| Acronym | Meaning |
| IAH | International Association Hydrogeologists |
| RCNDO/S | Rydberg CNDO/screened |
| HAGAR | High Altitude Gas Analyzer |
| PAC | Powdered Activated Carbon |
| CAC | Continuous Annular Chromatograph |
| GUS | Groundwater Ubiquity Score |
| SF CC | Space-fixed Close-coupled (equation |
| GHRS | Goddard High Resolution Spectrograph |
| NDT | Nil Ductility Temperature |
| LREE | Light Rare Earth Element(s) |