Italian television brought coffee to the lab, and the results where not reassuring (from minute 18 onward, only Italian, I am sorry)
https://www.rai.it/programmi/report/inchieste/Un-espresso-a-...
aluminum was at around 1/6 of the EU recommended maximum safe concentration. But you could cut this in half using the stainless steel moka. Apparently about half of the aluminum came from the coffee powder itself and half from the moka.
A lot of metals from the coffee itself, apparently because of fertilizers and insecticides.
Anyway the moka itself released around 0.3 mg per liter of aluminum