Radiochemical characterization of algae products commercialized for human consumption

Natural radionuclides and 137Cs were determined by alpha (238U, 234U, 230Th, 210Po, 232Th, and 228Th) and gamma spectrometry (137Cs, 40K, 226Ra, 210Pb, and 228Ra via 228Ac) in 14 dried seaweeds commercialized for human nutrition in Italy. The study was carried out in order to provide information on the concentrations of natural and artificial radionuclides. Cesium-137 (137Cs) concentrations in all analyzed samples were always <2.0 Bq kg-1 (dry weight), while the naturally occurring radionuclide concentrations were detectable in all the samples and significantly different in the analyzed seaweeds. Potassium-40 (40K) showed a mean activity of 894 Bq kg-1 with a range of 14.1-3,256 Bq kg-1. The mean of activity for 210Po was 5.1 Bq kg-1 with a range of 1.5-13.6 Bq kg-1. The mean of activity for 210Pb was 8.9 Bq kg-1 with a range of 2.9-25.7 Bq kg-1. The mean of 238U and 226Ra activity concentration was 4.7 and 8.4 Bq kg-1 with a range of 0.1-27.7 and 3.2-24.6 Bq kg-1, respectively. The mean activity concentrations for 232Th, 228Th, and 228Ra were 0.69, 3.0, and 6.6 Bq kg-1 with ranges of 0.05-3.39, 0.24-15.7, and 0.5-35.6 Bq kg-1, respectively. Radionuclide activity concentrations were within ranges reported in the scientific literature. The committed effective dose due to all the radionuclides analyzed, from ingestion of 1 kg y-1 of seaweeds, accounts for 0.66% of the natural radiation exposure in Italy.