Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $5,000 Total Non-Federal Funds: $10,204
Principal Investigators: Julian Fairey
Abstract: This proposal for a student research supplement is aimed at elucidating a novel reaction pathway for N-nitrosamine formation. N-nitrosamines are a non-halogenated group of disinfection byproducts (DBPs) that are acknowledged carcinogens at realistic exposure concentrations in drinking water. Although N-nitrosamines are comprised of approximately 200 individual species, occurrence data has been limited to the seven species (EPA7N) listed in EPA Method 521. Of the EPA7N species, N-nitrosodimethylamine (NDMA) is the most prevalent, occurring in approximately 10% of US drinking water systems, many of which that use chloramines. As a result, N-nitrosamines are under consideration for regulation at low ng/L levels, and five of the EPA7N species, including NDMA, are listed on the EPA Contaminant Candidate List 3. This proposed research supplement supports an ongoing 104B-funded project (2014AR349B) in which a method was developed and validated to quantify total N-nitrosamines (TONO, i.e., all 200 species in aggregate). The objective of this proposal is to leverage the TONO method to elucidate a novel reaction pathway for N-nitrosamine formation, hypothesized to involve a previously unidentified reaction intermediate prevalent in nitrification. A series of kinetic experiments will be completed using a reductionist approach to elucidate the role of nitroxyl in TONO formation. Batch kinetic tests will be completed on 500 mL samples to assess the role of pH (to probe the roles of dichloramine and monochloramine), hydroxylamine, and dissolved oxygen in the formation of TONO.