Catchment-scale herbicides transport: Theory and application

► Travel time formulation of transport is here extended to the description of the dynamics of solutes that are partially taken up by transpiration. ► The framework is applied to the study of atrazine circulation at catchment scale. ► Differences of residence times for water compared to those of solutes are addressed. ► Tools for ecological risk assessment related to herbicides are evaluated via a probabilistic analysis using Monte Carlo simulations.