Comparative toxicological and hygienic assessment and combined action of modern fungicides based on azoxystrobin, pydiflumetofen, propiconazole

Abstract

Introduction. The creation of combined pesticide formulations for the purpose of more effective protection of agricultural crops is a significant factor in the importance of assessing their synergistic effects. Substances that produce a similar pesticidal effect, in combination with each other, can enhance the toxic effect and, therefore, show dose additivity. The aim is toxicological and hygienic evaluation and determination of the type of combined action of pydiflumetofen, azoxystrobin and propiconazole - the active substances of the mixed formulations «Miravis Ace 275 SE» and «Miravis Neo 300 SE» according to toxicity indicators. Materials and methods. Analytical review of scientific publications was carried out using data from EFSA, FAO, ECHA, PPDB, Internet sites. According to the literature, a comparative toxicological-hygienic evaluation of fungicidal preparations and their active substances was carried out. The general mechanism of fungicidal action was evaluated according to the classification developed by the Fungicide Resistance Action Committee (FRAC). The hazard class according to the toxic metric parameters of the substances under study was determined in accordance with the Hygienic classification of pesticides according to the degree of hazard (DSanPiN 8.8.1.002-98). The nature and type of combined action was carried out according to the Finney method with evaluation according to the criteria of acute toxicity. Results and discussion. As a result of the conducted research, the most toxic mixed fungicide «Miravis Neo 300 SE» based on three active substances was determined (the average lethal dose (LD50) is 550 mg/kg). It has been established that in cases of combinations of active substances to obtain a lethal effect, a dose of substances that does not exceed 100% in total is required, which indicates the strengthening (potentiation) of toxicity. It was pointed out that the share of propiconazole in the potentiation of the toxic effect in both mixed preparations is the highest compared to other active substances and is 0.87 for «Miravis Neo 300 SE» and 0.88 for «Miravis Ace 275 SE». It was observed that the adverse effects of simultaneous exposure to several pesticides may change during the transition from acute to chronic exposure. Therefore, it is important to continue the research of the active substances of pesticides with the determination of limiting criteria for harmfulness, taking into account the remote effects of exposure. Conclusions. The toxicological and hygienic assessment made it possible to establish that the combined fungicides «Miravis Neo 300 SE» and «Miravis Ace 275 SE» are more toxic in the mode of single oral exposure in comparison with the single-component fungicide «Miravis 200 SC». Increased toxicity (potentiation) can be considered as a consequence of the simultaneous exposure of several active substances. The active substance propiconazole poses the main danger of adverse effects on the body at the level of lethal doses. The obtained values of the potentiation coefficients will be taken into account in further studies of the risk assessment of complex and combined effects of pesticides on workers and their potential danger when entering the human body with food products.