Hygienic assessment of new pesticides translocation in “soil – plant” system

Abstract

Summary. Assessment and risk minimization of the harmful effects of pesticides on public health is an important task of preventive medicine. In particular, the study of the migration of new pesticides in the “soil-plant” system is relevant because of the leading role of the oral route of their entry into the human body.

The aim of the work – to establish the translocation patterns from soil to agricultural crops with new pesticides such as triazolone, amicarbazone, triketone, and bicyclopyroned carboxamide fungicide pydiflumetofen.

Materials and Methods. Mathematical modeling of the studied pesticide migration in the "soil-plant" system was carried out using regression equations. They describe the dependence between the maximum permissible concentration (MPC) of a substance in soil and its maximum residue limit (MRL) in food products of plant origin (stage I).  The translocation of amicarbazone, bicyclopyrone and pydiflumetofen in the “soil-plant” system was studied in three series of laboratory hygiene experiments (stage II). Content determination of the studied substances in the green mass of bread grains and vegetable crops was carried out by the method of high-performance liquid chromatography (HPLC).

Results. The concentrations of: amicarbazone – 0.2 mg/kg, bicyclopyrone – 0.25 mg/kg, and pydiflumetofen. – 0.12 mg/kg were recognized as threshold concentrations in soil according to the translocation indicator of harmfulness. They are formed in soil arable layer when applying the studied pesticides, respectively, in 4, 5, and 2 maximum rates of consumption. At these concentrations, the content of substances in the green mass of all phyto test plants does not exceed the hygienically significant level of 0.02 mg/kg,  0.02 mg/kg, and 0.01 mg/kg, therefore. Comparing the results of the I and II stages of the study, it was established that the experimentally determined threshold concentration of amicarbazone in soil coincided with the result of mathematical modeling; of bicyclopyrone – slightly (by 39 %)  exceeded the calculated result; of pydiflumetofen – 2.4 times higher than the calculated value.

Conclusions. It was established that the migration of amicarbazone, bicyclopyrone and pydiflumetofen from the soil will not exceed their hygienically significant level in plants when their content in soil is accordingly 0.2 mg/kg;  0.25 mg/kg; 0.12 mg/kg and below. The method of mathematical modeling of translocation demonstrated sufficient prognostic ability concerning all 3 researched pesticides. The obtained results were used in the substantiation of MPCs of amicarbazone, bicyclopyrone and pydiflumetofen in soil.