Green Remediation for the Sustainable Management of Oil Spills in Agricultural Areas

Abstract

Spills of petroleum products resulting from illegal pipeline extraction also affect agricultural areas. These areas must be subject to remediation interventions to bring the concentrations of contaminants below the alarm levels and avoid further damage to the environment and living beings. In these cases, green technologies such as bioremediation and phytoremediation are an excellent approach to reduce impacts on agriculture. This contribution evaluates the effectiveness of combining some green techniques in managing soil contaminated by oil spills. A feasibility test of phytoremediation at a microcosm scale with three plant species (corn, lupine and alfalfa) was conducted, combining the approach with plant growth-promoting rhizobacteria (PGPR). Particular attention was given to the reclamation from polycyclic aromatic hydrocarbons (PAHs). At the end of the experiments, biomass production and PAHs concentration in the soil and plants (roots and aerial parts) were determined. The remediation strategy was aimed at two concurrent objectives: the need to remove the maximum amount of contaminants from the soils affected by oil spills and the restoration of the agricultural activity to be carried out in absolute safety. The results show a decrease in the concentration of hydrocarbons in the soil favored by the presence of tested plants, which manage to grow satisfactorily on the soil under examination, albeit with an inevitable decrease in yield compared to uncontaminated soil. Looking at the concentration of pyrene, which is usually considered as indicator of PAHs contamination, the removal reaches values higher than 50 % in vegetated soils. The addition of the selected PGPR counteract the negative effect of contamination, favoring the growth of plants and allowing the production of fresh biomass comparable to that obtained on the uncontaminated control soil. This results in a further reduction of the contaminant in question up to an additional 20 %. Therefore, the presence of organic contaminants can be concretely reduced in a sustainable and cost-effective way by the joint action of plants and microorganisms that promote the processes of rizodegradation.