Department Environmental Chemistry

Tracking the formation of drinking water disinfection byproduct with stable isotopes

N-nitrosamines such as N-nitrosodimethylamine (NDMA) are of public and regulatory concern because these potent carcinogens can be formed as unintented by-products during drinking and waste water disinfection/oxidation.

Numerous compounds have been identified as precursors that lead to NDMA, once source waters are treated by chlorine, chloramine, or ozone. Unfortunately, the understanding of the mechanisms of N-nitrosamine formation is limited thus making it difficult to predict NDMA formation potentials of water constituents and to develop efficient mitigation strategies.

Our project aims at revealing typical pathways of N-nitrosamine formation from temporal variations of the natural abundance of stable C, N, and H isotope ratios of NDMA. The central hypothesis is that reactions leading to NDMA exhibit distinctly different kinetic isotope effects, which are revealed in the isotope fractionation of evolving NDMA.

Reprinted with permission from (Spahr et al, Anal. Chem. 2015, 2916). Copyright (2015) American Chemical Society.