The influence of organic matter content of contaminated soils on the leaching rate of heavy metals

Leaching studies of contaminated soils were conducted to remove heavy metal s, with the dim of recovering these species. Lead copper and zinc were extr acted using a leaching solution of HCl (0.1 M) and NaCl (1.9 M). Time-depen dent release was analyzed A Langmuir-type model fit well to the experimenta l data, allowing the determination of the maximum concentration of lead cop per and zinc that can be reached in the leaching solutions and the time req uired to attain dfixed leached concentration of metal. The influence of nat ural organic matter content of the soil on leaching time was evaluated. Nat ural organic matter content influenced leaching time, due to metal complexa tion dissolved organic matter transferred to the leaching solutions. Increa sing of natural organic matter content of contaminated soils reduced leachi ng time.