| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Citrus limon | Root | -- | -- | Jim Duke's personal files. | |
| Citrus reticulata | Root | -- | -- | * | |
| Citrus sinensis | Root | -- | -- | Jim Duke's personal files. | |
| Citrus paradisi | Root | -- | -- | CRC Handbook of Medicinal Herbs and/or CRC Handbook of Proximate Analyses |