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 metals, with the dim of recovering these species. Lead copper and zinc were extracted using a leaching solution of HCl (0.1 M) and NaCl (1.9 M). Time-dependent release was analyzed A Langmuir-type model fit well to the experimental data, allowing the determination of the maximum concentration of lead copper and zinc that can be reached in the leaching solutions and the time required to attain dfixed leached concentration of metal. The influence of natural organic matter content of the soil on leaching time was evaluated. Natural organic matter content influenced leaching time, due to metal complexation dissolved organic matter transferred to the leaching solutions. Increasing of natural organic matter content of contaminated soils reduced leaching time.