A blog by an academic who works on microplastics. I summarise new studies, explain how measurements are made, and check how well the claims that keep appearing in the news hold up against the evidence. Every statement comes with its source.
A 2024 study reported more heart attacks, strokes and deaths among patients whose carotid artery plaque contained microplastics. The study is observational, and questions have since been raised about the measurement method it used.
New Studies · 2 November 2026 · Also in Turkish
Finding microplastics in a sample involves collecting it, cleaning it up, identifying the polymer and controlling for contamination. Each step affects the result. A step-by-step guide to what to look for when reading a study.
Methods and Measurement · 2 November 2026 · Also in Turkish
Microplastics are usually defined as plastic pieces smaller than 5 millimetres. Some are added to products on purpose; most come from tyres, fabrics and larger plastic waste wearing down and breaking apart.
The Basics · 2 November 2026 · Also in Turkish
We take in microplastics through food, water and air, but the evidence on what that does to our health is still thin. A look at where things stand, based on the World Health Organization's reviews, a recent clinical study and the debate over measurement methods.
Health · 2 November 2026 · Also in Turkish
The EU has restricted microplastics added to products on purpose since 2023, but as of 1 November 2026 there is still no global plastics treaty. A referenced summary of the rules in force and the state of the talks.
Policy and Regulation · 2 November 2026 · Also in Turkish
Every link in that chain can change the result.
Illustrative drawing; the particle counts are not measurements.
Water, sediment, food or tissue: how much is collected, and how, determines from the outset which particles can be counted at all. The review scores sampling method and sample size separately [10].
Question to ask: Is the sample large enough for the particle size being targeted and the concentration expected?
A sample contains a lot besides plastic: organic matter, minerals, tissue. To remove these, the sample usually goes through a digestion step. In the review, this step ("sample treatment") was among the criteria with the lowest average scores [10].
Question to ask: What treatment was used, and was it shown to remove enough of the non-plastic material?
The key distinction here: is a particle called plastic because of how it looks, or because of its chemistry? The polymer type should be confirmed, preferably with FTIR or Raman spectroscopy, Py-GC/MS or TGA-GC/MS [10].
Question to ask: Was the polymer confirmed chemically?
Samples can also pick up particles from outside while in the lab. A blank is a control that goes through every step of the procedure but contains no sample. If particles turn up in the blank too, that count has to be taken into account when interpreting the real sample.
Question to ask: Were blanks used, and are their results reported?
A positive control means adding a known amount of plastic to a sample and measuring how much of it the method gets back. This too was among the criteria with low average scores in the review [10].
Question to ask: Do we know how much plastic the method misses?
Across the 50 studies reviewed, reported concentrations ranged from roughly 0.01 to 100 million particles per cubic metre, a spread of about ten orders of magnitude [10]. So a number from one study should not be compared with a number from another without first looking at how each was obtained.
How are microplastics measured?
[10] Koelmans, A. A. et al. (2019). Microplastics in freshwaters and drinking water. doi.org/10.1016/j.watres.2019.02.054
What microplastics are, the main types and where they come from. A good place to start. 1 post
How people are exposed to microplastics and what the evidence says about health effects. 1 post
Sampling, lab analysis and quality control, and what makes a measurement trustworthy or not. 1 post
Summaries of published papers: what was done, what was found, and where the limits are. 1 post
Bans, restrictions and international negotiations: what is in force and what is still being discussed. 1 post
New to the subject? These three posts cover the basics in order:
Definitions, types and main sources.
Where the evidence stands today.
What to look for when reading a study.
For questions about a post, corrections, or a written comment, see the Contact page. Every post ends with a reference list and citation details.