Influencia de tratamientos térmicos de diferente severidad en la disponibilidad de metales pesados en el suelo

Resumo

The effect of soil heating on Ni, Cu, Zn, Mn, Pb and Fe mobilization was studied in a forest soil. For this purpose, laboratory experiments were carried out under microcosm conditions. The soil was subjected to thermal shock and subsequent washing. Soil heating was conducted using infrared lamps to increase the temperature until 246 and 406 ºC at 1 cm depth, similar to those temperatures reached in moderate and high severity forest fires, re- spectively. In general, it was observed that heating does not affect the chemical speciation of heavy metals, ex- cept in the case of Mn due to the increase of its exchangeable forms.Soil washing was carried out using an exper- imental device designed to simulate subsurface flow to warranty water flowing through the whole soil. Lecheates analysis showed significant increases only for Mn with the increase of the thermal shock severity. However, the total amount of Mn leached does not suppose a significant lost in the soil because it is an abundant metal, and the risk in aquatic systems is not relevant due to its low toxicity.