What Are Microplastics—and Where Are They Found in Humans?

Microplastics are tiny synthetic particles under 5 mm, with nanoplastics even smaller. They emerge from degradation of larger plastics (e.g., bottles, packaging), synthetic textiles, cosmetics, and environmental sources.

Alarming research has traced these particles deep within the human body:

• Placentas: Microplastics were found in all placentas tested, raising concerns about fetal ex

  posure and development.

• Newborn stool: Infants have markedly higher levels of PET microplastics—roughly 10–20 times more than adults.
• Various tissues: Microplastics have been detected in blood vessels, arteries, lungs, the brain, and heart tissues. In patients with arterial blockages, particles were associated with increased risks of heart attack, stroke, and early death.

However, while these findings highlight widespread contamination, the direct health risks to humans remain largely unknown. Studies in labs and animal models show potential for inflammation, oxidative stress, cell damage, immune disruption, and hormone interference—but human evidence is still emerging.

Notably, researchers are raising the alarm: the Australian Medical Association and University of Sydney experts highlight possible links with respiratory issues, chronic inflammation, cancer risk, reproductive impacts, and fetal development concerns—though they underscore the need for more research.

Why Babies and Kids May Be at Higher Risk

Biological and Behavioral Vulnerability

• Higher exposure per body weight: Infants consume more food, drink, and air relative to their size, increasing dose by weight.
• Immature physiological systems: Babies have less mature metabolic and detoxification systems, making it harder to rid their bodies of harmful substances.
• Developing organs: Brain, immune, and barrier systems are at a delicate stage, potentially more vulnerable to disruption.

Observable Exposure and Effects

• Feeding bottles: Studies estimate that infants fed with polypropylene bottles ingest around

  1.6 million microplastic particles per day.

• Airborne and dust exposure: Indoor home air may contain thousands of microplastic particles per gram of dust; baby masks and surfaces can contribute airborne microplastic exposure.
• Breast milk and formula: Microplastics appear in breast milk, infant formula, and storage bags, showing direct exposure routes.
• Potential health concerns: Though causation isn’t proven, studies suggest possible links to developmental changes, neurodevelopmental issues, endocrine disruption, fetal and infant health problems, cancer risk, DNA damage, miscarriage, and fertility effects.

To reduce household microplastic exposure, steps include:

• Avoid plastic for food preparation—use glass containers, skip microwaving plastics
• Opt for fresh, organic food, reduce dust with HEPA filters, wet mopping, and a no-shoe indoor policy
• Favour natural clothing, shop secondhand if possible

Key Takeaways & Final Thoughts

• Microplastics are widespread—found in placentas, infant stools, and multiple organs in both children and adults.
•  The health implications remain uncertain, but lab and early human research raise concerns: inflammation, immune response, hormone disruption, developmental and reproductive impacts.
• Babies and children are particularly vulnerable due to higher exposure relative to body weight, immature systems, and prevalent microplastic sources in their environment.
• You can take practical, cost-effective steps today to reduce exposure: filtering water, reducing plastic use, choosing safer feeding practices, improving indoor air quality.

Australia’s health and environmental communities—including researchers at UQ, CSIRO, and national health advisory bodies—are calling for stronger precautionary policies, improved research, and reduced plastic contamination across the lifecycle. These efforts will benefit current and future generations.