2. Young-onset cancers (especially colorectal cancer) which were inferred to be caused by a rise in microplastics are being linked explicitly to other mechanisms and cohorts. (https://ascopubs.org/doi/10.1200/JCO.2025.43.16_suppl.3619)
This does not say that and it's irresponsible to summarize it that way. That's a letter addressing a specific study from 2024 (which did record baseline levels because that's a standard experimental design step), arguing that it used an inadequate control so may have had background contamination when reporting the level of microplastics found in bottled water.
A "cohort of core studies" were not involved, and nothing was "judged to have invalid methodology". The study authors also replied, arguing that their choice of blanks was actually the better one: https://www.pnas.org/doi/10.1073/pnas.2415874121
There's been a slightly weird trend of people on HN that seem so eager to judge the microplastic story as overblown and unsupported that they're overstating and overextrapolating the smallest counter evidence into its own competing narrative, as if what we needed were more narratives. Resist this! That's not how good science or science communication is done.
> There's been a slightly weird trend of people on HN that seem so eager to judge the microplastic story as overblown and unsupported that they're overstating and overextrapolating the smallest counter evidence into its own competing narrative, as if what we needed were more narratives. Resist this! That's not how good science or science communication is done.
This is completely true and well stated. However, this sort of rush to counter narrative is imo inevitable as a response the original rush to craft the narrative that we were all gonna die immediately micro plastics unless we did a Marxism right away.
I am deeply concerned for the environment of the Earth, I believe strongly that we should embed that concern into our economics (i.e. priced externalities, etc. ) so that we make a fewer bad decisions that pollute our nest.
However, I have sadly come to feel that many journalists who write about science, and perhaps even some scientists, see their role as activism toward a specific outcome rather than discovering and describing reality as it exists.
So while I agree, it’s not productive, I totally understanding the glee felt at the possible puncturing of the original narrative.
Can't read the full study, but it seems to be specifically about people who run ultramarathons. Which sounds like a very small subset of the general population. I doubt that tiny cohort is in any way responsible for the overall increase in bowel cancer in younger people.
I think those papers mostly show that parts of the microplastics literature were overstated or methodologically weak, not that microplastics are harmless.
The PNAS paper is a pretty good critique of contamination/baseline issues, and I agree some of the “microplastics are causing young-onset cancer” claims got ahead of the evidence.
But the broader concern still exists: people are clearly exposed constantly, particles are being found in human tissue, and there are plausible mechanisms for harm. So no, there is not "much less to worry".
I agree that there is not evidence to "not worry", but many explicit worries are being accounted for.
Also - in terms of human tissue:
"The problem is that some small molecules in the fumes derived from polyethylene and PVC can also be produced from fats in human tissue. Human samples are “digested” with chemicals to remove tissue before analysis, but if some remains the result can be false positives for MNPs. Rauert’s paper lists 18 studies that did not include consideration of the risk of such false positives." (https://www.theguardian.com/environment/2026/jan/13/micropla...)
Summary: dry contact with nearly any laboratory glove will lead to sample contamination and over estimation of microplastics.
They found one type of clean room gloves that contaminate less.
Is there any indication on how bad this really is?
Around 2000 to over 7000 false positives per mm^2 based on the type of glove. Essentially, regular lab gloves shed enough particles to swamp microplastic measurements to warrant switching to clean room gloves for this type of analysis.
It's difficult to avoid contamination, since everything (samples, containers, equipements, etc) will have been in contact with glove at least once, and good decontamination is very hard.
Let's say you want to determine the amount of microplastics in ocean water samples.
You'd create a control by creating saline solution with distilled water and sodium chloride. Then you treat both the control and your sample(s) the same way in the analysis.
Surely something should tick you off when the microplastic levels aren't much lower in your control compared to your actual sample?
Actually bare hands ok while working in food production if correctly washed with an antimicrobial agent, and assuming one doesn't pick his nose on the job.
There is growing evidence that there is much less to worry about on microplastics on several fronts.
1. A whole cohort of core studies have been judged to have invalid methodology due to not recording baseline microplastic levels (https://www.pnas.org/doi/10.1073/pnas.2411099121)
2. Young-onset cancers (especially colorectal cancer) which were inferred to be caused by a rise in microplastics are being linked explicitly to other mechanisms and cohorts. (https://ascopubs.org/doi/10.1200/JCO.2025.43.16_suppl.3619)
> A whole cohort of core studies have been judged to have invalid methodology due to not recording baseline microplastic levels (https://www.pnas.org/doi/10.1073/pnas.2411099121)
This does not say that and it's irresponsible to summarize it that way. That's a letter addressing a specific study from 2024 (which did record baseline levels because that's a standard experimental design step), arguing that it used an inadequate control so may have had background contamination when reporting the level of microplastics found in bottled water.
A "cohort of core studies" were not involved, and nothing was "judged to have invalid methodology". The study authors also replied, arguing that their choice of blanks was actually the better one: https://www.pnas.org/doi/10.1073/pnas.2415874121
There's been a slightly weird trend of people on HN that seem so eager to judge the microplastic story as overblown and unsupported that they're overstating and overextrapolating the smallest counter evidence into its own competing narrative, as if what we needed were more narratives. Resist this! That's not how good science or science communication is done.
> There's been a slightly weird trend of people on HN that seem so eager to judge the microplastic story as overblown and unsupported that they're overstating and overextrapolating the smallest counter evidence into its own competing narrative, as if what we needed were more narratives. Resist this! That's not how good science or science communication is done.
This is completely true and well stated. However, this sort of rush to counter narrative is imo inevitable as a response the original rush to craft the narrative that we were all gonna die immediately micro plastics unless we did a Marxism right away.
I am deeply concerned for the environment of the Earth, I believe strongly that we should embed that concern into our economics (i.e. priced externalities, etc. ) so that we make a fewer bad decisions that pollute our nest.
However, I have sadly come to feel that many journalists who write about science, and perhaps even some scientists, see their role as activism toward a specific outcome rather than discovering and describing reality as it exists.
So while I agree, it’s not productive, I totally understanding the glee felt at the possible puncturing of the original narrative.
"Exercise induced gastrointestinal injury"!
Can't read the full study, but it seems to be specifically about people who run ultramarathons. Which sounds like a very small subset of the general population. I doubt that tiny cohort is in any way responsible for the overall increase in bowel cancer in younger people.
I think those papers mostly show that parts of the microplastics literature were overstated or methodologically weak, not that microplastics are harmless.
The PNAS paper is a pretty good critique of contamination/baseline issues, and I agree some of the “microplastics are causing young-onset cancer” claims got ahead of the evidence.
But the broader concern still exists: people are clearly exposed constantly, particles are being found in human tissue, and there are plausible mechanisms for harm. So no, there is not "much less to worry".
I agree that there is not evidence to "not worry", but many explicit worries are being accounted for.
Also - in terms of human tissue:
"The problem is that some small molecules in the fumes derived from polyethylene and PVC can also be produced from fats in human tissue. Human samples are “digested” with chemicals to remove tissue before analysis, but if some remains the result can be false positives for MNPs. Rauert’s paper lists 18 studies that did not include consideration of the risk of such false positives." (https://www.theguardian.com/environment/2026/jan/13/micropla...)
and Rauert's paper (https://pubs.acs.org/doi/10.1021/acs.est.4c12599)
Summary: dry contact with nearly any laboratory glove will lead to sample contamination and over estimation of microplastics. They found one type of clean room gloves that contaminate less.
Is there any indication on how bad this really is?
Around 2000 to over 7000 false positives per mm^2 based on the type of glove. Essentially, regular lab gloves shed enough particles to swamp microplastic measurements to warrant switching to clean room gloves for this type of analysis.
Shouldn't any lab analysis have control samples to detect environment contamination like this?
It's difficult to avoid contamination, since everything (samples, containers, equipements, etc) will have been in contact with glove at least once, and good decontamination is very hard.
Yes, exactly, that's why you use control samples to get the baseline.
You see how it's a bit of a self-starting problem?
Let's say you want to determine the amount of microplastics in ocean water samples.
You'd create a control by creating saline solution with distilled water and sodium chloride. Then you treat both the control and your sample(s) the same way in the analysis.
Surely something should tick you off when the microplastic levels aren't much lower in your control compared to your actual sample?
Now, I'm worried about people preparing my food with gloves.
“Are you wearing gloves? That’s disgusting. Use your bare hands, you animal.”
Actually bare hands ok while working in food production if correctly washed with an antimicrobial agent, and assuming one doesn't pick his nose on the job.
Picking noses presumably isn't a unique problem to bare hand prep, unless the ungloved finger is somehow a more tempting scoop?
"I only allow robots with stainless steel tools to prepare and serve my food."