Unveiling the Contamination\nof Thiocyanate, Perchlorate,\nand Chlorate in Edible Microalgae: Detection, Distribution, and Risk\nAssessment in Sustainable Food Sources

With the growing interest in microalgae\nas a sustainable food source,\nconcerns about potential chemical contaminants in these products have\nemerged. In this study, a sensitive and reliable LC-MS/MS method was\ndeveloped for the simultaneous detection of thiocyanate, perchlorate,\nand chlorate in edible microalgae samples. The method was validated\nwith excellent linearity (R<sup>2</sup> > 0.998), low detection\nlimits\n(LOD: 1–8 μg/kg), quantification limits (LOQ: 4–26\nμg/kg), and high recovery rates (75–101.9%) across different\nsample types. We collected a total of 77 microalgae products based\non the available varieties in the market, including 43 Spirulina powder\nsamples, 10 Chlorella powder samples, and 24 microalgae-based food\nproducts, sourced from key microalgae production regions in China.\nThe contamination levels for thiocyanate (median: 1843.06–2645.72\nμg/kg) and perchlorate (median: 23.29–31.4 μg/kg)\nwere consistently quantitated in all samples, while chlorate concentrations\nshowed greater variability (median: 18.94–160.21 μg/kg).\nRisk assessment revealed a significant dietary exposure risk to thiocyanate,\nwith estimated daily intake (EDI) values exceeding the EPA’s\nsubchronic reference dose, whereas no significant risk was identified\nfor perchlorate or chlorate. Monte Carlo simulations further supported\nthe conclusion that perchlorate and chlorate posed minimal dietary\nrisks, while thiocyanate exposure warrants concern. This study not\nonly provides a foundational method for monitoring these contaminants\nin microalgae but also contributes critical data for future food safety\nstandards and regulatory practices regarding edible microalgae products.