title: Uranium levels in Cypriot groundwater samples determined by ICP-MS and α-spectroscopy.
abstract: The uranium concentration and the isotopic ratio (238)U/(234)U have been determined in Cypriot groundwater samples by ICP-MS after ultrafiltration and acidification of the samples and α-spectroscopy after pre-concentration and separation of uranium by cation-exchange (Chelex 100 resin) and electro-deposition on stainless steel discs. The uranium concentration in the groundwater samples varies strongly between 0.1 and 40 μg l(-1). The highest uranium concentrations are found in groundwater samples associated with sedimentary rock formations and the obtained isotopic ratio (238)U/(234)U varies between 0.95 and 1.2 indicating basically the presence of natural uranium in the studied samples. The pH of the groundwater samples is neutral to weak alkaline (7 < pH < 8) and this is attributed to the carbonaceous content of the sedimentary rocks and the ophiolitic origin of the igneous rocks, which form the background geology in Cyprus. Generally, in groundwaters uranium concentration in solution increases with decreasing pH (7 < pH < 8) and this is attributed to the fact that at lower pH dissolution of soil minerals occurs, and uranium, which is adsorbed or forms solid solution with the geological matrix enters the aqueous phase. This is also corroborated by the strong correlation between the uranium concentration and the electrical conductivity (e.g. dissolved solids) measured in the groundwaters under investigation.
authors.affiliation: State General Laboratory, Ministry of Health, 44 Kimonos Str., Cy-1451 Nicosia, Cyprus.
authors.forename: Chrystalla
authors.initials: C
authors.lastname: Charalambous
authors.forename: Maria
authors.initials: M
authors.lastname: Aletrari
authors.forename: Panagiota
authors.initials: P
authors.lastname: Piera
authors.forename: Popi
authors.initials: P
authors.lastname: Nicolaidou-Kanari
authors.forename: Maria
authors.initials: M
authors.lastname: Efstathiou
authors.forename: Ioannis
authors.initials: I
authors.lastname: Pashalidis
mesh_terms: D003535:Cyprus; D004553:Electric Conductivity; D060587:Groundwater / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry / Q000379:methods; D011834:Radiation Monitoring; D013057:Spectrum Analysis / Q000379:methods; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium