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 (PEC_GW), based on parameters like DT₅₀, K_OC, and application rate. This study used simulated PEC_GW from PEARL and PELMO for training with over 870 combinations of K_OC 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 (PEC_GAM) with the simulated PEC_GW 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.