A screening model for managing periodic pesticide application in residential lawn soils

Improved Pesticide Product Labeling Information for Household Lawn Management: Recommended Safe Durations in Support of Minimizing Children’s Exposure to Pesticides

“…Therefore, the application pattern of pesticides in urban areas (e.g., rates and frequency) should be further evaluated to comply with environmental standards. For example, Guo et al demonstrated that the use of some current pesticides (e.g., 2,4-D and glyphosate) in household gardens, under manufacturer’s recommendations, is unlikely to violate current soil standards . However, there is a lack of studies on linking the pesticide application in urban areas to residue concentrations in other environmental media (i.e., groundwater, edible parts of plants, and influent flows of wastewater) for the regulatory purpose.…”

“…The half-lives of pesticides in the lawn environment were obtained from modeling studies in the literature (first-order kinetic screening models). ,, Because the household application method of pesticides typically differs from that of croplands (i.e., intensive aerial sprays), in this study, we assumed that, after pesticide application on lawns, pesticide residues would first deposit on the grass surface and in surface soil compartments and then be transported to the air. Thus, dissipation half-lives of pesticides on the grass surface and in surface soil compartments were used, and the residue level in the air was estimated based on a simple partitioning rule. , …”

“…The overall dissipation process of the pesticide in the surface soil compartment comprises degradation, volatilization, and water-induced elimination (surface runoff and infiltration) processes. ,, The overall dissipation half-life of the pesticide in the surface soil can then be expressed as follows: where (d) is the overall dissipation half-life of the pesticide in the surface soil. k d,Soil , k Plant , k Air , k Rain ,Soil , and k Irri,Soil are first-order rate constants (d –1 ) of the pesticide for degradation, plant uptake, volatilization, rainfall-induced elimination, and irrigation-induced elimination processes, respectively.…”

“…k d,Soil , k Plant , k Air , k Rain ,Soil , and k Irri,Soil are first-order rate constants (d –1 ) of the pesticide for degradation, plant uptake, volatilization, rainfall-induced elimination, and irrigation-induced elimination processes, respectively. These rate constants of pesticides were obtained from a modeling study on the fate and transport of pesticides in soil. , The plant uptake and water-induced elimination processes of the pesticide could be described using the first-order kinetic rate constants because it was demonstrated that these elimination processes of the pesticide in the surface soil can be approximated as a continuous advection process (time-weighted rainfall- or irrigation-induced advection transport) . Similar to the surface soil compartment, the overall dissipation half-life of the pesticide in the grass surface compartment ( ) can be expressed as follows: where k GS , k Rain ,GS , and k Irri ,GS are the dissipation (no precipitation), rainfall-induced elimination, and irrigation-induced elimination rate constants, respectively.…”

“…Second, some population groups, such as children and elderly individuals, are more vulnerable to pesticides than other groups, particularly for children whose special behaviors always lead to more exposure to pesticides. , Third, many consumers worry about residue levels in the environment near their residence, and they should be informed about the fate of residues in a simple, clear manner. In addition, studies have shown that many currently used pesticides can dissipate quickly in the environment, such that avoiding contact with residues for several days after pesticide application would be promising to reduce residue exposure …”