AWWA ACE71095

This powerpoint presentation begins by providing a brief overview of NDMA and other nitrosamines. A current study is presented by covering the following topics: EPSRC-funded, Sept 2007-Sept 2009 (extended to Feb 2010); six water treatment works, five United Kingdom water companies; lowland, upland, groundwater sources; chloraminated and chlorinated systems, amine-based coagulants; source waters with elevated N content and/or organic content; raw, filtered, disinfected, distributed water samples; seasonal sampling (four intervals in 2008, one in 2009); NDMA, NMEA, NDEA, NDPA, NDBA, NPYR, NPIP, NMOR; method - SPE + GC/MS; source water quality characterization; and, QA/QC comparison analysis by another university lab and by a certified commercial lab in the United Kingdom. Study summary and ongoing work indicates that: NDMA and other nitrosamines not detected in the vast majority of samples; first round of sampling (February 2008) exhibited higher nitrosamine levels than in subsequent rounds - cause uncertain, not seen again in February 2009 round; NDBA consistently above the MDL in one of the distribution systems; no consistent relationship between nitrosamine levels and contact time in the distribution network; no observed link between nitrosamine levels and source water characteristics or particular treatment processes; nitrosamine formation studies to be completed in the lab later this year - formation by various combinations of disinfectants (NH₄Cl, HOCl, UV, O₃) under different water quality conditions. Includes tables, figures.