Authors: Mikel Anza, Oihane Salazar, Lur Epelde, José María Becerril, Itziar Alkorta and Carlos Garbisu
Journal: Applied Sciences
Vol: 9, 4757; doi:10.3390/app9224757
Here, we aimed to bioremediate organically contaminated soil with Brassica napus and a bacterial consortium. The bioaugmentation consortium consisted of four endophyte strains that showed plant growth-promoting traits (three Pseudomonas and one Microbacterium) plus three strains with the capacity to degrade organic compounds (Burkholderia xenovorans LB400, Paenibacillus sp. and Lysinibacillus sp.). The organically contaminated soil was supplemented with rhamnolipid biosurfactant and sodium dodecyl benzenesulfonate to increase the degradability of the sorbed contaminants. Soils were treated with organic amendments (composted horse manure vs. dried cow slurry) to promote plant growth and stimulate soil microbial activity. Apart from quantification of the expected decrease in contaminant concentrations (total petroleum hydrocarbons, polycyclic aromatic hydrocarbons), the eectiveness of our approach was assessed in terms of the recovery of soil health, as reflected by the values of dierent microbial indicators of soil health. Although the
applied treatments did not achieve a significant decrease in contaminant concentrations, a significant improvement of soil health was observed in our amended soils (especially in soils amended with dried cow slurry), pointing out a not-so-uncommon situation in which remediation eorts fail from the point of view of the reduction in contaminant concentrations while succeeding to recover soil health.