Lead proposal with collaborative proposal 0651333 (Michael Plewa, UIUC)
This project seeks to investigate the formation, toxicity, and occurrence of nitrogenous disinfection by-products (N-DBPs) using three approaches: (1) bench-scale experiments investigating single and multiple disinfectants; (2) sampling of water treatment facilities; and (3) bench-scale in-vitro toxicity assays. N-DBPs of past and current interest consist primarily of low molecular weight compounds such as chloropicrin and N-nitrosodimethylamine (NDMA). However, concentrations of their amine precursors (e.g., mono- and dimethylamine) typically are two orders of magnitude lower in source waters than those of combined amino acids containing primary and secondary amines in their side chains. Formation of N-DBPs (e.g., nitrosated amino acids) from amino acid precursors thus may represent a significant human health risk if the toxicity (e.g., carcinogenic potential) of such compounds is similar to chloropicrin and NDMA. The project will evaluate disinfection schemes that minimize N-DBP formation. Utilities currently are altering their disinfection practices to reduce THM and HAA concentrations, and the results of this project will be useful to avoid schemes that promote the formation of more toxic DBPs.
