“…Coexisting solutes in the water can affect the reductive dissolution process in two ways. ,,,− First, certain solutes can reduce PbO 2 to Pb(II); these solutes include Br – , I – , Fe(II), Mn(II), and Mn(III). ,,,, Natural organic matter (NOM) is a collection of molecules, and some of these molecules can also reduce PbO 2 . , PbO 2 reduction by water is even thermodynamically favorable . Second, some ions can inhibit reductive dissolution via adsorption and precipitation. ,, For example, Pb(II) and PO 4 3– can adsorb onto the PbO 2 surface, which decreases the proportion of Pb(IV) surface species that are accessible to reductants and inhibits the reductive dissolution of PbO 2 . , The presence of Ca(II) and phosphate can form a precipitate on the PbO 2 surface, which blocks the reductant from active sites …”