| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Zea mays | Seed | -- | -- | * | |
| Vitis vinifera | Fruit Juice | -- | -- | * | |
| Spinacia oleracea | Leaf | -- | 15.0 | * | |
| Nicotiana tabacum | Leaf | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Malus domestica | Fruit | -- | 3.0 | * | |
| Humulus lupulus | Flower | -- | 3.1 | * | |
| Humulus lupulus | Inflorescence | -- | 3.1 | * | |
| Hordeum vulgare | Seed | -- | 5.7 | * |