Pb, Zn, Cd AND Ni LEACHING IN RED-YELLOW PODZOLIC SOIL TREATED WITH IRON SMELTER RESIDUES

ABSTRACT

Air dried subsurface samples of a heavy textured Red-Yellow Podzolic soil, representative of the industrial solid residue pilot landfill (ISRL) of the National Steel Works (Companhia Siderúrgica Nacional-CSN), were packed in 5.4 cm width and 37 cm high glass columns. An acid and alkaline iron smelter residue were placed on the top of the soil columns to make a 4:1 soil-residue ratio, in consonance with the basic CSN project. To evaluate, Ni, Zn, Cd and Pb mobilities the system soil-residue was leached with 50 pore volumes of deionized water at pH 4.5. After leaching the residue was removed from the tops and the soil columns were sectioned into 4 equal parts. Pb dissolved from the acid residue was retained in the upper 0-5 cm soil columns. Zn, Ni and Cd showed the same distribution pattern, i.e, increased concentration with depth. In the effluents leaching out the columns with acid residue the levels of Zn and Ni were higher than the standard limits allowed by FEEMA.

Key words:
heavy metal; steel work residue; landfill; leaching; metal mobility