title: The uranium isotopes in the characterisation of groundwater in the Thermi-Vasilika region, northern Greece.
abstract: The activity concentrations of (238)U and (234)U have been determined in groundwater samples in the Thermi-Vasilika region, northern Greece. The analysis was performed by alpha spectrometry after pre-concentration and separation of uranium by cation exchange and finally its electrodeposition on stainless steel discs. The obtained isotopic ratio (234)U/(238)U varies between 0.95 and 3.50 and is correlated with the different aquifer types and water flow paths in the study area. Lower values (up to 1.10) are located in the shallow porous aquifer indicating younger waters. Moderate values of the activity ratio characterise the deeper porous aquifer as well as the fissured rock aquifer (1.5-2.05). The geothermal spring illustrates the highest activity ratio (3.5) due to older water.
authors.affiliation: a Chemistry Department, Laboratory of Inorganic Chemistry , Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: Fotini
authors.initials: F
authors.lastname: Noli
authors.affiliation: b Geology Department, Laboratory of Engineering Geology & Hydrogeology , Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: Nerantzis
authors.initials: N
authors.lastname: Kazakis
authors.affiliation: c Geology Department, Laboratory of Applied Geophysics , Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: George
authors.initials: G
authors.lastname: Vargemezis
authors.affiliation: d Physics Department, Nuclear Physics Laboratory , Aristotle University of Thessaloniki , Thessaloniki , Greece.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ioannidou
mesh_terms: D006115:Greece; D060587:Groundwater / Q000032:analysis* / Q000737:chemistry; D011834:Radiation Monitoring; D011868:Radioisotopes / Q000032:analysis; D013057:Spectrum Analysis; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D011868:Radioisotopes; D014875:Water Pollutants, Radioactive; D014501:Uranium
keywords: 234U/238U activity ratio; Age dating; alpha spectrometry; groundwater resources; natural radioactivity; uranium-234; uranium-238