Given the previous issue of contamination from the lab and that huge amounts of "sterile" lab stuff is both plastic or wrapped in plastic I'd need to see some serious lvl5 clean-room assurances to take any of these new findings seriously.
It's worse than that. This study analyzed already-extracted brain samples, so even if they could eliminate all contamination during the study, it's still susceptible to contamination outside of the control of the study.
Could it be this?
"Nitrile and latex gloves may cause overestimation of microplastics, U-M study reveals"