Nuclear magnetic resonance at the laboratory and field scale as a tool for detecting redox fronts in aquifers

Surface nuclear magnetic resonance (NMR) provides informa-tion not only on the lithology and water transport characteristics of aquifer systems but also on the state of iron mineralization within the pore space. This feature makes surface NMR a poten-tial tool for the observation of changing redox conditions in the aquifer, which control the type and oxidation state of iron min-erals and, relatedly, the buffering or release of pollutants that may pose a threat to drinking water resources. Our study aims on test-ing this potential and focuses on pyrite contained in the matrix of a sandy aquifer that serves as a natural denitrification buffer in a drinking water catchment area with intensive agricultural use. We observe a significant change in the surface-NMR relaxation times

Automated summary

Surface nuclear magnetic resonance (NMR) provides information on aquifer systems and iron mineralization. This makes it a potential tool for observing changing redox conditions and their impact on drinking water resources. Our study focuses on pyrite in a sandy aquifer serving as a natural denitrification buffer, and we observe significant changes in surface-NMR relaxation times.