Modeling pesticides in global surface soils: Exploring relationships between continuous and discrete emission...

Area of Science:

• Environmental Science
• Environmental Chemistry
• Ecotoxicology

Background:

• Pesticide emission patterns significantly influence environmental concentrations.
• Continuous emission models offer simplicity but may not reflect real-world discrete application events.
• Accurate modeling is crucial for effective pesticide risk assessment and management.

Purpose of the Study:

• To develop and validate a simple equivalent approach for relating continuous and discrete pesticide emission patterns.
• To compare simulated surface soil pesticide concentrations under both emission scenarios.
• To integrate the equivalent approach into the USEtox model for practical application.

Main Methods:

• Comparison of simulated surface soil pesticide concentrations under continuous and discrete emission scenarios.
• Development of an equivalent approach based on time-integrated fate factors.
• Incorporation of the equivalent approach into the USEtox screening-level model.

Main Results:

• Continuous and discrete emission scenarios showed similar average concentrations at high dissipation rates and low emission frequencies.
• Continuous models using simple average emission rates overestimated soil concentrations compared to discrete models over a one-year period.
• The equivalent approach integrated into USEtox accurately approximated average soil concentrations for most tested pesticides under annual or semi-annual emission patterns.

Conclusions:

• The developed equivalent approach effectively bridges continuous and discrete pesticide emission modeling.
• This method improves the utility of continuous-emission-based models for approximating discrete pesticide applications.
• The approach enhances surface soil pesticide management by providing a more realistic simulation of emission patterns.