title: Occurrence of N-nitrosamines in U.S. freshwater sediments near wastewater treatment plants.
abstract: In the present study, 40 freshwater sediments collected near 14 wastewater treatment plants (WWTPs) across the United States were analyzed for eight N-nitrosamines by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Three N-nitrosamines were detected for the first time in freshwater sediments in units of ng/g dry weight at the specified detection frequency: N-nitrosodibutylamine (NDBA; 0.2-3.3; 58%), N-nitrosodiphenylamine (NDPhA; 0.2-4.7; 50%), and N-nitrosopyrrolidine (NPYR; 3.4-19.6; 18%). At least one N-nitrosamine was detected in 70% (28/40) of sediments analyzed. Non-detect values in units of ng/g dw were obtained for N-nitrosodimethylamine (NDMA; <10.2), N-nitrosomethylethylamine (NMEA; <1.7), N-nitrosodiethylamine (NDEA; <3.9), N-nitroso-di-n-propylamine (NDPA; <1.7), and N-nitrosopiperidine (NPIP; <3.6). Principal component analysis specifically points to two of multiple potential pathways explaining N-nitrosamine occurrences in sediment: NDBA and NDPhA were positively correlated with bulk water ammonia and pH levels, and NPYR with sediment content of organic carbon and iron. Interestingly, N-nitrosamine occurrences up- and downstream of WWTPs were statistically indistinguishable (p>0.05). This is the first report on the occurrence of the carcinogenic N-nitrosamines NDBA, NDPhA, and NPYR in U.S. freshwater sediments. Discovery of this phenomenon warrants further research on the compounds' origin, environmental persistence, aquatic toxicity, and risks posed.
authors.affiliation: Center for Environmental Security, The Biodesign Institute, Global Security Initiative, Arizona State University, 781 E. Terrace Mall, Tempe, AZ 85287, United States.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Gushgari
authors.affiliation: Center for Environmental Security, The Biodesign Institute, Global Security Initiative, Arizona State University, 781 E. Terrace Mall, Tempe, AZ 85287, United States. Electronic address: rolf.halden@asu.edu.
authors.forename: Rolf U
authors.initials: RU
authors.lastname: Halden
authors.affiliation: Center for Environmental Security, The Biodesign Institute, Global Security Initiative, Arizona State University, 781 E. Terrace Mall, Tempe, AZ 85287, United States.
authors.forename: Arjun K
authors.initials: AK
authors.lastname: Venkatesan
keywords: Environmental fate; N-Nitrosamine; Sediment contamination; Wastewater treatment plant