Measurement of plutonium pollution in sediments and algae in marine environment: Cienfuegos bay and la Maddalena Islands

Several methods are available for the measurement of Pu in the marine environment. The paper is mainly focused on the determination of Pu in marine sediments, following the experimental activity of some of the authors in that field. The selected method for radiochemical separation is anionic chromatography and measurement technique is the quadrupole inductively coupled plasma mass spectrometry (QICP-MS). Levels of 239Pu in analyzed marine sediments (Cienfuegos Bay, Cuba) are in the range of (0.10-0.86 Bq kg-1): this radionuclide, therefore, is only due to global fallout. This method turns out to be an efficient one in case of routine measurements. To set up a complete monitoring chain for Pu marine pollution, useful for accidental pollution too, another method is briefly presented. In this method, some types of seaweeds (like Jania rubens and Corallina elongata) are sampled and analysed, since they quickly metabolise plutonium. With the autoradiography technique, the samples are put in contact with particular films, sensible to α-rays of selected energy (Kodak Pathè LR-115). As a case study, seaweeds have been sampled in the Mediterranean Sea close to Northern Sardinia Island after a suspect release of radioactivity due to a nuclear submarine accident. Some types of seaweeds, in particular, showed the presence of "hot spots", due to the concentration of alpha-emitting pollutants in the form of radioactive granules resting on the surfaces of seaweeds: this is the index of Pu artificial pollution not due to global fallout.