Evaluation of the origin of nitrate influencing the Ključ groundwater source, Serbia

• Published in: Water science and technology Vol. 66; no. 3; pp. 472 - 478
• Main Authors: Miljević, Nada, Boreli-Zdravković, Djulija, Obradović, Vesna, Golobočanin, Dušan, Mayer, Bernhard
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.01.2012
• Subjects: Alluvial aquifers; Animal wastes; Aquifers; Contamination; Denitrification; Evaluation; Fertilizers; Geography; Gravel; Groundwater; Groundwater - chemistry; Human wastes; Isotope ratios; Isotopes; Nitrates; Nitrates - analysis; Nitrification; Nitrogen Isotopes; Observation wells; Organic nitrogen; Organic soils; Organic wastes; Oxygen Isotopes; Ratios; River water; Rivers; Sediments; Septic systems; Serbia; Sewage; Soil; Soil contamination; Solubility; Water Pollutants, Chemical - analysis; Water wells; Serbia
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2012.179

This paper describes the use of the dual isotope method involving δ(15)N and δ(18)O measurements of dissolved nitrates to assess the origin and fate of groundwater nitrate at the Ključ groundwater source, Serbia. A sampling campaign was conducted in September 2007 during flow conditions obtaining groundwater from observation wells and river water fed by a shallow aquifer hosted in alluvial (sandy-gravel) sediments. Nitrate isotope ratios ranged from +5.3 to +16.9‰ and δ(18)O(NO(3)) values varied from -2.3 to +5.0‰. Two major contamination sources were identified with isotopic compositions characteristic for nitrate derived from nitrification of soil organic nitrogen (+5.3 to +7.8‰ for δ(15)N) resulting in nitrate concentrations of 33.6 and 78.8 mg/L and nitrate derived from animal wastes or human sewage, e.g. via septic systems, yielding δ(15)N values of +9.9 to +11.9‰ and elevated nitrate concentrations of 31.2-245.8 mg/L. The occurrence of nitrification and denitrification was also revealed based on concentration and isotope data for dissolved nitrate.