Grant Wallace (North Carolina) co-authored an article entitled "Quantifying the electron donating capacities of sulfide and dissolved organic matter in sediment pore waters of wetlands" that was published in the journal Environmental Science: Processes & Impacts on April 25, 2017.

The paper concerns the estimation of electron donating capacity (EDC) values for a set of pore water samples collected from the sediments of four separate wetlands in the Cottonwood Lakes Study Area in Jamestown, North Dakota. EDC values were estimated by mediated electrochemical analysis, reaction with substituted nitro(so)benzenes, and calculation based on measured organic carbon and sulfide concentrations. Samples were taken from four hydrologically connected and increasingly sulfidic wetlands within the study site. Parallel trends in EDC values related to hydrologic conditions and in situ reduced sulfur content were observed by all three methodologies. In particular, it was found that sulfide and dissolved organic matter (DOM) are the primary and secondary reductants, respectively, in these systems. The efficacy of these reductants in transforming organic contaminants, however, is largely driven by reduced sulfur content in the native pore water. Manipulation of the systems demonstrate that while DOM is capable of reducing highly oxidized contaminants or reactive intermediates, this likely only occurs once the reducing capacity of the sulfide is exhausted. Sulfide therefore was the dominant electron donor in the pore water samples. This research is being used to understand potential degradation mechanisms and products of emerging contaminants, pesticides in particular, expected to enter these sulfidic wetland environments.

The paper was based on Grant's Master's Degree research at the University of Minnesota. His co-authors were Michael Sander, Yu-Ping Chin and William Arnold from the University of Minnesota.

Abstract

Electron donating capacity (EDC) values were determined for a set of pore water samples collected from the sediments of four separate wetlands in the Cottonwood Lakes Study Area in Jamestown, ND by mediated electrochemical analysis, reaction with substituted nitro(so)benzenes, and calculation based on measured organic carbon and sulfide concentrations. The samples were taken from four hydrologically connected and increasingly sulfidic wetlands within the study site. Parallel trends in EDC values related to hydrologic conditions and to in situ reduced sulfur content were observed by all three methodologies. In particular, it was found that sulfide and dissolved organic matter (DOM) are the primary and secondary reductants, respectively, in these systems. The efficacy of these reductants in transforming organic contaminants, however, is largely driven by native pore water reduced sulfur content. Manipulation of the systems demonstrate that while DOM is capable of reducing highly oxidized contaminants or reactive intermediates, this likely only occurs once the reducing capacity of the sulfide is exhausted. Sulfide therefore was the dominant electron donor in the pore water samples.

More Information

For more information regarding the article, visit: Environmental Science: Processes & Impacts
For more information on electron donating capacities of sulfide and dissolved organic matter in sediment pore waters of wetlands, contact Grant Wallace at This email address is being protected from spambots. You need JavaScript enabled to view it..
To learn more about Grant see his profile at: https://www.linkedin.com/in/grant-wallace-212691106/