Table 2.
Selected methods for calculating Gdanth; elements and approaches used.
| Reference | Elements used | Interpolation/extrapolation | Specifics |
|---|---|---|---|
| Bau and Dulski (1996) | Sm, Tb | linear | Gd behaves as a LREEa |
| Hissler et al. (2015) | Nd, Dy | linear | Gd behaves as a MREE |
| Ogata and Terakado (2006) | Sm, Dy | logarithmic | Gd behaves as a HREE |
| Kulaksiz and Bau (2013) | Eu, Nd | logarithmic | Not usable if MREE are enriched or water is slightly acidic, rich in organic colloids |
| Kulaksiz and Bau (2011a) | Pr, Nd, Sm | geometric | Gd behaves as a LREE |
| Möller et al. (2002) | all Ln except Ce, Eu | third grade polynomial fit | no implicit assumption about the behavior of Gd |
a
No specifics stated in the original manuscript but implied in (Bau et al., 2006); LREE - light rare earth element, MREE - middle rare earth element, HREE - heavy rare earth element (terminology is referring to the original literature).