DEGRADATION OF MEPANIPYRIM BY PHOTOCATALYTIC OZONATION

The occurrence of not easily degradable pesticides in the hydrosphere, due to intensive agricultural activities, is of particular concern for surface and groundwater quality. In this respect, it is advisable to strengthen existing technologies for the decontamination of water, with the aim of enhance the degradation methods for recalcitrant organic compounds. [1] In our previous study, we have demonstrated that the application of advanced oxidation processes promises to be a profitable expedient for the rapid degradation and detoxification of persistent herbicides as imazethapyr. [2] The capabilities of the oxidation processes to degrade organic pollutants in water and the variety of derivatives formed is illustrated here by the case of Mepanipyrim [N-(4-methyl-6-prop-1-ynylpyrimidin-2-yl)aniline], a widely used pyrimidinic fungicide. The purpose of this study was to simulate the production of degradation compounds, which can be arisen in water treatment plants where physical or chemical oxidation methods are normally used. Comparisons between different oxidation techniques can provide useful information on the mechanisms of these processes, and are of particular concern in the assessment of the most efficient experimental conditions for the destruction of organic pollutants. The advanced oxidation methods compared were ozonation (without application of any initiator), UV-photolysis and UV-O3 coupled treatment. Kinetics of reactions were determined. Numerous degradation products were identified and characterised through MS spectra analyses. Toxicity tests on Microtox, Daphnia magna and Lactuca sativa were carried out on the mix of degradation products.