Overview
The McNeill Research Group studies chemical reactions in aquatic systems, focusing on detailed mechanisms of fate processes of organic molecules. The group develops and applies new methods in an effort to bring a deeper chemical understanding of aquatic systems. There is an additional emphasis on maintaining a broad range of expertise and project types in the group. Presently, there are projects in analytical chemistry (e.g., analysis of novel dioxins in sediments), laser spectroscopy (e.g., photochemical mechanisms), synthetic organic chemistry (e.g., preparation of molecular probes for reactive oxygen species), mechanistic inorganic chemistry (e.g., defluorination catalysis), and field studies.
Check out our group publications on Google Scholar.
Emerging contaminant photochemistry
Emerging classes of environmental contaminants, which often differ significantly from traditional legacy pollutant classes in their molecular properties, provide many significant research challenges. Pharmaceutical compounds in surface waters are a good example of this category of contaminants and represent a major research effort in our group. In collaboration with Prof. William Arnold (Univ. of Minnesota, Dept. of Civil and Environmental Engineering), we are developing mechanism-based models that will help predict the photochemical lifetimes of pharmaceuticals in natural systems. In addition to pharmaceuticals, we have ongoing projects on the degradation mechanisms of brominated flame retardant chemicals, and new classes of pesticides.
Representative Recent Publications
K. L. Platt, O. Yushchenko, J. R. Laszakovitz, Y. Zhang, N. A. Pflug, K. McNeill*, Aquatic Thermal and Photochemical Reactivity of N-(1,3-dimethylbutyl)-N’-(phenyl-p-phenylenediamine (6PPD), N-isopropyl-N’-(phenyl-p-phenylenediamine (IPPD), and 6PPD-quinone, Environ. Sci. Technol. 2025, 59, 12900-12909.
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Y. Cai, J. N. Apell, N. C. Pflug, K. McNeill, U. E. Bollmann, Photochemical fate of medetomidine in coastal and marine environments, Water Research 2021, 116791.
R. U. Halden, A. E. Lindeman, A. E. Aiello, D. Andrews, W. A. Arnold, P. Fair, R. E. Fuoco, L. A. Geer, P. I. Johnson, R. Lohmann, K. McNeill, V. P. Sacks, T. Schettler, R. Weber, R. R. Zoeller, A. Blum, The Florence Statement on Triclosan and Triclocarban, Environ. Health Persp. 2017, 125, DOI:10.1289/EHP1788.
C. Davis, P. R. Erickson, K. McNeill, E. M.-L. Janssen, Environmental Photochemistry of Fenamate NSAIDs Environ. Sci. Processes Impacts 2017, 19, 656-665
K. H. Wammer, K. C. Anderson, P. R. Erickson, S. Kliegman, M. E. Moffatt, S. M. Berg, J. A. Heitzman, N. C. Pflug, K. McNeill, D. Martinovic-Weigelt, R. Abagyan, D. M. Cwiertny, E. P. Kolodziej, Environmental Photochemistry of Altrenogest: Photoisomerization to a Bioactive Product with Increased Environmental Persistence via Reversible Photohydration, Environ. Sci. Technol. 2016, 40, 7480-7488.
Photochemistry of natural organic matter
A major area of interest in our group is the photochemistry of natural organic matter (NOM), including the production and consumption of reactive oxygen species (ROS) from the photochemical and non-photochemical reactions of NOM. Projects in this area include studying the photochemistry and the sulfur cycle, developing detection methods for ROS, studying the spatial distribution of these species in natural waters, and understanding how they interact with their precursor material, natural organic matter.
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Representative Recent Publications
S. B. Partanen, K. McNeill, Global corrections to reference irradiance spectra for non-clear-sky conditions, Environ. Sci. Technol. 2023, 57, 2682-2690.
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R. Ossola, R. Gruseck, J. Houska, A. Manfrin, M. Vallieres, K. McNeill, Photochemical production of carbon monoxide from dissolved organic matter: The role of lignin methoxyarene functional groups, Environ. Sci. Technol. 2022, 56, 13449-13460.
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S. B. Partanen, J. N. Apell, J. Lin, K. McNeill, Factors affecting the mixed-layer concentrations of singlet oxygen in sunlit lakes, Environ. Sci. Processes Impacts 2021, 23, 1130-1145.
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R. Ossola, O. M. Jönsson, K. J. Moor, K. McNeill, Singlet Oxygen Quantum Yields in Environmental Waters, Chem. Rev. 2021, 121, 4100 - 4146.
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R. Ossola, B. Clerc, K. McNeill, Mechanistic insights into dissolved organic sulfur photomineralization through the study of cysteine sulfinic acid, Environ. Sci. Technol. 2020, 54, 13066-13076.
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R. Ossola, J. Tolu, B. Clerc., P. R. Erickson, L. H. E. Winkel, K. McNeill, Photoproduction of sulfate and methanesulfonic acid from dissolved organic sulfur, Environ. Sci. Technol. 2019, 53, 13191–13200.
G. McKay, J. A. Korak, P. R. Erickson, D. E. Latch, K. McNeill, F. L. Rosario-Ortiz, The case against charge transfer interactions in dissolved organic matter photophysics, Environ. Sci. Technol. 2018, 52, 406-414.
M. Schmitt, P. R. Erickson, K. McNeill, Triplet state dissolved organic matter quantum yields and lifetimes from direct observation of aromatic amine oxidation, Environ. Sci. Technol. 2017, 51, 13151-13160.
V. S. Lin, M. Grandbois, K. McNeill, Fluorescent molecular probes for detection of one-electron oxidants photochemically generated by dissolved organic matter, Environ. Sci. Technol. 2017, 51, 9033 - 9041.
E. Appiani, R. Ossola, D. E. Latch, P. R. Erickson, K. McNeill, Aqueous singlet oxygen reaction kinetics of furfuryl alcohol: Effect of temperature, pH, and salt content, Environ. Sci. Processes Impacts 2017, 19, 507-516.
K. McNeill, S. Canonica, Triplet state dissolved organic matter in aquatic photochemistry: Reaction mechanisms, substrate scope, and photophysical properties, Environ. Sci. Processes Impacts 2016, 18, 1381-1399.​​
Chemical products of the future
Part of our research group concerns itself with chemical products that are thought to increase in significance in the coming decades. Two classes of chemicals that we are currently studying are fluorocarbons and biodegradable polymers, in collaboration with Dr. Michael Sander, who leads the polymer project. In both of these cases, there is expected to be major growth in the production and use of these compound classes, and there is limited knowledge about their environmental behavior. Whether fluorocarbons follow the same trajectory as chlorocarbons and become widespread persistent organic pollutants remains an open question. Nevertheless, we are seeking remediation solutions for these compounds in anticipation of contaminated sites in the future. In the case of biodegradable polymers, these are materials that have been specifically designed to limit their environmental impact and are therefore have potential to replace conventional polymers in various applications. Even so, it is important to study the environmental fate of these materials before their use increases.
Representative Recent Publications
T. F. Mundhenke, M. G. Balestra, C. R. Scholtz, J. R. Laszakovits, S. Ambrogetti, K. McNeill, W. C. K. Pomerantz, W. A. Arnold, Stranger Rings: How Heteroarenes and Degree of Methyl Group Fluorination Affect Photolysis Kinetics and Fluorinated Product Formation, Environ. Sci. Technol. 2025, 59, 25010–25021.
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T. F. Nelson, R. Baumgartner, M. Jaggi, S. M. Bernasconi, G. Battagliarin, C. Sinkel, A. Künkel, H.-P. Kohler, K. McNeill, M. Sander, Biodegradation of synthetic aliphatic-aromatic polyesters in soils: linking chemical structure to biodegradability, Environ. Sci. Technol. 2025, 59, 19966–19977.
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K. Kleemann, M. Jaggi, S. Bernasconi, R. Schmitz, G. Battagliarin, A. Künkel. C. Simon, K. McNeill, M. Sander, Photochemical Chain Scissions Enhance Polyethylene Glycol Biodegradability: From Probabilistic Modelling to Experimental Demonstration, Environ. Sci. Technol. 2025, 59, 17773-17784.
M. T. Zumstein, A. Schintlmeister, T. F. Nelson, R. Baumgartner, D. Woebken, M. Wagner, H.-P. E. Kohler, K. McNeill, M. Sander, Biodegradation of synthetic polymers in soils: tracking carbon into CO2 and microbial biomass, Science Advances 2018, 4, aas9024.
G. X. De Hoe, M. T. Zumstein, B. J. Tiegs, J. P. Brutman, K. McNeill, M. Sander, G. W. Coates, M. A. Hillmyer, Sustainable Polyester Elastomers from Lactones: Synthesis, Properties, and Enzymatic Hydrolyzability. J. Am. Chem. Soc. 2018, 140, 963 - 973.
L. Schinkel, S. Lehner, M. Knobloch, P. Lienemann, C. Bogdal, K. McNeill, N. V. Heeb, Transformation of chlorinated paraffins to olefins during metal work and thermal exposure – Deconvolution of mass spectra and kinetics, Chemosphere, 2018, 194, 803–811.
M. T. Zumstein, D. Rechsteiner, N. Roduner, V. Perz, D. Ribitsch, G. M. Guebitz, H.-P. Kohler, K. McNeill, M. Sander, Enzymatic hydrolysis of polyester thin films at the nanoscale: effects of polyester structure and enzyme active-site accessibility, Environ. Sci. Technol. 2017, 51, 7476–7485.
L. Schinkel, S. Lehner, N. Heeb, P. Lienemann, K. McNeill, C. Bogdal, Deconvolution of mass spectral interferences of chlorinated alkanes and their thermal degradation products: chlorinated alkenes, Analytical Chemistry 2017, 89, 5923-5931.
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M. T. Zumstein, H.-P. E. Kohler, K. McNeill, M. Sander, High-throughput analysis of enzymatic polyester hydrolysis by monitoring co-hydrolysis of a polyester-embedded fluorogenic probe, Environ. Sci. Technol. 2017, 51, 4358–4367.
R. Baumgartner, G. Stieger, K. McNeill, Complete Hydrodehalogenation of Polyfluorinated and other Polyhalogenated Benzenes under Mild Catalytic Conditions, Environ. Sci. Technol., 2013, 47, 6545-6553.
R. Baumgartner, K. McNeill, Hydrodefluorination and hydrogenation of fluorobenzene under mild aqueous conditions Environ. Sci. Technol., 2012, 46, 10199–10205.
Photochemistry of amino acids and peptides
Amino acids are central building blocks of life and a key component of the global nitrogen cycle. The environmental fate processes of amino acids thus play an important role in biogeochemistry, but are as of yet poorly defined. We have several projects focused on defining the important fate processes of amino-acid based biomolecules in the environment. These projects cover amino acids at different levels of organization, from individual amino acids to intact proteins and further to protein assemblies in virus capsids.
Representative Recent Publications
R. Ossola, B. Clerc, K. McNeill, Mechanistic insights into dissolved organic sulfur photomineralization through the study of cysteine sulfinic acid, Environ. Sci. Technol. 2020, 54, 13066-13076.
C. Chu, D. Stamatelatos, K. McNeill, Aquatic photochemical transformations of natural peptidic thiols: Impact of thiol properties, solution pH, solution salinity and metal ions, Environ. Sci. Processes Impacts, 2017, 19, 1518 - 1527.
C. Chu, P. R. Erickson, R. A. Lundeen, D. Stamatelatos, P. J. Alaimo, D. E. Latch, K. McNeill, Photochemical and non-photochemical transformations of cysteine with dissolved organic matter, Environ. Sci. Technol., 2016, 50, 6363-6373.
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R. A. Lundeen, C. Chu, M. Sander, K. McNeill, Photooxidation of the antimicrobial, nonribosomal peptide bacitracin A by singlet oxygen under environmentally relevant conditions, Environ. Sci. Technol. 2016, 60, 8586-8595.
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C. Chu, R. A. Lundeen, M. Sander, K. McNeill, Assessing the indirect photochemical transformation of dissolved combined amino acids through the use of systematically designed histidine-containing oligopeptides, Environ. Sci. Technol. 2015, 49, 12798-12807.
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C. Chu, R. A. Lundeen, C. K. Remucal, M. Sander, K. McNeill, Enhanced indirect photochemical transformation of histidine and histamine through association with chromophoric dissolved organic matter, Environ. Sci. Technol. 2015, 49, 5511-5519.
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E. M.-L. Janssen, K. McNeill, Environmental photoinactivation of extracellular phosphatase and the effects of dissolved organic matter, Environ. Sci. Technol. 2015, 49, 889-896.