ENVIRONMENTAL GEOCHEMISTRY AND HEALTH
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2025
·Vol. 48
·期 1
·24
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IF 3.8
Wang Bin,Yao Yiming,Sun Hongwen,Zhao Hongyan,Yu Qingxia
Wastewater treatment plants (WWTPs) and landfill represent critical point sources for per- and polyfluoroalkyl substance (PFAS) emission to the atmosphere. This study aimed to (1) quantitatively characterize both neutral and ionizable PFAS in air samples from these sources, and (2) estimate the potential emission contributions of unknown PFAS precursors. Using an optimized cartridge-based active air sampler, we collected atmospheric samples from a WWTP and landfill in Tianjin, China. Quantitative analysis revealed comparable concentration ranges for neutral (Σn-PFAS: 2,816–564,343 pg/m 3 ) were higher than ionizable PFAS (Σi-PFAS: 4,275–13,360 pg/m 3 ), with 8:2 fluorotelomer alcohol (8:2 FTOH; 2,273–13,360 pg/m 3 ) dominating neutral species and trifluoroacetic acid (TFA; 2,490–10,575 pg/m 3 ) prevailing among ionizable compounds. The total oxidizable precursor assay demonstrated that unknown precursors accounted 46.4–58.4 mol% of total PFAS. These findings provide the quantitative evidence of airborne PFAS speciation and associated unknown precursor-derived emission contributions in the WWTP and landfill.
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Menglan Gao,Xiaobin Liao,Shuting Chen,Xiaoying Li,Yirou Zhang,Chao Chen,Huan Qi
Bromide ion (Br - ) in water sources has been found to affect the formation of carcinogenic non-brominated N-nitrosodimethylamine (NDMA) during ozonation of typical amines. The increasing bromide levels bring more concern due to climate change and industrial discharge, but its effects on actual water matrixes were still unclear. In this study, NDMA formation from three actual water matrixes during ozonation as the Br - concentration increased from 0 to 100 µM were investigated (promotion (100.4 ∼ 231.6 ng/L), promotion then inhibition (399.5 ∼ 461.2 ∼ 428.2 ng/L), and subtle influence (51.9 ± 6.9 ng/L)); from which the NDMA precursors were screened and 8 precursors were selected for exploring the influencing mechanisms. The results indicated that the roles of Br - on NDMA formation significantly depended on the water characteristics of actual matrixes. A total of 16 typical NDMA precursors, which were mainly derived from industrial, agricultural and pharmaceutical sources, were identified. Moreover, 6 brominated substance (Br-DMA, Br-UDMH, Br-DMSC, Br-DMS, Br-TMDS, Br 2 -TMDS), which were thought to play a crucial role in promoting NDMA formation, were also identified in actual water by precursor ion scan (PIS) method. Hypobromous acid (HOBr), which has been proved to be the culprit to the generation of brominated substances, tend to attack the electron-donating groups of amines, such as acylamino (–NHCO-R) or amidogen (–NH 2 ) groups. However, the reactive bromine species (∙Br and ∙Br 2 - ) was inclined to attack the aromatic and anti-oxidant moieties then result in Br - release, as no bromine substitution but free radical transfer reaction occurs. Therefore, decreasing HOBr formation is the crucial step to reduce NDMA generation. This work would provide technical guide for NDMA risks control during ozonation of Br - -amines co-containing water matrixes.
研究领域:
环境科学
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化学
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FOOD CHEMISTRY
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2020
·
IF 6.306
Christoph Cerny,Hedwig Schlichtherle-Cerny,Romelo Gibe,Yuan Yuan
This study investigated the role of furfuryl alcohol (FFA) in the formation of furfurylthiol (FFT), the most important odorant in roasted coffee, using in-bean and spiking experiments. Green beans were spiked with FFA, and after roasting FFT was quantified by stable isotope dilution analysis. The FFT level in the roasted beans increased dose-dependently with addition of FFA. Additionally, beans were spiked with isotopically labelled d 2 -FFA which generated isotopically labelled d 2 -FFT after roasting. However, no labelled furfural was observed. The results unambiguously show that FFA serves as a precursor of FFT in coffee. On the other hand, the data indicate that furfural stems not from oxidation of FFA and plays no major role as precursor for FFT formation during coffee roasting. The suggested formation pathway leads from FFA to the furfuryl cation, then protein-bound S-furfuryl- l -cysteine and by subsequent elimination to FFT.
研究领域:
食品科学
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化学
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ACS Food Science & Technology
·
2023
·
IF 2.3
Xinjie Xiong,Caixia Ding,Haiming Shi,Hong Zhang,Yanlan Bi,Xuebing Xu
Fragrant rapeseed oil is produced through roasting and hot-pressing. However, the formation of trimethylamine (TMA) during its production can negatively impact the aroma of the oil. This study aimed to find the potential precursors and pathways of TMA formation in fragrant rapeseed oils. A simplified model containing water, oil, and various possible precursors (choline, sinapine, betaine, choline glycerophosphate, phosphatidylcholine, and trimethylamine oxide) was used to quantify the changes in the precursors and intermediates involved in the formation of TMA. The results showed that all of the precursors contributed to the formation of TMA with choline exhibiting the highest conversion rate (24.88%). Choline was found to serve as both a precursor and an intermediate. Sinapine, which was present in rapeseed at a high level (8920.85 mg/kg), was also identified as an important precursor for TMA formation. Furthermore, a higher heating temperature, a longer heating time, and a higher amount of water content were found to potentially lead to increased TMA formation.
研究领域:
食品科学
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生物化学
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WATER RESEARCH
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2021
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IF 11.236
Jinxiu Lou,Huijie Lu,Wei Wang,Lizhong Zhu
Halobenzoquinones (HBQs) are emerging disinfection byproducts generated during the reaction of chlorine disinfectant with natural organic matter (NOM) in source water. In this study, the correlations between molecular weight and HBQs generation of river NOM was evaluated. The compositional and functional characteristics of primary HBQs precursors were revealed by using Orbitrap mass spectrometry combined with molecular tagging. The NOM fraction larger than 50 kDa resulted in approximately 9 times more HBQs (50.9 ± 2.7 ng/mgC) than low molecular weight fractions. Significant correlations were found between the yields of HBQs and lignin-like and highly oxygen compounds in NOM, suggesting their critical roles in HBQs formation. Derivatizating the aldehydes, ketones, hydroxyl and carboxyl groups in NOM could reduce HBQs yields by 90.7%–100%. Unraveling the molecular characteristics of HBQs precursors in NOM would greatly benefit the prediction of HBQs yields of different source water, and develop more efficient disinfection byproduct control strategies.
研究领域:
环境科学
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分析化学
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2021
·
IF 9.028
Di Zhang,Tom Bond,Mingli Li,Shengkun Dong,Yang Pan,Erdeng Du,Rong Xiao,Wenhai Chu
Chlorophenylacetonitriles (CPANs) are an emerging group of aromatic nitrogenous disinfection byproducts (DBPs). However, their dominant precursors and formation pathways remain unclear, which hinders the further development of effective control strategies. For the first time, CPAN precursors were screened by conducting formation potential (FP) tests on real water samples from six drinking water treatment plants (DWTPs). The average overall removal of CPAN precursors across all six DWTPs was only 10%. Moreover, ozonation increased CPAN precursors by 140% on average. Fluorescence spectroscopy showed a dramatic reduction in aromatic proteins, tyrosine-like proteins, and tryptophan-like proteins following ozonation. Low-apparent-molecular-weight (AMW) (<1 kDa) substances were correlated with the CPAN FP in these samples. We therefore hypothesized that protein fragments with low AMW, such as amino acids, are important CPAN precursors during downstream chlor(am)ination. Two aromatic free amino acids, tyrosine and tryptophan, were selected to investigate the formation of CPANs during chlor(am)ination. Both amino acids were found to act as CPAN precursors for the first time. CPAN formation pathways from these model precursors were proposed based on the frontier molecular orbital theory and intermediate products identified using high-resolution mass spectrometry. This study provides a powerful theoretical foundation for controlling CPAN formation in drinking water.
研究领域:
环境科学
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饮用水处理
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Journal of the Taiwan Institute of Chemical Engineers
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2018
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IF 3.849
Weirui Chen,Zulin Zhang,Xukai Li,Dan Wu,Ying Xue,Laisheng Li
Fe-Cu-MCM-41/O 3 was first used as an alternative to O 3 to control disinfection by-products generation from chlorinated-disinfection of Br-containing Diclofenac. Accompanying with decrease of TOC , THMs and HAAs had an initial increase, reaching the highest at 30 min, then gradually decreased. Coupling Fe-Cu-MCM-41 with O 3 successfully enhanced TOC removal and inhibited bromate, THMs and HAAs formation in post-chlorination when compared with those in ozonation . Four kinds of THMs and six kinds of HAAs were detected. CHCl 3 was main Cl-THMs and CHBrCl 2 was main Br-THMs. CHCl 2 COOH was the dominant Cl-HAAs and CHClBrCOOH was main Br-HAAs. A converse Br-THMs order was observed in O 3 and Fe-Cu-MCM-41/O 3 pre-treatment. Fe-Cu-MCM-41 decreased ozone exposure, reducing the direct reaction of O 3 with Br − to form bromate. More DBPs precursors in Fe-Cu-MCM-41/O 3 were removed by ·OH. H 2 O 2 , which generated during pre-treatment process, reduced HBrO/BrO − to Br − , inhibiting both its reaction with Br-DBPs precursors and bromate formation. The pre-treatment process changed intermediates’ properties and hydrophilic DOM was the dominant component. Hydrophobic acids and transphilic DOM were the main chlorine consuming intermediates and had major contribution to DBPs formation. Fulvic-like intermediates was suggested as precursors of Br-DBPs. Fe-Cu-MCM-41/O 3 were suggested as a good alternative to O 3 pretreatment.
研究领域:
环境科学
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水处理工程
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SCIENCE OF THE TOTAL ENVIRONMENT
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2021
·
IF 7.963
Ji Liu,Wei Zhao,Shuang-wei Yang,Bin Hu,Ming-xin Xu,Shan-Wei Ma,Qiang Lu
Incineration of food waste leads to the release of NO x pollutants, whereas the formation mechanism of the NO x precursors (HCN, NH 3 , and HNCO) during the initial pyrolysis process is far from well-studied, limiting the source control on NO x release. In this work, 2,5-diketopiperazine (DKP) was selected as the N-containing model compound to study the formation mechanism of NO x precursors in food waste pyrolysis, by combining experiments and density functional theory (DFT) calculations. The C1-N2 bond broken via the N2-to-N5 H-transfer possesses the lowest energy barrier, together with the largest reaction rate constants in the range of 400–800 °C. NH 3 can be easily generated with low energy barriers and high rate constants at low temperatures (below 630 °C). Whereas, the rate constants of the pathways for HCN formation will exceed those for NH 3 generation in the range of 630–740 °C. In addition, the DKP pyrolysis can also lead to the formation of HNCO with a very low energy barrier, and it can convert into HCN and NH 3 through further hydrogenation and decomposition. These calculation results are exactly consistent with the experimental results that NH 3 was the main precursor in the range of 400–600 °C, and the yield of HCN exceeded that of NH 3 when the temperature was over 600 °C. Our current work on the formation mechanism of NO x precursors during the pyrolysis of DKP can provide theoretical guidance for the development of NO x control technology in the pyrolysis/combustion process of organic waste.
研究领域:
环境科学
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化学工程
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能源科学
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JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Xiaoyu Liu,Xianli Wang,Shuang Hong,Huatian Zhou,Xiaolong Cao,Kepiao Li,Qicai Zhang,Chunxia Yao,Wanchao Chen,Wen Li,Weiguo Song,Qinxiong Rao
Per-and polyfluoroalkyl substances (PFASs) have garnered significant attention owing to their prevalence and adverse effects on humans. The direct dietary intake of perfluoroalkyl acids (PFAAs) and PFAAs precursors (pre-PFAAs) biotransformation are considered major contributors to human exposure to PFASs. However, little information is available on analytical methods for the simultaneous detection of PFAAs and pre-PFAAs. In the present study, a single-step sample-treatment-based supramolecular solvents-dispersed liquid-liquid microextraction (SUPRASs-DLLME) technique was established for the analysis of 16 PFAAs and 7 pre-PFAAs in aquatic food. SUPRASs were synthesized using 1-heptanol (3 mL) and tetrahydrofuran (4 mL), which were self-assembled in water. The parameters for microextraction, such as extraction method and enrichment capacity, were optimized. Under the optimum conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.03–0.15 ng·g −1 and 0.1–0.5 ng·g −1 , respectively. Good linearities (R 2 > 0.996) were obtained for all the target compounds, and the recoveries ranged 81.1–120 % with relative standard deviations (RSDs) lower than 20 %. This method was applied to the analysis of 16 PFAAs and 7 pre-PFAAs in aquatic food samples (crabs, prawns, and fish). This study provides a new idea for analyzing other pollutants in biological samples.
研究领域:
分析化学
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环境科学
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食品安全
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Jingna Li,Wei Zhang,Yaming Sun,Chenchen Song,Hailiang Zhao,Yangyong Lv,Yuansen Hu,Shusheng Zhang,Lijun He
Early warning detection based on aflatoxin B 1 (AFB 1 ) biosynthesis precursors is an effective strategy for the prevention of AFB 1 contamination. However, the development of effective methods for accurately tracking the dynamic changes of AFB 1 and its precursors presents a major challenge. This difficulty is due to the continual variations in precursor species and concentrations, structural differences of AFB 1 and its precursors, as well as the complexity of the dynamically changed sample matrix. Herein, an ionic liquid-impregnated covalent triazine polymer composite (IL@CTP) was fabricated, which exhibited excellent extraction performance for structurally different AFB 1 and its three typical precursors in moldy grains. The high performance was attributed to the multiple interactions between the prepared composite and analytes, as well as a mesopore filling effect. The combined use of IL@CTP with dispersive solid-phase extraction and ultra high-performance liquid chromatography-mass spectrometry achieved negligible matrix effects, with low limits of detection (0.01–0.03 ng/g), wide linearity (0.06–200 ng/g) and satisfactory relative recoveries of 85.3 %-113.0 %. Therefore, the developed method can accurately track the dynamic changes of AFB 1 and its precursors in stored maize inoculated with Aspergillus flavus . Correlation analysis between AFB 1 and its precursors showed that it was necessary to simultaneously serve averantin, O-methylsterigmatocystin and sterigmatocystin as early warning molecules, allowing the accurate identification of AFB 1 contamination risks up to 5 days in advance.
研究领域:
食品安全
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分析化学
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真菌学
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Frontiers in Microbiology
·
2019
·
IF 4.259
Wu Hao,Guo Ye,Chen Lei,Chen Guiguang,Liang Zhiqun
This study characterized the biosynthetic pathway of the secondary metabolite 1-deoxynojirimycin (DNJ) from Streptomyces lavendulae. The results revealed that glucose was a preferable precursor for DNJ synthesis, and its carbon skeleton underwent a C2-N-C6 cyclization reaction during synthesis. The biosynthetic pathway was related to the glycolysis pathway, and started from fructose-6-phosphate, and involved amination, dephosphorylation, oxidation, cyclization, dehydration, and reduction reaction steps, yielding DNJ. Then, based on clarified biosynthetic pathway information, precursors, analogs, and metabolism inhibitors were used as novel regulators to enhance the production of DNJ. The results demonstrated that the titer of DNJ could reach 296.56 mg/L, which was 3.3-fold higher than that of a control group (90 mg/L) when sodium citrate (0 h, 5 g/L), sorbose (0 h, 1 g/L), iodoacetic acid (20 h, 50 mg/L), and glucose (26 h, 7 g/L) were added during the fermentation process. This study provides a new understanding of the biosynthetic pathway of DNJ, and also provides an efficient strategy to regulate the production of DNJ based on this biosynthetic pathway, which is a new perspective for the regulation of other secondary metabolites.
研究领域:
微生物学
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代谢工程
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WATER RESEARCH
·
2020
·
IF 9.13
Jijie He,Minghao Shi,Feifei Wang,Youli Duan,Tiantao Zhao,Shihu Shu,Wenhai Chu
In addition to surface water and groundwater, rainwater is used as an important drinking water source in many parts of the world, especially in areas with serious water pollution or insufficient water resources. Conventional drinking water treatment technologies can remove dissolved organic matter and therefore reduce the formation of disinfection by-products (DBPs) during subsequent disinfection using surface water or groundwater as drinking water sources. However, little information has been known about the effect of conventional water treatment processes on DBP formation when rainwater is used as drinking water source. This study evaluated CX 3 R-type DBP precursors removal from rainwater by conventional drinking water treatments and the corresponding decrease of CX 3 R-type DBP (trihalomethanes (THMs), haloaldehydes (HALs), haloacetonitriles (HANs) and haloacetamides (HAMs)) formation and toxicity during the subsequent chlor(am)ination. The result showed that both sand filtration (SF) and activated carbon filtration (GAC) were able to remove DBP precursors and GAC outperformed SF, but no DBP precursors removal was observed during coagulation-sedimentation treatment. Among all treatments, SF + GAC was the most effective for DBP precursors removal, with removal efficiencies of 64.2% DOC , 98% DON and 76.6% UV 254 . Correspondingly, both SF and GAC decreased the formation of THMs, HALs, HANs and HAMs, and GAC performed better than SF. The combination of SF and GAC, especially SF + GAC, greatly decreased DBP formation, with average reduction of 79.2% and 85% during chlorination and chloramination respectively. After different treatments, the comprehensive toxicity risk of CX 3 R-type DBPs was all reduced, among which GAC + SF exhibited superior performance. Generally, the main contribution of integrated toxicity was HANs during chlor(am)ination. The formation potential of THMs, HALs, HANs and HAMs and the corresponding integrated toxicity were greater during chlorination than that during chloramination. Therefore, the combination of GAC and chloramination was promising in mitigating the comprehensive toxicity risk of THMs, HALs, HANs and HAMs for rainwater.
研究领域:
环境科学
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公共卫生
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危险品化学品经营许可证（带存储）