RVGHS7PE

3058

6 avril 2021 18:28

6 avril 2021 18:28

This work reviews applications of stable isotope analysis to the studies of transport and transformation of N species in groundwater under agricultural areas. It summarizes evidence regarding factors affecting the isotopic composition of NO3−, NH4+ and N2O in subsurface, and discusses the use of 11B, 18O, 13C, 34S, 87Sr/86Sr isotopes to support the analysis of δ15N values. The isotopic composition of NO3−, NH4+ and N2O varies depending on their sources and dynamics of N cycle processes. The reported δ15N-NO3− values for sources of NO3− are: soil organic N – +3‰–+8‰, mineral fertilizers – −8‰–+7‰; manure/household waste – +5‰ to +35‰. For NH4+ sources, the isotopic signature ranges are: organic matter – +2.4–+4.1‰, rainwater – −13.4–+2.3‰, mineral fertilizers – −7.4–+5.1‰, household waste – +5–+9‰; animal manure – +8–+11‰. For N2O, isotopic composition depends on isotopic signatures of substrate pools and reaction rates. δ15N values of NO3− are influenced by fractionation effects occurring during denitrification (ɛ=5–40‰), nitrification (ɛ=5–35‰) and DNRA (ɛ not reported). The isotopic signature of NH4+ is also affected by nitrification and DNRA as well as mineralization (ɛ=1‰), sorption (ɛ=1–8‰), anammox (ɛ=4.3–7.4‰) and volatilization (ɛ=25‰). As for the N2O, production of N2O leads to its depletion in 15N, whereas consumption – to enrichment in 15N. The magnitude of fractionation effects occurring during the considered processes depends on temperature, pH, DO, C/NO3− ratio, size of the substrate pool, availability of electron donors, water content in subsoil, residence time, land use, hydrogeology. While previous studies have accumulated rich data on isotopic composition of NO3− in groundwater, evidence remains scarce in the cases of NH4+ and N2O. Further research is required to consider variability of δ15N-NH4+ and δ15N-N2O in groundwater across agricultural ecosystems.

None

• AB - Non-spécifique
• FREDO environnement
• GEO Europe
• eau
• nitrate
• nitrogen

• agriculture
• groundwater pollution
• n anthropogenic sources
• n cycle processes
• n isotopes
• stable isotope analysis

Science of The Total Environment

621

1415-1432

April 15, 2018

15 avril 2018

10.1016/j.scitotenv.2017.10.086 Le DOI est une URL unique de référencement d'une publication. Il est donc plus fiable et permanent qu'une URL classique

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