Epithermal neutrons activation analysis, radiochemical and radiometric investigations of evaporitic deposits of Slanic-Prahova (Romania) salt mine

Three highly sensitive analytical methods: epithermal neutron activation analysis (ENAA), radiometric assay and UV/Vis spectroscopy were used to investigate the elemental composition of both halite and mineral fractions (sediments) of salt collected from the Slanic-Prahova salt mine, near the location of Low Background Radiation Laboratory. For halite with all three methods and within experimental uncertainties, it was not possible to observe the presence of any natural radioactive elements. For the mineral fraction both radiometric and ENAA showed the presence of 40K, 232Th and 238U in concentrations comparable to the upper continental core (UCC). The same was true for the distribution in the mineral fraction of 7 other major (Na, Al, Cl, K, Ca, Ti and Fe) and 29 trace elements (Sc, Cr, V, Mn, Ni, Co, Zn, Cu, As, Br, Rb, Sr, Zr, Mo, Sn, Sb, Cs, Ba, La, Ce, Ne, Eu, Sm, Tb, Hf, Ta, W, Th, U) as determined by epithermal neutron activation analysis (ENAA), which demonstrates a continental origin of the sediments in the existing salt deposit.