Extracción de Elementos Potencialmente Tóxicos en un suelo contaminado con Creosota

Abstract

[EN]: Hazardous waste sites are commonly contaminated with both organic and metal pollutants. The objective of the current study was to evaluate the performance of several cyclodextrins (β-CD derivatives) and the rhamnolipid JBR 425 (RL) on the removal rates of several potentially toxic elements (PTEs) in a soil with a mixed contamination. PTE extraction with all the tested extractants was similar to that obtained with the Ca(NO3)2 background solution alone. However, PTEs extraction by RLs was much higher in the absence of Ca(NO3)2 solution. In the presence of Ca2+, RLs form giant vesicle-like structures which precipitate on specific soil surfaces, decreasing PTEs extraction. However, As was not removed from the soil by any of the extractants used, probably due to its presence in soils as anionic compounds. The availability of PTEs after the extraction treatments was measured. Zn and Cd, the more mobile PTEs, were less available after any treatment; no effect on Cu and Pb availability was observed, probably due to their strong complexes with organic matter; Ni, Cr, and As, those more associated to Fe and Al oxides, increased their availability in soils treated with RLs (25, 50, and 200%, respectively), due to the mobilization of these co-existing metals in the presence of the biosurfactant.

[ES]: Hazardous waste sites are commonly contaminated with both organic and metal pollutants. The objective of the current study was to evaluate the performance of several cyclodextrins (β-CD derivatives) and the rhamnolipid JBR 425 (RL) on the removal rates of several potentially toxic elements (PTEs) in a soil with a mixed contamination. PTE extraction with all the tested extractants was similar to that obtained with the Ca(NO3)2 background solution alone. However, PTEs extraction by RLs was much higher in the absence of Ca(NO3)2 solution. In the presence of Ca2+, RLs form giant vesicle-like structures which precipitate on specific soil surfaces, decreasing PTEs extraction. However, As was not removed from the soil by any of the extractants used, probably due to its presence in soils as anionic compounds. The availability of PTEs after the extraction treatments was measured. Zn and Cd, the more mobile PTEs, were less available after any treatment; no effect on Cu and Pb availability was observed, probably due to their strong complexes with organic matter; Ni, Cr, and As, those more associated to Fe and Al oxides, increased their availability in soils treated with RLs (25, 50, and 200%, respectively), due to the mobilization of these co-existing metals in the presence of the biosurfactant.