Radiocontamination level of mussels (M. Galloprovincialis) collected in italy from apulian coasts and assessed dose to population

Abstract

Due to their particular metabolism, bio-filtering mollusks accumulate elements essential for their sustenance, but even radioactive isotopes of natural elements, such as Uranium and Polonium. Many of these cannot be directly determined by gamma spectrometry, since chemical separation from the matrix is needed before determining activity concentration by means of different spectrometric techniques and the dose to the consumer. In this paper, the authors describe the methods and present the results of alpha, beta and gamma radiometric measurements on filtering mollusks samples (M. Galloprovincialis) collected along the Apulian coast (Italy) during 2021. The analyses were carried in order to give an overall picture of the radio-contamination on the Italian side of the Adriatic Sea. The artificial gamma-emitting radionuclides (e.g. I-131, Co-60, Cs-134) were not detected in all samples. Strontium-90 alone was often found to be present at extremely low concentration, in the range 0.01 – 0.57 Bq kg−1. With reference to natural radionuclides (i.e., U-234, U-235, U-238 and Lead-210) the activity concentrations were limited to a few Bq kg−1. Po-210 represents a particular case, since it results more accumulated than its parent nuclide Lead-210, indicating that polonium is selectively accumulated by mussels. Using ICRP-Dose software, the annual dose to population was assessed. The results demonstrated that the annual limit of one mSv (Italian law) could be exceeded only if the annual consumption exceeds 200 kg per capita of fresh mussels. In conclusion the analysis showed that Polonium-210 and Lead-210 were selectively accumulated by mussels, with particular reference to Polonium. However, the activities are in any case such as not to cause concern for consumers.