Speciation of natural and antropogenic radionuclides in different sea sediment samples

A sequential extraction method consisting of six operationally-defined frac tions was used to determine the geochemical partitioning of natural (U, Th, ) and antropogenic (Pu, Am,Cs-137) radionuclides in three sediment samples of different origin (Venice Lagoon, Adriatic Sea; Gaeta Gulf, Thyrrhenian S ea; IAEA-367, Enewetak Atoll, Central Pacific Ocean). Fe, Mn, Al, Ti, Ca, S r, Pb, Ba, K were also determined in the different fractions to get more in formation about the chemical association of the single radionuclides. The e xperimental results were compared to those described in the literature for an IAEA-135 Sea Sediment collected in the Irish Sea in front of the Sellafi eld Plant (UK).