[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.

4 páginas.-- 3 tablas.-- 6 referencias.-- Póster presentado en el VIII Congreso Ibérico de las Ciencias del Suelo. VIII Congresso Ibérico de Ciências do Solo. DONOSTIA-SAN SEBASTIÁN. 20 - 22 junio 2018..-- El documento completo se encuentra para su descarga en http://www.cics2018.com/libro-de-abstracts/

Los autores agradecen a ADIF (Ministerio de Fomento) por las facilidades para el muestreo del suelo contaminado. Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad (cofinanciado con fondos FEDER) bajo el proyecto de investigación CTM2013-42599-R.

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