To oversimplify by a lot, Civil/Environmental = urban/industrial (e.g. industrial/municipal wastewater treatment, air pollution), Environmental = agricultural/resources (e.g. soil management, biofuels, soil decontamination for mining/oil).
That's roughly how it was divided at my college, anyway.
Right,
What is the difference between Civil/Environmental and Environmental ?
It seems the best bet is to study something like mining since the R_0 is so low there.