Chlorinated water adversely affects PEX pipes. I don’t know that the amount of microplastics or nanoplastics has been quantified in a study yet.

https://pubs.acs.org/doi/10.1021/acs.est.9b03673

The mechanical properties and lifetime of PEX were reduced after exposure to chlorinated water. (6) Prompted by concerns about the effect of chlorine dioxide on the chemical integrity of pipe materials, the pressure, tensile strength, and oxidation induction time were evaluated at constant temperature to assess the damage to pipe samples after exposure to chlorine dioxide for one year. (7) Overall, pipe aging due to long-term disinfectant exposure could cause decreased antioxidant contents; increased crystallinity; chain rupture; hydroxyl, carbonyl, and/or vinyl group production; and visible cracks in pipe walls.

Can such an aging process lead to MP and/or NP leaching into the drinking water network? On the basis of aging mechanisms and material performance characteristics, we propose that MPs and/or NPs can be leached from aging pipes.

The Brita pitcher comment is about my own growing paranoia about plastics that get scratched or cracked. I don’t know the conditions and time line under which this particular formulation of plastic keeps it from shedding MPs.

There’s also carpeting, synthetic fibers from clothing, PVC and PEX piping for water supply, paint, etc. The one that gets me is the plastic Brita filter pitcher. This thing is supposed to clean my water.

It took us decades to get to this point and it’ll take us more time to back out of it. And we have to start somewhere.

There are (huge) costs to retooling production to move from imperial to metric. Even if a company wanted to make that move they’d have to transition in phases and will likely end up with additional equipment to maintain. There’s also significant training for workers (who will likely commit errors in the beginning) which will impact production. And what happens to the old equipment? I’d guess a significant portion of that would end up getting scrapped and landfilled.

omg thanks for asking