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Speciation and bioavailability of lead in complementary medicines
S Bolan1, R Naidu2, A Kunhikrishnan3
1School of Natural and Built Environments, University of South Australia, SA 5095, Australia; Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW 2308, Australia.
The Science of the Total Environment
|September 14, 2015
Summary
Toxic heavy metal contamination, particularly lead (Pb), poses risks in complementary medicines. Ayurvedic medicines showed higher Pb levels and bioavailability than herbal ones, potentially exceeding safe intake thresholds.
Area of Science:
- Environmental Chemistry
- Toxicology
- Pharmacology
Background:
- Complementary medicines can contain toxic heavy metal(loid)s and pesticides.
- Lead (Pb) contamination is a significant concern in herbal and ayurvedic products.
Purpose of the Study:
- To investigate the speciation and bioavailability of lead (Pb) in selected herbal and ayurvedic medicines.
- To compare daily Pb intake from these medicines with established safety guidelines.
Main Methods:
- Analysis of total heavy metal(loid)s (As, Cd, Pb, Hg).
- Lead (Pb) speciation using sequential fractionation and extended x-ray absorption fine structure (EXAFS).
- In vitro assessment of Pb bioavailability using a physiologically-based extraction test (PBET).
Main Results:
- Ayurvedic medicines generally contained higher heavy metal(loid) levels, with Pb being predominant.
- Organic-bound Pb species were found in herbal medicines, while inorganic-bound Pb species dominated ayurvedic medicines.
- Pb bioavailability was higher in ayurvedic medicines, linked to soluble Pb fractions and likely mineral inputs.
Conclusions:
- Lead (Pb) in herbal medicines may originate from plant uptake, while ayurvedic medicines likely incorporate inorganic mineral sources.
- Higher Pb bioavailability in ayurvedic medicines suggests a greater risk of toxicity.
- Daily Pb intake from certain ayurvedic medicines may surpass safe limits, warranting further investigation into potential Pb toxicity.
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