RADIOCHEMICAL CHARACTERIZATION OF ALGAE PRODUCTS COMMERCIALIZED FOR HUMAN CONSUMPTION

Natural radionuclides and Cs-137 were determined by alpha (U-238, U-234, Th-230, Po-210, Th-232, and Th-228) and gamma spectrometry (Cs-137, K-40, Ra-226, Pb-210, and Ra-228 via Ac-228) 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 (Cs-137) 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 (K-40) 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 Po-210 was 5.1 Bq kg(-1) with a range of 1.5-13.6 Bq kg(-1). The mean of activity for Pb-210 was 8.9 Bq kg(-1) with a range of 2.9-25.7 Bq kg(-1). The mean of U-238 and Ra-226 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 Th-232, Th-228, and Ra-228 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.