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Determination of Heavy Metal Contaminants (Pb, Cd, Hg) in Spirulina Dietary Supplements Available in the Thai Online Market

Authors

Thanawat Wattanaset Master of Science Student (Anti-Aging and Regenerative Medicine), College of Integrative Medicine, Dhurakij Pundit University
Pariwat Surasirianan Master of Science Student (Anti-Aging and Regenerative Medicine), College of Integrative Medicine, Dhurakij Pundit University

Keywords:

Spirulina, Heavy metals, Lead, Cadmium, Mercury

Abstract

This cross-sectional analytical descriptive study aimed to survey and analyze the contamination of heavy metals-lead (Pb), cadmium (Cd), and mercury (Hg) in spirulina dietary supplements sold through online platforms in Thailand. Because spirulina readily absorbs and bioaccumulates heavy metals from its culture environment, contaminated products may pose a health risk to consumers when quality control across the production chain is inadequate. A purposive sample of 10 branded products was selected from e-commerce platforms, comprising 7 domestic and 3 imported items, and covering three product forms (tablet, capsule, and powder). Heavy metal concentrations were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and compared with the maximum limits set by the Notification of the Ministry of Public Health (No. 414).

The results showed that 80% of the products exceeded the lead standard. Domestic products contained a mean lead concentration of 0.161±0.150 mg/kg, while imported products contained 0.194±0.111 mg/kg. Capsule-form products showed the highest mean lead level and failed the standard in all samples, whereas powder-form products showed the lowest mean level. Cadmium was detected in some samples but remained within the safety limit, and mercury was not detected in any sample. Notably, products bearing international certifications such as USFDA and Organic still exceeded the lead limit.

These findings indicate that spirulina dietary supplements sold online in Thailand continue to pose a considerable risk of lead contamination, particularly capsule-form and imported products, and that international certification marks do not necessarily guarantee safety from heavy metals. Continuous surveillance and targeted random inspection of these higher-risk product groups are therefore recommended to protect consumer safety in the long term.

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