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.
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> 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.