Metamodel for Groundwater Leaching Assessment in Europe

Under Regulation (EC) 1107/2009, FOCUS leaching models forecast the concentration of plant protection product (PPP) active substances in groundwater, known as the predicted environmental concentration (PECGW), based on parameters like DT50, KOC, and application rate. This study used simulated PECGW from PEARL and PELMO for training with over 870 combinations of KOC and DT50 across 174 different crop-location-software scenarios. Generalized additive models (GAMs) were trained on these simulations, achieving 96–99% accuracy for in-sample and out-of-sample validation, comparing the predicted environmental concentration in GAM (PECGAM) with the simulated PECGW relative to the 0.1 μg/L regulatory limit. Our GAM approach offers rapid PEC calculations for numerous substances across 174 scenarios, significantly accelerating early-stage molecule development analogue selection.