Complémentarité fonctionnelle en phytoremédiation dans un sol à contamination mixte
Mixed contaminated soils with both organic and inorganic compounds represent about 40% of all contaminated sites. Phytoremediation is a promising green technology to decontaminate and restore mixed contaminated sites. The objective of the study was to evaluation the phytoremediation potential of a co-planting system between a shrub and an herbaceous species compared to the species in monocultures. A pot experiment with a woody specie, Salix interior, and one herbaceous species, Achillea millefolium, Trifolium pratense or Festuca arundinacea, and an unplanted control was conducted in a mixed CCA- and PCP-contaminated soil and non-contaminated soil for 120 days. Native and naturalized species with distinct functional traits were chosen for their possibly different and complementary phytoremediation abilities. Plant aboveground and belowground dry weights in all pots, trace element concentrations in plant tissues, and soil trace element and PCP concentrations in contaminated soil were recorded at the end of the cultivation period. Soil contamination and co-planting did not affect species biomass production, except in the S. interior + F. arundinacea treatment (SF) where roots yield was higher in the contaminated soil. The polyculture SF led to increased Cr and Cu total uptake in the roots of F. arundinacea. Furthermore, species in polycultures all had equal or superior trace element concentrations in their tissues compared to their monocultures. Death of S. interior in co-cropping with F. arundinacea was observed with no distinction of soil contamination and lead to mitigated conclusions. Treatments effects on PCP dissipation are inconclusive given the low soil concentrations found at the beginning and at the end of the experiment and because of the variability between the pots. We can therefore suggest that the co-planting of a shrub species and a species with different traits seems to lead to higher phytoremediation potential, but further investigation is required.
co-plantation Phytoremediation Functional complementarity Co-planting Mixed contamination