title: Formation, precursors, control, and occurrence of nitrosamines in drinking water: a review.
abstract: This review summarizes major findings over the last decade related to nitrosamines in drinking water, with a particular focus on N-nitrosodimethylamine (NDMA), because it is among the most widely detected nitrosamines in drinking waters. The reaction of inorganic dichloramine with amine precursors is likely the dominant mechanism responsible for NDMA formation in drinking waters. Even when occurrence surveys found NDMA formation in chlorinated drinking waters, it is unclear whether chloramination resulted from ammonia in the source waters. NDMA formation has been associated with the use of quaternary amine-based coagulants and anion exchange resins, and wastewater-impaired source waters. Specific NDMA precursors in wastewater-impacted source waters may include tertiary amine-containing pharmaceuticals or other quaternary amine-containing constituents of personal care products. Options for nitrosamine control include physical removal of precursors by activated carbon or precursor deactivation by application of oxidants, particularly ozone or chlorine, upstream of chloramination. Although NDMA has been the most prevalent nitrosamine detected in worldwide occurrence surveys, it may account for only ≈ 5% of all nitrosamines in chloraminated drinking waters. Other significant contributors to total nitrosamines are poorly characterized. However, high levels of certain low molecular weight nitrosamines have been detected in certain Chinese waters suspected to be impaired by industrial effluents. The review concludes by identifying research needs that should be addressed over the next decade.
authors.affiliation: Metropolitan Water District of Southern California, 700 Moreno Avenue, La Verne, CA 91750, USA. skrasner@mwdh2o.com
authors.forename: Stuart W
authors.initials: SW
authors.lastname: Krasner
authors.forename: William A
authors.initials: WA
authors.lastname: Mitch
authors.forename: Daniel L
authors.initials: DL
authors.lastname: McCurry
authors.forename: David
authors.initials: D
authors.lastname: Hanigan
authors.forename: Paul
authors.initials: P
authors.lastname: Westerhoff
mesh_terms: D060766:Drinking Water / Q000737:chemistry*; D009602:Nitrosamines / Q000737:chemistry* / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D060766:Drinking Water; D009602:Nitrosamines; D014874:Water Pollutants, Chemical
keywords: Chloramination; Disinfection by-products; Drinking water; NDMA; Nitrosamines; Wastewater; polyDADMAC