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Tracking Water Disinfection By-Product Formation by Multi-Element Isotope Fractionation Analysis

English title Tracking Water Disinfection By-Product Formation by Multi-Element Isotope Fractionation Analysis
Applicant Hofstetter Thomas
Number 140545
Funding scheme Project funding
Research institution Umweltchemie Eawag
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Other disciplines of Environmental Sciences
Start/End 01.08.2012 - 31.07.2016
Approved amount 270'689.00
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All Disciplines (2)

Discipline
Other disciplines of Environmental Sciences
Hydrology, Limnology, Glaciology

Keywords (11)

ozonation; isotope fractionation; wastewater; Compound-specific isotope analysis; nitrosamines; kinetic isotope effect; drinking water; disinfection by-product; water treatment; chloramination; water disinfection

Lay Summary (English)

Lead
Lay summary

Maintaining the quality of raw waters and wastewaters and providing access to safe drinking water are some of the major environmental issues. While chemical disinfection through chlorination, chloramination, and ozonation are widely used methods for pathogen elimination, these approaches can give rise to potentially toxic disinfection by-products (DBPs) through reactions of the disinfectant with organic material and aquatic micropollutants. Unfortunately, the pathways leading to DBPs are poorly understood and it is currently impossible to assess the DBP formation kinetics and potential in raw waters and wastewaters by characterizing organic precursors and inorganic solutes. Moreover, even though a large number of chlorinated and N-containing DBPs including trihalomethanes, haloacetic acids, N-nitrosamines is known, only a minor share can be attributed to identifiable precursors. Novel approaches are therefore required to elucidate the reaction kinetics and pathways of disinfectants with natural organic matter and organic micropollutant leading to toxic DBPs and to develop methods that allow for predicting DBP formation potentials. One innovative approach, which we intend to pursue with the proposed project, is to obtain a reaction-related characterization of the functional groups responsible for DBPs from the use of isotope effects (i) as probes for reactive precursor moieties and (ii) as means to elucidate the mechanisms of DBP formation.

Over the last years, we have been able to show how C, H, and N-kinetic isotope effects pertinent to chemical reactions can be applied to elucidate transformation mechanisms of organic micropollutants via identification of the chemical bonds and functional groups involved therein. In the proposed study, we build on this knowledge and aim at using compound-specific isotope analysis to infer isotope effects and reaction mechanisms leading to the highly carcinogenic N-nitrosodimethylamine (NDMA) from natural and anthropogenic precursor materials. We will develop model systems for drinking water and wastewater disinfection/oxidation with ozone, chlorine, and chloramine, in which we can study a combination of C, H, N, and O isotope fractionation of NDMA, selected precursor materials, as well as other water constituents and reaction intermediates. Our approach is based on the investigation of three proposed pathways of NDMA formation via (a) a hypohalous acid induced ozonation of sulfamides, (b) nitrosation, and (c) dimethylhydrazine-mediated process. These pathways are very likely to produce NDMA in reactions giving rise to distinctly different isotope effects. Isotope fractionation trends in NDMA will be used to identify the pathways and precursors responsible for NDMA during disinfection/oxidation of micropollutant-containing raw waters and wastewater effluents. Scientific evidence obtained in this project will contribute to an improved assessment of the NDMA formation potential in waters from various sources and will aid in developing improved control strategies.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Carbon, Hydrogen, and Nitrogen Isotope Fractionation Trends in N -Nitrosodimethylamine Reflect the Formation Pathway during Chloramination of Tertiary Amines
Spahr Stephanie, von Gunten Urs, Hofstetter Thomas B. (2017), Carbon, Hydrogen, and Nitrogen Isotope Fractionation Trends in N -Nitrosodimethylamine Reflect the Formation Pathway during Chloramination of Tertiary Amines, in Environmental Science & Technology, 51(22), 13170-13179.
Formation of N -Nitrosodimethylamine during Chloramination of Secondary and Tertiary Amines: Role of Molecular Oxygen and Radical Intermediates
Spahr Stephanie, Cirpka Olaf A., von Gunten Urs, Hofstetter Thomas B. (2016), Formation of N -Nitrosodimethylamine during Chloramination of Secondary and Tertiary Amines: Role of Molecular Oxygen and Radical Intermediates, in Environmental Science & Technology, 51(1), 280-290.
Compound-specific carbon, nitrogen, and hydrogen isotope analysis of \emph{N}-nitrosodimethylamine in aqueous solutions
Spahr Stephanie, Bolotin Jakov, Schleucher Jürgen, Ehlers Ina, von Gunten Urs, Hofstetter Thomas (2015), Compound-specific carbon, nitrogen, and hydrogen isotope analysis of \emph{N}-nitrosodimethylamine in aqueous solutions, in Analytical Chemistry, 87(5), 2916-2924.

Collaboration

Group / person Country
Types of collaboration
Prof. Stefano M. Bernasconi Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Prof. Jürgen Schleuer Sweden (Europe)
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Jahrestagung der Arbeitsgemeinschaft Stabile Isotope e.V. Talk given at a conference C, N, and H isotope analysis of N-nitrosodimethylamine (NDMA) 15.10.2015 München, Germany Hofstetter Thomas; von Gunten Urs; Spahr Stephanie;
Jahrestagung der Arbeitsgemeinschaft Stabile Isotope e.V. Poster Can Changes in the Natural Isotopic Composition of NDMA Provide New Insights into Its Formation Pathway? 28.09.2015 Heidelberg, Germany Hofstetter Thomas; von Gunten Urs; Spahr Stephanie;
Gordon Research Conference on Drinking Water Disinfection By-Products Poster Can Changes in the Natural Isotopic Composition of NDMA Provide New Insights into Its Formation Pathway? 09.08.2015 South Hadley, MA, United States of America Hofstetter Thomas; von Gunten Urs; Spahr Stephanie;
Gordon Research Seminar on Drinking Water Disinfection By-Products Talk given at a conference Can Changes in the Natural Isotopic Composition of NDMA Provide New Insights into Its Formation Pathway? 08.08.2015 South Hadley, MA, United States of America von Gunten Urs; Hofstetter Thomas; Spahr Stephanie;
PhD congress of the Institute of Biogeochemistry and Pollutant Dynamics, Eawag Poster Compound-specific isotope analysis of N-nitrosodimethylamine (NDMA) 10.04.2015 Dübendorf, Switzerland von Gunten Urs; Hofstetter Thomas; Spahr Stephanie;
National Meeting of the American Chemical Society, Division of Environmental Chemistry Talk given at a conference Tracking NDMA formation during water disinfection processes by multi-element isotope fractionation analysis 10.08.2014 San Francisco, United States of America von Gunten Urs; Spahr Stephanie; Hofstetter Thomas;
Gordon Research Conference (GRC) on Environmental Science Water Poster Tracking N-nitrosodimethylamine formation during water disinfection processes by multi-element isotope fractionation analysis 22.06.2014 Holderness, NH, United States of America von Gunten Urs; Spahr Stephanie; Hofstetter Thomas;
PhD congress of the Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich Poster Tracking NDMA formation during water disinfection processes by multi-element isotope fractionation analysis 25.04.2014 Zürich, Switzerland Spahr Stephanie; Hofstetter Thomas;
GRC Isotope Effects in Chemical and Biological Sciences Poster Tracking N-nitrosodimethylamine formation during water disinfection processes by multi-element isotope fractionation analysis 02.02.2014 Galveston, TX, United States of America Spahr Stephanie; Hofstetter Thomas; von Gunten Urs;


Awards

Title Year
American Chemical Society (ACS) Disinfection By-Product Symposium Student Oral Presentation Winners 2014
American Chemical Society (ACS) Travel Award 2014

Associated projects

Number Title Start Funding scheme
172950 Biodegradation of organic pollutants by mono- and dioxygenation: Insights into rates and mechanisms from isotope effects of oxygen activation and substrate oxygenation 01.03.2018 Project funding
116447 Using nitrogen isotope fractionation to assess redox reactions of organic contaminants 01.03.2008 Project funding
134720 Using nitrogen isotope fractionation to assess redox reactions of organic contaminants 01.04.2011 Project funding

Abstract

Maintaining the quality of raw waters and wastewaters and providing access to safe drinking water are some of the major environmental issues. While chemical disinfection through chlorination, chloramination, and ozonation are widely used methods for pathogen elimination, these approaches can give rise to potentially toxic disinfection by-products (DBPs) through reactions of the disinfectant with organic material and aquatic micropollutants. Unfortunately, the pathways leading to DBPs are poorly understood and it is currently impossible to assess the DBP formation kinetics and potential in raw waters and wastewaters by characterizing organic precursors and inorganic solutes. Moreover, even though a large number of chlorinated and N-containing DBPs including trihalomethanes, haloacetic acids, N-nitrosamines is known, only a minor share can be attributed to identifiable precursors. Novel approaches are therefore required to elucidate the reaction kinetics and pathways of disinfectants with natural organic matter and organic micropollutant leading to toxic DBPs and to develop methods that allow for predicting DBP formation potentials. One innovative approach, which we intend to pursue with the proposed project, is to obtain a reaction-related characterization of the functional groups responsible for DBPs from the use of isotope effects (i) as probes for reactive precursor moieties and (ii) as means to elucidate the mechanisms of DBP formation.In our preceding, SNF-funded project (no. 200020-116'447/134'720), we have shown how 13C-, 2H-, and 15N-kinetic isotope effects pertinent to chemical reactions can be applied to elucidate transformation mechanisms of organic micropollutants via identification of the chemical bonds and functional groups involved therein. In the proposed study, we build on this knowledge and aim at using compound-specific isotope analysis to infer isotope effects and reaction mechanisms leading to the highly carcinogenic N-nitrosodimethylamine (NDMA) from natural and anthropogenic precursor materials. To this end, we will develop model systems for drinking water and wastewater disinfection/oxidation with ozone, chlorine, and chloramine, in which we can study a combination of C, H, N, and O isotope fractionation of NDMA, selected precursor materials, as well as other water constituents and reaction intermediates. Our approach is based on the investigation of three proposed pathways of NDMA formation via (a) a hypohalous acid induced ozonation of sulfamides, (b) nitrosation, and (c) dimethylhydrazine-mediated process. These pathways are very likely to produce NDMA in reactions giving rise to distinctly different isotope effects. Isotope fractionation trends in NDMA will be used to identify the pathways and precursors responsible for NDMA during disinfection/oxidation of micropollutant-containing raw waters and wastewater effluents. Scientific evidence obtained in this project will contribute to an improved assessment of the NDMA formation potential in waters from various sources and will aid in developing improved control strategies.
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