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    Evaluation of Functional Groups Responsible for Chloroform Formation during Water Chlorination Using Compound Specific Isotope Analysis
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    Department of Civil Engineering, University of Minnesota, 500 Pillsbury Dr. Southeast, Minneapolis, Minnesota 55455, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 133 Überlandstrasse, 8600, Dübendorf, Switzerland, and Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092, Zürich, Switzerland
    * Address correspondence to either author. Phone: 612-625-8582 (W.A.A); +41 44 632 8328 (T.B.H.). Fax: 612-626-7750 (W.A.A.); +41 44 633 11 22 (T.B.H.). E-mail: [email protected] (W.A.A.); [email protected] (T.B.H.).
    †University of Minnesota.
    ‡Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich.
    §Eawag, Swiss Federal Institute of Aquatic Science and Technology.
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    Environmental Science & Technology

    Cite this: Environ. Sci. Technol. 2008, 42, 21, 7778–7785
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    https://doi.org/10.1021/es800399a
    Published July 11, 2008
    Copyright © 2008 American Chemical Society
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    Abstract

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    Compound-specific isotope analysis was used to monitor the δ13C signature of chloroform produced upon the chlorination of model compounds representing natural organic matter functional groups (resorcinol, acetylacetone, acetophenone, phenol, and 2,4,6-trichlorophenol) and a natural water sample. For each model compound, a different apparent kinetic isotope effect was found for chloroform formation. Normal isotope effects were found for resorcinol, acetylacetone, and acetophenone, and ranged from 1.009 ± 0.002 to 1.024 ± 0.004. For the two phenols, an inverse effect was found (0.980 ± 0.004). Lake Zürich water also had a inverse effect (0.997 ± <0.001) indicating that phenols are likely chloroform precursors in NOM, but that other functional groups may also participate. The apparent 13C kinetic isotope effect for the addition/elimination reaction of 1,1,1-trichloropropanone mediated by OH− to yield chloroform is 1.014 ± 0.002. A comparison of this value to those found for the chlorination of the model precursors and an evaluation of the differences in chloroform production kinetics for the different model precursors argue against a mechanism in which all NOM precursors react via a common intermediate. Compound specific isotope analysis may give additional insights into chloroform formation mechanisms beyond those allowed by current techniques.

    Copyright © 2008 American Chemical Society

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    Supporting Information

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    Chloroform formation upon chlorination the acetophenone, acetylacetone, and 2,4,6-trichlorophenol, and the hydrolysis of 1,1,1-trichloropropanone; plot of ln RC vs ln C for 1,1,1-trichloropropanone. This material is available free of charge via the Internet at http://pubs.acs.org.

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    Cite this: Environ. Sci. Technol. 2008, 42, 21, 7778–7785
    Click to copy citationCitation copied!
    https://doi.org/10.1021/es800399a
    Published July 11, 2008
    Copyright © 2008 American Chemical Society
    Request reuse permissions

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