An Efficient Method for Detoxification of Organophosphorous Pesticide-Contaminated Soil with Ozonation in Fluidized Bed Reactor

Pesticides, essential for controlling pests and weeds, significantly boost agricultural productivity. However, their excessive use leads to substantial contamination of environmental matrices, including soil and water. Organophosphorus compounds, which constitute more than 30% of the global use of insecticides and herbicides, are particularly concerning, and their widespread application raises alarms among environmentalists and regulatory agencies due to their high toxicity to aquatic organisms. Therefore, to avoid the spread of these compounds within the environment, the contaminated sites may be treated with various methods. This study explored a soil detoxification procedure utilizing gaseous ozone. As a representative of organophosphorus pesticides, chlorfenvinphos was utilized as soil contaminant. This compound is still reported to occur in a number of environmental matrixes. The method used in this study involved the exposure of the soil matrix in a fluidized state to an ozone-enriched atmosphere. The ozonation procedure enabled the removal of the pesticide from the soil matrix. During its oxidation, some degradation products were detected; in particular, they included 2,4-dichlorobenzoic acid and 2-chloro-1-(2,4-dichloro-phenyl)-ethanone, whose presence was confirmed by a GC-MS system and the NIST database. However, they also underwent degradation. Moreover, on the basis of stereoselective reaction of Z and E isomers, the pesticide degradation pathway was proposed. Additionally, the efficacy of this detoxication method was evaluated using a combination of chronic and acute toxicity tests, employing Eisenia foetida earthworms as bioindicators. On the basis of the obtained results, it can be concluded that organophosphorus herbicides containing unsaturated bonds in their structure, including glyphosate, can be removed using this method.