| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Tanacetum parthenium | Plant | -- | -- | Newall, C. A., Anderson, L. A. and Phillipson, J. D. 1996. Herbal Medicine - A Guide for Health-care Professionals. The Pharmaceutical Press, London. 296pp. | |
| Zingiber officinale | Essential Oil | -- | -- | * | |
| Zingiber officinale | Rhizome | 245.0 | 4910.0 | * |