The question is not if there is... Any natural fiber will have some because soil always has metals in various amounts and plants pick it up. The question is how much, in what form, and can those forms leach out or be tranformed (by secretions, microbiome...) in forms that can leach.
As is stated in another comment current technology can almost detect single atoms... And virtually every food item would be positive as well.
> The metal concentrations varied by where the tampons were purchased (US vs. EU/UK), organic vs. non-organic, and store- vs. name-brand. However, they found that metals were present in all types of tampons; no category had consistently lower concentrations of all or most metals. Lead concentrations were higher in non-organic tampons but arsenic was higher in organic tampons.
>
> Metals could make their way into tampons a number of ways: The cotton material could have absorbed the metals from water, air, soil, through a nearby contaminant (for example, if a cotton field was near a lead smelter), or some might be added intentionally during manufacturing as part of a pigment, whitener, antibacterial agent, or some other process in the factory producing the products.
(I read the source article relatively fast, not thoroughly but closer than 'skimmed')
Much is made of "measurable" and MDL (method detection limit) using a "using a PerkinElmer NexION 350S Inductively Coupled Plasma Mass Spectrometry with dynamic reaction cell (ICP-DRC-MS)".
Such equipment can almost count atoms.
Even before man idustrialised there were trace metals, toxic metals, to be found at measurable (with modern equipment) levels in the purest clear mountain streams (as water leached lead and other solubles from rocks, etc).
I'm not diminishing the problem here, there is a real danger from industrial by product landing on cotton fields and making its way to human skin .. but what's the baseline?
Do we have a study on raw cotton from various fields?
Australian cotton from Kimberley fields would likely have the least industrial addition of metals, how do such samples compare to cotton from fields adjacent to smelters, etc.
