Reducing lead bioavailability

Abstract

A method for reducing the solubility of lead during digestion or in the environment has been developed. Lead is incorporated into a solid material formed by the in situ oxidation of iron. This can be accomplished by introducing ferrous iron into the soil, either in solid or liquid form, and then oxidizing the iron with either air or an introduced oxidant. Solubility of the lead is significantly reduced even under very acidic conditions by incorporation into the iron oxide material. Acid generated during the oxidation and precipitation of iron can be neutralized using common neutralizing agents such as limestone, lime, magnesium oxide, or magnesium hydroxide. In another method, the calcium or magnesium can be added either as neutral salts or as salts of alkaline anions, e.g., calcium carbonate. The calcium and magnesium ions form strong complexes with digestive enzymes, preventing the lead from forming soluble lead complexes with the enzymes. This reduces the bioavailability of the lead.