Copper, Zinc, and Manganese Mobilization in a Soil Contaminated by a Metallurgy Waste used as Micronutrient Source

Leaching of copper (Cu), zinc (Zn), and manganese (Mn) from a soil contaminated by metallurgy waste (used as a micronutrient source) was carried out in a column experiment. The main objective was to evaluate the effect of the chelates ethylenediaminetetraacetic acid (EDTA), ethylenediaminedisuccinic acid (EDDS), and citrate at doses of 2, 4, and 8mmolkg-1. The two synthetic chelating agents increased metal contents in the lower part of the column, which was filled with an uncontaminated sample of the same soil. No Cu or Zn was present in the leachates. Although Mn could be detected, values were not related to treatments. Water by itself was also able to mobilize metal inside the soil column. The retention of metals by the uncontaminated soil layer was explained by its large adsorptive capacity, as demonstrated by the corresponding adsorption isotherms.