Evaluation of Functional Groups Responsible for Chloroform Formation during Water Chlorination Using Compound Specific Isotope Analysis

Compound-specific isotope analysis was used to monitor the delta C-13 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 Zurich water also had a inverse effect (0.997 +/-