title: Radiometric, SEM and XRD investigation of the Chituc black sands, southern Danube Delta, Romania.
abstract: The black sand of the Chituc marine sand bank, northern of the city of Navodari (Romania), presents anomalous high radioactivity. Field measurements recorded in some places dose rate up to 200 nSv/h, significantly overpassing the average value of 44 ± 20 nSv/h along the entire Southern sector of Romanian Black Sea shore. Gamma ray spectrometry performed on both Slanic-Prahova Underground Low Background Laboratory and Geological Institute of Romania Radiometric Facilities showed with clarity the dominance of (228)Ac radioisotope in the 50 microns fraction together with the (226)Ra and traces of (40)K. No significant amount of anthropogenic (137)Cs was identified. Based on radiometric as well as on SEM-EDAX and XRD determinations we come to the conclusion that the evidenced radioactivity could be attributed to both uranium and thorium series in the zircon and monazite fractions and to a lesser extent to potassium in the feldspars.
authors.affiliation: Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-06, 077125 Magurele (Ilfov), Romania.
authors.forename: R M
authors.initials: RM
authors.lastname: Margineanu
authors.affiliation: Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-06, 077125 Magurele (Ilfov), Romania.
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Blebea-Apostu
authors.affiliation: Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-06, 077125 Magurele (Ilfov), Romania.
authors.forename: Aurelia
authors.initials: A
authors.lastname: Celarel
authors.affiliation: Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O. Box MG-06, 077125 Magurele (Ilfov), Romania.
authors.forename: Claudia-Mariana
authors.initials: CM
authors.lastname: Gomoiu
authors.affiliation: Geological Institute of Romania, 1, Caransebes str., 012271 Bucharest, Romania.
authors.forename: C
authors.initials: C
authors.lastname: Costea
authors.affiliation: Geological Institute of Romania, 1, Caransebes str., 012271 Bucharest, Romania; National Geological Museum, 2, Pavel Dimitrievici Kiseleff avenue, 011345 Bucharest, Romania.
authors.forename: Delia
authors.initials: D
authors.lastname: Dumitras
authors.affiliation: Geological Institute of Romania, 1, Caransebes str., 012271 Bucharest, Romania.
authors.forename: Adriana
authors.initials: A
authors.lastname: Ion
authors.affiliation: University of Bucharest, Department of Structure of Matter, Earth and Atmospheric Physics and Astrophysics, P.O. Box MG-11, 077125 Magurele (Ilfov), Romania. Electronic address: o.duliu@upcmail.ro.
authors.forename: O G
authors.initials: OG
authors.lastname: Duliu
mesh_terms: D001417:Background Radiation; D019015:Geologic Sediments / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011834:Radiation Monitoring; D011868:Radioisotopes / Q000032:analysis*; D012383:Romania; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D013051:Spectrometry, Gamma; D013052:Spectrometry, X-Ray Emission; D014961:X-Ray Diffraction
chemical_list: D011868:Radioisotopes; D012990:Soil Pollutants, Radioactive
keywords: Black sand; Chituc sand bank; High background; Natural radioactivity; Western Black Sea shore