Edafología. Volumen 7-2. Mayo 2000. pag 157-164.
An incubation experiment was conducted to compare the effect of the application of 100 Tm ha-1 of three different biosolids (sewage sludge) -digested, composted or biosolids-ashes- on the total and available forms of Cd, Cu, Zn, Pb, Ni, Co y Cr in a degraded soil. The addition of biosolids increased total and available concentrations of Cu, Zn and Pb in the soil. However, concentrations of Ni, Co and Cr were scarcely affected. Comparatively, increases of Cu, Zn and Pb due to the addition of biosolid decreased as follows: digested biosolids > composted biosolids > biosolids-ashes. In spite of the recorded increases, the levels of Cu, Zn and Pb would not constitute a contamination risk in the used soil.
Key words: digested biosolids, composted biosolids, biosolids-ash, soil, heavy metals, availability