Can the Human Body Expel Microplastics?

Most microplastics can be excreted through the digestive system, but a small fraction may be absorbed by the intestines or accumulate in organs. The long-term health risks of such accumulation remain unclear, and there is no definitive evidence that the body can eliminate all ingested microplastics entirely. Therefore, minimizing daily exposure is crucial.

1. The Fate of Microplastics in the Human Body

• Excretion via feces: Studies suggest ~90% of ingested microplastics pass through the intestines with food waste, as larger particles (0.1–5 mm) struggle to penetrate gut barriers.
• Potential absorption: Nanoscale particles (<0.1 µm) may enter the bloodstream or lymphatic system via intestinal cells, depositing in organs like the liver and kidneys. Animal studies indicate these particles could trigger localized inflammation.
• Long-term retention risks: While microplastics are chemically stable, their surfaces may adsorb heavy metals or persistent organic pollutants (e.g., PCBs), amplifying toxicity. Additives (e.g., plasticizers) might also leach over time.

2. Primary Pathways of Human Exposure

Dietary intake:

• Bottled beverages: Contain dozens to hundreds of particles per liter.
• Seafood/salt: Shellfish/fish ingest microplastics via gills or feeding, entering the food chain; trace amounts are also found in sea salt.

Inhalation:

• Airborne particles from synthetic textiles/tire wear can enter the lungs.

Personal care products:

• Toothpastes/exfoliants with plastic microbeads may breach the skin or cause oral exposure.

3. Practical Tips to Reduce Exposure

- Switch packaging: Opt for biodegradable/glass/stainless steel over plastic bottles/bags.

- Diet adjustments:

•  Rinse shellfish viscera thoroughly.
•  Choose salt packaged in non-plastic materials.
•  Use water filters (replace cartridges regularly).

- Avoid microbeads: Check labels for polyethylene (PE)/polypropylene (PP) in scrubs.

- Lifestyle changes:

•   Minimize takeout packaging.
•   Clean indoor air to reduce plastic dust.

4. Ongoing Research & Unanswered Questions

• Detection limits: Current tech struggles to trace nanoplastics; actual bodily loads may be underestimated.
• Long-term effects: Animal studies link microplastics to endocrine disruption/gut microbiome damage, but human data are scarce.
• Vulnerable groups: Children, pregnant individuals, or those with compromised immunity may face higher risks, warranting targeted safeguards.
• While the body can expel some microplastics, proactive exposure reduction is the best defense until further research clarifies long-term impacts.