It would be worth checking that the concentrations of microplastics used in this study are of a similar concentration to those found naturally. Otherwise the research is not very meaningful.
So this article was working with concentrations 10x larger on mice (usually worse ability to filter). Beyond that, they admitted that microplastics did not induce an effect which is most of the plastics found in the ocean, etc...
Get some nice PCBs stuck to plastic particles and they may not trip contamination sensors, but get deposited in your body where the PCBs become mobile again and end up in your system.
> After two months of daily ingestion of nanoplastics at the estimated human consumption dose, nanoplastic-exposed mice exhibited reduced cognition and short-term memory as assessed by standard neurological assessments such as the open-field test, novel object recognition assay, and the Morris water maze.
I'm a bit confused about whether it makes sense to feed the "estimated human consumption dose" of something to a mouse when a human weighs something like 2000 times as much.
If the concentrations of those used in a lab are far in excess of those in the real world, then these results may be of less concern.
It's obviously not possible to give a mouse a smaller dose of microplastics over 30 years and measure the cognitive effects.
This is all to say -- your prior shouldn't be "this thing that was never supposed to go into the body is safe until proven otherwise"