Research · Systematic review
Microalgae as a source of contaminants: a review
Rzymski & Niedzielski · 2015 · Algal Research
Key finding
Comprehensive review of contaminant data from commercial spirulina and chlorella products found that heavy metals (lead, arsenic, cadmium), microcystins, and microbial contaminants are the primary safety concerns. Open-pond cultivation in areas with agricultural runoff carries higher contamination risk. Third-party testing on each production batch is the only reliable mitigation.
Why this matters for consumers
The definitive scientific reference for understanding spirulina safety risks. The key takeaway for consumers: origin and batch-level testing matter. A brand's country of origin and farming system are the strongest predictors of contamination risk — which is exactly why we require a published CoA from every brand in our directory.
Study limitations
Review methodology; contamination varies significantly between specific producers even within the same region.
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