CONICET | Buscador de Institutos y Recursos Humanos

Soil phytoremediation is a promising in situ technology involving the plant-assisted removal of contaminants. The high hydrophobicity of DDTs and Endosulfans leads to lower availability and became a limiting factor in the phytoremediaton process. However, there are evidences that low-molecular-weight organic acids and surfactants increase pesticides desorption from soil and plant accumulation. Greenhouse experiments were conducted to evaluate the effect of Tween80 (Tw), root exudate and oxalate-citrate mixture (CA) in the uptake of DDTs and END (Endosulfan I, II and sulphate) by Salix sp. Plants were grown in soil contaminated with DDTs (≈500 ng/g) and END (≈3ng/g), treatments and control (water) were performed in individual pots covered to avoid volatilisation (n=3). Pesticides quantification in bulk soil (BS), near root (NR), rhizosphere (RI), root and leaves were carried out by GC-ECD. Control pots showed the pattern RI>BS>NR for all pesticides. A different pattern was found on treatments, being BS<NR<RI for END and BS=RI<NR for DDTs. Root levels (ng/g wet weight) ranged between 7-12 for END and 1300-1900 for DDTs. Although root bioconcentration factors were >1, treated plants showed the lowest values. Tw and CA increased DDTs availability and translocation, being well correlated with an increase extracted aqueous concentration. END translocation >1 was only found in CA treatment. However, in all conditions it was dependent on specific-isomers (I=II>sulphate). Willow uptake of pesticides was affected by the studied amendments. Differences for pesticides in Tw and CA treatments could be related with specific amendment-pesticide interaction. It will be further investigated since could play a significant role in the phytoremediation of these pesticides.

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