278 Understanding Temporal Dynamics in Hydrogeochemistry and Sedimentary Processes in Estuarine Environments

This session explores temporal changes in estuarine environments with respect to water chemistry and sediment inputs. Effects of evolving physiochemical properties and isotopic composition of water, as well as the geochemical attributes of sediments on the environment will be presented.

Wednesday, 22 October 2025
1:30 PM - 5:30 PM
HBGCC, 213AB

Natural Solutes and Signals for Characterizing Advection and Dispersion During Tracer Tests

Paper number: 278-3
Program: Technical Sessions
Time: 2:10 PM – 2:25 PM

Authors

Abstract

Traditional tracer tests that commonly utilize added non-reactive solutes such as halides and benzoates to characterize advection and dispersion often incur significant time and laboratory costs. However, field measurements of natural non-reactive solutes such as chloride and natural non-reactive signals such as conductance and temperature may be accurate proxies for added non-reactive solutes at a fraction of the time and costs. The objective of this study was to evaluate the efficacy of natural chloride, conductance, and temperature as proxies for characterizing advection and dispersion, in comparison to traditional added halide and benzoate tracers. A series of eight single-well injection-drift tests were performed, involving the injection of tracer-amended solutions into a well and subsequent monitoring of solute transport in the same well over a period of several days to weeks. Data was analyzed for breakthrough curve separation, residuals, errors and strengths with respect to the traditional added halide tracer. Chloride showed the lowest relative errors across a range of high signal strengths. Conductance showed slightly higher relative errors across a similar range of signal strengths. Temperature showed the highest relative errors across a range of low signal strengths.  An inverse power-law relationship was observed between relative error and signal strength across chloride, conductance, and temperature. This study provides insights into the suitability of natural non-reactive solutes and signals as cost-effective alternatives to traditional tracers, demonstrating a range of applicability in their use for characterizing advection and dispersion.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412259

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