2024/12/03 by Lamine Boumaiza, Randy L. Stotler, Bernhard Mayer +9 · 1 voice · 1 citation
Earth and Planetary Sciences · Environmental Science · #Groundwater and Isotope Geochemistry #Isotope Analysis in Ecology #Radioactive contamination and transfer
paper · doi:10.1021/acsestwater.4c00796
openalex publication_date 2024/12/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Stable isotope values of δ 15 N NO 3 and δ 18 O NO 3 of dissolved nitrate (NO 3 ) are commonly used to identify the occurrence of denitrification as there is a progressive increase of δ 15 N NO 3 and δ 18 O NO 3 values accompanied by a decrease in NO 3 concentration. Thus, denitrification results in a positive trendline on the dual plot of δ 18 O NO 3 versus δ 15 N NO 3 . The combination of two trendlines with different slopes provides the “typical expected isotopic range of denitrification (TEIRD)” on the δ 18 O NO 3 versus δ 15 N NO 3 plot. Many studies distinguished denitrified groundwaters by applying the TEIRD concept that is incorrectly introduced because it assumes a single NO 3 source even though multiple NO 3 sources exist. Also, most TEIRD applications rely on specific denitrification slopes although these are known to vary owing to the aquifer’s changing biogeochemical conditions. Alternatively, an accurate delineation of the TEIRD requires the identification of all potential NO 3 sources in aquifer with their measured or reconstructed δ 15 N NO 3 and δ 18 O NO 3 values. This allows then for an accurate TEIRD to be traced with two denitrification trendlines having a slope corresponding to that from the correlation of the measured δ 18 O NO 3 and δ 15 N NO 3 values. Ultimately, each NO 3 source can have a specific TEIRD, although denitrification trendlines for multiple NO 3 sources can feature the same slope within a single aquifer.