ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2026
·
IF 12.2
Menglan Gao,Tingting Zhao,Xiaobin Liao,Tao Huan,Qiming Shen,K. N. Minh Chau,Di Zhang,Zhenkun Chen,Huatong Ma,Xing-Fang Li
N-Nitrosodimethylamine (NDMA) is a carcinogenic byproduct formed from nitrogen-containing organics during water disinfection. Identifying its precursors in source water is necessary for reducing or eliminating NDMA formation. Previous studies focused on model precursors with a dimethylamine group (DMA: −N(CH3)2), missing precursors without DMA that can form NDMA during chloramination. Here, we aimed to develop a new approach enhancing the discovery of various NDMA precursors. By analyzing MS/MS spectra of 39 model NDMA precursors, we identified three diagnostic fragment ions: [C2H6N]+, [C2H7N]•+, and [C2H8N]+. Using these fragments to query the NIST23 MS/MS library revealed 763 candidate compounds. Among 21 commercially available candidates, seven were experimentally confirmed as NDMA precursors through chloramination─four with DMA moieties and three without. Additionally, five drugs lacking DMA were newly identified as NDMA precursors. To facilitate large-scale screening, we developed NitrosAmine Precursor eXplorer (NitraPreX) for nontargeted LC-HRMS analysis. When applied to analyze Suwannee River Humic Acid reference material and real local water samples, NitraPreX tentatively identified over 200 potential NDMA precursors and confirmed two non-DMA-containing compounds, hydroxychloroquine and N,N-bis(2-hydroxyethyl)dodecanamide, as NDMA precursors. This approach provides a robust framework for uncovering a wider range of NDMA precursors.
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JOURNAL OF HAZARDOUS MATERIALS
·
2025
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IF 11.3
Qing Bai,Qian-Yuan Wu,Yun-peng Wu,Yu-jia Nong,Zi-Bo Jing,Min-Yong Lee,Wen-Long Wang
Nitrate photolysis under UV222 irradiation has increasingly attracted attention as an advanced oxidation process, while fundamental mechanisms remain incompletely understood in various water matrices. This study revealed that the observed nitrate photodecay under UV222 represented a dynamic balance between innate photolysis and significant reformation, with the innate quantum yield (0.52 mol·Ein −1 ) substantially 7.1–11.0 times higher than the observed quantum yield (0.047–0.073 mol·Ein −1 ). Inorganic carbon (IC) and organic carbon (OC), ubiquitous water matrix components, influenced UV222/nitrate through distinctly different mechanisms: IC suppressed nitrate photodecay 12.6–58.3 % via enhancing ONOO⁻-mediated nitrate reformation without affecting innate photolysis, while OC promoted observed nitrate photodecay 19.6–54.5 % by scavenging reactive intermediates involved in nitrate reformation. UV222/nitrate effectively degraded various micropollutants via direct photolysis (e.g., N-nitrosodimethylamine), • OH oxidation (e.g., carbamazepine), and a combination of pathways including reactive nitrogen species (RNSs) oxidation (e.g., sulfamethoxazole). IC selectively promoted RNSs oxidation while suppressing • OH oxidation pathway, leading to selective effects for various micropollutant degradation and the increased nitration byproducts formation. In contrast, OC uniformly reduced all oxidation pathways through non-selective scavenging of reactive species. This mechanistic understanding explained the complex effects of water matrix components on UV/nitrate performance and provides a fundamental basis for optimizing UV222 driven advanced oxidation processes for micropollutant control in diverse water conditions.
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DRUG AND CHEMICAL TOXICOLOGY
·
2026
·
IF 1.9
Wenxin Wang,Shuhua Xi,Yue Wang
N-nitrosodimethylamine (NDMA), as a disinfection by-product of drinking water, has been detected in various water. Epidemiological investigations have found that exposure to NDMA can exacerbate the development of diseases related to insulin resistance. In this study, male C57BL/6 mice were exposed to 0.5 and 12.5 mg/L NDMA by drinking water for 12 weeks. The mice in 12.5 mg/L NDMA group appeared fasting blood glucose elevation, and glucose tolerance and insulin sensitivity decreased. NDMA exposure enhanced hepatic gluconeogenesis and suppressed glycolysis of mice, but not affecting glycogen synthesis. In addition, NDMA exposure inhibited the phosphorylation of AMPK and FoxO1 as well as GLUT2 protein expression, and increased PGC-1α protein levels. GLUT2 protein decreasing could reduce glucose uptake of hepatocyte and enhance blood glucose concentration. Dephosphorylated FoxO1 might translocate to the nucleus, binding promoters of gluconeogenesis key enzymes PEPCK and G6Pase to upregulate their expression and promote gluconeogenesis. PGC-1α could also stimulate the expression of PEPCK and G6Pase. Furthermore, human normal liver cells (MIHA) were treated with NDMA for 24 hours. AMPK as a central energy sensor, regulates hepatic glucose production, uptake, and the process of glycolmetabolism. Therefore, AMPK agonist AICAR was used to explore the mechanism of NDMA causing hyperglycemia. AICAR reversed p-FoxO1, PGC-1α, GLUT2, PEPCK and G6Pase proteins expression and improved the glycolysis and glucose uptake capacity in NDMA treated MIHA cells. In conclusion, NDMA in drinking water led to fasting blood glucose enhancing, impairment of glucose tolerance and insulin sensitivity, increasing hepatic gluconeogenesis via AMPK signaling.
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FOOD CHEMISTRY
·
2022
·
IF 9.231
Zhiqin Ding,Mengdie Cai,Weimin Gan,Ping Yuan,Lijun Wei,Xianglei Cheng
In this paper, a novel, selective and sensitive high performance liquid chromatography-UV photolysis-fluorescence detection (HPLC-UV-FLD) method for nitrosamines (NAs) is proposed based on terbium-doped carbon dots (Tb-CDs). Experimental studies have shown that nitrosamines can be degraded by UV photolysis with wavelength at 254 nm to produce NO 2 − , while NO 2 − can rapidly and specifically quench the fluorescence of Tb-CDs. Based on this principle, N -nitrosodimethylamine (NDMA), Nnitrosomorpholine (NMor), N -nitrosopyrrolidine (NPYR), N -nitrosodiethylamine (NDEA) and N -nitrosopiperidine (NPIP) are separated within 8 min by HPLC. These five kinds of NAs showed a good linear relationship in the range of 10–2000 μg/L, and the limit of detection was as low as 2.25 μg/L. The proposed method is successfully applied to the detection of sweet potato, lotus root, potato, water chestnut, tomato and cucumber. The sample recoveries range from 77.35 % to 119.3 %.
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Journal of Cleaner Production
·
2017
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IF 5.715
Yuanan Hu,Yuanzhen He,Hefa Cheng
N -nitrosodimethylamine (NDMA), a highly toxic and carcinogenic disinfection byproduct , cannot be efficiently removed by conventional water treatment processes , while sorption by microporous minerals, followed by destruction with microwave irradiation has been developed as a promising alternative. This work examined the impact of surface cation density and type on sorption of NDMA on dealuminated ZSM-5 zeolites , and on microwave-induced degradation of the sorbed NDMA, as well as the non-thermal effect of microwave. NDMA sorption was found to increase with the framework Si/Al ratio of dealuminated ZSM-5 zeolites (i.e., decreasing density of surface cations), and was also influenced by the type of surface cations. Degradation of the sorbed NDMA proceeded faster with increases in the power level of microwave and in the micropores with higher densities of surface cations, which was attributed to the increases in the number and/or temperature of micro-scale “hot spots” formed by microwave dielectric superheating of the surface cations. The degradation rate of sorbed NDMA was also found to be inversely correlated with the hydration free energy of surface cations present in the zeolite micropores . The apparent activation energy estimated from the temperature dependence of NDMA degradation in the micropores under microwave irradiation was 18.2 kJ/mol, which is much lower than those of typical thermolysis reactions and is indicative of significant contribution from the non-thermal effect of microwave.
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Water
·
2024
·Vol. 16
·期 18
·2689
·
IF 3
Kaili Huang,Haiqing Huang,Xuhui Huang,An Lao,Zheng Zheng,Hanqi Wu
Disinfection by-products (DBPs) such as chloroacetic acids (CAAs) and N-Nitrosodimethylamine (NDMA) are prevalent pollutants in surface waters, particularly with the increasing use of chlorine-based disinfectants. The entry of these DBPs into water bodies may increase accordingly, posing ecological risks to aquatic life. To assess the toxic effects of CAAs and NDMA on submerged macrophytes,Vallisneria natanswas exposed to different concentrations of CAAs (1.0, 10.0, and 100.0 μg L−1) and NDMA (0.1, 1.0, and 10.0 μg L−1). A RI value of <1 indicates that simultaneous exposure to CAAs and NDMA can produce an antagonistic effect. Both CAAs and NDMA adversely affect the photosynthetic system of plants. In the NDMA treatment group, chlorophyll a content decreases with increasing concentration, accounting for 96.03%, 60.80%, and 58.67% of the CT group, respectively. Additionally, it effectively triggers the plant’s antioxidant response, with significant increases in SOD, POD, and GSH levels. Among these, the combined treatment group AN2 (10 + 1 μg L−1) showed the most significant change in SOD activity, reaching 3.57 times that of the CT group. Ultrastructural changes also revealed stress responses in leaf cells and damage to organelles. Furthermore, metabolomics provided insights into the metabolic responses induced by CAAs or NDMA inV. natansleaves, where the composition and metabolism of lipids, fatty acids, cofactors and vitamins, amino acids, nucleotides, and some antioxidants were regulated, affecting plant growth. This study provides preliminary information for the ecological risk assessment of submerged plants by complex contamination with the disinfection by-products CAA and NDMA.
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