S06 - Session P5 - Remediation of soils polluted with neonicotinoid insecticides residues by ozonation at field scale

Authors: Carmen María Martínez Escudero *, Isabel Garrido, Fulgencio Contreras, Marina Aliste, Pilar Flores, Pilar Hellín, Jose Fenoll

Pesticides are compounds designed to be toxic to target organisms. Although their usage has enhanced crops quality and agricultural production, it has also become a concerning cause of environmental pollution. In this work we have studied the effectiveness of ozonation for the elimination of four neonicotinoid insecticide residues (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) in soil. Field trials were conducted in plots located inside a greenhouse during the winter season. Ozonation treatments were carried out using an ozone generator connected to an ozone destructor and an analyzer. Prior to ozone exposure, soils were covered with polyethylene film. Five different treatments were assayed to evaluate the influence of this technology in insecticides removal: S- soil with film covering, SOS- film covering + surface ozone application, SOD- film covering + deep application, SODS- film covering + dual application, and C-without any treatment. After 50 days since the beginning of the experiment the higher degradation percentages were observed in ozonized soils, in particular for SODS treatment, when ozone is dually applied at surface and 10 cm depth. Results exhibit that the utilisation of ozone, parallel to the placement of polyethylene film onto the soil, represent a valid method for degrading residues of the studied insecticides and suggest that ozonation technique could be considered as a promising alternative remediation tool for pesticides polluted soils and could be applied to larger scale.