Thus, under the given conditions, most of the NTA in equilibrium with solid PbCO3 would be present as the lead complex. As in the previous example, at a trisodium NTA level of 25 mg/L, the concentration of soluble lead(II) would be approximately
20 mg/L. At relatively higher concentrations of HCO3-, the tendency to solubilize lead would be diminished, whereas at lower concentrations of HCO3-, NTA would be more effective in solubilizing lead