The Ayurvedic medicines have drawn attention in recent years due to the illegal limit of toxic metals present in it. In Ayurveda, two types of drugs are used mostly i.e. Rasakalpa (containing inorganic & organic ingredients) and Ayurvedic herbal drugs (containing organic ingredients).

It is estimated that about 70–80% of the world’s population relies on non-conventional medicine, mainly of herbal origin. As Ayurvedic herbal drug contains only organic ingredients, it is assuming that there is no side effect of using it. However, owing to the nature and sources of herbal medicines, they are sometimes contaminated with toxic heavy metals such as lead, arsenic, mercury and cadmium, which impose serious health risks to consumers.

As most heavy metals are toxic and can cause poisoning, so there should be strict monitoring and regulations regarding heavy metal concentrations in herbal products. The indiscriminate use of fertilizers, pesticides, atmospheric deposition from town wastes and industrial emissions are the major sources of heavy metal pollution. Medicinal plants are easily contaminated with heavy metals during growth, development, harvest, drying, storage and processing.

As medicinal herbs are collected indiscriminately from eco-friendly as well as non-environment-friendly areas by untrained people and supplied as raw material to the pharmaceutical industry. Good agricultural practices, testing of herbal products at laboratories can control the quality of such products. ‘Heavy Metal content in Ayurvedic herbal drugs’ is currently most controversial issue in research section. Many research papers are found published regarding this issue. These articles showed that Ayurvedic herbal preparations contained heavy metals beyond limits, which can affect human health. Nowadays Ayurvedic herbal medicines popularity is growing in worldwide, but these kind of articles can hamper Ayurveda.

Solutions

• Good agricultural practices include use of good fertilizers and provision of integrated disease management.
• The standard operative procedures (SOP) should be adopted at every stage of drug preparation and it starts with careful selection of standard raw materials free of contaminants.
• Quantitative analysis (e.g. chromatography, spectroscopy), of heavy metals should be done on raw materials of herbal drugs.

Observed values should be Compared with alloy able human dose of heavy metal in herbal plant as per WHO (World Health Organisation) and FDA (Federal Drug Administration).

Heavy Metal Maximum Permissible Limit
Arsenic (As) 10³ng/g
Cadmium (Cd) 0.3 μg/
Lead (Pb) 10 μg/g
Mercury (Hg) 1 μg/g

Also, American National Standards Institute ANSI 173 states that dietary supplements should not contain undeclared metals that would cause intakes greater than 20μg/d of lead, 20 μg/d of mercury, and 10 μg/d of arsenic. Enforcement Act (California Proposition 65) has established maximum allowable dose levels for chemicals causing reproductive toxicity (for lead, 0.5 μg/d).
The Food and Agricultural Organization/World Health Organization Joint Expert Committee on Food Additives establishes provisional tolerable weekly intakes for contaminants in foods of 25μg/kg of lead,1.6μg/kg of mercury, and 15 μg/kg of arsenic, corresponding to acceptable daily intakes of 250 μg/d of lead, 50 μg/d of mercury, and 150 μg/d of arsenic for a 70-kg adult.

References
(Articles -which are published regarding heavy metal contamination in herbal medicines)
http://www.ncbi.nlm.nih.gov/pubmed/15598918
http://www.ncbi.nlm.nih.gov/pubmed/11936709
http://www.ncbi.nlm.nih.gov/pubmed/19275871
http://informahealthcare.com/doi/abs/10.1076/phbi.39.5.384.5898
http://www.ncbi.nlm.nih.gov/pubmed/18728265
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3224858/?tool=pubmed#R34
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2755247/?tool=pubmed