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Podgorski DC, Zito P, Kellerman AM, Bekins BA, Cozzarelli IM, Smith DF, Cao X, Schmidt-Rohr K, Wagner S, Stubbins A, Spencer RGM. Hydrocarbons to carboxyl-rich alicyclic molecules: A continuum model to describe biodegradation of petroleum-derived dissolved organic matter in contaminated groundwater plumes. J Hazard Mater 2021; 402:123998. [PMID: 33254831 DOI: 10.1016/j.jhazmat.2020.123998] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 08/17/2020] [Accepted: 09/13/2020] [Indexed: 06/12/2023]
Abstract
Relationships between dissolved organic matter (DOM) reactivity and chemical composition in a groundwater plume containing petroleum-derived DOM (DOMHC) were examined by quantitative and qualitative measurements to determine the source and chemical composition of the compounds that persist downgradient. Samples were collected from a transect down the core of the plume in the direction of groundwater flow. An exponential decrease in dissolved organic carbon concentration resulting from biodegradation along the transect correlated with a continuous shift in fluorescent DOMHC from shorter to longer wavelengths. Moreover, ultrahigh resolution mass spectrometry showed a shift from low molecular weight (MW) aliphatic, reduced compounds to high MW, unsaturated (alicyclic/aromatic), high oxygen compounds that are consistent with carboxyl-rich alicyclic molecules. The degree of condensed aromaticity increased downgradient, indicating that compounds with larger, conjugated aromatic core structures were less susceptible to biodegradation. Nuclear magnetic resonance spectroscopy showed a decrease in alkyl (particularly methyl) and an increase in aromatic/olefinic structural motifs. Collectively, data obtained from the combination of these complementary analytical techniques indicated that changes in the DOMHC composition of a groundwater plume are gradual, as relatively low molecular weight (MW), reduced, aliphatic compounds from the oil source were selectively degraded and high MW, alicyclic/aromatic, oxidized compounds persisted.
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Affiliation(s)
- David C Podgorski
- Pontchartrain Institute for Environmental Sciences, Department of Chemistry, Chemical Analysis & Mass Spectrometry Facility, University of New Orleans, New Orleans, LA 70148, USA.
| | - Phoebe Zito
- Pontchartrain Institute for Environmental Sciences, Department of Chemistry, Chemical Analysis & Mass Spectrometry Facility, University of New Orleans, New Orleans, LA 70148, USA
| | - Anne M Kellerman
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA; National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | | | | | - Donald F Smith
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Xiaoyan Cao
- Department of Chemistry, Brandeis University, Waltham, MA 02453, USA
| | | | - Sasha Wagner
- Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA; Department of Chemistry and Chemical Biology, Department of Marine and Environmental Sciences, Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Aron Stubbins
- Department of Chemistry and Chemical Biology, Department of Marine and Environmental Sciences, Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Robert G M Spencer
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, USA; National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
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