Plastics Part 2 – Plastics in Our Bodies

Microplastics Part 2 – Toxins in Our Bodies

Fast Facts

• Microplastics have been found in human blood, lungs, liver, placenta, and breast milk.
• We may ingest or inhale tens of thousands of particles per year.
• Plastics act as carriers for toxic chemicals like PCBs and heavy metals.
• Wildlife impacts include blocked digestion, infertility, and immune damage.
• The long-term human health impacts are still being uncovered—but warning signs are clear.

Plastic in Our Bodies: How It Gets In, What We Carry, and Why It Matters

Plastic pollution is no longer just an environmental issue—it’s becoming a health issue. Tiny plastic fragments—known as microplastics and nanoplastics—are showing up in our air, water, food, and even in human tissues. This isn’t science fiction; it’s increasingly supported by emerging research. Below is a deep dive into how plastic ends up inside living beings, how much may accumulate, and the health and ecological risks we’re only beginning to understand.

1. How It Gets In

Plastic doesn’t magically vanish—it breaks down into ever-smaller pieces, infiltrating nearly every ecosystem. These fragments find multiple paths into our bodies:

Ingestion

• Food & water: Microplastics are present in tap water, bottled water, seafood, salt, sugar, honey, and even produce.
• Trophic transfer: Animals we eat (fish, shellfish) often ingest microplastics themselves, which then pass “up the food chain.”  
• Leaching from packaging: Plastic containers or films in contact with food may shed tiny particles, especially under heat or wear.

Inhalation

• Airborne microplastics and nanoplastics: Fibres and particles drift in indoor and outdoor air. Some studies estimate humans inhale thousands to tens of thousands of plastic particles each day.  
• Dust and fibres: Household dust, synthetic textiles, tire wear, and building materials contribute plastic fibres that become airborne.

• The skin is generally a strong barrier, but under certain conditions—tiny particles, abrasions, or chemical carriers—some plastics or associated chemicals might penetrate skin layers.  

Dermal (skin) contact

Once inside, the smallest particles (microplastics under ~10–20 micrometers, or nanoplastics) may cross cell membranes, enter tissues, or even cross into organs like the liver, brain, or placenta. 

2. How Much We Carry

Quantifying exactly how much plastic accumulates in our bodies is difficult—but here’s what the science suggests so far:

• Estimates of ingestion & inhalation: Some models and measurements suggest the average person may ingest or inhale tens of thousands of microplastic particles per year.  
• Presence in tissues: Microplastics and nanoplastics have been documented in human blood, lung tissue, liver, colon, placenta, breast milk, semen, and other tissues.  
• Retention and clearance: The exact dynamics—how long particles stay, whether they accumulate further, or are excreted—remain poorly understood. Some may be trapped in tissues; others may be cleared.  
• Relative burden: One framing from press sources suggests we may be carrying around the equivalent of a “credit card’s worth” of plastic over time (though that’s a metaphor, not a precise measure).

In short: we know there is microplastic burden inside us, but we don’t (yet) know precisely how much, or how it accumulates over a lifetime.

3. Why It Matters

Why should we care about plastic inside bodies? Several compelling reasons:

Physical effects

Particles can irritate tissues, create micro-lesions, provoke inflammation, or interfere with cellular mechanisms. Some may physically block or damage delicate barriers. 

Chemical effects

Plastic particles often carry chemical additives (e.g. phthalates, bisphenol A, flame retardants) or absorb environmental pollutants (e.g. PCBs, heavy metals). These chemicals may leach into tissues, disrupting endocrine, immune, or metabolic systems. 

Synergistic toxicity

Microplastics can magnify the effects of other toxins, by acting as carriers or altering absorption/metabolism of pollutants. 

Systemic and long-term disruption

Over time, chronic low-level exposure may promote oxidative stress, disrupt cellular signaling, interfere with hormone systems, or impair organ function. Eventually, these may raise susceptibility to disease. 

Even beyond individual health, plastic’s presence in bodies underscores how deeply plastic pollution has insinuated itself into the biosphere—there’s no clean “outside” anymore.

4. Health Risks: What the Evidence Suggests

Because this is a relatively new field, many findings are preliminary or from animal or cell studies—but the cumulative evidence raises real concern.

Humans

Here are some of the health risks flagged so far:

System / Condition	Evidence & Mechanisms	Caveats
Respiratory / lung	Inhaled microplastics may trigger lung inflammation, oxidative stress, or asthma-like conditions.	Few direct human epidemiological studies so far
Gastrointestinal / digestive	Ingested particles may damage the gut lining, alter the microbiome, disturb intestinal absorption, or promote colon inflammation/cancer.	Animal and lab models dominate evidence
Reproductive / developmental	Animal studies link exposure to reduced sperm count, ovarian damage, and altered development. Some human studies suggest links to birth weight, gestational age, and fetal growth.	More large-scale human research needed
Endocrine / metabolic	Some microplastic-associated chemicals are endocrine disruptors, possibly affecting hormones, metabolism, and obesity risk.	The complexity of chemical mixtures complicates attribution
Immune system / inflammation	Microplastics may trigger chronic low-grade inflammation, immune dysregulation, or oxidative stress.	Dose thresholds and long-term impacts unclear
Cancer / genotoxicity	Cell studies and models show DNA damage, oxidative stress, and gene expression changes (all known cancer pathways).	No conclusive human cancer data yet

Bottom line: the risks are real and plausible, though the precise magnitudes, thresholds, and cause-and-effect relationships remain areas of active research.

5. Effects in Wildlife & Marine Animals

Plastic inside animals is even better documented than in humans, and the ecological impacts are severe.

Ingestion, entanglement, and obstruction

Many species mistake plastic bits for food. Once ingested, plastics can clog intestines, perforate tissues, or reduce appetite and nutrient absorption. 

Physiological damage

Research has shown damage to gills, liver, digestive tracts, and brain tissues in fish, crustaceans, mollusks, birds, and marine mammals. 

Behavioral & ecological disruption

Exposed animals may change foraging behavior, reproduction, migration, or predator-avoidance patterns. 

Toxic accumulation

Plastics can absorb persistent pollutants (PCBs, DDT, heavy metals). When animals ingest plastics, they may also ingest associated toxins, magnifying harm. 

Food web effects

Microplastics at the bottom of the food chain (e.g. in zooplankton) get carried upward, potentially affecting entire ecosystems and ultimately humans. 

One caution: while many impacts are documented in lab settings (often at higher concentrations), researchers are still working to map real-world exposure levels to ecological outcomes.

6. What We Don’t Yet Know (But Need to)

• Precise exposure thresholds: At what dose do plastics become harmful?
• Long-term accumulation: Do microplastics build up over decades?
• Particle behaviour: How do size, shape, surface chemistry, and polymer type influence biological interactions?
• Human epidemiology: Larger-scale, long-term human studies are scarce.
• Interaction effects: How plastics interact with other pollutants, medications, or lifestyle factors.
• Mitigation strategies: Best ways to reduce exposure on personal, community, and regulatory levels.

7. What We Can Do (Precautionary Steps)

While science catches up, here are practical steps you or your readers can take:

1. Reduce single-use plastics: Favour glass, stainless steel, or reusable alternatives.
2. Avoid heating food or liquids in plastic containers: Heat can speed leaching or shedding.
3. Use water filters: Some filters (e.g. fine-micron filters) reduce microplastic content.
4. Improve indoor air quality: Use HEPA air purifiers, reduce synthetic textile dust, and vacuum regularly with filters.
5. Support policy change: Ban microbeads, mandate plastic reduction, improve waste and recycling infrastructure.
6. Stay informed & demand transparency: Press manufacturers to disclose plastic additives and promote safer alternatives.

8. Conclusion

The idea that “plastic is everywhere” is no longer abstract. It’s personal.

Microplastics and nanoplastics are infiltrating our bodies, our ecosystems, and our food. The health and ecological risks are real, although much is still being uncovered. What is clear: relying only on future research is no longer enough.

The precautionary approach demands we act now. Reducing plastic use, improving regulation, and elevating public awareness.