Development of a Dutch Drainpipe exposure scenario

In the new Dutch pesticide authorisation procedure, the leaching of pesticides to surface waters will be evaluated. The 90th percentile of the peak concentrations in all Dutch ditches will be used for the exposure assessment of aquatic organisms The peak concentration in surface waters is primarily affected by fast transfer routes (amongst others by macropores). For this reason, we developed a macropore version of the pesticide leaching model PEARL. The macropore version of PEARL describes transport of pesticides through the soil matrix and through two preferential flow domains, i.e. a bypass domain and an internal catchment domain.