Screening safe pesticide application rates in crop fields for protecting consumer health: A backward model for interim recommended rates.

Abstract

To reduce human health risks and comply with regulatory standards, it is necessary to provide safe application rates of pesticides in crop fields. In this study, a screening-level model is proposed to improve the regulation of pesticide application rates based on the dynamiCrop platform, which can serve as a complementary approach to field trials for regulatory agencies. The screening-level model can conveniently simulate safe application rates of pesticides based on consumer health risks and maximum residue levels (MRLs). Using 2,4-D as an example, the simulation results agreed with the data of field trials under Good Agricultural Practices and demonstrated that current manufacturers' recommended application rates can effectively comply with MRLs and protect human health. In addition, we simulated the default safe application rates of 449 pesticides in five common crops using the default values of the acceptable daily intake (ADI; 0.01 mg kg-1 day-1 ) and MRL (0.01 mg kg-1 ). The results demonstrated that aerial-fruit crops (e.g., tomatoes and apples) had much lower default safe application rates of pesticides than tuber crops due to the different pesticide uptake mechanisms of plants. In addition, the MRL-based default safe application rates were significantly lower than the ADI-based default rates, indicating that the default MRL of 0.01 mg kg-1 adopted by current regulatory agencies is very conservative regarding population health risks. Although other factors, such as the variability of residue levels in crops, occupational exposure (farmers and operators), and multiple pesticide application patterns, need to be considered in future studies, our screening-level model could be used as a complementary tool in field trials to assist regulatory agencies in regulating pesticide application rates in crop fields. Integr Environ Assess Manag 2023;19:126-138. © 2022 SETAC.