Sources and fate of nitrate in groundwater at agricultural operations overlying glacial sediments

Abstract

Leaching of nitrate (${\mathrm{NO}}_{\mathrm{3}}^{-}$ ) from animal waste or fertilisers at agricultural operations can result in ${\mathrm{NO}}_{\mathrm{3}}^{-}$ contamination of groundwater, lakes, and streams. Understanding the sources and fate of nitrate in groundwater systems in glacial sediments, which underlie many agricultural operations, is critical for managing impacts of human food production on the environment. Elevated ${\mathrm{NO}}_{\mathrm{3}}^{-}$ concentrations in groundwater can be naturally attenuated through mixing or denitrification. Here we use isotopic enrichment of the stable isotope values of ${\mathrm{NO}}_{\mathrm{3}}^{-}$ to quantify the amount of denitrification in groundwater at two confined feeding operations overlying glacial sediments in Alberta, Canada. Uncertainty in ${\mathit{\delta }}^{\mathrm{15}}{\mathrm{N}}_{{\mathrm{NO}}_{\mathrm{3}}}$ and ${\mathit{\delta }}^{\mathrm{18}}{\mathrm{O}}_{{\mathrm{NO}}_{\mathrm{3}}}$ values of the ${\mathrm{NO}}_{\mathrm{3}}^{-}$ source and denitrification enrichment factors are accounted for using a Monte Carlo approach. When denitrification could be quantified, we used these values to constrain a mixing model based on

Keywords

• DSPMATH
• MROW
• MATHVARIANT
• XMLNS
• SVG
• HTTP
• SCI.NET/23/1355/2019/HESS

Funding Information

• Natural Sciences and Engineering Research Council of Canada (184573)

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