Posted by giuliomagnifico 11 hours ago
Clough prepared the substrates while wearing nitrile gloves, which is recommended by the guidance of literature in the microplastics field. But when she examined the substrates to estimate how many microplastics she captured, the results were many thousands of times greater than what she expected to find."
------------------
The very first thing that should have been done is to run results for a substrate that hadn't been placed in the sampler. You need to know what a zero result looks like just to characterize your setup. You'd also want to run samples with known and controlled micro-plastic concentrations. Why didn't they do this? Their results are utterly meaningless if they didn't.
In surface science the baggy clear polyethylene are widely known to be cleaner than other options.
they tracked levels of plastic-related chemicals and fertility markers. after plastic detox 3 out of 6 couples got pregnant.
the whole research process methodology, not just measurement, miss critical assessment
The below meta-study largely discusses sampling methods and protection from cross contamination so everyone here acting like this one study’s somehow invalidates decades of quality research:
>Due to the wide contamination of the environment with microplastics, including air [29], measures should be taken during sampling to reduce the contamination with these particles and fibers. The five rules to reduce cross-contamination of microplastic samples are: (1) using glass and metal equipment instead of plastics, which can introduce contamination; (2) avoiding the use of synthetic textiles during sampling or sample handling, preferring the use of 100% cotton lab coat; (3) cleaning the surfaces with 70% ethanol and paper towels, washing the equipment with acid followed by ultrapure water, using consumables directly from packaging and filtering all working solutions; (4) using open petri dishes, procedural blanks and replicates to control for airborne contamination; (5) keeping samples covered as much as possible and handling them in clean rooms with controlled air circulation, limited access (e.g. doors and windows closed) and limited circulation, preferentially in a fume hood or algae-culturing unit, or by covering the equipment during handling [15], [26], [95], [105], [107]. A fume hood can reduce 50% of the contamination [105] while covering samples during filtration, digestion and visual identification can reduce more than 90% of contamination [95].
So don’t ghost ride the whip about the death of the microplastic plague just yet.
https://www.sciencedirect.com/science/article/pii/S016599361...
> That’s not to say that there is no microplastics pollution, the U-M researchers are quick to say. > > “We may be overestimating microplastics, but there should be none. There’s still a lot out there, and that’s the problem,”
Keeping things meticulously clean on the microscopic level is a complicated task. One of the many reasons why so few EUV chip fabs even exist.
"When Good Intentions Go Bad — False Positive Microplastic Detection Caused by Disposable Gloves" - https://pubs.acs.org/doi/10.1021/acs.est.0c03742
From the study in the OP you cannot derive that current studies on microplastics are not valid. The headline framing that scientists have been measuring their own gloves, is science journalism doing what it does best...
Stearates are water soluble soaps, so any study using standard wet chemistry extraction, and that is most of them, washes them away before analysis even begins. Stearates also cant mimic polystyrene, PET, PVC, nylon, or any of the dozens of other polymers routinely found in environmental and human tissue samples.
Nothing to see here.
> To be honest, after reading some of these microplastics papers I'm starting to suspect most of them are bullshit. Plastics are everywhere in a modern lab and rarely do these papers have proper controls, which I suspect would show that there is a baseline level of microplastic contamination in labs that is unavoidable. Petri dishes, pipettes, microplates, EVERYTHING is plastic, packaged in plastic, and cleaned using plastic tools, all by people wearing tons of synthetic fibers.
> We went through this same nonsense when genetic sequencers first became available until people got it into their heads that DNA contamination was everywhere and that we had to be really careful with sample collection and statistical methods. [1]
It took years to figure out proper methods and many subfields have their own adjusted procedures and sometimes even statistical models. At least with DNA you could denature it very effectively, I’m not sure how they’re going to figure out the contamination issue with microplastics.
I can't imagine wafting your hands over the tubes would change the plastic amounts substantially compared to whatever negative controls the papers used. But again, I am not an expert on this kind of analytical chemistry. I always worry more about batch effects. But it does seem like microplastics are becoming the new microbiome.
But as mentioned elsewhere in the thread, everyone knows that it's possible and take measure to mitigate it.
A paper that said those mitigations were insufficient or empirically found not to work would be interesting. A paper saying "you should mitigate this" is... not very interesting.
From the article:
> They found that on average, the gloves imparted about 2,000 false positives per millimeter squared area.
I dunno, that seems like a lot of false positives. Doesn’t that strongly imply that overestimation would be a pretty likely outcome here? Sounds like a completely sterile 1mm^2 area would raise a ton of false positives because of just the gloves.
Then the tested result is Actual Sample Result - Negative Sample Result.
So you'd expect a microplastic sample to have 2,000 plus N per mm^2, and N is the result of your test.
Maybe so, but plastics are also everywhere in our daily lives, including on the food we eat and in the clothes we wear. As we speak I just took some eggs out of a plastic carton, unwrapped some cheese from plastic wrap, and got oatmeal out of a plastic bag. The socks and pants I'm wearing are made of polyester.
If plastics cause contamination in a lab, would you not also expect similar contamination outside of the lab?
When I was an automation engineer at a lab, each liquid handler alone could go through several pounds of plastic pipette tips in a single day. All of that is made out of plastic and coated in a different thin layer of plastic to change the wettability of the tip. Even the glassware often comes coated in plastic and all these coatings are the thin layers most likely to create microplastics from abrasion (like the force of the pipette picking up the tip!). Throw all the packaging on top of that and there is just an insane amount of plastic.
The only place I've seen more plastic consumed is industrial and food manufacturing where everything is sprayed and resprayed with plastic coatings to reduce fouling.