Spatial and Temporal Variability of Uranium and Toxic Metals in Snow and Rainwater from an Oil Industry and Urban Area in Thessaloniki-Greece

The concentrations of uranium and nine elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in snow and rainwater samples were determined. Samples were collected in Thessaloniki-northern Greece in three sites, one in the industrial area close to an oil production power plant and two in the centre of the city. Snow samples were collected during January-February 2019 and 2021 whereas in the case of rainwater, a two-year survey has been performed during 2019 and 2020.The activity concentrations of the uranium radioisotopes were measured by alpha spectrometry whereas the metals concentrations were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The elevated concentrations of uranium and the deviation of the isotopic ratio of U-234/U-238 from the equilibrium value indicated intensive dissolution of uranium. The results of the metal concentrations were analyzed using statistical analysis (Shapiro-Wilk, Friedman and Kruskal-Wallis tests). The obtained data and the calculated enrichment factors (Ef) denote variation of the concentration values between industrial and urban area and different elemental distribution influenced from anthropogenic contributions, meteorological conditions and the COVID-19 pandemic