Water Resources Research Act Program

Details for Project ID 2007NE151B

Formation of N-Nitrosamine and Hydrazine Derivatives of Pesticides and Pharmaceuticals During Disinfection of Drinking Water and Wastewater

Institute: Nebraska
Year Established: 2007 Start Date: 2007-03-01 End Date: 2008-02-29
Total Federal Funds: $19,210 Total Non-Federal Funds: $43,665

Principal Investigators: Patrick Shea

Project Summary: N-nitrosamines are potentially carcinogenic compounds and hydrazine is a highly reactive base and reducing agent that can be highly carcinogenic and mutagenic. Recent research indicates that these toxins can form from the reaction of secondary or tertiary amines with chloramine, which is becoming the preferred treatment for disinfecting drinking water and wastewater. Some pharmaceuticals used by humans and in the livestock industry are secondary (or tertiary) amines. While pharmaceuticals are often metabolized before they are excreted, others are only moderately or poorly metabolized and some are excreted completely intact. Several pesticides, such as the widely-used herbicide atrazine are also secondary amines. Pharmaceuticals, pesticides, and their metabolites enter municipal sewage and water treatment plants. If these compounds and their metabolites are not eliminated during treatment, they may remain as contaminants of drinking water or may enter the environment with treated waste effluent. In related research, we evaluated the potential formation of N-nitrosamines from atrazine and nine secondary amine pharmaceuticals from reaction with nitrite under acidic conditions (simulating the human stomach). We have evidence supporting the formation N-nitrosamine derivatives of atrazine, ethambutol, furosemide, metoprolol, procainamide and ranitidine, while cefadroxil, chlorpheneramine, diphenhydramine, metoprolol, and propranolol did not react. Thus, the reactivity of these contaminants varies and we expect similar variability in their reactions with chloramine, nitrite, and hypochlorous acid. Our project will extend the research on the reactions of chloramines with dimethylamine by Valentine and associates at the University of Iowa and by Mitch and associates at Yale to include secondary and tertiary amine pesticides and pharmaceuticals. We will determine: (1) formation of N-nitrosamine and hydrazine derivatives from exposure of secondary or tertiary amine pharmaceuticals and pesticides to (a) chloramine and (b) nitrite and hypochlorous acid; (2) the effects of pH, redox, metal/nonmetal salts, and dissolved organic matter on these reactions; and (3) the stability of the N-nitrosamine and hydrazine derivatives in treated water and their decomposition products. Laboratory experiments will be conducted following the general procedures of Valentine and associates and by Mitch and associates. In the initial tests, deionized, distilled water will be amended with the pharmaceuticals and pesticides of interest and treated with chloramine (prepared by reaction of sodium hypochlorite with ammonium sulfate solution) or with sodium hypochlorite in the presence of nitrite and selected metal and non-metal salts. Solution pH will be adjusted (buffered) to reflect that typical of finished drinking water and acidic to alkaline wastewaters (approximately pH 5-9). Where the formation of hydrazine and/or N-nitrosamine derivatives is observed, additional experiments will be conducted with treated drinking water or wastewater. The chloramination treatment strategies reported by Mitch and associates to reduce the formation of N-nitrosodimethylamine will be evaluated concerning the formation of N-nitrosated pesticides and pharmaceuticals. Nitrosamine and hydrazine derivatives of the pesticides and pharmaceuticals (and other products) will be identified and quantified by HPLC, LC/MS/MS, or GC/MS using documented procedures or methods developed in our laboratories. We expect that some of the secondary and tertiary amine pharmaceuticals and pesticides will react under the imposed water treatments, producing N-nitrosamine derivatives. Hydrazine intermediates may be found in some of these reactions and these compounds may similarly vary in their stability depending on treatment conditions. Research results will identify potentially hazardous products of chloramine-based disinfection treatment processes in water containing secondary or tertiary amine pesticides and pharmaceuticals. This information will provide guidance for treatment and mitigation protocols.