Seid, Mingizem Gashaw Son, Aseom Ejerssa, Wondesen Workneh Moon, Byeong Cheul Byun, Jeehye Hong, Seok Won 2026-01-13T06:30:04Z 2026-01-13T06:30:04Z 2026-01-12 2026-01 0304-3894 https://pubs.kist.re.kr/handle/201004/153976 With growing freshwater scarcity, alternative sources such as harvested rainwater, atmospheric water, and stormwater are attracting increasing attention. However, their use may pose health risks due to contamination and the formation of carcinogenic N-Nitrosamines. This study systematically evaluated the occurrence and formation potentials (FPs) of nine N-Nitrosamines detected in harvested waters. Five N-Nitrosamines—N-Nitrosodimethylamine, N-Nitrosodiethylamine, N-Nitrosomorpholine, N-Nitrosopyrrolidine, and N-Nitrosodibutylamine—were consistently detected (2.2–23.1 ng L⁻¹) or formed during chloramination at concentrations ranging from 3.7 to 40 ng L⁻¹ , while N-Nitrosomethylethylamine, N-Nitrosodipropylamine, and N-Nitrosodiphenylamine were detected exclusively in stormwater samples. N-Nitrosopiperidine appeared only sporadically at low levels in rainwater. Spatiotemporal variability was most pronounced in stormwater, where first-flush events caused sharp increases. Correlation analysis indicated that N-Nitrosamine-FPs were strongly influenced by metals and bromide, and were closely associated with secondary amines and hydrophilic dissolved organic nitrogen fractions. Estimated lifetime cancer risks from chloraminated waters (2.69 × 10⁻⁵ to 1.08 × 10⁻⁴) exceeded the USEPA negligible risk level of 1.0 × 10⁻⁶ by 27–370 times. Pretreatment strategies prior to chloramination showed contrasting performances. Sand filtration achieved little removal, while Mn(VII) and UV/NH2Cl sometimes increased N-Nitrosamine-FPs. In contrast, UV/HOCl achieved up to 90 % reduction under environmentally relevant conditions (oxidant dose ≤ 4 mg L⁻¹, UV fluence > 700 mJ cm⁻²), outperforming UV/H2O2, Fe(VI), and powdered activated carbon. Overall, harvested waters represent a significant N-Nitrosamine risk, but effective pretreatments can substantially mitigate formation. These findings highlight the need for integrated treatment and disinfection strategies to ensure safe water harvesting and reuse. English Elsevier BV Occurrence, formation, and treatment implications of N-Nitrosamine risks in harvested waters Article 10.1016/j.jhazmat.2025.140766 3 Journal of Hazardous Materials, v.501 Journal of Hazardous Materials 501 N 001641087000001 2-s2.0-105024233621 Engineering, Environmental Environmental Sciences Engineering Environmental Sciences & Ecology Article NDMA FORMATION NITROSODIMETHYLAMINE PRECURSORS FORMATION POTENTIALS OXIDATION MATTER RIVER N-Nitrosamine Harvested water Chloramination Disinfection byproducts Pretreatment strategies