Metal adsorption by garden soils as a function of soil solution pH, indicated increasing metal adsorption with pH. At pH >5.0 more Pb was adsorbed than Zn or Cd. Soluble Zn, Pb and Cd concentrations in soils after 600 hours of reactions decreased Это и многое другое вы найдете в книге Bioavailability and solubility equilibria of heavy metals in soils (Gloria Egwu)