Resumo

AMEZCUA-ALLIERI, Myriam A.  e  RODRIGUEZ-VAZQUEZ, Refugio. Impact on metal bioavailability and plant uptake during the bioremediation of a phenanthrene-contaminated soil. Terra Latinoam [online]. 2008, vol.26, n.4, pp.351-359. ISSN 2395-8030.

The impact on bioavailability (Pb, Ni, Cu) behaviour was assessed prior and subsequent to fungal bioremediation of phenanthrene contaminated soil. Metal fluxes were assessed by diffusive gradients in thin-films (DGT) and metal uptake was quantified in roots and leaves of Echinochloa polystachya and Triticum aestivum. DGT metal fluxes were found to significantly increase (at the 95% confidence level • = 0.05, • = 0.001) after the addition of fungus in the presence of plants. Plants mobilized significantly less metals without fungus, although plants did cause the fluxes to increase above background levels in the presence of phenanthrene. Fluxes were increased significantly, approximately 0.05 pg cm^-1 s^-1 for Cu and Pb and 0.1 pg cm^-1 s^-1 for Ni before bioremediation and approximately 0.5 pg cm^-1 s^-1 for Cu and Pb and 1.2 -2.0 pg cm^-1 s^-1 for Ni after fungal addition. The two plant species showed higher metal uptake in the presence of fungus than in its absence, which corresponds with DGT fluxes. Nevertheless, while DGT responded immediately to uptake, plant uptake does not start immediately. For both Cu and Pb, uptake was fairly low for nine days after fungal addition before increasing rapidly over the last six days, while Ni accumulation was slow over the entire period. However, Ni was freely translocated, whereas Pb was not translocated and Cu was only partially translocated. The results indicate that phenanthrene bioremediation increased the supply of metals to plants but certain inhibitory mechanisms were actively used by the plants to partially reduce metal uptake at high flux levels.

Palavras-chave : DGT; diffusive gradient in thin-film; PAHs; polyaromatic hydrocarbons; metal uptake.