Heavy Metals in Herbal Preparations

Heavy Metals in Herbal Preparations

The following is the table summarizing information about heavy metals in herbal preparations: 

Raw Material Type of Heavy Metal Maximum Limits (ppm) Legislation/Regulation Analytical Tests
Milk Thistle (Silybum marianum) Lead Not more than 10 ppm Examples include milk thistle dried ripe fruit (pappus removed). Determination of lead content based on sulphide ion coloration tests.
Echinacea angustifolia, E. pallida, E. purpurea Lead Not more than 10 ppm Examples include dried rhizomes, roots, and aerial parts of Echinacea species. Sulphide ion coloration tests for underground parts (rhizomes, roots).
Red Clover (Trifolium pratense) Lead Not more than 10 ppm Examples include dried inflorescences of red clover. Similar methods as for other underground parts, focusing on roots and rhizomes.
Horsechestnut (Aesculus hippocastanum) Lead Not more than 20 ppm Examples include dried seeds of horsechestnut. Analysis for lead content using sulphide ion coloration tests.
Goldenseal (Hydrastis canadensis) Lead Not more than 20 ppm Examples include dried roots and rhizomes of goldenseal. Specific tests for lead content due to potential soil contamination.
Asian Ginseng (Panax ginseng) Lead Not more than 20 ppm Examples include dried roots of Asian ginseng. Methods for detecting lead levels in rhizomes and roots.
Licorice (Glycyrrhiza glabra or G. uralensis) Lead Not more than 30 ppm Roots, rhizomes, and stolons of licorice. Testing for lead content in licorice root parts.
Valerian (Valeriana officinalis) Lead Not more than 50 ppm Subterranean parts including rhizome, roots, and stolons of valerian. Analytical methods ensuring compliance with lead limits in valerian root.
Kelp (Fucus vesiculosus, F. serratus, Ascophyllum nodosum) Arsenic, Cadmium, Lead, Mercury Arsenic (max 90 ppm), Cadmium (max 4 ppm), Lead (max 5 ppm), Mercury (max 0.1 ppm) European Pharmacopoeia monograph for kelp (Fragmented dried thallus). Specific methods outlined in the European Pharmacopoeia for arsenic, cadmium, lead, and mercury determination.
Linseed (Linum usitatissimum) Cadmium Not more than 0.5 ppm European Pharmacopoeia monograph for linseed (Dried ripe seeds). Analytical techniques specified in pharmacopoeia standards for cadmium content in linseed.


Notes:
 

  • Raw Material: Herbal plant or plant part analyzed for heavy metal content. 
  • Type of Heavy Metal: Specific heavy metal(s) of concern. 
  • Maximum Limits (ppm): Maximum allowable concentration of each heavy metal. 
  • Legislation/Regulation: Relevant regulatory framework governing heavy metal limits. 
  • Analytical Tests: Methods used to determine heavy metal content, often specified by pharmacopoeial standards. 

These tables provide a comprehensive overview of the maximum allowable limits for heavy metals in various herbal preparations, as well as the methods used to analyze and ensure compliance with these limits. 

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