Distribution, fractionation and mobility assessment of heavy metals in a spiked soil using a multi-species soil system

The concentration, distribution and fractionation of metals in a metal spiked soils were studied using a Multi-SpeciesSoil-System (MS·3), a terrestrial microcosms that allows a combined assessment of the chemical fate and effects on ter restrial organisms. Samples of a natural soil were spiked with a mixture of the metals Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn and placed on the top of soil columns simulating the heavy metal concentration due to an agricultural organic amendment (manure,sewagesludge) equivalentto2,5and10timestheoriginalbackgroundofsoilmetalconcentration.After21days exposure, metal mobility was assessed using three complementary approaches: the metal concentrations at four depths in the soil profiles (I, II, III and IV), the metal fractionation in the top soil and the percent metal detected in leachates. The upper soil profile had the highest metal concentration for the majority of the metals . For Cd, Mn and Co highest concen trations were in the bottom profile. Maximum metal mobility in leachates was for Cd (24.67%) > Co (3.65%) > Mn (3.18%) > Zn (0.55%) > and Cu (0.012%) . Nickel and Cr percentages were 0.1%. Lead mobility from soil to water was 0.004% and 0.008% for the lowest and highest treatments, respectively.