title: Using stable isotopes in tracing contaminant sources in an industrial area: A case study on the hydrological basin of the Olt River, Romania.
abstract: Tracing pollution sources and transformation of nitrogen compounds in surface- and groundwater is an issue of great significance worldwide due to the increased human activity, translated in high demand of water resources and pollution. In this work, the hydrological basin of an important chemical industrial platform in Romania (Ramnicu Valcea industrial area) was characterized in terms of the physico-chemical and isotope composition of δ(18)O and δ(2)H in water samples and δ(15)N of the inorganic nitrogen species. Throughout a period of one year, water samples from the Olt River and its more important tributaries were collected monthly in the industrial area, when the seasonal and spatial isotope patterns of the surface waters and the main sources of pollution were determined. Higher inorganic nitrogen concentrations (up to 10.2 mg N L(-1)) were measured between November 2012 and April 2013, which were designated as anthropogenic additions using the mixing calculations. The main sources of pollution with inorganic nitrogen were agriculture and residential release. The inorganic nitrogen from the industrial waste water duct had a distinct δ(15)N fingerprint (mean of -8.6‰). Also, one industrial release into the environment was identified for Olt River, at Ionesti site, in November 2012. The mean precipitation samples had the lowest inorganic nitrogen concentrations (less than 5.5 mg N L(-1)) with a distinct δ(15)N fingerprint compared to the surface and industrial waters.
authors.affiliation: National Research and Development Institute for Cryogenics and Isotopic Technologies, ICSI Ramnicu Valcea, 4 Uzinei Str, RO-240050 Ramnicu-Valcea, Romania.
authors.forename: Raluca
authors.initials: R
authors.lastname: Popescu
authors.affiliation: Faculty of Science and Technology, Free University of Bozen-Bolzano, University Plaza no. 5, I-39100 Bolzano, Italy.
authors.forename: Tanja
authors.initials: T
authors.lastname: Mimmo
authors.affiliation: National Research and Development Institute for Cryogenics and Isotopic Technologies, ICSI Ramnicu Valcea, 4 Uzinei Str, RO-240050 Ramnicu-Valcea, Romania.
authors.forename: Oana Romina
authors.initials: OR
authors.lastname: Dinca
authors.affiliation: Faculty of Science and Technology, Free University of Bozen-Bolzano, University Plaza no. 5, I-39100 Bolzano, Italy.
authors.forename: Calogero
authors.initials: C
authors.lastname: Capici
authors.affiliation: National Research and Development Institute for Cryogenics and Isotopic Technologies, ICSI Ramnicu Valcea, 4 Uzinei Str, RO-240050 Ramnicu-Valcea, Romania.
authors.forename: Diana
authors.initials: D
authors.lastname: Costinel
authors.affiliation: National Research and Development Institute for Cryogenics and Isotopic Technologies, ICSI Ramnicu Valcea, 4 Uzinei Str, RO-240050 Ramnicu-Valcea, Romania.
authors.forename: Claudia
authors.initials: C
authors.lastname: Sandru
authors.affiliation: National Research and Development Institute for Cryogenics and Isotopic Technologies, ICSI Ramnicu Valcea, 4 Uzinei Str, RO-240050 Ramnicu-Valcea, Romania. Electronic address: roxana.ionete@icsi.ro.
authors.forename: Roxana Elena
authors.initials: RE
authors.lastname: Ionete
authors.affiliation: National Research and Development Institute for Cryogenics and Isotopic Technologies, ICSI Ramnicu Valcea, 4 Uzinei Str, RO-240050 Ramnicu-Valcea, Romania.
authors.forename: Ioan
authors.initials: I
authors.lastname: Stefanescu
authors.affiliation: National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Str., RO-400293 Cluj-Napoca, Romania.
authors.forename: Damian
authors.initials: D
authors.lastname: Axente
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D062070:Hydrology; D007220:Industrial Waste / Q000032:analysis*; D007554:Isotopes / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D012383:Romania; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007220:Industrial Waste; D007554:Isotopes; D014874:Water Pollutants, Chemical
keywords: Industrial area; Inorganic nitrogen species; Pollution source; Stable isotopes; Surface water