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

Abstract

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 40K, 137Cs, 226Ra, 228Ra, and 234Th 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 (137Cs) followed by 1.76–10.7 (226Ra), 0.20–12.7 (228Ra), 11.6–24.2 (234Th), and 20.1–400 (40K). Also, the effective radiation doses from 40K, 137Cs, 226Ra, 228Ra, and 234Th decay ingested with analyzed algae supplements have been estimated. The highest annual effective dose reaching 15.1 µSv/year has been assessed for naturally occurring 226Ra in Chlorella vulgaris from Japan. The Fukushima Nuclear Power Plant has not significantly impacted the effective dose from 137Cs 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.