Study of residual amounts of flonicamide in apples and justification of medical and sanitary standards for the safe use of insecticide based on it

Abstract

Flonicamid is a new systemic pyridine carboxamide insecticide with selective activity against a wide range of insects on various agricultural crops. In Ukraine, field tests were conducted to justify the possibility of its safe use for the protection of apple trees. Materials and Methods. The content dynamics of flonicamid residual amounts in apples and apple juice was studied in the steppe zone of Ukraine during two growing seasons of 2019-2020 with three times of insecticide use with a consumption rate of 0.07 kg/ha. The residual amounts of flonicamid in apples and apple juice were determined by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. The limits of quantitative determination (LQ) by HPLC in apples and apple juice are 0.01 mg/kg. Results. During the research period 2019-2020, the amount of flonicamid in the yield of apples and juice from them (as the sum of flonicamid and TFNA and TFNG metabolites in terms of flonicamid) was 0.019-0.071 mg/kg and 0.017-0.032 mg/kg, respectively. After applying the insecticide, the recommended waiting period before harvesting apples is 35 days. The decrease in the flonicamid content in apples occurs on an exponential curve in accordance with the first-order kinetic equation. The calculated half-life (T50) for apples is 23 days for flonicamid, and 27 days for flonicamid (as the sum of flonicamid and TFNA and TFNG metabolites in terms of flonicamid). The possible daily intake of flonicamid in the human body with apples and apple juice is 9.5% of the level of safe intake with the diet (6.6% of its permissible daily intake). The maximum permissible levels of flonicamid content are justified: apples – 0.3 (the sum of flonicamid and TFNA and TFNG metabolites in terms of flonicamid, (LQ by HPLC – 0.01 mg/kg for each compound); apple juice – 0.03 mg / kg (the sum of flonicamid and TFNA and TFNG metabolites in terms of flonicamid. Conclusions. Flonicamid belongs to the hazard class 2 pesticides in terms of degradation in apple trees. The MPL-approved safe content of the active substance in apples and apple juice and the waiting period before harvesting ensure the safety of using a flonicamid-based insecticide. Keywords: flonicamid, residual amounts, chromatography, field tests.