inverse modeling : interpretation and selection of optimal model

[hyedy]

I have  questions...

1. When i run inverse modeling (with some  constraints, i.e. force to precipitate / dissolution), the result showed several cases of mineral reactions that can occur along the flow path. Then, how can i choose best fit model?? In some papers, they didn't mentioned the criterion of selecting best fit model. just choose model with comparing results from conventional approaches to interpret change of chemical compositions??

2. Situation is... if the i set initial/final points along the path that flow urban area, then two points might be effected by the contamination from urban area. But when i run inverse model, i only take into account the water-mineral interactions, which indicate natural source of ions in samples.

For example, in case of ca2+, na+, and so42-, the results from simulation show mass transfer related to carbonate, sulfate and silicate minerals that can be the natural source of those  ions. However, amounts of the mass transfer of related minerals are quite small comparing to the concentration difference between two points.
Is is okay to interpret the results, along the flow path, the water might be effected by the contamination?

3. Last question is related to the weathering of silicate minerals. Is it possible to occur inside the groundwater along the path both precipitation of primary minerals such as albite, feldspar and dissolution of secondary minerals such as clay minerals (kaolinite, montmorillonite...) ???

thanks :))