NORM-TENORM: Characterization of Uranium, Radium, Lead and Polonium levels in the area of the phosphogypsum basin in South Italy. Radiochemical measurement techniques

The characterization of NORM/TENORM materials must be performed using different nuclear techniques, able to show the complete scheme of the equilibrium of the radionuclides in the different natural chains. The characterization must be done in order to be able to determine the levels of radionuclides present in them, in order to verify the clearance levels for the correct management of the material, of the area management in which they are located and determine any breakage of the natural chains to identify NORM/TENORM pollution phenomena in the environment where these materials are stored. All this is particularly important in order to organize the remediation of polluted sites.

In the site of national interest of Tito Scalo (South Italy), "ex Liquichimica" Area, following specific samplings, characterizations were carried out for the determination of Uranium, ²²⁶Ra, ²¹⁰Pb and ²¹⁰Po as well as the gamma emitters with various analytical techniques and through specific radiochemical procedures.

The above determinations were performed on various matrices, including surface and groundwater, soils, silt-sediments and plants, for a total of 257 soil samples, 47 groundwater samples, 8 surface water samples, 8 silt-sediment and 10 plant samples.

The analyzes were conducted using radiochemical procedures, such as the IAEA/AQ/34:2014 procedure, accredited according to the UNI EN ISO 17025 standard, specific for the determination of U, Ra, Pb and Po in phosphogypsum.

The analytical techniques used are complex and involve multiple steps for the treatment of the sample and the sequential separation of the radionuclides for their determination: in particular, the above procedure involves the use of liquid scintillation, alpha and gamma spectrometry after radiochemical treatment of the starting matrix. Processes of this type require, in addition to specific skills, a qualitative process that guarantees the goodness of the entire process.

This work shows in detail the IAEA/AQ/34 procedure for the radiological characterization of the phosphogypsum basin of the "ex Liquichimica" area of Tito Scalo, as well as analytical data for each group of analyzed matrices.