| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Citrus paradisi | Fruit | -- | -- | * | |
| Citrus sinensis | Fruit | -- | -- | * | |
| Althaea officinalis | Plant | -- | -- | Pakistan Encyclopedia Planta Medica. 1986. | |
| Corylus avellana | Wood | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. | |
| Coffea arabica | Seed | -- | -- | * | |
| Juncus effusus | Plant | -- | -- | * |