Most microplastic headlines are about detection plastic found in blood, in lungs, in placentas. A study published in July 2026 did something more useful: it measured microplastics and nanoplastics in three matched tissues from the same people, and found a clear pattern in where particles end up and why. That pattern matters for anyone trying to do something practical about exposure.
The study, in one paragraph
Researchers quantified microplastics (MPs, under 5 mm) and nanoplastics (NPs, under 1 µm) in matched samples of blood, bone tissue and intervertebral disc from 21 donors undergoing spinal fusion surgery. They used laser micro-Raman spectroscopy alongside pyrolysis gas chromatography–mass spectrometry (Py-GC/MS) two methods that together can describe particle size, shape and polymer type while also quantifying mass. The paper was published in npj Emerging Contaminants, a Nature Portfolio journal, on 3 July 2026, and is open access.
The headline finding is a gradient: microplastic abundance in blood was significantly lower than in bone and disc tissue (p < 0.05). More interesting than the gradient is the explanation and the specific tissue that behaves like a long-term storage compartment.
The numbers
| Measure | Blood | Bone tissue | Intervertebral disc |
|---|---|---|---|
| Detection rate (MPs) | 21/21 (100%) | 20/21 (95.2%) | 21/21 (100%) |
| Mean MP abundance | 6.74 ± 4.40 n/mL | 13.26 ± 5.49 n/g | 13.55 ± 4.48 n/g |
| Mean particle size | 64.50 ± 38.20 µm | 57.10 ± 33.80 µm | 77.60 ± 53.40 µm |
| Share of MPs < 100 µm | 90.0% | 92.5% | 62.5% |
| Share of MPs > 100 µm | lowest | low | 17.5% |
Two things stand out. First, the size ordering is inverted relative to the concentration ordering: the largest particles were found in the disc and the smallest in blood, with sizes across all tissues ranging from 9.79 to 193.29 µm. Second, discs held a higher proportion of particles over 100 µm than either of the other tissues which is not what you would expect if particles were simply passing through.
Nine polymer types were identified across the cohort: PET, PE, EVA, PS, PP, PDMS, PBT, PVC and PVP. Fragment-shaped PET dominated every tissue, accounting for 58.60% of all detected particles, followed by PE and PS. Blood showed the widest polymer diversity, including trace PDMS, PBT and PVC; bone and disc showed narrower profiles. PBT appeared only in discs, and PET fibres were more abundant there than in blood or bone.
The nanoplastics picture is different — and PVC-heavy
Nanoplastic analysis covered 15 matched tissue samples from 5 donors. NPs were detected in every single sample, at mass concentrations from 0.16 to 20.28 µg/g.
| Polymer | Share of total NP mass | Notable tissue pattern |
|---|---|---|
| PVC | 46.9% | Highest average concentration in bone (7.74 µg/g); 2.39 µg/g in blood |
| PA66 | 31.3% | Relatively enriched in intervertebral discs (6.28 µg/g) |
| PS | 18.8% | Low across all three tissues |
| PMMA | 3.1% | Detected only in one donor’s disc |
PVC and PA66 together accounted for 78.2% of total nanoplastic mass. Note the divergence: PET and PE dominate the microplastic fraction, while PVC and PA66 dominate the nanoplastic fraction. The individual extremes are striking 20.28 µg/g of PVC in one donor’s bone, 18.75 µg/g of PA66 in another donor’s disc.
Why the disc is the interesting part
The intervertebral disc is the largest avascular tissue in the human body. It has no direct blood supply; nutrients arrive by diffusion, and there is no efficient cellular clearance pathway. That is exactly the kind of environment where particles, once in, do not readily leave.
The authors’ reasoning is a combination of entry and exit. Entry into the disc is limited, but possible through three proposed routes: degeneration-associated vascular ingrowth (new blood vessels that grow into a degenerating disc), lymphatic structures recently identified within disc tissue, and cell-mediated transport by immune cells such as macrophages that engulf particles and migrate between tissues. Exit, by contrast, is close to absent.
Retention is then a physical chemistry problem, and this is the detail worth reading twice. The disc matrix is rich in negatively charged proteoglycans and glycosaminoglycan side chains, and weathered microplastics also carry a negative surface charge so direct electrostatic attraction is unlikely. The paper instead points to cation bridging, where divalent cations such as calcium and magnesium crosslink carboxyl or hydroxyl groups on the plastic surface to the anionic matrix, alongside hydrophobic and van der Waals interactions, physical entrapment in the porous GAG network, and local charge heterogeneity that creates stable adsorption sites.
One finding that connects directly to how binding fibres work
Buried in the mechanism discussion is a fact with wider relevance than the disc itself: environmental weathering introduces oxygen-containing functional groups hydroxyl and carboxyl onto microplastic surfaces, which makes their surface charge more negative.
That is precisely the surface condition that makes a cationic (positively charged) material effective at attracting plastic particles. It is also the same charge logic behind chitosan’s proposed gut-binding mechanism, and the same reason chitosan has been used industrially as a flocculant for decades opposite charges attract, particles aggregate, aggregates settle out or move through.
The important distinction is location. The disc finding describes what happens to particles that have already entered tissue. The binding mechanism describes what can happen to particles that are still in the digestive tract. These are different compartments, and conflating them is the central error in most microplastic-detox marketing.
What this study does not show
Being precise about boundaries is what separates a research summary from a sales pitch.
- No intervention was tested. This is an observational, cross-sectional measurement study. It tested no supplement, no fibre, no therapy, and no dietary protocol. Chitosan is not mentioned anywhere in the paper.
- It does not show that anything can remove particles from tissue. It shows that particles accumulate in tissue, particularly in discs. That is a burden finding, not a removal finding — and it strengthens, rather than weakens, the case against claiming that any oral product “cleans” organs or blood.
- Sample sizes are small and the cohort is specific. 21 donors for microplastics and 5 for nanoplastics, all undergoing spinal fusion surgery. Surgical patients are not the general population, and neither the entry pathways nor the phenotype classification can be generalised without larger work.
- No causation. The study reports associations. For example, the paper notes a 4.53-fold higher composite risk of cardiovascular events among people with MNPs detected in carotid plaques, citing Marfella et al. in the New England Journal of Medicine (2024). That is an association reported in the literature, not proof that plastic causes the events.
The risk calculus, read honestly
The study ran a health risk assessment across ingestion, inhalation and dermal pathways. The results deserve to be reported straight:
| Indicator | Result | How to read it |
|---|---|---|
| Hazard quotient (HQ) | Gradient disc > bone > blood; highest disc value 9.0 × 10⁻¹ | All HQ values remained below 1 — within accepted safety limits for chemical risk |
| Hazard index (HI) | Mean 3.8 × 10⁻¹, same tissue gradient | Below 1; the disc was the main contributor in most donors |
| Cancer risk (CR) | No pathway exceeded 10⁻⁶ | Below the conventional threshold of concern |
So by the standard chemical-toxicology measures, these concentrations sit inside the limits. The authors’ concern is elsewhere, and it is worth quoting the framing rather than paraphrasing it away: the substantial nanoplastic sequestration in the avascular disc suggests “an overlooked mechanism of long-term physical burden and potential tissue degradation.” The risk they are flagging is physical and cumulative, not acute chemical toxicity a distinction that matters because it shifts the question from “is this dose poisonous?” to “what does a decade of accumulation do to a tissue that cannot clear itself?”
What the individual variation tells us
Some of the most human detail in the paper sits in the donor-level data:
- One donor had no microplastics in bone at all despite detectable MPs in blood and disc. That donor reported a lifestyle with minimal plastic exposure and no underlying disease. One case proves nothing on its own, but it is the direction the exposure-reduction argument points.
- The highest-abundance donor across all three tissues reported frequent bottled-beverage and takeaway-food consumption. Again: association, not proof.
- Microplastic abundance in blood was negatively correlated with age (p ≤ 0.01), while blood and bone abundance correlated positively with each other (p ≤ 0.01) consistent with systemic circulation distributing particles to tissues.
- Multivariate analysis grouped donors into three accumulation phenotypes: disc-enriched (10 of 21), intermediate, and blood-enriched. Nearly half the cohort sat in the disc-enriched group.
- The features most associated with disc and bone retention were fibre morphology, white colour, larger particle size, and PET/PE polymers. Transparent particles, polypropylene and microspheres tracked with blood instead.
That last point has a practical echo for anyone auditing their own exposure: fibres and larger PET/PE fragments are the fraction that seems to lodge in tissue. Fibres are also the fraction most associated with textiles and airborne dust indoors, which is why indoor air quality deserves a place in any exposure-reduction routine.
What to do with this and what not to
The study doesn’t change the two things that were already true, and it does make both more urgent.
1. Reduce intake before it becomes burden
Every particle that never enters the body is a particle that never needs clearing. That means filtered drinking water (see bottled water vs tap water and microplastics in bottled water), no plastic in heat contact with food (what heating food in plastic does), ventilation against airborne fibres, and attention to where exposure actually concentrates during meals (reducing exposure during meals). The broader route-by-route picture is in microplastics in food and water.
2. Support clearance in the compartment where you actually can
What is demonstrably in your control is the digestive tract particles present there, before they are absorbed or cross into tissue. That is the compartment where a cationic binding fibre has a demonstrated mechanism, and it is why timing matters. Our analysis of the 2025 evidence and its limits is in can chitosan bind microplastics and the detailed study breakdown in chitosan and microplastic excretion research. For the specification question molecular weight, DDA, source see the most effective form of chitosan.
3. Do not claim tissue removal and do not buy from anyone who does
This study is the strongest argument yet for that discipline. Particles demonstrably persist in avascular tissue; no published intervention removes them from there. Any product promising to “flush microplastics from your organs” is, on the current evidence, selling you something that does not exist. Our position on where the boundary sits is set out in how to remove microplastics from your body and the step-by-step version in the microplastic detox protocol.
The practical version
- Cut the biggest leaks first — water and heat-contact plastic beat every supplement decision in impact.
- If you use a binding fibre, take it with meals, at the moment particles enter the gut the logic is covered in how to take chitosan with meals.
- Buy on documentation, not story. Purity, DDA, molecular weight, origin and third-party COAs — the checklist in microplastic detox supplement comparison, and what a label should disclose in Microplastic Protect ingredients.
- Keep dietary fibre high — vegetables and fibre-rich foods support the transit half of clearance: foods that may help remove microplastics.
- Compare candidates honestly — Microplastic Protect vs regular chitosan supplements.
Why this paper is worth a permanent place in the reading list
Most microplastic-and-health research is either a detection study (plastic is here) or a toxicology study (plastic does something in cells). This one sits in the middle and answers a question that had been genuinely open: if particles enter the body, where do they settle, and how long do they stay?
The answer — a gradient favouring bone and disc over blood, larger particles preferentially retained in the least vascular tissue, and nanoplastic mass dominated by PVC and PA66 reframes the practical problem. It is not primarily a question of acute toxicity. It is a question of steady accumulation in tissues with no clearance route. That makes intake reduction the highest-leverage action, gut-compartment clearance support the next most defensible one, and tissue-removal claims indefensible.
For a broader look at where chitosan interacts with particles including the water-treatment and flocculation side, where the same chemistry is used at industrial scale see chitosan for microplastic removal and how the positive charge of chitosan works.
Frequently asked questions
Did this study find microplastics in human bone and disc tissue?
Yes. Microplastics were detected in 100% of blood samples (21/21), 95.2% of bone samples (20/21) and 100% of intervertebral disc samples (21/21). Nanoplastics were detected in all 15 tissue samples analysed from 5 donors.
Is it true that microplastics concentrate in the intervertebral disc more than in blood?
In this cohort, yes. Mean microplastic abundance was significantly lower in blood (6.74 ± 4.40 n/mL) than in bone (13.26 ± 5.49 n/g) and disc (13.55 ± 4.48 n/g), p < 0.05. Note that units differ by matrix — per millilitre for blood, per gram for tissue.
Does that mean a supplement can remove microplastics from discs or bone?
No. Nothing in this study, or in the published literature to date, demonstrates removal of particles already deposited in tissue. The demonstrated scope for an oral binding fibre is the gastrointestinal tract. Treat any product claiming organ or tissue detoxification as unsupported.
Which plastics were most common?
In the microplastic fraction, fragment-shaped PET dominated (58.60% of detected particles), followed by polyethylene and polystyrene. In the nanoplastic fraction the picture reverses: PVC (46.9% of mass) and PA66 (31.3%) together accounted for 78.2% of total nanoplastic mass.
Should I be worried?
The study’s own chemical risk assessment stayed within accepted safety limits all hazard quotients below 1 and no cancer-risk pathway above 10⁻⁶. The authors’ concern is long-term physical burden in tissue that cannot clear itself, which is a cumulative question rather than an acute one. Reasonable action follows from that: reduce intake, support gut-compartment clearance, and be sceptical of anyone selling certainty about the rest.
References
- Li, X., Wang, Y., Feng, Z., Zhang, J., Xing, B., Ding, T. et al. Microplastics and nanoplastics in matched human blood, bone, and intervertebral discs: Accumulation patterns and risks. npj Emerging Contaminants 2, 22 (2026). DOI 10.1038/s44454-026-00041-5. Open access, CC BY-NC-ND 4.0.
- Liu & Shimizu — Ingesting chitosan can promote excretion of microplastics. Scientific Reports (Nature Portfolio), 2025. Cited for the gut-binding comparison; not part of the 2026 tissue study.
- Marfella, R. et al. — Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. New England Journal of Medicine 390, 900–910 (2024). Cited within the 2026 paper.
About this article. Chitosan Global manufactures and supplies chitosan materials across food, agricultural, environmental and specialty applications, with published specifications, third-party testing and technical support. We update this article as new research publishes.
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