Generalizable consistency of soil quality standards for pesticides: Modeling perspectives

Soil quality standards for pesticides play a crucial role in protecting plants and preventing potential health hazards to humans. Here we discuss modeling approaches to define pesticide soil quality standards from two effect endpoints, which ensures consistency throughout the entire pesticide life cycle from application to human exposure assessment. Given that pesticides are applied in a pulse-like emission pattern and their soil concentrations change over time, both a ceiling legal limit and an average legal limit for pesticide soil quality standards should apply to the initial pesticide application practice and the potential human health effect. The timing intervals for pesticide application and the dissipation half-life in the soil can be used to quantify the relationship between the ceiling and average legal limits. By analyzing primary exposure pathways related to soil contamination, the average legal limit can be linked to theoretical human health risks, which requires a comprehensive evaluation for an adequate safety margin, including human interactions with soil, exposure assessment of soil pesticides, and allocation exposure assessment. To establish acceptable human health risks, the average legal limit can be determined, and the ceiling legal limit can be estimated based on the quantitative relationship between the ceiling and average legal limits. Additionally, we discuss situation-specific factors, including climate-pattern and behavior-pattern factors, to define pesticide soil quality standards to further complete the modeling framework. We hope insights presented in this paper will assist regulatory agencies worldwide in defining pesticide soil quality standards that meet their specific regulatory needs throughout the entire pesticide life cycle.