Modeling frameworks are poorly developed for EPs' fate – with the exception of pesticides – in the soil–water
environment and require further development.The challenge is to model transport and fate of various EPs from all
possible sources (urban,industrial,agriculture), through catchments to their outlet (Fig. 2). EPs from diffuse sources
are transported via the soil–water system to the sink (water body) (McGuire&McDonnell,2006). Depending on
their properties, EPs can be transported by different processes, such as by runoff, erosion or leaching and enter into
ground water or surface water.They may be intercepted by the soil through adsorption or can be degraded during the
transport and never reach the water bodies. Once water bodies are reached, further transport downstream in solution
or attached to suspended material may occur. As EPs are “emerging”, little experimental evidence is available on
their transport and partitioning in catchments – and models to simulate this transport have not been parameterized for
EPs except for pesticides.