Figure 12
This graph provides a visual representation of the offsets between predicted and observed drinking water values calculated using existing water/enamel conversion equations. Differences between predicted drinking water oxygen (δ18Odw) values and observed drinking water oxygen values as measured by (a) tap water (δ18Otap) and (b) OIPC (δ18OOIPC) for all samples from the current study (n = 75). The best predictors fall closest to 0 (solid line), which occurs when predicted drinking water values equal observed drinking water values. δ18Odw values were predicted from actual enamel carbonate oxygen values using existing water/enamel conversion equations indicated by the various colours. Phosphate/carbonate conversion equations were applied to water/enamel equations when direct water/enamel conversions were not possible. Shapes denote applied phosphate/conversion equations.
