys that easily break down.
• Wash baby items carefully––Avoid harsh scrubbing of plastic items, which accelerates microplastic release.
• Choose plastic-free toothbrushes (bamboo handles, soft bristles).
• Skip glitter, slime, and plastic craft materials.

Personal Care Products

• Avoid products with microbeads (often labeled polyethylene or polypropylene).
• Use simple, fragrance-free soaps and shampoos.
• Avoid exfoliating scrubs marketed as “plastic-based.”

Play Spaces & Surfaces

• Choose natural surfaces when possible: grass, dirt, sand, wood chips, or mulch instead of rubberized or artificial turf.
• Avoid artificial turf fields (crumb rubber infill is a major microplastic source).
• When visiting playgrounds, prefer those with wood or metal equipment over heavily plastic ones.
• Bring a blanket made from cotton or wool for sitting instead of plastic picnic mats.

Outdoor Toys

• Choose wood, metal, silicone, or rubber toys (buckets, shovels, balls).
• Avoid cheap plastic toys that crack, flake, or fade—these shed microplastics quickly.
• Skip toys that rub against pavement (plastic ride-ons, scooters with plastic decks).
• Store outdoor toys out of direct sun, which degrades plastics.

Clothing for Outdoor Play

• Dress children in natural fibers (cotton, linen, wool) instead of polyester or fleece.
• Avoid fleece jackets and hats, especially on windy days (they shed microfibers).
• Choose leather, canvas, or rubber shoes over synthetic mesh when possible.
• Wash outdoor clothes separately and shake them outside before washing.

Sunscreen & Personal Products

• Avoid spray sunscreens with plastic polymers (often listed as acrylates or copolymers).
• Choose mineral sunscreens in cream form (zinc oxide or titanium dioxide).
• Skip glittery or “shimmer” sunscreens and body products.

Food, Snacks & Water Outdoors

• Pack snacks in stainless steel or glass containers (with silicone lids).
• Avoid plastic wrap, squeeze pouches, and disposable snack bags.
• Bring filtered water in stainless steel bottles.

After-Play Habits (very effective)

• Handwashing after outdoor play removes dust-bound microplastics.
• Change clothes after playground or park time, especially after sandy or dusty play.
• Rinse hands and face before eating outdoors.

Wind, Traffic & Location

• Play farther from busy roads when possible (tire wear is a major microplastic source).
• Avoid outdoor play on very windy days near traffic or construction zones.

High-impact priorities for highest impact with minimal effort, focus on:

These steps significantly lower a child’s overall microplastic exposure without creating anxiety or requiring perfection.

At home:

• Switching food and drink containers away from plastic
• Filtering drinking water
• Reducing synthetic clothing and household dust

Out of doors:

• Avoid artificial turf and crumb rubber playgrounds
• Use natural-fiber clothing and blankets
• Wash hands and change clothes after play

These steps significantly reduce exposure while keeping outdoor play fun, active, and unrestricted.

Policies to Reduce Plastic Pollution
Although many local and national policies exist to limit plastic pollution, few comprehensive international agreements are currently in place to decrease plastic pollution. Agreements that have been reached include the 2019 Convention Plastic Waste Amendments, which control transboundary movements of plastic waste into countries with limited recycling options (such as insufficient recycling plants or lack of technical expertise to recycle in an environmentally sound manner), and the MARPOL Annex V, a legally binding agreement signed by more than 150 countries that prohibits ships from dumping plastic waste into the ocean.

The United Nations Global Plastics Treaty has been in negotiation since March 2022 after a resolution was adopted to develop an international, legally binding agreement on plastic pollution, including in the marine environment, with a goal of addressing “the full life cycle of plastics, including their production, design, and disposal.”

Although microplastics have been called an “impossible problem” by some policy experts, there is some progress in reducing environmental contamination but there is far to go.

• Some states are introducing:
• Extended Producer Responsibility (EPR) laws
• Bans on single-use plastics
• Companies are experimenting with:
• Chemical recycling (still controversial)
• Reusable packaging systems
• Development of products that do not break up into microplastics even when subjected to extreme conditions

Conclusions
Microplastics have been detected in human tissues at increasing rates and are associated with known and potential adverse health effects, raising concerns over the high levels of plastic pollutants in the air, water, and soil. International cooperation to limit plastic pollution and to find environmentally safe plastic alternatives is needed.

A recent Journal of the American Medical Association (JAMA) Insights article titled “Microplastics and Human Health” (published October 14, 2025, in JAMA) summarizes growing evidence that microplastics—plastic fragments smaller than 5 mm—are widely present in the human body and may pose several health risks.

What JAMA says about exposure

• Microplastics have been detected in air, water, food, beverages, clothing, cosmetics, and many consumer products, leading to continuous low‑level human exposure.
• Studies show microplastics in human blood, placenta, lungs, liver, and other tissues, with concentrations appearing to increase over time.

Potential health effects

• Laboratory and observational data link microplastic exposure to cellular damage, DNA injury, and altered immune responses.
• Higher microplastic levels in tissues have been associated with increased risks of cardiovascular events (heart attack, stroke), dementia‑related outcomes, and earlier mortality, although causality is not yet proven.

Mechanisms and concerns

• Microplastics can carry toxic additives (e.g., phthalates, PFAS, flame retardants) and adsorb environmental pollutants, acting as “vehicles” for these chemicals into the body.
• Their small size and persistence raise concerns about chronic inflammation, oxidative stress, and disruption of endocrine and metabolic systems, particularly in vulnerable groups such as pregnant people and children.

Policy and prevention points in JAMA

• The authors call for stronger international regulation of plastic production and pollution, plus investment in safer alternatives and waste‑management systems.
• They recommend individual‑level measures such as reducing single‑use plastics, choosing glass or metal containers when possible, and minimizing consumption of heavily packaged or ultra‑processed foods to lower exposure.

Reference: Mahalingaiah S, Nadeau KC, Christiani DC. Microplastics and Human Health. JAMA. 2025;334(21):1941–1942. doi:10.1001/jama.2025.14718

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