| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Althaea officinalis | Root | -- | 40000.0 | 2.8 | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. |
| Triticum aestivum | Shoot | -- | 1640.0 | 2.2 | * |
| Lycium chinense | Leaf | -- | 13800.0 | 1.0 | Hansel, R., Keller, K., Rimpler, H., and Schneider, G. eds. 1992. Hager's Handbuch der Pharmazeutischen Praxis, Drogen (A-D), 1209 pp., 1993 (E-O), 970 pp., 1994 (P-Z), 1196 pp. Springer-Verlag, Berlin. |
| Cola acuminata | Seed | -- | 2500.0 | 1.0 | * |
| Lycium barbarum | Fruit | -- | 10000.0 | 1.0 | * |
| Lycium chilense | Fruit | -- | 10000.0 | 1.0 | Foster, S. and Yue, C-G. 1992. Herbal Emissaries-Bringing Chinese Herbs to the West. Healing Arts Press, Rochester VT. 356 pp. |
| Zea mays | Shoot | -- | 234.0 | -0.2 | * |
| Echinacea angustifolia | Root | -- | 1000.0 | -0.3 | Jim Duke's personal files. |
| Hordeum vulgare | Root | -- | 234.0 | -0.3 | * |
| Triticum aestivum | Root | -- | 82.0 | -0.4 | * |
| Pisum sativum | Root | -- | 59.0 | -0.4 | * |
| Zea mays | Root | -- | 59.0 | -0.4 | * |
| Daucus carota | Root | -- | 35.0 | -0.4 | * |
| Lycopersicon esculentum | Root | -- | 23.0 | -0.4 | * |
| Avena sativa | Root | -- | 0.1 | -0.4 | * |
| Pisum sativum | Shoot | -- | 94.0 | -0.4 | * |
| Lycopersicon esculentum | Shoot | -- | 69.0 | -0.5 | * |
| Avena sativa | Shoot | -- | 2.0 | -0.6 | * |
| Hordeum vulgare | Shoot | -- | 1.8 | -0.6 | * |
| Lycium chinense | Fruit | -- | 1000.0 | -1.0 | * |