MIGRATION OF HERBICIDE OF DERIVATIVE ARYL CARBOXYLIC ACIDS IN THE SYSTEM OF SOIL-AIR

Abstract

Introduction. The main source of pesticides entrance to the air is the treatment of crops, seeds, forest areas, and other environmental objects. Pesticides enter the air with the soil dust during wind erosion and harvesting operations. A significant number of them enter atmospheric dust areas, where the intensive chemical treatment is practiced. In most of the cases, the system of soil-atmospheric air is the first link, by which pesticides are entered, as a result of the first demolition of preparations during their application, as well as a result of processes of vaporation and evaporation from the surface of the soil, plants, water basins, etc. Along with atmospheric flows, contained in the air, the pesticides can be transported for long distances.The aim of this research is the obtaining of the reasonable threshold concentration of the pesticide in the soil by this index of hazard. By the threshold, concentration is implied the amount of pesticide in the soil (mg/kg of the absolutely dry soil), where the entrance the compounds into the atmospheric air is not accompanied by the increase of its average daily maximum permissible concentration (MPC). Material and methods. In the tasks of the experimental studies, the results of which are introduced in the article there were included the investigations of the migration-air index of harm, rated to the active substance of the pesticide referred to the derivatives of aryloxychromones acids. A migration-air index of the hazard characterizes migration processes (with soil dust, evaporation, co-evaporation with water vapors, etc.) of pesticide from the soil to atmospheric air. Results. The resulting value is necessary for the subsequent selection of limiting index of hazard, considering all the indices (translocation, migration, and water, sanitary), determining the MPC pesticide in the soil. The studies were carried out in standard conditions and, therefore, comparable soil and microclimate conditions using a special microclimate chamber. The method of laboratory modeling is a required step in the normalization of pesticides in the soil.