Abstract
Abstract
Background
When experimentally determined dislodgeable foliar residue (DFR) values are not available, regulatory agencies use conservative default DFR values as a first-tier approach to assess post-application dermal exposures to plant protection products (PPPs). These default values are based on a limited set of field studies, are very conservative, and potentially overestimate exposures from DFRs.
Objective
Use Random Forest to develop classification and regression-type ensemble models to predict DFR values after last application (DFR0) by considering experimentally-based variability due to differences in physical and chemical properties of PPPs, agronomic practices, crop type, and climatic conditions.
Methods
Random Forest algorithm was used to develop in-silico ensemble DFR0 prediction models using more than 100 DFR studies from Corteva AgriscienceTM. Several variables related to the active ingredient (a.i.) that was applied, crop, and climate conditions at the time of last application were considered as model parameters.
Results
The proposed ensemble models demonstrated 98% prediction accuracy that if a DFR0 is predicted to be less than the European Food Safety Authority (EFSA) default DFR0 value of 3 µg/cm2/kg a.i./ha, it is highly indicative that the measured DFR value will be less than the default if the study is conducted. If a value is predicted to be larger than or equal to the EFSA default, the model has an 83% prediction accuracy.
Impact statement
This manuscript is expected to have significant impact globally as it provides:
A framework for incorporating in silico DFR data into worker exposure assessment,
A roadmap for a tiered approach for conducting re-entry exposure assessment, and
A proof of concept for using existing DFR data to provide a read-across framework that can easily be harmonized across all regulatory agencies to provide more robust assessments for PPP exposures.
Publisher
Springer Science and Business Media LLC
Reference23 articles.
1. EFSA. Guidance on the assessment of exposure of operators, workers, residents and bystanders in the risk assessment of plant protection products. EFSA J. 2022;20:7032. https://doi.org/10.2903/j.efsa.2022.7032.
2. US EPA. Office of Pesticide Programs, Science Advisory Council for Exposure (ExpoSAC). Washington DC, USA: US EPA; 2021.
3. Toumi K, Joly L, Vleminckx C, Schiffers B. Exposure of workers to pesticide residues during re-entry activities: A review. Hum Ecol Risk Assess Int J. 2019;25:2193–215. https://doi.org/10.1080/10807039.2018.1485092.
4. EUROPOEM II. Post-application exposure of workers to pesticides in agriculture: Report of the re-entry working group; EUROPOEM II Project, FAIR3-CT96-1406. EUROPOEM II; 2002.
5. US EPA. Guidance for Requiring/Waiving Turf Transferrable Residue (TTR) and Dislodgeable Foliar Residue (DFR) Studies, US EPA Memorandum. Washington DC, USA: US EPA; 2012.