Organizations: Environmental Isotopes Variables: dissolved_organic_carbon alkalinity concentration Substances: Sulfate (InChI=1S/H2O4S/c1-5(2,3)4/h(H2,1,2,3,4)/p-2 Oxygen (InChI=1S/O2/c1-2) Krypton (InChI=1S/Kr) Nitrate (InChI=1S/NO3/c2-1(3)4/q-1) Systems: groundwater Keywords: noble gases groundwater riparian zone denitrification