Get the lead out!

Workers manufacturing the pigment white lead (Pb(OH)₂^.2PbCO₃ apparently made a habit of adding dilute sulfuric acid to their drinking water to prevent lead poisoning. The reaction of the sulfate ions (SO₄^2-) with the aqueous lead ions (Pb²⁺) forms an insoluble precipitate of lead sulfate, effectively removing the lead from the water (as long as you let the precipipate settle before drinking!). This risk of lead poisoning in these workers was so high that it was referred to as "painter's colic".