Radioactive isotopes( 40)K, Cs-137, Ra-226, Ra-228, Th-234 in algae supplements - Potential radiotoxicity of aquatic superfoods

Many food products are recommended to give health benefits. Thus algae superfoods consumption is growing worldwide, although quite a few studies have examined the quantities of radionuclides they contain and their potential effects on human health. The study presents radioactive K-40, Cs-137, Ra-226, Ra-228, and Th-234 in algae supplements available worldwide for human consumption. Samples have been quantified by gamma-ray spectrometry and the activity concentrations (Bq/kg dw) ranged 0.23-0.65 (Cs-137) followed by 1.76-10.7 (Ra-226), 0.20-12.7 (Ra-228), 11.6-24.2 (Th-234), and 20.1-400 (K-40). Also, the effective radiation doses from K-40, Cs-137, Ra-226,Ra- 228, and Th-234 decay ingested with analyzed algae supplements have been estimated. The highest annual effective dose reaching 15.1 mu Sv/year has been assessed for naturally occurring Ra-226 in Chlorella vulgaris from Japan. The Fukushima Nuclear Power Plant has not significantly impacted the effective dose from Cs-137 present in algal superfoods. Based on the study, the activity concentrations of radionuclides seem to be low, the naturally occurring radionuclides would give the highest effective doses, and the investigated algae supplements could be considered safe food.Funding Agencies|Chinese Academy of Sciences [2020VBB0008]; Ministry of Education and Science [DS/531-T030-D841-22]