Hydrologic Control on Arsenic Cycling at the Groundwater–Surface Water Interface of a Tidal Channel

• DOI: 10.1021/acs.est.2c05930
• Publication Date: 2022-12-19T19:57:25Z
• Authors: Xuan Yu; Joshua J. LeMonte; Junxia Li; Jason W. Stuckey; Donald L. Sparks; John G. Cargill; Christopher J. Ru...; Holly A. Michael
• Keywords: Biogeochemical Cycle; Submarine groundwater discharge; Tidal river; Groundwater discharge

Historical industrial activities have resulted in soil contamination at sites globally. Many of these are located along coastlines, making them vulnerable to hydrologic and biogeochemical alterations due climate change sea-level rise. However, the impact dynamics on contaminant mobility tidal environments has not been well studied. Here, we collected data from pressure transducers wells, multi-level redox sensors, porewater samplers an As-contaminated site adjacent a freshwater channel. Results indicate that sharp gradients exist conditions vary seasonal timescales sub-daily water level fluctuations channel groundwater–surface interactions. The As Fe2+ concentrations decreased during periods net discharge changes were greater than variations both Eh concentrations, indicating impacts mechanism stronger those table fluctuations. A conceptual model describing hydro-biogeochemical coupling is presented. These findings broad implications for understanding rise natural anthropogenic coastal solutes.