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Mayer PM, Moran KD, Miller EL, Brander SM, Harper S, Garcia-Jaramillo M, Carrasco-Navarro V, Ho KT, Burgess RM, Thornton Hampton LM, Granek EF, McCauley M, McIntyre JK, Kolodziej EP, Hu X, Williams AJ, Beckingham BA, Jackson ME, Sanders-Smith RD, Fender CL, King GA, Bollman M, Kaushal SS, Cunningham BE, Hutton SJ, Lang J, Goss HV, Siddiqui S, Sutton R, Lin D, Mendez M. Where the rubber meets the road: Emerging environmental impacts of tire wear particles and their chemical cocktails. Sci Total Environ 2024; 927:171153. [PMID: 38460683 DOI: 10.1016/j.scitotenv.2024.171153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/18/2024] [Accepted: 02/19/2024] [Indexed: 03/11/2024]
Abstract
About 3 billion new tires are produced each year and about 800 million tires become waste annually. Global dependence upon tires produced from natural rubber and petroleum-based compounds represents a persistent and complex environmental problem with only partial and often-times, ineffective solutions. Tire emissions may be in the form of whole tires, tire particles, and chemical compounds, each of which is transported through various atmospheric, terrestrial, and aquatic routes in the natural and built environments. Production and use of tires generates multiple heavy metals, plastics, PAH's, and other compounds that can be toxic alone or as chemical cocktails. Used tires require storage space, are energy intensive to recycle, and generally have few post-wear uses that are not also potential sources of pollutants (e.g., crumb rubber, pavements, burning). Tire particles emitted during use are a major component of microplastics in urban runoff and a source of unique and highly potent toxic substances. Thus, tires represent a ubiquitous and complex pollutant that requires a comprehensive examination to develop effective management and remediation. We approach the issue of tire pollution holistically by examining the life cycle of tires across production, emissions, recycling, and disposal. In this paper, we synthesize recent research and data about the environmental and human health risks associated with the production, use, and disposal of tires and discuss gaps in our knowledge about fate and transport, as well as the toxicology of tire particles and chemical leachates. We examine potential management and remediation approaches for addressing exposure risks across the life cycle of tires. We consider tires as pollutants across three levels: tires in their whole state, as particulates, and as a mixture of chemical cocktails. Finally, we discuss information gaps in our understanding of tires as a pollutant and outline key questions to improve our knowledge and ability to manage and remediate tire pollution.
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Affiliation(s)
- Paul M Mayer
- US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, OR 97333, United States of America.
| | - Kelly D Moran
- San Francisco Estuary Institute, 4911 Central Ave, Richmond, CA 94804, United States of America.
| | - Ezra L Miller
- San Francisco Estuary Institute, 4911 Central Ave, Richmond, CA 94804, United States of America.
| | - Susanne M Brander
- Department of Fisheries, Wildlife, and Conservation Sciences, Coastal Oregon Marine Experiment Station, Oregon State University, Corvallis, OR 97331, United States of America.
| | - Stacey Harper
- Department of Environmental and Molecular Toxicology, School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97333, United States of America.
| | - Manuel Garcia-Jaramillo
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, United States of America.
| | - Victor Carrasco-Navarro
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio Campus, Yliopistonranta 1 E, 70211 Kuopio, Finland.
| | - Kay T Ho
- US Environmental Protection Agency, ORD/CEMM Atlantic Coastal Environmental Sciences Division, Narragansett, RI 02882, United States of America.
| | - Robert M Burgess
- US Environmental Protection Agency, ORD/CEMM Atlantic Coastal Environmental Sciences Division, Narragansett, RI 02882, United States of America.
| | - Leah M Thornton Hampton
- Southern California Coastal Water Research Project, 3535 Harbor Blvd, Suite 110, Costa Mesa, CA 92626, United States of America.
| | - Elise F Granek
- Environmental Science & Management, Portland State University, Portland, OR 97201, United States of America.
| | - Margaret McCauley
- US Environmental Protection Agency, Region 10, Seattle, WA 98101, United States of America.
| | - Jenifer K McIntyre
- School of the Environment, Washington State University, Puyallup Research & Extension Center, Washington Stormwater Center, 2606 W Pioneer Ave, Puyallup, WA 98371, United States of America.
| | - Edward P Kolodziej
- Interdisciplinary Arts and Sciences (UW Tacoma), Civil and Environmental Engineering (UW Seattle), Center for Urban Waters, University of Washington, Tacoma, WA 98402, United States of America.
| | - Ximin Hu
- Civil and Environmental Engineering (UW Seattle), University of Washington, Seattle, WA 98195, United States of America.
| | - Antony J Williams
- US Environmental Protection Agency, Center for Computational Toxicology and Exposure, Chemical Characterization and Exposure Division, Computational Chemistry & Cheminformatics Branch, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, United States of America.
| | - Barbara A Beckingham
- Department of Geology & Environmental Geosciences, College of Charleston, Charleston, SC, 66 George Street Charleston, SC 29424, United States of America.
| | - Miranda E Jackson
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, United States of America.
| | - Rhea D Sanders-Smith
- Washington State Department of Ecology, 300 Desmond Drive SE, Lacey, WA 98503, United States of America.
| | - Chloe L Fender
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331, United States of America.
| | - George A King
- CSS, Inc., 200 SW 35th St, Corvallis, OR 97333, United States of America.
| | - Michael Bollman
- US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, OR 97333, United States of America.
| | - Sujay S Kaushal
- Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740, United States of America.
| | - Brittany E Cunningham
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97333, United States of America.
| | - Sara J Hutton
- GSI Environmental, Inc., Olympia, Washington 98502, USA.
| | - Jackelyn Lang
- Department of Anatomy, Physiology, and Cell Biology, Department of Medicine and Epidemiology and the Karen C. Drayer Wildlife Health Center, University of California, Davis School of Veterinary Medicine, Davis, CA 95616, United States of America.
| | - Heather V Goss
- US Environmental Protection Agency, Office of Water, Office of Wastewater Management, Washington, DC 20004, United States of America.
| | - Samreen Siddiqui
- Department of Fisheries, Wildlife, and Conservation Sciences, Coastal Oregon Marine Experiment Station, Oregon State University, Corvallis, OR 97331, United States of America.
| | - Rebecca Sutton
- San Francisco Estuary Institute, 4911 Central Ave, Richmond, CA 94804, United States of America.
| | - Diana Lin
- San Francisco Estuary Institute, 4911 Central Ave, Richmond, CA 94804, United States of America.
| | - Miguel Mendez
- San Francisco Estuary Institute, 4911 Central Ave, Richmond, CA 94804, United States of America.
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Shelton SA, Kaushal SS, Mayer PM, Shatkay RR, Rippy MA, Grant SB, Newcomer-Johnson TA. Salty chemical cocktails as water quality signatures: Longitudinal trends and breakpoints along different U.S. streams. Sci Total Environ 2024; 930:172777. [PMID: 38670384 DOI: 10.1016/j.scitotenv.2024.172777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/23/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024]
Abstract
Along urban streams and rivers, various processes, including road salt application, sewage leaks, and weathering of the built environment, contribute to novel chemical cocktails made up of metals, salts, nutrients, and organic matter. In order to track the impacts of urbanization and management strategies on water quality, we conducted longitudinal stream synoptic (LSS) monitoring in nine watersheds in five major metropolitan areas of the U.S. During each LSS monitoring survey, 10-53 sites were sampled along the flowpath of streams as they flowed along rural to urban gradients. Results demonstrated that major ions derived from salts (Ca2+, Mg2+, Na+, and K+) and correlated elements (e.g. Sr2+, N, Cu) formed 'salty chemical cocktails' that increased along rural to urban flowpaths. Salty chemical cocktails explained 46.1% of the overall variability in geochemistry among streams and showed distinct typologies, trends, and transitions along flowpaths through metropolitan regions. Multiple linear regression predicted 62.9% of the variance in the salty chemical cocktails using the six following significant drivers (p < 0.05): percent urban land, wastewater treatment plant discharge, mean annual precipitation, percent silicic residual material, percent volcanic material, and percent carbonate residual material. Mean annual precipitation and percent urban area were the most important in the regression, explaining 29.6% and 13.0% of the variance. Different pollution sources (wastewater, road salt, urban runoff) in streams were tracked downstream based on salty chemical cocktails. Streams flowing through stream-floodplain restoration projects and conservation areas with extensive riparian forest buffers did not show longitudinal increases in salty chemical cocktails, suggesting that there could be attenuation via conservation and restoration. Salinization represents a common urban water quality signature and longitudinal patterns of distinct chemical cocktails and ionic mixtures have the potential to track the sources, fate, and transport of different point and nonpoint pollution sources along streams across different regions.
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Affiliation(s)
- Sydney A Shelton
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, Geology Building 237, College Park, MD 20742, USA; ORISE Fellow at Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, 200 SW 35th Street, Corvallis, OR 97333, USA.
| | - Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, Geology Building 237, College Park, MD 20742, USA.
| | - Paul M Mayer
- Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, U.S. Environmental Protection Agency, 200 SW 35th Street, Corvallis, OR 97333, USA.
| | - Ruth R Shatkay
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, Geology Building 237, College Park, MD 20742, USA.
| | - Megan A Rippy
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William St, Manassas, VA 20110, USA; Center for Coastal Studies, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Stanley B Grant
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William St, Manassas, VA 20110, USA; Center for Coastal Studies, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Tammy A Newcomer-Johnson
- United States Environmental Protection Agency, Center for Environmental Measurement and Modeling, Watershed and Ecosystem Characterization Division, 26 Martin Luther King Dr W, Cincinnati, OH 45220, USA.
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Malin JT, Kaushal SS, Mayer PM, Maas CM, Hohman SP, Rippy MA. Longitudinal stream synoptic (LSS) monitoring to evaluate water quality in restored streams. Environ Monit Assess 2024; 196:437. [PMID: 38592553 PMCID: PMC11069387 DOI: 10.1007/s10661-024-12570-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 03/23/2024] [Indexed: 04/10/2024]
Abstract
Impervious surface cover increases peak flows and degrades stream health, contributing to a variety of hydrologic, water quality, and ecological symptoms, collectively known as the urban stream syndrome. Strategies to combat the urban stream syndrome often employ engineering approaches to enhance stream-floodplain reconnection, dissipate erosive forces from urban runoff, and enhance contaminant retention, but it is not always clear how effective such practices are or how to monitor for their effectiveness. In this study, we explore applications of longitudinal stream synoptic (LSS) monitoring (an approach where multiple samples are collected along stream flowpaths across both space and time) to narrow this knowledge gap. Specifically, we investigate (1) whether LSS monitoring can be used to detect changes in water chemistry along longitudinal flowpaths in response to stream-floodplain reconnection and (2) what is the scale over which restoration efforts improve stream quality. We present results for four different classes of water quality constituents (carbon, nutrients, salt ions, and metals) across five watersheds with varying degrees of stream-floodplain reconnection. Our work suggests that LSS monitoring can be used to evaluate stream restoration strategies when implemented at meter to kilometer scales. As streams flow through restoration features, concentrations of nutrients, salts, and metals significantly decline (p < 0.05) or remain unchanged. This same pattern is not evident in unrestored streams, where salt ion concentrations (e.g., Na+, Ca2+, K+) significantly increase with increasing impervious cover. When used in concert with statistical approaches like principal component analysis, we find that LSS monitoring reveals changes in entire chemical mixtures (e.g., salts, metals, and nutrients), not just individual water quality constituents. These chemical mixtures are locally responsive to restoration projects, but can be obscured at the watershed scale and overwhelmed during storm events.
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Affiliation(s)
- Joseph T Malin
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, 20742, USA.
- Environmental Quality Resources, L.L.C., 2391 Brandermill Blvd., Suite 301, Gambrills, MD, 21054, USA.
| | - Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, 20742, USA
| | - Paul M Mayer
- Environmental Protection Agency, 805 SW Broadway #500, Portland, OR, 97205, USA
| | - Carly M Maas
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, 20742, USA
- United States Geological Survey, 1730 E Parham Road, Richmond, VA, 23228, USA
| | - Steven P Hohman
- Environmental Protection Agency, 1650 Arch St, Philadelphia, PA, 19103, USA
| | - Megan A Rippy
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA, USA
- Center for Coastal Studies, Virginia Tech, 1068A Derring Hall (0420), Blacksburg, VA, USA
- Disaster Resilience and Risk Management (DRRM), 1068A Derring Hall, 405 Perry Street, Blacksburg, VA, 24061, USA
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4
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Lowe B, Cardona AL, Salas J, Bodi A, Mayer PM, Burgos Paci MA. What a difference a chlorine makes: The remarkable unimolecular ion chemistry of phenyl formate and phenyl chloroformate. J Mass Spectrom 2024; 59:e5004. [PMID: 38311470 DOI: 10.1002/jms.5004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/27/2023] [Accepted: 12/07/2023] [Indexed: 02/06/2024]
Abstract
Imaging photoelectron photoion coincidence (iPEPICO) spectroscopy and tandem mass spectrometry were employed to explore the ionisation and dissociative ionisation of phenyl formate (PF) and phenyl chloroformate (PCF). The threshold photoelectron spectra of both compounds are featureless and lack a definitive origin transition, owing to the internal rotation of the formate functional group relative to the benzene ring, active upon ionisation. CBS-QB3 calculations yield ionisation energies of 8.88 and 9.03 eV for PF and PCF, respectively. Ionised PF dissociates by the loss of CO via a transition state composed of a phenoxy cation and HCO moieties. The dissociation of PCF ions involves the competing losses of CO (m/z 128/130), Cl (m/z 121) and CO2 (m/z 112/114), with Cl loss also shown to occur from the second excited state in a non-statistical process. The primary CO- and Cl-loss fragment ions undergo sequential reactions leading to fragment ions at m/z 98 and 77. The mass-analysed ion kinetic energy (MIKE) spectrum of PCF+ showed that the loss of CO2 occurs with a large reverse energy barrier, which is consistent with the computationally derived minimum energy reaction pathway.
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Affiliation(s)
- Bethany Lowe
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
| | - Alejandro L Cardona
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juana Salas
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
| | - Maxi A Burgos Paci
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
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White Buenger E, Mayer PM. Unraveling the Unimolecular Ion Chemistry of Protonated Isoprene and Prenol. J Am Soc Mass Spectrom 2024; 35:31-39. [PMID: 38014876 DOI: 10.1021/jasms.3c00297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The atmospheric chemistries of isoprene and prenol have been studied extensively; however, much of that research has focused on neutral or radical chemistry. Recent studies have demonstrated that under acidic conditions, isoprene and prenol can become protonated in the atmosphere, and we have explored the unimolecular chemistry of protonated isoprene and prenol with tandem mass spectrometry (using a triple-quadrupole mass spectrometer) and density functional theory. The collision-induced dissociation of protonated isoprene revealed two product ion channels: the neutral losses of C2H4 and H2, the former dominating over the latter. Protonated prenol dissociates by four product ion channels: the neutral losses of water, formaldehyde, methanol, and propene, with the former two being minor channels and the latter two being major channels. Density functional theory supplemented with CBS-QB3 single-point calculations revealed the underlying mechanisms to explain the breakdown behavior. The two competing channels from protonated isoprene could easily be rationalized due to the relative energy difference between key transition states along the reaction coordinates. However, in the case of protonated prenol, it was revealed that the minor products observed in the breakdown of protonated prenol had significantly lower reaction barriers when compared to the major products, an apparent contradiction. This could be rationalized if the initial ion population entering the collision cell is comproed of several isomeric species on the minimum energy reaction pathway, species populated by collisional excitation in the ion source region.
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Affiliation(s)
- Edgar White Buenger
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
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Rossi C, Muller G, Thissen R, Romanzin C, Alcaraz C, Gondarry S, Mayer PM, Jacovella U. New light on the imbroglio surrounding the C 8H +6 isomers formed from ionized azulene and naphthalene using ion-molecule reactions. Chem Sci 2023; 15:317-327. [PMID: 38131094 PMCID: PMC10731908 DOI: 10.1039/d3sc03015f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023] Open
Abstract
Most polycyclic aromatic hydrocarbons (PAHs) can isomerize with internal energies near to or below the dissociation threshold. The C10H+8 group of ions, made up of the naphthalene (Naph+) and the azulene (Azu+) radical cations, is a prototypical example. C8H+6 isomers are important species in the growth kinetics and formation of complex organic molecules, and more generally fragments from larger PAHs, yet information about C8H+6 structures is scarce and contradictory. Here, ion-molecule reactions were carried out and the tunable photoionization chemical monitoring technique was used to probe the C8H+6 isomers formed upon C2H2-loss from Naph+ and Azu+. The experimental findings were interpreted with the support of ab initio and kinetics calculations. To facilitate the interpretation of these data, chemical reactivity starting from phenylacetylene (PA) was studied. It was found that most of the C8H+6 ions formed from C10H8, in a timescale of 40 μs, are PA+ in the vicinity of the dissociation threshold. No evidence of the pentalene radical cation (PE+) was observed and explanations to reconcile previous results are presented.
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Affiliation(s)
- Corentin Rossi
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay 91405 Orsay France
| | - Giel Muller
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong Wollongong New South Wales 2522 Australia
| | - Roland Thissen
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000 91405 Orsay France
- Synchrotron SOLEIL L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette France
| | - Claire Romanzin
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000 91405 Orsay France
- Synchrotron SOLEIL L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette France
| | - Christian Alcaraz
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000 91405 Orsay France
- Synchrotron SOLEIL L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette France
| | - Sandesh Gondarry
- Department of Chemistry and Biomolecular Sciences, University of Ottawa Ottawa K1N 6N5 Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa Ottawa K1N 6N5 Canada
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay 91405 Orsay France
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Lowe B, Cardona AL, Bodi A, Mayer PM, Burgos Paci MA. The Unimolecular Chemistry of Methyl Chloroformate Ions and Neutrals: A Story of Near-Threshold Decomposition. J Am Soc Mass Spectrom 2023; 34:2831-2839. [PMID: 38008918 DOI: 10.1021/jasms.3c00334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
The near-threshold dissociation of ionized and neutral methyl chloroformate (CH3COOCl, MCF) was explored with imaging photoelectron photoion coincidence spectroscopy. The threshold photoelectron spectrum (TPES) for MCF was acquired for the first time; the large geometry changes upon ionization of MCF result in a broad, poorly defined TPES. Franck-Condon simulations are consistent with an adiabatic ionization energy (IE) of 10.90 ± 0.05 eV. Ionized MCF dissociates by chlorine atom loss at a measured 0 K appearance energy (AE) of 11.30 ± 0.01 eV. Together with the above IE, this AE suggests a reaction barrier of 0.40 ± 0.05 eV, consistent with the SVECV-f12 computational result of 0.41 eV. At higher internal energies, the loss of CH3O• becomes competitive due to its lower entropy of activation. Pyrolysis of neutral MCF formed the anticipated major products CH3Cl + CO2 (R1) and the minor products HCl + CO + CH2O (R2). The thermal decomposition products were identified by their photoion mass-selected threshold photoelectron spectrum (ms-TPES). Possible reaction pathways were explored computationally to confirm the dominant ones: R1 proceeds by a concerted Cl atom migration via a four-membered transition state in agreement with the mechanism proposed in the literature. R2 is a two-step reaction first yielding 2-oxiranone by HCl loss, which then decomposes to CH2O and CO. Kinetic modeling of the neutral decomposition could simulate the observed reactions only if the vibrational temperature of the MCF was assumed not to cool in the expansion.
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Affiliation(s)
- Bethany Lowe
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
| | - Alejandro L Cardona
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina X5000HUA
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
| | - Maxi A Burgos Paci
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina X5000HUA
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Galella JG, Kaushal SS, Mayer PM, Maas CM, Shatkay RR, Inamdar S, Belt KT. Freshwater Salinization Syndrome Alters Nitrogen Transport in Urban Watersheds. Water (Basel) 2023; 15:1-22. [PMID: 38313692 PMCID: PMC10831318 DOI: 10.3390/w15223956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Anthropogenic salt inputs have impacted many streams in the U.S. for over a century. Urban stream salinity is often chronically elevated and punctuated by episodic salinization events, which can last hours to days after snowstorms and the application of road salt. Here, we investigated the impacts of freshwater salinization on total dissolved nitrogen (TDN) and NO 3 - / NO 2 - concentrations and fluxes across time in urban watersheds in the Baltimore-Washington D.C. metropolitan area of the Chesapeake Bay region. Episodic salinization from road salt applications and snowmelt quickly mobilized TDN in streams likely through soil ion exchange, hydrologic flushing, and other biogeochemical processes. Previous experimental work from other studies has shown that salinization can mobilize nitrogen from sediments, but less work has investigated this phenomenon with high-frequency sensors and targeted monitoring during road salt events. We found that urban streams exhibited elevated concentrations and fluxes of TDN, NO 3 - / NO 2 - , and specific conductance that rapidly peaked during and after winter road salt events, and then rapidly declined afterwards. We observed plateaus in TDN concentrations in the ranges of the highest specific conductance values (between 1000 and 2000 μS/cm) caused by road salt events. Plateaus in TDN concentrations beyond a certain threshold of specific conductance values suggested source limitation of TDN in watersheds (at the highest ranges in chloride concentrations and ranges); salts were likely extracting nitrogen from soils and streams through ion exchange in soils and sediments, ion pairing in soils and waters, and sodium dispersion of soils to a certain threshold level. When watershed transport was compared across land use, including a forested reference watershed, there was a positive relationship between Cl- loads and NO 3 - / NO 2 - loads. This relationship occurred across all sites regardless of land use, which suggests that the mass transport of Cl- and NO 3 - / NO 2 - are likely influenced by similar factors such as soil ion exchange, ion pairing, sodium dispersion of soils, hydrologic flushing, and biogeochemical processes. Freshwater salinization has the potential to alter the magnitude and timing of total dissolved nitrogen delivery to receiving waters during winter months following road salt applications, and further work should investigate the seasonal relationships of N transport with salinization in urban watersheds.
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Affiliation(s)
- Joseph G. Galella
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20140, USA
| | - Sujay S. Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20140, USA
| | - Paul M. Mayer
- US Environmental Protection Agency Office of Research and Development, Center for Public Health and Environmental Assessment, Corvallis, OR 97333, USA
| | - Carly M. Maas
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20140, USA
| | - Ruth R. Shatkay
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20140, USA
| | - Shreeram Inamdar
- Water Science and Policy Graduate Program, University of Delaware, Newark, DE 19716, USA
| | - Kenneth T. Belt
- Department of Geography and Environmental Systems, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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Kaushal SS, Likens GE, Mayer PM, Shatkay RR, Shelton SA, Grant SB, Utz RM, Yaculak AM, Maas CM, Reimer JE, Bhide SV, Malin JT, Rippy MA. The Anthropogenic Salt Cycle. Nat Rev Earth Environ 2023; 4:770-784. [PMID: 38515734 PMCID: PMC10953805 DOI: 10.1038/s43017-023-00485-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/05/2023] [Indexed: 03/23/2024]
Abstract
Increasing salt production and use is shifting the natural balances of salt ions across Earth systems, causing interrelated effects across biophysical systems collectively known as freshwater salinization syndrome. In this Review, we conceptualize the natural salt cycle and synthesize increasing global trends of salt production and riverine salt concentrations and fluxes. The natural salt cycle is primarily driven by relatively slow geologic and hydrologic processes that bring different salts to the surface of the Earth. Anthropogenic activities have accelerated the processes, timescales and magnitudes of salt fluxes and altered their directionality, creating an anthropogenic salt cycle. Global salt production has increased rapidly over the past century for different salts, with approximately 300 Mt of NaCl produced per year. A salt budget for the USA suggests that salt fluxes in rivers can be within similar orders of magnitude as anthropogenic salt fluxes, and there can be substantial accumulation of salt in watersheds. Excess salt propagates along the anthropogenic salt cycle, causing freshwater salinization syndrome to extend beyond freshwater supplies and affect food and energy production, air quality, human health and infrastructure. There is a need to identify environmental limits and thresholds for salt ions and reduce salinization before planetary boundaries are exceeded, causing serious or irreversible damage across Earth systems.
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Affiliation(s)
- Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Gene E Likens
- Cary Institute of Ecosystem Studies, Millbrook, NY, USA
- University of Connecticut, Storrs, CT, USA
| | - Paul M Mayer
- US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, OR, USA
| | - Ruth R Shatkay
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Sydney A Shelton
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Stanley B Grant
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, USA
- Center for Coastal Studies, Virginia Tech, Blacksburg, VA, USA
| | | | - Alexis M Yaculak
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Carly M Maas
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Jenna E Reimer
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Shantanu V Bhide
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, USA
| | - Joseph T Malin
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - Megan A Rippy
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, USA
- Center for Coastal Studies, Virginia Tech, Blacksburg, VA, USA
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Maas CM, Kaushal SS, Rippy MA, Mayer PM, Grant SB, Shatkay RR, Malin JT, Bhide SV, Vikesland P, Krauss L, Reimer JE, Yaculak AM. Freshwater salinization syndrome limits management efforts to improve water quality. Front Environ Sci 2023; 11:1-20. [PMID: 37841559 PMCID: PMC10568995 DOI: 10.3389/fenvs.2023.1106581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Freshwater Salinization Syndrome (FSS) refers to groups of biological, physical, and chemical impacts which commonly occur together in response to salinization. FSS can be assessed by the mobilization of chemical mixtures, termed "chemical cocktails", in watersheds. Currently, we do not know if salinization and mobilization of chemical cocktails along streams can be mitigated or reversed using restoration and conservation strategies. We investigated 1) the formation of chemical cocktails temporally and spatially along streams experiencing different levels of restoration and riparian forest conservation and 2) the potential for attenuation of chemical cocktails and salt ions along flowpaths through conservation and restoration areas. We monitored high-frequency temporal and longitudinal changes in streamwater chemistry in response to different pollution events (i.e., road salt, stormwater runoff, wastewater effluent, and baseflow conditions) and several types of watershed management or conservation efforts in six urban watersheds in the Chesapeake Bay watershed. Principal component analysis (PCA) indicates that chemical cocktails which formed along flowpaths (i.e., permanent reaches of a stream) varied due to pollution events. In response to winter road salt applications, the chemical cocktails were enriched in salts and metals (e.g., Na+, Mn, and Cu). During most baseflow and stormflow conditions, chemical cocktails were less enriched in salt ions and trace metals. Downstream attenuation of salt ions occurred during baseflow and stormflow conditions along flowpaths through regional parks, stream-floodplain restorations, and a national park. Conversely, chemical mixtures of salt ions and metals, which formed in response to multiple road salt applications or prolonged road salt exposure, did not show patterns of rapid attenuation downstream. Multiple linear regression was used to investigate variables that influence changes in chemical cocktails along flowpaths. Attenuation and dilution of salt ions and chemical cocktails along stream flowpaths was significantly related to riparian forest buffer width, types of salt pollution, and distance downstream. Although salt ions and chemical cocktails can be attenuated and diluted in response to conservation and restoration efforts at lower concentration ranges, there can be limitations in attenuation during road salt events, particularly if storm drains bypass riparian buffers.
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Affiliation(s)
- Carly M. Maas
- Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Sujay S. Kaushal
- Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Megan A. Rippy
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
- Center for Coastal Studies, Virginia Tech, Blacksburg, VA, United States
| | - Paul M. Mayer
- US Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, OR, United States
| | - Stanley B. Grant
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
- Center for Coastal Studies, Virginia Tech, Blacksburg, VA, United States
| | - Ruth R. Shatkay
- Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Joseph T. Malin
- Department of Geology and Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Shantanu V. Bhide
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
| | - Peter Vikesland
- The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, United States
| | - Lauren Krauss
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
| | - Jenna E. Reimer
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
| | - Alexis M. Yaculak
- Water Sciences and Policy Graduate Program, University of Delaware, Newark, DE, United States
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11
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Kaushal SS, Maas CM, Mayer PM, Newcomer-Johnson TA, Grant SB, Rippy MA, Shatkay RR, Leathers J, Gold AJ, Smith C, McMullen EC, Haq S, Smith R, Duan S, Malin J, Yaculak A, Reimer JE, Newcomb KD, Raley AS, Collison DC, Galella JG, Grese M, Sivirichi G, Doody TR, Vikesland P, Bhide SV, Krauss L, Daugherty M, Stavrou C, Etheredge M, Ziegler J, Kirschnick A, England W, Belt KT. Longitudinal stream synoptic monitoring tracks chemicals along watershed continuums: a typology of trends. Front Environ Sci 2023; 11:1-28. [PMID: 37475839 PMCID: PMC10355011 DOI: 10.3389/fenvs.2023.1122485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
There are challenges in monitoring and managing water quality due to spatial and temporal heterogeneity in contaminant sources, transport, and transformations. We demonstrate the importance of longitudinal stream synoptic (LSS) monitoring, which can track combinations of water quality parameters along flowpaths across space and time. Specifically, we analyze longitudinal patterns of chemical mixtures of carbon, nutrients, greenhouse gasses, salts, and metals concentrations along 10 flowpaths draining 1,765 km2 of the Chesapeake Bay region. These 10 longitudinal stream flowpaths are drained by watersheds experiencing either urban degradation, forest and wetland conservation, or stream and floodplain restoration. Along the 10 longitudinal stream flowpaths, we monitored over 300 total sampling sites along a combined stream length of 337 km. Synoptic monitoring along longitudinal flowpaths revealed: (1) increasing, decreasing, piecewise, or no trends and transitions in water quality with increasing distance downstream, which provide insights into water quality processes along flowpaths; (2) longitudinal trends and transitions in water quality along flowpaths can be quantified and compared using simple linear and non-linear statistical relationships with distance downstream and/or land use/land cover attributes, (3) attenuation and transformation of chemical cocktails along flowpaths depend on: spatial scales, pollution sources, and transitions in land use and management, hydrology, and restoration. We compared our LSS patterns with others from the global literature to synthesize a typology of longitudinal water quality trends and transitions in streams and rivers based on hydrological, biological, and geochemical processes. Applications of LSS monitoring along flowpaths from our results and the literature reveal: (1) if there are shifts in pollution sources, trends, and transitions along flowpaths, (2) which pollution sources can spread further downstream to sensitive receiving waters such as drinking water supplies and coastal zones, and (3) if transitions in land use, conservation, management, or restoration can attenuate downstream transport of pollution sources. Our typology of longitudinal water quality responses along flowpaths combines many observations across suites of chemicals that can follow predictable patterns based on watershed characteristics. Our typology of longitudinal water quality responses also provides a foundation for future studies, watershed assessments, evaluating watershed management and stream restoration, and comparing watershed responses to non-point and point pollution sources along streams and rivers. LSS monitoring, which integrates both spatial and temporal dimensions and considers multiple contaminants together (a chemical cocktail approach), can be a comprehensive strategy for tracking sources, fate, and transport of pollutants along stream flowpaths and making comparisons of water quality patterns across different watersheds and regions.
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Affiliation(s)
- Sujay S. Kaushal
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Carly M. Maas
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Paul M. Mayer
- United States Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, OR, United States
| | - Tammy A. Newcomer-Johnson
- United States Environmental Protection Agency, Center for Environmental Measurement and Modeling, Watershed and Ecosystem Characterization Division, Cincinnati, OH, United States
| | - Stanley B. Grant
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
- Center for Coastal Studies, Virginia Tech, Blacksburg, VA, United States
| | - Megan A. Rippy
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
- Center for Coastal Studies, Virginia Tech, Blacksburg, VA, United States
| | - Ruth R. Shatkay
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | | | - Arthur J. Gold
- Department of Natural Resources Science, University of Rhode Island, Kingston, RI, United States
| | - Cassandra Smith
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Evan C. McMullen
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Shahan Haq
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Rose Smith
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Shuiwang Duan
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Joseph Malin
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Alexis Yaculak
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Jenna E. Reimer
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Katie Delaney Newcomb
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Ashley Sides Raley
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Daniel C. Collison
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Joseph G. Galella
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | | | | | - Thomas R. Doody
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, United States
| | - Peter Vikesland
- The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, United States
| | - Shantanu V. Bhide
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
| | - Lauren Krauss
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via, Jr. Department of Civil and Environmental Engineering, Virginia Tech, Manassas, VA, United States
| | | | | | | | | | | | | | - Kenneth T. Belt
- Department of Geography and Environmental Systems, University of Maryland Baltimore County, Baltimore, MD, United States
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Diedhiou M, Mayer PM. On the Gas-Phase Interactions of Alkyl and Phenyl Formates with Water: Ion-Molecule Reactions with Proton-Bound Water Clusters. Molecules 2023; 28:molecules28114431. [PMID: 37298907 DOI: 10.3390/molecules28114431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/26/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023] Open
Abstract
Ion-molecule reactions between the neutral ethyl- (EF), isopropyl- (IF), t-butyl- (TF) and phenyl formate (PF) and proton-bound water clusters W2H+ and W3H+ (W = H2O) showed that the major reaction product is water loss from the initial encounter complex, followed ultimately by the formation of the protonated formate. Collision-induced dissociation breakdown curves of the formate-water complexes were obtained as a function of collision energy and modeled to extract relative activation energies for the observed channels. Density functional theory calculations (B3LYP/6-311+G(d,p)) of the water loss reactions were consistent with reactions having no reverse energy barrier in each case. Overall, the results indicate that the interaction of formates with atmospheric water can form stable encounter complexes that will dissociate by sequential water loss to form protonated formates.
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Affiliation(s)
- Malick Diedhiou
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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13
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Galella JG, Kaushal SS, Mayer PM, Maas CM, Shatkay RR, Stutzke RA. Stormwater Best Management Practices: Experimental Evaluation of Chemical Cocktails Mobilized by Freshwater Salinization Syndrome. Front Environ Sci 2023; 11:1-20. [PMID: 37234950 PMCID: PMC10208307 DOI: 10.3389/fenvs.2023.1020914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Freshwater Salinization Syndrome (FSS) refers to the suite of physical, biological, and chemical impacts of salt ions on the degradation of natural, engineered, and social systems. Impacts of FSS on mobilization of chemical cocktails has been documented in streams and groundwater, but little research has focused on the effects of FSS on stormwater best management practices (BMPs) such as: constructed wetlands, bioswales, ponds, and bioretention. However emerging research suggests that stormwater BMPs may be both sources and sinks of contaminants, shifting seasonally with road salt applications. We conducted lab experiments to investigate this premise; replicate water and soil samples were collected from four distinct stormwater feature types (bioretention, bioswale, constructed wetlands and retention ponds) and were used in salt incubation experiments conducted under six different salinities with three different salts (NaCl, CaCl2, and MgCl2). Increased salt concentrations had profound effects on major and trace element mobilization, with all three salts showing significant positive relationships across nearly all elements analyzed. Across all sites, mean salt retention was 34%, 28%, and 26% for Na+, Mg2+ and Ca2+ respectively, and there were significant differences among stormwater BMPs. Salt type showed preferential mobilization of certain elements. NaCl mobilized Cu, a potent toxicant to aquatic biota, at rates over an order of magnitude greater than both CaCl2 and MgCl2. Stormwater BMP type also had a significant effect on elemental mobilization, with ponds mobilizing significantly more Mn than other sites. However, salt concentration and salt type consistently had significant effects on mean concentrations of elements mobilized across all stormwater BMPs (p<0.05), suggesting that processes such as ion exchange mobilize metals mobilize metals and salt ions regardless of BMP type. Our results suggest that decisions regarding the amounts and types of salts used as deicers can have significant effects on reducing contaminant mobilization to freshwater ecosystems.
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Affiliation(s)
- Joseph G Galella
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Paul M Mayer
- US Environmental Protection Agency Office of Research and Development Center for Public Health and Environmental Assessment Corvallis, OR 97333
| | - Carly M Maas
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Ruth R Shatkay
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Robert A Stutzke
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
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Kaushal SS, Mayer PM, Likens GE, Reimer JE, Maas CM, Rippy MA, Grant SB, Hart I, Utz RM, Shatkay RR, Wessel BM, Maietta CE, Pace ML, Duan S, Boger WL, Yaculak AM, Galella JG, Wood KL, Morel CJ, Nguyen W, Querubin SEC, Sukert RA, Lowien A, Houde AW, Roussel A, Houston AJ, Cacopardo A, Ho C, Talbot-Wendlandt H, Widmer JM, Slagle J, Bader JA, Chong JH, Wollney J, Kim J, Shepherd L, Wilfong MT, Houlihan M, Sedghi N, Butcher R, Chaudhary S, Becker WD. Five state factors control progressive stages of freshwater salinization syndrome. Limnol Oceanogr Lett 2023; 8:190-211. [PMID: 37539375 PMCID: PMC10395323 DOI: 10.1002/lol2.10248] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 02/21/2022] [Indexed: 08/05/2023]
Abstract
Factors driving freshwater salinization syndrome (FSS) influence the severity of impacts and chances for recovery. We hypothesize that spread of FSS across ecosystems is a function of interactions among five state factors: human activities, geology, flowpaths, climate, and time. (1) Human activities drive pulsed or chronic inputs of salt ions and mobilization of chemical contaminants. (2) Geology drives rates of erosion, weathering, ion exchange, and acidification-alkalinization. (3) Flowpaths drive salinization and contaminant mobilization along hydrologic cycles. (4) Climate drives rising water temperatures, salt stress, and evaporative concentration of ions and saltwater intrusion. (5) Time influences consequences, thresholds, and potentials for ecosystem recovery. We hypothesize that state factors advance FSS in distinct stages, which eventually contribute to failures in systems-level functions (supporting drinking water, crops, biodiversity, infrastructure, etc.). We present future research directions for protecting freshwaters at risk based on five state factors and stages from diagnosis to prognosis to cure.
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Affiliation(s)
- Sujay S. Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Paul M. Mayer
- Pacific Ecological Systems Division, US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Corvallis, Oregon
| | - Gene E. Likens
- Cary Institute of Ecosystem Studies, Millbrook, New York
- University of Connecticut, Storrs, Connecticut
| | - Jenna E. Reimer
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Carly M. Maas
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Megan A. Rippy
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, Manassas, Virginia
- Center for Coastal Studies, Virginia Tech, Blacksburg, Virginia
| | - Stanley B. Grant
- Occoquan Watershed Monitoring Laboratory, The Charles E. Via Jr Department of Civil and Environmental Engineering, Virginia Tech, Manassas, Virginia
- Center for Coastal Studies, Virginia Tech, Blacksburg, Virginia
| | - Ian Hart
- Chatham University, Gibsonia, Pennsylvania
| | | | - Ruth R. Shatkay
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Barret M. Wessel
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland
| | - Christine E. Maietta
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland
| | - Michael L. Pace
- Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia
| | - Shuiwang Duan
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Walter L. Boger
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Alexis M. Yaculak
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Joseph G. Galella
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Kelsey L. Wood
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Carol J. Morel
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - William Nguyen
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Shane Elizabeth C. Querubin
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Rebecca A. Sukert
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Anna Lowien
- Environmental Science & Policy Program, University of Maryland, College Park, Maryland
| | - Alyssa Wellman Houde
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland
| | - Anaïs Roussel
- Department of Biology, Georgetown University, Washington, District of Columbia
| | - Andrew J. Houston
- Department of Geology, University of Maryland, College Park, Maryland
| | - Ari Cacopardo
- Department of Geology, University of Maryland, College Park, Maryland
| | - Cristy Ho
- Department of Geology, University of Maryland, College Park, Maryland
| | | | - Jacob M. Widmer
- Department of Geology, University of Maryland, College Park, Maryland
| | - Jairus Slagle
- Department of Geology, University of Maryland, College Park, Maryland
| | - James A. Bader
- Department of Geology, University of Maryland, College Park, Maryland
| | - Jeng Hann Chong
- Department of Geology, University of Maryland, College Park, Maryland
| | - Jenna Wollney
- Department of Geology, University of Maryland, College Park, Maryland
| | - Jordan Kim
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland
| | - Lauren Shepherd
- Department of Geology, University of Maryland, College Park, Maryland
| | - Matthew T. Wilfong
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland
| | - Megan Houlihan
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland
| | - Nathan Sedghi
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland
| | - Rebecca Butcher
- Department of Geology, University of Maryland, College Park, Maryland
| | - Sona Chaudhary
- Department of Geology, University of Maryland, College Park, Maryland
| | - William D. Becker
- Department of Geology, University of Maryland, College Park, Maryland
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Lowe B, Cardona AL, Salas J, Bodi A, Mayer PM, Burgos Paci MA. Probing the pyrolysis of ethyl formate in the dilute gas phase by synchrotron radiation and theory. J Mass Spectrom 2023; 58:e4901. [PMID: 36691327 DOI: 10.1002/jms.4901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 10/31/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
The thermal decomposition of the atmospheric constituent ethyl formate was studied by coupling flash pyrolysis with imaging photoelectron photoion coincidence (iPEPICO) spectroscopy using synchrotron vacuum ultraviolet (VUV) radiation at the Swiss Light Source (SLS). iPEPICO allows photoion mass-selected threshold photoelectron spectra (ms-TPES) to be obtained for pyrolysis products. By threshold photoionization and ion imaging, parent ions of neutral pyrolysis products and dissociative photoionization products could be distinguished, and multiple spectral carriers could be identified in several ms-TPES. The TPES and mass-selected TPES for ethyl formate are reported for the first time and appear to correspond to ionization of the lowest energy conformer having a cis (eclipsed) configuration of the O=C(H)-O-C(H2 )-CH3 and trans (staggered) configuration of the O=C(H)-O-C(H2 )-CH3 dihedral angles. We observed the following ethyl formate pyrolysis products: CH3 CH2 OH, CH3 CHO, C2 H6 , C2 H4 , HC(O)OH, CH2 O, CO2 , and CO, with HC(O)OH and C2 H4 pyrolyzing further, forming CO + H2 O and C2 H2 + H2 . The reaction paths and energetics leading to these products, together with the products of two homolytic bond cleavage reactions, CH3 CH2 O + CHO and CH3 CH2 + HC(O)O, were studied computationally at the M06-2X-GD3/aug-cc-pVTZ and SVECV-f12 levels of theory, complemented by further theoretical methods for comparison. The calculated reaction pathways were used to derive Arrhenius parameters for each reaction. The reaction rate constants and branching ratios are discussed in terms of the residence time and newly suggest carbon monoxide as a competitive primary fragmentation product at high temperatures.
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Affiliation(s)
- Bethany Lowe
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
| | - Alejandro L Cardona
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juana Salas
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
| | - Maxi A Burgos Paci
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
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16
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Overton SM, Chea P, Mayer PM. Probing fragmentation mechanisms of deprotonated isomaltotriose: Charge-remote or charge-directed? Chem Phys 2023. [DOI: 10.1016/j.chemphys.2022.111722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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17
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Gholami A, Hampe O, Mayer PM. Structures and Dissociation of Iron Porphyrin Complexes by Ion Mobility and Collision-Induced Dissociation Mass Spectrometry. CAN J CHEM 2022. [DOI: 10.1139/cjc-2022-0133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A combination of ion mobility mass spectrometry (IMS-MS), collision-induced dissociation (CID), RRKM modeling, and computational chemistry was used to determine the structure and unimolecular chemistry of dimeric and trimeric sulfonated meso-tetraphenylporphyrins with negative charges from -2 to -5. By comparing experimental collision cross-sections obtained from calibrated IMS drift times with calculated cross sections for the lowest energy calculated structures, it was confirmed that dimer species have a bridged structure where the two monomers are connected through iron-sulfonic interactions. Dimer species with the charge states -4 and -5 dissociate into two monomer units where the charge is distributed between the monomers. Dimers with lower charge states also lose neutral SO2 and SO3 groups. For trimeric species with charge states of -3 and -4, IMS identifies three and two isomers, respectively. It was confirmed that the -4 charged trimer isomers consist of one with three stacked monomers and one in which the third monomer unit is connected to a stacked dimer via two iron-sulfonic bonds (bridged/stacked). Both yielded the same CID breakdown diagram confirming that the two isomers likely interconvert prior to dissociation. The significantly larger density of states of the bridged-stacked structure compared to the stacked structure means the former is likely the reactive configuration.
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Affiliation(s)
- Ameneh Gholami
- University of Ottawa, 6363, Department of Chemistry and Biomolecular Sciences, Ottawa, Canada
| | - Oliver Hampe
- Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Paul M Mayer
- University of Ottawa, 6363, Department of Chemistry and Biomolecular Sciences, Ottawa, Canada
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18
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Gondarry S, Mayer PM. The Fate of Protonated Guaiacol and Its Derivatives in the Gas Phase. J Phys Chem A 2022; 126:9051-9058. [PMID: 36442159 DOI: 10.1021/acs.jpca.2c04692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Guaiacol (2-methoxyphenol) and its derivatives are a class of semivolatile polar organic molecules possessing low molecular weights. Owing to their volatility, guaiacol and its derivatives can interact with atmospheric water and form protonated methoxyphenols through proton transfer. The aim of the present work is to study the dissociation of these protonated ions and hence, potentially, their atmospheric fate. Tandem mass spectrometry was employed to analyze the unimolecular dissociation of the protonated forms of guaiacol (2-methoxyphenol, 1), creosol (2-methoxy-4-methylphenol, 2), 4-ethylguaiacol (4-ethyl-2-methoxyphenol, 3), 4-vinylguaiacol (2-methoxy-4-vinylphenol, 4), eugenol (2-methoxy-4-prop-2-enylphenol, 5), and vanillin (4-hydroxy-3-methoxybenzaldehyde, 6). Density functional theory at the B3LYP/6-31G(d) (1-5) and B3LYP/6-311+G(d,p) (6) levels of theory were applied to determine the observed minimum energy reaction pathways, and reliable energetics were acquired using CBS-QB3 single-point energy calculations. All the protonated ions, with the exception of 6, exhibit the loss of CH3OH via a series of hydrogen transfers, followed by ring contraction to lose CO. This common dissociation pathway leads to the formation of a cyclopentadienyl ion as the main dissociation product. Conversely, 6 first exhibits the loss of CO, followed by sequential losses of CH3OH and CO to generate a cyclopentadienyl ion. Additionally, minor fragmentation channels are also observed for the different protonated ions: CH2 loss in 1; CH4 and H2O losses in 3; CH3 loss in 4, 5, and 6; C2H4 and CH2CHCH2 losses in 5; H loss in 6. Altogether, the protonated ions primarily lose CH3OH and CO as neutral molecules and generate a cyclopentadienyl ion as a dissociation product.
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Affiliation(s)
- Sandesh Gondarry
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, CanadaK1N 6N5
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, CanadaK1N 6N5
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19
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Kaushal SS, Reimer JE, Mayer PM, Shatkay RR, Maas CM, Nguyen WD, Boger WL, Yaculak AM, Doody TR, Pennino MJ, Bailey NW, Galella JG, Weingrad A, Collison DC, Wood KL, Haq S, Johnson TAN, Duan S, Belt KT. Freshwater Salinization Syndrome Alters Retention and Release of 'Chemical Cocktails' along Flowpaths: from Stormwater Management to Urban Streams. Freshw Sci 2022; 41:420-441. [PMID: 36213200 PMCID: PMC9533665 DOI: 10.1086/721469] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We investigate impacts of Freshwater Salinization Syndrome (FSS) on mobilization of salts, nutrients, and metals in urban streams and stormwater BMPs by analyzing original data on concentrations and fluxes of salts, nutrients, and metals from 7 urban watersheds in the Mid-Atlantic U.S. and synthesizing literature data. We also explore future critical research needs through a survey of practitioners and scientists. Our original data show: (1) sharp pulses in concentrations of salt ions and metals in urban streams directly following both road salt events and stream restoration construction (e.g., similar to the way concentrations increase during other soil disturbance activities); (2) sharp declines in pH (acidification) in response to road salt applications due to mobilization of H+ from soil exchange sites by Na+; (3) sharp increases in organic matter from microbial and algal sources (based on fluorescence spectroscopy) in response to road salt applications likely due to lysing cells and/or changes in solubility; (4) significant retention (~30-40%) of Na+ in stormwater BMP sediments and floodplains in response to salinization; (5) increased ion exchange and mobilization of diverse salt ions (Na+, Ca2+, K+, Mg2+), nutrients (N, P), and trace metals (Cu, Sr) from stormwater BMPs and restored streams in response to FSS; (6) downstream increasing loads of Cl-, SO4 2-, Br-, F-, and I- along flowpaths through urban streams, and P release from urban stormwater BMPs in response to salinization, and (7) a significant annual reduction (> 50%) in Na+ concentrations in an urban stream when road salt applications were dramatically reduced, which suggests potential for ecosystem recovery. We compared our original results to published metrics of contaminant retention and release across a broad range of stormwater management BMPs from North America and Europe. Overall, urban streams and stormwater management BMPs consistently retain Na+ and Cl- but mobilize multiple contaminants based on salt types and salinity levels. Finally, we present our top 10 research questions regarding FSS impacts on urban streams and stormwater management BMPs. Reducing diverse 'chemical cocktails' of contaminants mobilized by freshwater salinization is now a priority for effectively and holistically restoring urban waters.
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Affiliation(s)
- Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Jenna E Reimer
- US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, Oregon, 97333, USA
| | - Paul M Mayer
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Ruth R Shatkay
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Carly M Maas
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - William D Nguyen
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Walter L Boger
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Alexis M Yaculak
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Thomas R Doody
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Michael J Pennino
- US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Integrate Environmental Assessment Branch, 1200 Pennsylvania Ave, NW, Washington, D.C. 20460, USA
| | - Nathan W Bailey
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Joseph G Galella
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Aaron Weingrad
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Daniel C Collison
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Kelsey L Wood
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Shahan Haq
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Tamara A Newcomer Johnson
- US Environmental Protection Agency, Center for Environmental Measurement and Modeling, Watershed and Ecosystem Characterization Division, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, USA
| | - Shuiwang Duan
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Kenneth T Belt
- Department of Geography and Environmental Systems, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA
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20
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Weitzman JN, Brooks JR, Compton JE, Faulkner BR, Mayer PM, Peachey RE, Rugh WD, Coulombe RA, Hatteberg B, Hutchins SR. Deep soil nitrogen storage slows nitrate leaching through the vadose zone. Agric Ecosyst Environ 2022; 332:1-13. [PMID: 35400773 DOI: 10.23719/1524264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nitrogen (N) fertilizer applications are important for agricultural yield, yet not all the applied N is taken up by crops, leading to surplus N storage in soil or leaching to groundwater and surface water. Leaching loss of fertilizer N represents a cost for farmers and has consequences for human health and the environment, especially in the southern Willamette Valley, Oregon, USA, where groundwater nitrate contamination is prevalent. While improved nutrient management and conservation practices have been implemented to minimize leaching, nitrate levels in groundwater continue to increase in many long-term monitoring wells. To elucidate controls on leaching rates and N dynamics in agricultural soils across soil depths, and in response to seasonal and annual variation in management (e.g., fertilizer input amount and summer irrigation), we intensively monitored the transport of water and nitrate every two weeks for four years through the vadose zone at three depths (0.8, 1.5, and 3.0 m) in a sweet corn (maize) field. Though nitrate leaching was highly variable among lysimeters at the same depth and across years, a strong pattern emerged: annual nitrate leaching significantly decreased with depth across the study, averaging ~104 kg N ha-1 yr-1 near the surface (0.8 m) versus ~56 kg N ha-1 yr-1 in the deep soil (3.0 m), a 54% reduction in leaching between the soil layers. Even though crops were irrigated in summer, most leaching (~72% below 3.0 m) occurred during the wet fall and winter. Based on steady state assumptions, a net equivalent of ~29% of surface N inputs leached below 3.0 m into the deeper soil and groundwater, while ~44% was removed in crop harvest, indicating considerable N retention in the soil (~27% of inputs or approximately 58 kg N ha-1 yr-1). The accumulation and long-term dynamics of deep soil N is a legacy of agricultural management that should be further studied to better manage and reduce nitrate loss to groundwater.
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Affiliation(s)
- Julie N Weitzman
- ORISE Fellow at Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - J Renée Brooks
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - Jana E Compton
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - Barton R Faulkner
- Groundwater Characterization and Remediation Division, Center for Environmental Solutions and Emergency Response, Office of Research and Development, US Environmental Protection Agency, 919 Kerr Research Drive, Ada, OK, 74820, USA
| | - Paul M Mayer
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - Ronald E Peachey
- Department of Horticulture, College of Agricultural Sciences, Oregon State University, 4045 Agriculture and Life Sciences Building, Corvallis, OR, 97331, USA
| | - William D Rugh
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | | | | | - Stephen R Hutchins
- Groundwater Characterization and Remediation Division, Center for Environmental Solutions and Emergency Response, Office of Research and Development, US Environmental Protection Agency, 919 Kerr Research Drive, Ada, OK, 74820, USA
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21
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Weitzman JN, Brooks JR, Compton JE, Faulkner BR, Mayer PM, Peachey RE, Rugh WD, Coulombe RA, Hatteberg B, Hutchins SR. Deep soil nitrogen storage slows nitrate leaching through the vadose zone. Agric Ecosyst Environ 2022; 332:1-13. [PMID: 35400773 PMCID: PMC8988158 DOI: 10.1016/j.agee.2022.107949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Nitrogen (N) fertilizer applications are important for agricultural yield, yet not all the applied N is taken up by crops, leading to surplus N storage in soil or leaching to groundwater and surface water. Leaching loss of fertilizer N represents a cost for farmers and has consequences for human health and the environment, especially in the southern Willamette Valley, Oregon, USA, where groundwater nitrate contamination is prevalent. While improved nutrient management and conservation practices have been implemented to minimize leaching, nitrate levels in groundwater continue to increase in many long-term monitoring wells. To elucidate controls on leaching rates and N dynamics in agricultural soils across soil depths, and in response to seasonal and annual variation in management (e.g., fertilizer input amount and summer irrigation), we intensively monitored the transport of water and nitrate every two weeks for four years through the vadose zone at three depths (0.8, 1.5, and 3.0 m) in a sweet corn (maize) field. Though nitrate leaching was highly variable among lysimeters at the same depth and across years, a strong pattern emerged: annual nitrate leaching significantly decreased with depth across the study, averaging ~104 kg N ha-1 yr-1 near the surface (0.8 m) versus ~56 kg N ha-1 yr-1 in the deep soil (3.0 m), a 54% reduction in leaching between the soil layers. Even though crops were irrigated in summer, most leaching (~72% below 3.0 m) occurred during the wet fall and winter. Based on steady state assumptions, a net equivalent of ~29% of surface N inputs leached below 3.0 m into the deeper soil and groundwater, while ~44% was removed in crop harvest, indicating considerable N retention in the soil (~27% of inputs or approximately 58 kg N ha-1 yr-1). The accumulation and long-term dynamics of deep soil N is a legacy of agricultural management that should be further studied to better manage and reduce nitrate loss to groundwater.
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Affiliation(s)
- Julie N. Weitzman
- ORISE Fellow at Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
- Corresponding author.
| | - J. Renée Brooks
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - Jana E. Compton
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - Barton R. Faulkner
- Groundwater Characterization and Remediation Division, Center for Environmental Solutions and Emergency Response, Office of Research and Development, US Environmental Protection Agency, 919 Kerr Research Drive, Ada, OK, 74820, USA
| | - Paul M. Mayer
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | - Ronald E. Peachey
- Department of Horticulture, College of Agricultural Sciences, Oregon State University, 4045 Agriculture and Life Sciences Building, Corvallis, OR, 97331, USA
| | - William D. Rugh
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 200 SW 35 Street, Corvallis, OR, 97333, USA
| | | | | | - Stephen R. Hutchins
- Groundwater Characterization and Remediation Division, Center for Environmental Solutions and Emergency Response, Office of Research and Development, US Environmental Protection Agency, 919 Kerr Research Drive, Ada, OK, 74820, USA
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22
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Lowe B, Cardona AL, Salas J, Bodi A, Burgos Paci MA, Mayer PM. Probing the pyrolysis of methyl formate in the dilute gas phase by synchrotron radiation and theory. J Mass Spectrom 2022; 57:e4868. [PMID: 35698788 DOI: 10.1002/jms.4868] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/22/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
The thermal dissociation of the atmospheric constituent methyl formate was probed by coupling pyrolysis with imaging photoelectron photoion coincidence spectroscopy (iPEPICO) using synchrotron VUV radiation at the Swiss Light Source (SLS). iPEPICO allows threshold photoelectron spectra to be obtained for pyrolysis products, distinguishing isomers and separating ionic and neutral dissociation pathways. In this work, the pyrolysis products of dilute methyl formate, CH3 OC(O)H, were elucidated to be CH3 OH + CO, 2 CH2 O and CH4 + CO2 as in part distinct from the dissociation of the radical cation (CH3 OH+• + CO and CH2 OH+ + HCO). Density functional theory, CCSD(T), and CBS-QB3 calculations were used to describe the experimentally observed reaction mechanisms, and the thermal decomposition kinetics and the competition between the reaction channels are addressed in a statistical model. One result of the theoretical model is that CH2 O formation was predicted to come directly from methyl formate at temperatures below 1200 K, while above 1800 K, it is formed primarily from the thermal decomposition of methanol.
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Affiliation(s)
- Bethany Lowe
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Alejandro L Cardona
- INFIQC-CONICET, Departamento Fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juana Salas
- INFIQC-CONICET, Departamento Fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Maxi A Burgos Paci
- INFIQC-CONICET, Departamento Fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
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23
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Zinck N, Bodi A, Mayer PM. VUV photoprocessing of oxygen-containing polycyclic aromatic hydrocarbons: iPEPICO study of the unimolecular dissociation of ionized benzofuran. CAN J CHEM 2022. [DOI: 10.1139/cjc-2022-0062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) are potential contributors to the 11.3 m band in interstellar observations. To further explore their role in the interstellar medium, we have investigated their fate after photoprocessing by VUV radiation; in particular, we studied the dissociative photoionization of the simplest OPAH, benzofuran, with imaging photoelectron photoion coincidence spectroscopy, iPEPICO. Ionized benzofuran dissociates by loss of CO, followed by a sequential H atom loss. The parallel HCO-loss channel, leading to the same bicyclic C7H5+ fragment ion, is not competitive at low excess energies above the ionization threshold. However, the collision-induced dissociation tandem mass spectrometry results suggest that CO and HCO may be formed in parallel at higher energies. An RRKM fragmentation model reproduced the iPEPICO data well assuming the initial 1,2-H shift transition state to be rate determining to CO loss. The breakdown diagram and the measured dissociation rates agreed well at the CBS-QB3-calculated activation energy of 2.99 eV, which could be relaxed to 3.25 eV, and only a slight adjustment of the ab initio activation entropy. The model barrier to sequential H-loss is larger than the computed H-loss threshold and the breakdown diagram rises less steeply than predicted, which indicates suprastatistical kinetic energy release after the tight H-transfer transition state of the first step. HCO cleavage is possible after a ring-opening transition state, which is looser than and isoenergetic with the CO-loss transition state. However, a subsequent ring formation transition state at 3.85 eV is moderately tight, which suppresses HCO loss at low excess energies.
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Affiliation(s)
- Nicholas Zinck
- University of Ottawa, 6363, Chemistry and Biomolecular Sciences, Ottawa, Ontario, Canada
| | - Andras Bodi
- Paul Scherrer Institut PSI, 28498, Laboratory for Synchrotron Radiation and Femtochemistry, Villigen, Aargau, Switzerland
| | - Paul M Mayer
- University of Ottawa, 6363, Chemistry and Biomolecular Sciences, Ottawa, Ontario, Canada,
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24
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Diedhiou M, Mayer PM. Fate of Protonated Formates in the Gas Phase. J Phys Chem A 2021; 125:5096-5102. [PMID: 34086463 DOI: 10.1021/acs.jpca.1c03814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Formates are a class of organic molecules emitted into the atmosphere from fuel additives and industrial solvents. Formate-derived esters can undergo a vast range of chemical reactions in the atmosphere, most of which are initiated by oxidation by hydroxyl radicals. One potential reaction upon their interaction with atmospheric water is proton transfer to form protonated formates. The goal of the present work is to explore the dissociation of these protonated species and thus their possible atmospheric fate. Tandem mass spectrometry was employed to study the unimolecular dissociation of the protonated forms of methyl- (1), ethyl- (2), isopropyl- (3), tert-butyl- (4), and phenylformate (5). 1 and 2 lose CO as a common fragmentation product, forming a protonated alcohol, and 2 also generates neutral ethanol (forming protonated CO). 3 and 4 readily lose the stable isopropyl and tert-butyl radicals as well as neutral alkenes propene and isobutene. Methanol loss is also observed from both ions. 5 exhibits both phenyl radical loss (similar to 3 and 4) and CO loss (like 1 and 2). Density functional theory was used to explore the observed minimum energy reaction pathways for each ion, and CBS-QB3 single-point energy calculations provided reliable energetics.
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Affiliation(s)
- Malick Diedhiou
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
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25
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Weitzman JN, Brooks JR, Mayer PM, Rugh WD, Compton JE. Coupling the dual isotopes of water (δ 2H and δ 18O) and nitrate (δ 15N and δ 18O): A new framework for classifying current and legacy groundwater pollution. Environ Res Lett 2021; 16:1-45008. [PMID: 33897808 PMCID: PMC8059602 DOI: 10.1088/1748-9326/abdcef] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nitrate contamination of groundwater is a concern globally, particularly in agricultural regions where decades of fertilizer nitrogen (N) use has led to a legacy of N accumulation in soils and groundwater. Linkages between current management practices and groundwater nitrate dynamics are often confounded by the legacy effect, and other processes unrelated to management. A coupled analysis of dual stable isotopes of water (δH2O = δ2H and δ18O) and nitrate (δNO3 - = δ15N and δ18O) can be a powerful approach to identify sources and processes responsible for groundwater pollution. To assess how management practices impact groundwater nitrate, we interpreted behavior of δH2O and δNO3 -, together with nitrate concentrations, in water samples collected from long-term monitoring wells in the Southern Willamette Valley (SWV), Oregon. The source(s) of nitrate and water varied among wells, suggesting that the nitrate concentration patterns were not uniform across the shallow aquifer of the valley. Analyzing the stability versus variability of a well's corresponding δH2O and δNO3 - values over time revealed the mechanisms controlling nitrate concentrations. Wells with stable δH2O and δNO3 - values and nitrate concentrations were influenced by one water source with a long residence time and one nitrate source. Variable nitrate concentrations of other wells were attributed to dilution with an alternate water source, mixing of two nitrate sources, or variances in the release of legacy N from overlying soils. Denitrification was not an important process influencing well nitrate dynamics. Understanding the drivers of nitrate dynamics and interaction with legacy N is crucial for managing water quality improvement. This case study illustrates when and where such coupled stable isotope approaches might provide key insights to management on groundwater nitrate contamination issues.
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Affiliation(s)
- Julie N. Weitzman
- ORISE Fellow at Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Newport, OR, United State of America
| | - J. Renée Brooks
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR, United States of America
| | - Paul M. Mayer
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR, United States of America
| | - William D. Rugh
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR, United States of America
| | - Jana E. Compton
- Pacific Ecological Systems Division, Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Corvallis, OR, United States of America
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26
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Bollman MA, DeSantis GE, Waschmann RS, Mayer PM. Effects of shading and composition on green roof media temperature and moisture. J Environ Manage 2021; 281:111882. [PMID: 33421937 PMCID: PMC8026110 DOI: 10.1016/j.jenvman.2020.111882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/15/2020] [Accepted: 12/19/2020] [Indexed: 06/12/2023]
Abstract
Three of the primary functions of green roofs in urban areas are to delay rainwater runoff, moderate building temperatures, and ameliorate the urban heat island (UHI) effect. A major impediment to the survival of plants on an unirrigated extensive green roof (EGR) is the harsh rooftop environment, including high temperatures and limited water during dry periods. Factors that influence EGR thermal and hydrologic performance include the albedo (reflectivity) of the roof and the composition of the green roof substrate (growing media). In this study we used white, reflective shading structures and three different media formulations to evaluate EGR thermal and hydrologic performance in the Pacific Northwest, USA. Shading significantly reduced daytime mean and maximum EGR media temperatures and significantly increased nighttime mean and minimum temperatures, which may provide energy benefits to buildings. Mean media moisture was greater in shaded trays than in exposed (unshaded) trays but differences were not statistically significant. Warmer nighttime media temperatures and lack of dew formation in shaded trays may have partially compensated for greater daytime evaporation from exposed trays. Media composition did not significantly influence media temperature or moisture. Results of this study suggest that adding shade structures to green roofs will combine thermal, hydrologic, and ecological benefits, and help achieve temperature and light regimes that allow for greater plant diversity on EGRs.
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Affiliation(s)
- Michael A Bollman
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, 200 SW 35th St., Corvallis, OR, 97333, USA.
| | - Grace E DeSantis
- U.S. Environmental Protection Agency, Greater Research Opportunities Undergraduate Fellowship, 200 SW 35th St., Corvallis, OR, 97333, USA
| | - Ronald S Waschmann
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, 200 SW 35th St., Corvallis, OR, 97333, USA
| | - Paul M Mayer
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, 200 SW 35th St., Corvallis, OR, 97333, USA
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Galella JG, Kaushal SS, Wood KL, Reimer JE, Mayer PM. Sensors track mobilization of 'chemical cocktails' in streams impacted by road salts in the Chesapeake Bay watershed. Environ Res Lett 2021; 16:035017-35017. [PMID: 34017359 PMCID: PMC8128710 DOI: 10.1088/1748-9326/abe48f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Increasing trends in base cations, pH, and salinity of freshwaters have been documented in U.S. streams over 50 years. These patterns, collectively known as Freshwater Salinization Syndrome (FSS), are driven by multiple processes, including applications of road salt and human-accelerated weathering of impervious surfaces, reductions in acid rain, and other anthropogenic legacies of change. FSS mobilizes chemical cocktails of distinct elemental mixtures via ion exchange, and other biogeochemical processes. We analyzed impacts of FSS on streamwater chemistry across five urban watersheds in the Baltimore-Washington, USA metropolitan region. Through combined grab-sampling and high-frequency monitoring by USGS sensors, regression relationships were developed among specific conductance and major ion and trace metal concentrations. These linear relationships were statistically significant in most of the urban streams (e.g., R2 = 0.62 and 0.43 for Mn and Cu, respectively), and showed that specific conductance could be used as a proxy to predict concentrations of major ions and trace metals. Major ions and trace metals analyzed via linear regression and principal component analysis (PCA) showed co-mobilization (i.e., correlations among combinations of specific conductance, Mn, Cu, Sr2+, and all base cations during certain times of year and hydrologic conditions). Co-mobilization of metals and base cations was strongest during peak snow events but could continue over 24 hours after specific conductance peaked, suggesting ongoing cation exchange in soils and stream sediments. Mn and Cu concentrations predicted from specific conductance as a proxy indicated acceptable goodness of fit for predicted vs. observed values (Nash-Sutcliffe Efficiency > 0.28). Metals concentrations remained elevated for days after specific conductance decreased following snowstorms, suggesting lag times and continued mobilization after road salt use. High-frequency sensor monitoring and proxies associated with FSS may help better predict contaminant pulses and contaminant exceedances in response to salinization and impacts on aquatic life, infrastructure, and drinking water.
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Affiliation(s)
- Joseph G Galella
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Kelsey L Wood
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Jenna E Reimer
- Department of Geology & Earth System Science Interdisciplinary Center University of Maryland College Park, MD 20140
| | - Paul M Mayer
- US Environmental Protection Agency Office of Research and Development Center for Public Health and Environmental Assessment Corvallis, OR 97333
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Kaushal SS, Wood KL, Galella JG, Gion AM, Haq S, Goodling PJ, Haviland KA, Reimer JE, Morel CJ, Wessel B, Nguyen W, Hollingsworth JW, Mei K, Leal J, Widmer J, Sharif R, Mayer PM, Johnson TAN, Newcomb KD, Smith E, Belt KT. Making 'Chemical Cocktails' - Evolution of Urban Geochemical Processes across the Periodic Table of Elements. Appl Geochem 2020; 119:1-104632. [PMID: 33746355 PMCID: PMC7970522 DOI: 10.1016/j.apgeochem.2020.104632] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Urbanization contributes to the formation of novel elemental combinations and signatures in terrestrial and aquatic watersheds, also known as 'chemical cocktails.' The composition of chemical cocktails evolves across space and time due to: (1) elevated concentrations from anthropogenic sources, (2) accelerated weathering and corrosion of the built environment, (3) increased drainage density and intensification of urban water conveyance systems, and (4) enhanced rates of geochemical transformations due to changes in temperature, ionic strength, pH, and redox potentials. Characterizing chemical cocktails and underlying geochemical processes is necessary for: (1) tracking pollution sources using complex chemical mixtures instead of individual elements or compounds; (2) developing new strategies for co-managing groups of contaminants; (3) identifying proxies for predicting transport of chemical mixtures using continuous sensor data; and (4) determining whether interactive effects of chemical cocktails produce ecosystem-scale impacts greater than the sum of individual chemical stressors. First, we discuss some unique urban geochemical processes which form chemical cocktails, such as urban soil formation, human-accelerated weathering, urban acidification-alkalinization, and freshwater salinization syndrome. Second, we review and synthesize global patterns in concentrations of major ions, carbon and nutrients, and trace elements in urban streams across different world regions and make comparisons with reference conditions. In addition to our global analysis, we highlight examples from some watersheds in the Baltimore-Washington DC region, which show increased transport of major ions, trace metals, and nutrients across streams draining a well-defined land-use gradient. Urbanization increased the concentrations of multiple major and trace elements in streams draining human-dominated watersheds compared to reference conditions. Chemical cocktails of major and trace elements were formed over diurnal cycles coinciding with changes in streamflow, dissolved oxygen, pH, and other variables measured by high-frequency sensors. Some chemical cocktails of major and trace elements were also significantly related to specific conductance (p<0.05), which can be measured by sensors. Concentrations of major and trace elements increased, peaked, or decreased longitudinally along streams as watershed urbanization increased, which is consistent with distinct shifts in chemical mixtures upstream and downstream of other major cities in the world. Our global analysis of urban streams shows that concentrations of multiple elements along the Periodic Table significantly increase when compared with reference conditions. Furthermore, similar biogeochemical patterns and processes can be grouped among distinct mixtures of elements of major ions, dissolved organic matter, nutrients, and trace elements as chemical cocktails. Chemical cocktails form in urban waters over diurnal cycles, decades, and throughout drainage basins. We conclude our global review and synthesis by proposing strategies for monitoring and managing chemical cocktails using source control, ecosystem restoration, and green infrastructure. We discuss future research directions applying the watershed chemical cocktail approach to diagnose and manage environmental problems. Ultimately, a chemical cocktail approach targeting sources, transport, and transformations of different and distinct elemental combinations is necessary to more holistically monitor and manage the emerging impacts of chemical mixtures in the world's fresh waters.
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Affiliation(s)
- Sujay S Kaushal
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Kelsey L Wood
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Joseph G Galella
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Austin M Gion
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Shahan Haq
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Phillip J Goodling
- MD-DE-DC US Geological Survey Water Science Center, 5522 Research Park Drive, Catonsville, Maryland 21228, USA
| | | | - Jenna E Reimer
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Carol J Morel
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Barret Wessel
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland 20740, USA
| | - William Nguyen
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - John W Hollingsworth
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Kevin Mei
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Julian Leal
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Jacob Widmer
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
| | - Rahat Sharif
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland 20740, USA
| | - Paul M Mayer
- US Environmental Protection Agency, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Western Ecology Division, 200 SW 35 Street, Corvallis, Oregon 97333, USA
| | - Tamara A Newcomer Johnson
- US Environmental Protection Agency, Center for Environmental Measurement and Modeling, Watershed and Ecosystem Characterization Division, 26 W. Martin Luther King Drive, Cincinnati, Ohio 45268, USA
| | | | - Evan Smith
- Department of Geology, University of Maryland, College Park, Maryland 20740, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland 20740, USA
| | - Kenneth T Belt
- Department of Geography and Environmental Systems, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250
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Diedhiou M, West BJ, Bouwman J, Mayer PM. Ion Dissociation Dynamics of 1,2,3,4-Tetrahydronaphthalene: Tetralin as a Test Case For Hydrogenated Polycyclic Aromatic Hydrocarbons. J Phys Chem A 2019; 123:10885-10892. [PMID: 31794665 DOI: 10.1021/acs.jpca.9b09511] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unimolecular dissociation of ionized tetralin was probed by tandem mass spectrometry, imaging photoelectron photoion coincidence (iPEPICO) spectroscopy, and theory. The major reactions observed were the loss of the hydrocarbons CH3•, C2H4, and C3H5• together with H•-atom loss. RRKM modeling of the iPEPICO data suggested a two-well potential energy surface. Ionized tetralin can lose all four neutrals via H-shift and ring-opening reactions or CH3• and C2H4 after interconversion to the 1-methylindane ion, a process similar to that found for ionized 1,2-dihydronaphthalene (isomerizing to form the 1-methylindene ion structure). This was confirmed at the B3LYP/6-31+G(d,p) level of theory, and potential mechanisms for all reactions are described. The ionization energy of tetralin was established from the threshold photoelectron spectrum to be 8.46 ± 0.01 eV.
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Affiliation(s)
- Malick Diedhiou
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Canada K1N 6N5
| | - Brandi J West
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Canada K1N 6N5
| | - Jordy Bouwman
- Laboratory for Astrophysics, Leiden Observatory , Leiden University , P.O. Box 9513, 2300RA Leiden , The Netherlands
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Canada K1N 6N5
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Lesniak L, West BJ, Mayer PM. Hydroxy-Substituted Polycyclic Aromatic Hydrocarbon Ions as Sources of CO and HCO in the Interstellar Medium. J Phys Chem A 2019; 123:10694-10699. [DOI: 10.1021/acs.jpca.9b10004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lukas Lesniak
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
| | - Brandi J. West
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
| | - Paul M. Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
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31
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Bollman MA, DeSantis GE, DuChanois RM, Etten-Bohm M, Olszyk DM, Lambrinos JG, Mayer PM. A framework for optimizing hydrologic performance of green roof media. Ecol Eng 2019; 140:1-105589. [PMID: 32020990 PMCID: PMC6997945 DOI: 10.1016/j.ecoleng.2019.105589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
One of the primary functions of green roofs in urban areas is to moderate rainwater runoff, and one of the major impediments to the survival of plants on an extensive green roof (EGR) is a lack of available water during dry periods. Runoff moderation and water storage are both influenced by the composition of the growing media. Here we present a framework for evaluating the hydrologic performance of EGR growing media and also provide hydrologic attribute data for several commonly used EGR media constituents. In this three-phase study, we: 1) measured hydrologic attributes of individual EGR media constituents, 2) predicted attributes of media mixtures using individual constituent data, and 3) tested the seven top-ranking mixtures to evaluate hydrologic performance. Hydrologic attributes included wet weight and water held at maximum retentive capacity, long-term water retention, and hydraulic conductivity. Because perlite was light in weight yet held the greatest amount of water both at its maximum retentive capacity and in the long term, media mixtures dominated by perlite were predicted to have the best overall hydrologic performance. Mixtures dominated by pumice were also predicted to perform relatively well but were heavier. Despite the slightly greater weight and slightly lower performance, pumice may be a preferred alternative to perlite because perlite is a processed constituent with greater estimated embodied energy. Results indicate that performance of mixtures can be adequately predicted using performance of individual constituents for wet weight, water held, and long-term water retention. Hydraulic conductivity was less predictable because the pore volume in mixtures can be unrelated to the pore volume of the individual constituents. The framework presented here can be used to evaluate the performance of other EGR media, and the media attribute data can be used in formulating EGR media mixtures for specific applications. In addition, the attribute data can serve as a benchmark for evaluating other EGR media. Our results underscore the need for standardization of methods for more effective comparisons of EGR substrates, and also reinforce the need to evaluate EGR components using real-world scenarios.
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Affiliation(s)
- Michael A. Bollman
- US EPA, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR 97333
| | - Grace E. DeSantis
- US EPA, Greater Research Opportunities Undergraduate Fellowship, Corvallis, OR 97333
| | - Ryan M. DuChanois
- US EPA, Greater Research Opportunities Undergraduate Fellowship, Corvallis, OR 97333
| | - Montana Etten-Bohm
- US EPA, Greater Research Opportunities Undergraduate Fellowship, Corvallis, OR 97333
| | - David M. Olszyk
- US EPA, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR 97333
| | | | - Paul M. Mayer
- US EPA, National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR 97333
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32
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Lesniak L, Salas J, Burner J, Diedhiou M, Burgos Paci MA, Bodi A, Mayer PM. Trifluoroacetic Acid and Trifluoroacetic Anhydride Radical Cations Dissociate near the Ionization Limit. J Phys Chem A 2019; 123:6313-6318. [DOI: 10.1021/acs.jpca.9b04883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lukas Lesniak
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Juana Salas
- INFIQC − CONICET, Departamento Fisicoquimica, Universidad Nacional de Córdoba, Cordoba 5000, Argentina
| | - Jake Burner
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Malick Diedhiou
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
| | - Maxi A Burgos Paci
- INFIQC − CONICET, Departamento Fisicoquimica, Universidad Nacional de Córdoba, Cordoba 5000, Argentina
| | - Andras Bodi
- Paul Scherrer Institute, Villigen, 5232 Switzerland
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
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33
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Burner J, West BJ, Mayer PM. What Will Photo-Processing of Large, Ionized Amino-Substituted Polycyclic Aromatic Hydrocarbons Produce in the Interstellar Medium? J Phys Chem A 2019; 123:5027-5034. [PMID: 31150240 DOI: 10.1021/acs.jpca.9b02395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Collision-energy resolved tandem mass spectrometry was used to probe the trends in unimolecular fragmentation in a series of ionized amino-substituted polycyclic aromatic hydrocarbons ranging from naphthalene to pyrene. As the ring system expands, the dominant dissociation process changes from HNC loss (aniline) to H loss for 1-aminopyrene. Imaging photoelectron photoion coincidence spectroscopy of 1-aminopyrene yielded threshold photon-energy resolved breakdown curves, the Rice-Ramsperger-Kassel-Marcus modeling of which gave a 0 K activation energy, E0, for H loss of 3.8 ± 0.4 eV. Calculations at the CCSD/6-31G(d)//B3LYP/6-31G(d) level of theory were used to explore the possible reaction mechanisms for H, HNC, and C,N,H2 losses, and details of the reaction pathways are presented. The H atom loss was found to be due both to direct N-H bond cleavage and isomerization to form an azepine derivative.
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Affiliation(s)
- Jake Burner
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa K1N 6N5 , Canada
| | - Brandi J West
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa K1N 6N5 , Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa K1N 6N5 , Canada
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34
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Affiliation(s)
- Brandi J. West
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
| | - Lukas Lesniak
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
| | - Paul M. Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada K1N 6N5
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35
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Duan S, Mayer PM, Kaushal SS, Wessel BM, Johnson T. Regenerative stormwater conveyance (RSC) for reducing nutrients in urban stormwater runoff depends upon carbon quantity and quality. Sci Total Environ 2019; 652:134-146. [PMID: 30359797 PMCID: PMC6529187 DOI: 10.1016/j.scitotenv.2018.10.197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/12/2018] [Accepted: 10/14/2018] [Indexed: 05/20/2023]
Abstract
Regenerative stormwater conveyance (RSC), a relatively new stormwater management approach, is extensively implemented throughout the mid-Atlantic for nutrient control, but little is known of its pollutant reduction capabilities and controlling factors. This study examined effects of organic carbon (C) quantity and quality on stream water quality and nutrient retention at two RSCs near Annapolis, Maryland, USA by comparing longitudinal changes in water quality at paired restored and unrestored stream reaches, and conducting lab experiments simulating RSC processes. Results showed that RSCs consistently had lower dissolved oxygen saturation (DO%) and pH relative to nearby unrestored streams, probably due to release of labile dissolved organic carbon (DOC). At one RSC, with high nitrate (NO3-) inputs, retention of N (16-37%) and release of DOC (18-54%) were observed with the highest retention of N during summer, and the rates of N retention and DOC release were larger than that of the adjacent unrestored tributary (N: 5-8%, DOC: <18%). At another RSC site with lower NO3- concentrations, N retention and DOC release were not apparent. Mesocosm experiments showed that NO3- retention varies with organic C quantity and quality depending on incubating temperature; retention of total N did not increase with organic C due to release of other N species (e.g., organic N). Lab mesocosms showed an increase in the release of soluble reactive phosphorus (SRP) with increasing organic C quantity and quality. However, field measurements did not show any evidence of SRP release at RSCs. The changes in SRP concentrations in streams seemed to be a function of iron levels and leaf litter inputs, but control factors for SRP warrant further investigation. This study suggests that RSC as a restoration approach may be effective for reducing N depending upon C quantity and quality as well as water temperature and N levels.
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Affiliation(s)
- Shuiwang Duan
- National Research Council Postdoctoral Research Associate, Washington, DC, United States of America; Department of Geology, University of Maryland, College Park, MD, United States of America.
| | - Paul M Mayer
- USEPA, National Health and Environmental Effects Research Laboratory, Corvallis, OR, United States of America
| | - Sujay S Kaushal
- Department of Geology, University of Maryland, College Park, MD, United States of America
| | - Barret M Wessel
- Department of Environmental Science and Technology, University of Maryland, College Park, MD, United States of America
| | - Thomas Johnson
- USEPA, National Center for Environmental Assessment, Washington, DC, United States of America
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36
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Barnhart BL, Golden HE, Kasprzyk JR, Pauer JJ, Jones CE, Sawicz KA, Hoghooghi N, Simon M, McKane RB, Mayer PM, Piscopo AN, Ficklin DL, Halama JJ, Pettus PB, Rashleigh B. Embedding co-production and addressing uncertainty in watershed modeling decision-support tools: successes and challenges. Environ Model Softw 2018; 109:368-379. [PMID: 30505208 PMCID: PMC6260939 DOI: 10.1016/j.envsoft.2018.08.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Decision-support tools (DSTs) are often produced from collaborations between technical experts and stakeholders to address environmental problems and inform decision making. Studies in the past two decades have provided key insights on the use of DSTs and the importance of bidirectional information flows among technical experts and stakeholders - a process that is variously referred to as co-production, participatory modeling, structured decision making, or simply stakeholder participation. Many of these studies have elicited foundational insights for the broad field of water resources management; however, questions remain on approaches for balancing co-production with uncertainty specifically for watershed modeling decision support tools. In this paper, we outline a simple conceptual model that focuses on the DST development process. Then, using watershed modeling case studies found in the literature, we discuss successful outcomes and challenges associated with embedding various forms of co-production into each stage of the conceptual model. We also emphasize the "3 Cs" (i.e., characterization, calculation, communication) of uncertainty and provide evidence-based suggestions for their incorporation in the watershed modeling DST development process. We conclude by presenting a list of best practices derived from current literature for achieving effective and robust watershed modeling decision-support tools.
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Affiliation(s)
- Bradley L. Barnhart
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Heather E. Golden
- United States Environmental Protection Agency, National
Exposure Research Laboratory, Systems Exposure Division, Cincinnati, Ohio,
45268
| | - Joseph R. Kasprzyk
- University of Colorado Boulder, Civil, Environmental and
Architectural Engineering, Boulder, Colorado, 80309
| | - James J. Pauer
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Mid-Continent Ecology
Division, Duluth, Minnesota, 55804
| | - Chas E. Jones
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Keith A. Sawicz
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Nahal Hoghooghi
- United States Environmental Protection Agency, National
Exposure Research Laboratory, Systems Exposure Division, Cincinnati, Ohio,
45268
- University of Georgia, School of Environmental, Civil,
Agricultural and Mechanical Engineering, Athens, GA, 30602
| | - Michelle Simon
- United States Environmental Protection Agency, National
Risk Management Research Laboratory, Water Supply and Water Resources Division,
Cincinnati, Ohio, 45268
| | - Robert B. McKane
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Paul M. Mayer
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Amy N. Piscopo
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Atlantic Ecology Division,
Narragansett, Rhode Island, 02882
| | - Darren L. Ficklin
- Indiana University, Department of Geography, Bloomington,
Indiana, 47405
| | - Jonathan J. Halama
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Paul B. Pettus
- United States Environmental Protection Agency, National
Health and Environmental Effects Research Laboratory, Western Ecology Division,
Corvallis, Oregon, 97330
| | - Brenda Rashleigh
- United States Environmental Protection Agency, National
Risk Management Research Laboratory, Water Supply and Water Resources Division,
Cincinnati, Ohio, 45268
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37
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Alotaibi N, Overton S, Curtis S, Nickerson JW, Attaran A, Gilmer S, Mayer PM. Toward Point-of-Care Drug Quality Assurance in Developing Countries: Comparison of Liquid Chromatography and Infrared Spectroscopy Quantitation of a Small-Scale Random Sample of Amoxicillin. Am J Trop Med Hyg 2018; 99:477-481. [PMID: 29893196 PMCID: PMC6090331 DOI: 10.4269/ajtmh.17-0779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Substandard antibiotics are thought to be a major threat to public health in developing countries and a cause of antimicrobial resistance. However, assessing quality outside of a laboratory setting, using simple equipment, is challenging. The aim of this study was to validate the use of a portable Fourier transform infrared (FT-IR) spectrometer for the identification of substandard antibiotics. Results are presented for amoxicillin packages from Haiti, Ghana, Sierra Leone, Democratic Republic of Congo, India, Papua New Guinea, and Ethiopia collected over the course of 6 months in 2017, including two field trips with the FT-IR to Ghana and Sierra Leone. Canadian samples were used as a control. Regarding drug quality, of 290 individual capsules of amoxicillin analyzed, 13 were found to be substandard with total active pharmaceutical ingredients (API) lying outside the acceptable range of 90–110%. Of these 13, four were below 80% API. The FT-IR reliably identified these outliers and was found to yield results in good agreement with the established pharmacopeia liquid chromatography protocol. We conclude that the portable FT-IR may be suitable to intercept substandard antibiotics in developing countries where more sophisticated techniques are not readily available.
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Affiliation(s)
- Norah Alotaibi
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Sean Overton
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Sharon Curtis
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Jason W Nickerson
- Faculty of Law, University of Ottawa, Ottawa, Ontario, Canada.,Bruyère Research Institute, Ottawa, Ontario, Canada
| | - Amir Attaran
- Faculty of Law, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
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West B, Lowe B, Mayer PM. Unimolecular Dissociation of 1-Methylpyrene Cations: Why Are 1-Methylenepyrene Cations Formed and Not a Tropylium-Containing Ion? J Phys Chem A 2018; 122:4730-4735. [PMID: 29727186 DOI: 10.1021/acs.jpca.8b02667] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1-Methylpyrene radical cations undergo the loss of a hydrogen atom at internal energies above the first dissociation threshold. Imaging photoelectron photoion coincidence spectroscopy was employed in combination with RRKM modeling to determine a 0 K activation energy of 2.78 ± 0.25 eV and an entropy of activation of 6 ± 19 J K-1 mol-1 for this H-loss reaction. The ionization energy of 1-methylpyrene was measured by mass-selected threshold photoelectron spectroscopy to be 7.27 ± 0.01 eV. These values were found to be consistent with calculations at the CCSD/6-31G(d)//B3-LYP/6-31G(d) level of theory showing that the formation of the 1-methylenepyrene cation (resulting from H loss from the methyl group) is kinetically more favorable than the formation of a tropylium-containing product ion that is structurally analogous to the formation of the tropylium cation in H loss from ionized toluene. The shift away from a tropylium-containing structure was found to be due to the increased ring strain imposed on the C7 moiety when it is bound to three fused benzene rings. The RRKM results allow for the derivation of the Δf H0o (1-methylenepyrene cation) of 945 ± 31 kJ mol-1.
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Affiliation(s)
- Brandi West
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Canada K1N 6N5
| | - Bethany Lowe
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Canada K1N 6N5
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Canada K1N 6N5
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West B, Rodriguez Castillo S, Sit A, Mohamad S, Lowe B, Joblin C, Bodi A, Mayer PM. Unimolecular reaction energies for polycyclic aromatic hydrocarbon ions. Phys Chem Chem Phys 2018; 20:7195-7205. [PMID: 29480289 PMCID: PMC6031295 DOI: 10.1039/c7cp07369k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Imaging photoelectron photoion coincidence spectroscopy was employed to explore the unimolecular dissociation of the ionized polycyclic aromatic hydrocarbons (PAHs) acenaphthylene, fluorene, cyclopenta[d,e,f]phenanthrene, pyrene, perylene, fluoranthene, dibenzo[a,e]pyrene, dibenzo[a,l]pyrene, coronene and corannulene. The primary reaction is always hydrogen atom loss, with the smaller species also exhibiting loss of C2H2 to varying extents. Combined with previous work on smaller PAH ions, trends in the reaction energies (E0) for loss of H from sp2-C and sp3-C centres, along with hydrocarbon molecule loss were found as a function of the number of carbon atoms in the ionized PAHs ranging in size from naphthalene to coronene. In the case of molecules which possessed at least one sp3-C centre, the activation energy for the loss of an H atom from this site was 2.34 eV, with the exception of cyclopenta[d,e,f]phenanthrene (CPP) ions, for which the E0 was 3.44 ± 0.86 eV due to steric constraints. The hydrogen loss from PAH cations and from their H-loss fragments exhibits two trends, depending on the number of unpaired electrons. For the loss of the first hydrogen atom, the energy is consistently ca. 4.40 eV, while the threshold to lose the second hydrogen atom is much lower at ca. 3.16 eV. The only exception was for the dibenzo[a,l]pyrene cation, which has a unique structure due to steric constraints, resulting in a low H loss reaction energy of 2.85 eV. If C2H2 is lost directly from the precursor cation, the energy required for this dissociation is 4.16 eV. No other fragmentation channels were observed over a large enough sample set for trends to be extrapolated, though data on CH3 and C4H2 loss obtained in previous studies is included for completeness. The dissociation reactions were also studied by collision induced dissociation after ionization by atmospheric pressure chemical ionization. When modeled with a simple temperature-based theory for the post-collision internal energy distribution, there was reasonable agreement between the two sets of data.
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Affiliation(s)
- Brandi West
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada.
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Arango CP, Beaulieu JJ, Fritz KM, Hill BH, Elonen CM, Pennino MJ, Mayer PM, Kaushal SS, Balz AD. Urban infrastructure influences dissolved organic matter quality and bacterial metabolism in an urban stream network. Freshw Biol 2017; 62:1917-1928. [PMID: 35340891 PMCID: PMC8943703 DOI: 10.1111/fwb.13035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
1. Urban streams are degraded by a suite of factors, including burial beneath urban infrastructure, such as roads or parking lots, which eliminates light and reduces direct organic matter inputs to streams from riparian zones. These changes to stream metabolism and terrestrial carbon contribution will likely have consequences for organic matter metabolism by microbes and dissolved organic matter (DOM) use patterns in streams. Respiration by heterotrophic biofilms drives the nitrogen and phosphorus cycles, but we lack a clear understanding of how stream burial and seasonality affect microbial carbon use. 2. We studied seasonal changes (autumn, spring, and summer) in organic matter metabolism by microbial communities in open and buried reaches of three urban streams in Cincinnati, OH. We characterised DOM quality using fluorescence spectroscopy and extracellular enzyme profiles, and we measured the respiration response to carbon supplements in nutrient diffusing substrata (NDS). We hypothesised: (1) that algal production would lead to higher quality DOM in spring compared to other seasons and in open compared to buried reaches, (2) lower reliance of microbial respiration on recalcitrant carbon sources in spring and in open reaches, and (3) that microbial respiration would increase in response to added carbon in autumn and in buried reaches. 3. Several fluorescence metrics showed higher quality DOM in spring than autumn, but only the metric of recalcitrant humic compounds varied by reach, with more humic DOM in open compared to buried reaches. This likely reflected open reaches as an avenue for direct terrestrial inputs from the riparian zone. 4. Extracellular enzyme assays showed that microbes in buried reaches allocated more effort to degrade recalcitrant carbon sources, consistent with a lack of labile carbon compounds due to limited photosynthesis. Nitrogen acquisition enzymes were highest in autumn coincident with riparian leaf inputs to the streams. Buried and open reaches both responded more strongly to added carbon in autumn when terrestrial leaf inputs dominated compared to the spring when vernal algal blooms were pronounced. 5. Our data show that stream burial affects the quality of the DOM pool with consequences for how microbes use those carbon sources, and that heterotrophic respiration increased on carbon-supplemented NDS in buried and open stream reaches in both seasons. Different carbon quality and use patterns suggest that urban stream infrastructure affects spatiotemporal patterns of bacterial respiration, with likely consequences for nitrogen and/or phosphorus cycling given that carbon use drives other biogeochemical cycles. Management actions that increase light to buried streams could shift the balance between allochthonous and autochthonous DOM in urban streams with consequences for spatiotemporal patterns in bacterial metabolism.
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Affiliation(s)
- Clay P. Arango
- Department of Biological Sciences, Central Washington University, Ellensburg, WA, U.S.A
| | - Jake J. Beaulieu
- Office of Research and Development, National Risk Management Research Laboratory, US EPA, Cincinnati, OH, U.S.A
| | - Ken M. Fritz
- Office of Research and Development, National Exposure Research Laboratory, US EPA, Cincinnati, OH, U.S.A
| | - Brian H. Hill
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, US EPA, Duluth, MN, U.S.A
| | - Colleen M. Elonen
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, US EPA, Duluth, MN, U.S.A
| | - Michael J. Pennino
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, US EPA, Corvallis, OR, U.S.A
| | - Paul M. Mayer
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, US EPA, Corvallis, OR, U.S.A
| | - Sujay S. Kaushal
- Department of Geology and Earth Systems Interdisciplinary Center, University of Maryland, College Park, MD, U.S.A
| | - Adam D. Balz
- Pegasus Technical Services, Cincinnati, OH, U.S.A
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Kaushal SS, Duan S, Doody TR, Haq S, Smith RM, Newcomer Johnson TA, Newcomb KD, Gorman J, Bowman N, Mayer PM, Wood KL, Belt KT, Stack WP. Human-accelerated weathering increases salinization, major ions, and alkalinization in fresh water across land use. Appl Geochem 2017; 83:121-135. [PMID: 30220785 PMCID: PMC6134868 DOI: 10.1016/j.apgeochem.2017.02.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Human-dominated land uses can increase transport of major ions in streams due to the combination of human-accelerated weathering and anthropogenic salts. Calcium, magnesium, sodium, alkalinity, and hardness significantly increased in the drinking water supply for Baltimore, Maryland over almost 50 years (p<0.05) coinciding with regional urbanization. Across a nearby land use gradient at the Baltimore Long-Term Ecological Research (LTER) site, there were significant increases in concentrations of dissolved inorganic carbon (DIC), Ca2+, Mg2+, Na+, and Si and pH with increasing impervious surfaces in 9 streams monitored bi-weekly over a 3-4 year period (p<0.05). Base cations in urban streams were up to 60 times greater than forest and agricultural streams, and elemental ratios suggested road salt and carbonate weathering from impervious surfaces as potential sources. Laboratory weathering experiments with concrete also indicated that impervious surfaces increased pH and DIC with potential to alkalinize urban waters. Ratios of Na+ and Cl- suggested that there was enhanced ion exchange in the watersheds from road salts, which could mobilize other base cations from soils to streams. There were significant relationships between Ca2+, Mg2+, Na+, and K+ concentrations and Cl-, SO42-, NO3- and DIC across land use (p<0.05), which suggested tight coupling of geochemical cycles. Finally, concentrations of Na+, Ca2+, Mg2+, and pH significantly increased with distance downstream (p<0.05) along a stream network draining 170 km2 of the Baltimore LTER site contributing to river alkalinization. Our results suggest that urbanization may dramatically increase major ions, ionic strength, and pH over decades from headwaters to coastal zones, which can impact integrity of aquatic life, infrastructure, drinking water, and coastal ocean alkalinization.
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Affiliation(s)
- Sujay S Kaushal
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Shuiwang Duan
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Thomas R Doody
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Shahan Haq
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Rose M Smith
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Tamara A Newcomer Johnson
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
- US Environmental Protection Agency, National Exposure Research Lab, Systems Exposure Division, Cincinnati, OH 45268, USA
| | - Katie Delaney Newcomb
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Julia Gorman
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Noah Bowman
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Paul M Mayer
- US Environmental Protection Agency, National Health and Environmental Effects Research Lab, Western Ecology Division, Corvallis, OR 97333, USA
| | - Kelsey L Wood
- Department of Geology & Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 21201, USA
| | - Kenneth T Belt
- Baltimore Field Station, USDA Forest Service, Baltimore, Maryland 21228 USA
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Solano EA, Mohamed S, Mayer PM. Modeling collision energy transfer in APCI/CID mass spectra of PAHs using thermal-like post-collision internal energy distributions. J Chem Phys 2016; 145:164311. [PMID: 27802636 DOI: 10.1063/1.4966186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The internal energy transferred when projectile molecular ions of naphthalene collide with argon gas atoms was extracted from the APCI-CID (atmospheric-pressure chemical ionization collision-induced dissociation) mass spectra acquired as a function of collision energy. Ion abundances were calculated by microcanonical integration of the differential rate equations using the Rice-Ramsperger-Kassel-Marcus rate constants derived from a UB3LYP/6-311G+(3df,2p)//UB3LYP/6-31G(d) fragmentation mechanism and thermal-like vibrational energy distributions pME,Tchar. The mean vibrational energy excess of the ions was characterized by the parameter Tchar ("characteristic temperature"), determined by fitting the theoretical ion abundances to the experimental breakdown graph (a plot of relative abundances of the ions as a function of kinetic energy) of activated naphthalene ions. According to these results, the APCI ion source produces species below Tchar = 1457 K, corresponding to 3.26 eV above the vibrational ground state. Subsequent collisions heat the ions up further, giving rise to a sigmoid curve of Tchar as a function of Ecom (center-of-mass-frame kinetic energy). The differential internal energy absorption per kinetic energy unit (dEvib/dEcom) changes with Ecom according to a symmetric bell-shaped function with a maximum at 6.38 ± 0.32 eV (corresponding to 6.51 ± 0.27 eV of vibrational energy excess), and a half-height full width of 6.30 ± 1.15 eV. This function imposes restrictions on the amount of energy that can be transferred by collisions, such that a maximum is reached as kinetic energy is increased. This behavior suggests that the collisional energy transfer exhibits a pronounced increase around some specific value of energy. Finally, the model is tested against the CID mass spectra of anthracene and pyrene ions and the corresponding results are discussed.
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Affiliation(s)
- Eduardo A Solano
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Sabria Mohamed
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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Liu L, Siuda I, Richards MR, Renaud J, Kitova EN, Mayer PM, Tieleman DP, Lowary TL, Klassen JS. Structure and Stability of Carbohydrate-Lipid Interactions. Methylmannose Polysaccharide-Fatty Acid Complexes. Chembiochem 2016; 17:1571-8. [PMID: 27253157 DOI: 10.1002/cbic.201600123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Indexed: 11/07/2022]
Abstract
We report a detailed study of the structure and stability of carbohydrate-lipid interactions. Complexes of a methylmannose polysaccharide (MMP) derivative and fatty acids (FAs) served as model systems. The dependence of solution affinities and gas-phase dissociation activation energies (Ea ) on FA length indicates a dominant role of carbohydrate-lipid interactions in stabilizing (MMP+FA) complexes. Solution (1) H NMR results reveal weak interactions between MMP methyl groups and FA acyl chain; MD simulations suggest the complexes are disordered. The contribution of FA methylene groups to the Ea is similar to that of heats of transfer of n-alkanes from the gas phase to polar solvents, thus suggesting that MMP binds lipids through dipole-induced dipole interactions. The MD results point to hydrophobic interactions and H-bonds with the FA carboxyl group. Comparison of collision cross sections of deprotonated (MMP+FA) ions with MD structures suggests that the gaseous complexes are disordered.
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Affiliation(s)
- Lan Liu
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Iwona Siuda
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Michele R Richards
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Justin Renaud
- Chemistry Department, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Elena N Kitova
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - Paul M Mayer
- Chemistry Department, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Todd L Lowary
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada
| | - John S Klassen
- Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
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Francisco BBA, Gee E, Butson J, Mayer PM. Halide anions are formed from reactions between atomic metal anions and halogenated aromatic molecules. J Mass Spectrom 2016; 51:586-590. [PMID: 28239962 DOI: 10.1002/jms.3793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 06/06/2023]
Abstract
Atomic metal anions (AMAs) Fe- , Cs- , Cu- and Ag- were generated in the gas phase by collisionally decomposing the corresponding metal-oxalate anion. Mass selected AMAs were allowed to react with halogenated and nitrated molecules (C6H5Cl, C6H4Cl2, C6H3Cl3, C6H5I, C6H5Br and C6H5NO2) in the collision hexapole of a triple-quadrupole mass spectrometer. Observed reactions include the predominant formation of X- (X = Cl, Br and I), as well as FeCl- , FeCl2- and FeCl3- when Fe- reacted with the mono, di and tri-chlorobenzenes; reactions between 1,4-dichlorobenzene and Cs- produced Cl- , CsCl- and CsCl2- ; reactions involving iodobenzene also produced, CsI- , CsI2- and AgI- . The results suggest that the reaction to form X- (X = Cl, Br, I and NO2) may be a promising route to improving the detection efficiency by mass spectrometry for such analytes. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Barbara B A Francisco
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, K1N 6N5, Canada
| | - Emily Gee
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, K1N 6N5, Canada
| | - Jeffery Butson
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, K1N 6N5, Canada
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, K1N 6N5, Canada
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Rashid S, Overton S, Mazigh B, Mayer PM. Dual-spray hydrogen/deuterium exchange (HDX) reactions: A new method of probing protein structure. Rapid Commun Mass Spectrom 2016; 30:1505-1512. [PMID: 27321838 DOI: 10.1002/rcm.7591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 04/13/2016] [Accepted: 04/18/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Traditionally, hydrogen/deuterium exchange (HDX) reactions are done in the solution phase. This usually involves incubating the protein with a suitable deuterating agent then acidifying the solution to quench the reaction. A more efficient method may be to conduct the reaction within the ion source of a mass spectrometer and subsequently analyze the products. METHODS Using the two electrospray emitters equipped on the Waters Synapt G1 mass spectrometer, HDX reactions were conducted within the ion source region in a controlled fashion ('dual-spray'). Peptide and protein solutions were electrosprayed through one emitter and the deuterating agent D2 O through the secondary electrospray emitter. For the relatively small peptides, Phe-Leu-Glu-Glu-Leu and oxytocin, the yield of products was calculated using deconvolution functions. Electrospray ionization (ESI) charge-state distributions and average number of deuterium exchanges were used to probe secondary and tertiary structures of ubiquitin, lysozyme, and cytochrome c in their native and unfolded states. RESULTS Clear shifts in isotope distributions indicated HDX occurring within the ion source. By ion mobility, simultaneous deuterium exchange for two isobaric species, the oxytocin monomer and dimer, was observed. For denatured ubiquitin, the 12+ and 13+ charge states have a lower average number of exchanges relative to the lower charge states which indicates that these charge states have segments which restrict the access of D2 O. Lysozyme has a linear relationship between the charge state and the average number of exchanges, indicating that lysozyme becomes increasingly unfolded as the charge state increases. The dual-spray HDX method was paired to high-performance liquid chromatography (HPLC) to demonstrate the applicability of the technique for probing gas-phase structures in protein mixtures. CONCLUSIONS ESI droplets formed from a secondary emitter penetrate primary ESI droplets and change the solvent composition. Dual-spray HDX is demonstrated to be a more efficient method for probing the structure of proteins than solution-phase HDX since the acid quenching step can be surpassed. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Shaan Rashid
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON, Canada, K1N 6N5
| | - Sean Overton
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON, Canada, K1N 6N5
| | - Bihac Mazigh
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON, Canada, K1N 6N5
| | - Paul M Mayer
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON, Canada, K1N 6N5
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Zhen J, Castillo SR, Joblin C, Mulas G, Sabbah H, Giuliani A, Nahon L, Martin S, Champeaux JP, Mayer PM. VUV photo-processing of PAH cations: quantitative study on the ionization versus fragmentation processes. Astrophys J 2016; 822:113. [PMID: 27212712 PMCID: PMC4872839 DOI: 10.3847/0004-637x/822/2/113] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Interstellar polycyclic aromatic hydrocarbons (PAHs) are strongly affected by the absorption of vacuum ultraviolet (VUV) photons in the interstellar medium (ISM), yet the branching ratio between ionization and fragmentation is poorly studied. This is crucial for the stability and charge state of PAHs in the ISM in different environments, affecting in turn the chemistry, the energy balance, and the contribution of PAHs to the extinction and emission curves. We studied the interaction of PAH cations with VUV photons in the 7 - 20 eV range from the synchrotron SOLEIL beamline, DESIRS. We recorded by action spectroscopy the relative intensities of photo-fragmentation and photo-ionization for a set of eight PAH cations ranging in size from 14 to 24 carbon atoms, with different structures. At photon energies below ~13.6 eV fragmentation dominates for the smaller species, while for larger species ionization is immediately competitive after the second ionization potential (IP). At higher photon energies, all species behave similarly, the ionization yield gradually increases, leveling off between 0.8 and 0.9 at ~18 eV. Among isomers, PAH structure appears to mainly affect the fragmentation cross section, but not the ionization cross section. We also measured the second IP for all species and the third IP for two of them, all are in good agreement with theoretical ones confirming that PAH cations can be further ionized in the diffuse ISM. Determining actual PAH dication abundances in the ISM will require detailed modeling. Our measured photo-ionization yields for several PAH cations provide a necessary ingredient for such models.
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Affiliation(s)
- Junfeng Zhen
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Sarah Rodriguez Castillo
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - Christine Joblin
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Giacomo Mulas
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
- Istituto Nazionale di Astrofisica - Osservatorio Astronomico di Cagliari, via della Scienza 5, 09047 Selargius (CA), Italy
| | - Hassan Sabbah
- Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
- CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, 31028, Toulouse Cedex 4, France
| | - Alexandre Giuliani
- Synchrotron SOLEIL, LOrme des Merisiers, 91192 Gif sur Yvette Cedex, France
- INRA, UAR1008 Caractérisation et Elaboration des Produits Issus de l’Agriculture, 44316 Nantes, France
| | - Laurent Nahon
- Synchrotron SOLEIL, LOrme des Merisiers, 91192 Gif sur Yvette Cedex, France
| | - Serge Martin
- Institut Lumière Matière, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Jean-Philippe Champeaux
- Laboratoire Collisions Agrégats Réactivité, Université de Toulouse, UPS-IRSAMC, CNRS, 118 Route de Narbonne, Bat 3R1B4, 31062 Toulouse Cedex 9, France
| | - Paul M. Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada
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Julian JP, Wilgruber NA, de Beurs KM, Mayer PM, Jawarneh RN. Long-term impacts of land cover changes on stream channel loss. Sci Total Environ 2015; 537:399-410. [PMID: 26282774 DOI: 10.1016/j.scitotenv.2015.07.147] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/23/2015] [Accepted: 07/29/2015] [Indexed: 06/04/2023]
Abstract
Land cover change and stream channel loss are two related global environmental changes that are expanding and intensifying. Here, we examine how different types and transitions of land cover change impact stream channel loss across a large urbanizing watershed. We present historical land cover in the 666-km(2) Lake Thunderbird watershed in central Oklahoma (USA) over a 137 year period and coinciding stream channel length changes for the most recent 70 years of this period. Combining these two datasets allowed us to assess the interaction of land cover changes with stream channel loss. Over this period, the upper third of the watershed shifted from predominantly native grassland to an agricultural landscape, followed by widespread urbanization. The lower two-thirds of the watershed changed from a forested landscape to a mosaic of agriculture, urban, forest, and open water. Most channel length lost in the watershed over time was replaced by agriculture. Urban development gradually increased channel loss and disconnection from 1942 to 2011, particularly in the headwaters. Intensities of channel loss for both agriculture and urban increased over time. The two longest connected segments of channel loss came from the creation of two large impoundments, resulting in 46 km and 25 km of lost stream channel, respectively. Overall, the results from this study demonstrate that multiple and various land-use changes over long time periods can lead to rapid losses of large channel lengths as well as gradual (but increasing) losses of small channel lengths across all stream sizes. When these stream channel losses are taken into account, the environmental impacts of anthropogenic land-use change are compounded.
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Affiliation(s)
- Jason P Julian
- Texas State University, Department of Geography, 601 University Drive, ELA 139, San Marcos, TX 78666, United States.
| | - Nicholas A Wilgruber
- University of Oklahoma, Department of Geography & Environmental Sustainability, 100 East Boyd St., Norman, OK 73019, USA
| | - Kirsten M de Beurs
- University of Oklahoma, Department of Geography & Environmental Sustainability, 100 East Boyd St., Norman, OK 73019, USA
| | - Paul M Mayer
- U.S. Environmental Protection Agency, National Health and Environmental Effects Research Lab, Western Ecology Division, 200 SW 35th Street, Corvallis, OR 97333, USA
| | - Rana N Jawarneh
- Yarmouk University, Department of Geography, P.O. Box 21163, Irbid, Jordan
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Berland K, Renaud JB, Mayer PM. Utilizing ion mobility and tandem mass spectrometry to evaluate the structure and behaviour of multimeric cyclodextrin complexes. CAN J CHEM 2015. [DOI: 10.1139/cjc-2014-0419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Characterizing noncovalent complexes of molecular dimers and higher complexes using tandem mass spectrometry (MS/MS) can be hindered due to spectral overlap in both the MS and the MS/MS. We investigated the structures and dissociation energetics of multimeric β-cyclodextrin (β-CD) complexes alone or with substrates using combinations of ion mobility spectrometry (IMS), MS/MS, and Rice–Ramsperger–Kassel–Marcus (RRKM) unimolecular rate modelling. The doubly charged β-CD dimers ([(β-CD)2 – 2H+]2−) dissociate to two [β-CD – H+]− ions with the same m/z. IMS was used to separate source generated [(β-CD)2 – 2H+]2− from [β-CD – H+]− and the extent of [(β-CD)2 – 2H+]2− dissociation versus collision energy was determined by modelling changes in the ion’s isotopic profile. The RRKM derived critical energy (E0) for dissociation of [(β-CD)2 – H+]− and [(β-CD)2 – 2H+]2− were 1.85 ± 0.11 eV and 1.79 ± 0.09 eV, respectively, corresponding to a slight decrease in complex stability due to increased charge–charge repulsion in the dianion. This approach was extended to include dimeric complexes complexed to 4,4′-(propane-1,3-diyl) dibenzoic acid (PDDA) and ibuprofen (Ibu).
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Affiliation(s)
- Kevin Berland
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Justin B. Renaud
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Paul M. Mayer
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
- Chemistry Department, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada
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Mayer PM, Pratt DA. Advances and applications in physical organic chemistry. Papers from the 22nd IUPAC International Conference on Physical Organic Chemistry, Ottawa, Canada, 10–15 August 2014. CAN J CHEM 2015. [DOI: 10.1139/cjc-2015-0405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Paul M. Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa
| | - Derek A. Pratt
- Department of Chemistry and Biomolecular Sciences, University of Ottawa
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Solano EA, Mayer PM. A complete map of the ion chemistry of the naphthalene radical cation? DFT and RRKM modeling of a complex potential energy surface. J Chem Phys 2015; 143:104305. [DOI: 10.1063/1.4930000] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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