o:6420 Delineation of the Main Conditions Affecting Nitrogen Form in Selected Anoxic Alluvial Aquifers in Serbia en Nitrogen complex chemistry is reflected in several oxidation states (from -3 to +5) in which nitrogen can persist depending on prevailing environmental biogeochemical conditions. The oxidation state of the elements in groundwater will preferably be determined by dissolved oxygen concentration and redox potential, followed by concentration and availability of present organic matter, nitrates, fero/manganese and sulfate ions, and dominant species of microorganisms. The aim of the paper is distinguishing which parameters are the main controllers of dominant reactions and final form of nitrogen present in anoxic alluvial aquifers, regardless of nitrogen origin. Research was conducted for selected drainage wells from Knicanin - Centa (Danube and Tisa river), Kovin - Dubovac (Danube river) and selected wells from Belgrade groundwater source (Sava River). Parameters such as Eh, O2, TOC, Fe2+ , H2S concentrations and BART test results were all analyzed. The obtained results were used to define prevailing nitrogen form and dominant nitrogen transformation reactions, indicating different anoxic aquifers potential for nitrogen loss (N2, N2O) or conservation (NH4+).The conclusion is that in anoxic alluvial groundwaters which were the subject of this research prevailing controlling factors are the concentration of total organic carbon (TOC), followed by presence of ferrous iron and sulfide, while C:N ratio would determine whether the nitrogen is subject of loss (N2O, N2) or conservation (NH4+). nitrogen transformation, anoxic groundwater, BART test 1552101 978-86-82565-46-8 2024-12-06T12:42:59.151Z 44 no 46 Marija Perović Jaroslav Černi Institute for the Developement of Water Resources, Belgrade 0000-0003-2045-001X Vesna Obradović Jaroslav Černi Institute for the Developement of Water Resources, Belgrade person 0009-0008-2157-0615 David Mitrinović Jaroslav Černi Institute for the Developement of Water Resources, Belgrade person 0000-0002-8097-2998 Tanja Vučković Jaroslav Černi Institute for the Developement of Water Resources, Belgrade person Tanja Nenin Jaroslav Černi Institute for the Developement of Water Resources, Belgrade person application/pdf 6441562 https://unilib.phaidrabg.rs/o:6420 no yes 1 70 92000004 71A04 IWA Specialist Groundwater Conference, Conference Proceedings and Book of Abstracts, 09-11 June 2016. Belgrade, Serbia 252 258 Jaroslav Černi Institute for the Development of Water Resources 2016 09-11 June 2016