White wine has lower concentrations of heavy metals than red wines, because of the white wine-making process (alcoholic fermentation without skins, since grape skins contain higher concentrations of metal than pulp).
Heavy metals concentration in wine also varies at different stages of the wine-making process. During fermentation, the concentrations are decreasing due to precipitation. Yeasts also consume metals such as copper, iron, and zinc.
Clarification of wine may also cause a decrease in heavy metals concentration. Long maceration duration and long contact times with metal-containing equipment increase the concentration of heavy metals.