Occurrence and Temporal Trends of Benzotriazole UV Stabilizers in Mollusks (2010-2018) from the Chinese Bohai Sea Revealed by Target, Suspect, and Nontarget Screening Analysis

Discovery of novel benzotriazole ultraviolet stabilizers in surface water

The comprehensive understanding of the occurrence of benzotriazole UV stabilizers (BZT-UVs) in environmental surface water is imperative due to their widespread application and potential aquatic toxicity. We conducted an analysis of 13 traditional BZT-UVs in surface water samples collected from Taihu Lake (TL, n = 23) and Qiantang River (QR, n = 22) in China. The results revealed that 5‑chloro-2-(3,5-di-tertbutyl-2-hydroxyphenyl)-benzotriazole (UV-327) was consistently the predominant BZT-UV in water samples from TL (mean 16 ng/L; detection frequency 96 %) and QR (14 ng/L; 91 %). Furthermore, we developed a characteristic fragment ion-based strategy to screen and identify unknown BZT-UVs in collected surface water, utilizing a high-resolution mass spectrometer. A total of seven novel BZT-UVs were discovered in water samples, and their chemical structures were proposed. Four of these novel BZT-UVs were further confirmed with standards provided by industrial manufacturers. Semi-quantitative analysis revealed that among discovered novel BZT-UVs, 2-(2‑hydroxy-3‑tert‑butyl‑5-methylphenyl)-benzotriazole was consistently the predominant novel BZT-UV in TL (mean 4.1 ng/L, detection frequency 70 %) and QR (2.8 ng/L, 77 %) water. In TL water, the second predominant novel BZT-UV was 2-(3-allyl-2‑hydroxy-5-methylphenyl)-2H-benzotriazole (mean 3.9 ng/L, Collapse

Key Words

• Benzotriazole UV stabilizers
• Non-target analysis
• Novel BZT-UVs
• Surface water
• UV-327

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MESH Headings

• Triazoles/chemistry
• Water Pollutants, Chemical/chemistry
• China
• Lakes/chemistry
• Ultraviolet Rays
• Rivers/chemistry
• Environmental Monitoring

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Grants Collapse

Affiliation(s)

Yuanchen Chen Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Ruyue Guo Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Kaizhen Liao Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Wenfei Yu Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China
Pengfei Wu Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, PR China
Hangbiao Jin Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, PR China.

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Uptake, accumulation and metabolism of UV-320 in vegetables and its impact on growth and quality

UV-320 is classified as a Substance of Very High Concern (SVHC) by the European Chemicals Agency and has attracted significant attention due to its presence in the environment. Understanding the uptake, translocation and metabolic patterns of UV-320 in vegetables is essential for assessing their ability to bioaccumulate and potential risks to human health. In this study, we investigated the uptake and translocation of UV-320 in lettuce and radish by hydroponic experiments. The results showed that the root concentration factors (Croot/Csolution, RCF) of lettuce and radish were in the range of 47.9 to 464 mL/g and 194 to 787 mL/g, respectively. The transfer factors (Cshoot/Croot, TF) were observed to be 0.001-0.012 for lettuce and 0.02-0.05 for radish. Additionally, non-targeted screening identified twelve phase I and one phase II metabolites of UV-320 in vegetables, which were confirmed based on their molecular formulas and structures. The metabolic pathways involving oxidation, ketonylation and deamination were proposed in vegetables. Also, we have observed that UV-320 inhibits the growth of vegetables. Meanwhile, we evaluated the health risk of UV-320 in lettuce and radish and found that the consumption of lettuce is relatively safe, while the consumption of radish has a risk of HQ >1 for both adults and children, which should be seriously considered. This study provides valuable insights into the behavior and ecological risks of UV-320 in the environment.

Occurrence and Ecological Risk of Alkylamine Triazines in Chinese Estuarine Sediments: An Emerging Class of Persistent, Mobile, and Toxic Substances

Identifying persistent, mobile, and toxic (PMT) substances from synthetic chemicals is critical for chemical management and ecological risk assessment. Inspired by the triazine analogues (e.g., atrazine and melamine) in the original European Union's list of PMT substances, the occurrence and compositions of alkylamine triazines (AATs) in the estuarine sediments of main rivers along the eastern coast of China were comprehensively explored by an integrated strategy of target, suspect, and nontarget screening analysis. A total of 44 AATs were identified, of which 23 were confirmed by comparison with authentic standards. Among the remaining tentatively identified analogues, 18 were emerging pollutants not previously reported in the environment. Tri- and di-AATs were the dominant analogues, and varied geographic distributions of AATs were apparent in the investigated regions. Toxic unit calculations indicated that there were acute and chronic risks to algae from AATs on a large geographical scale, with the antifouling biocide cybutryne as a key driver. The assessment of physicochemical properties further revealed that more than half of the AATs could be categorized as potential PMT and very persistent and very mobile substances at the screening level. These results highlight that AATs are a class of PMT substances posing high ecological impacts on the aquatic environment and therefore require more attention.

Neurotoxicity of Benzotriazole Ultraviolet Stabilizers in Teleost Fishes: A Review

Plastic additives that maintain integrity have been extensively studied for potential toxicity to fish; however, chemicals that protect polymers from (artificial) UV degradation are less studied. Benzotriazole UV stabilizers (BUVSs) are the most widely used UV stabilizers in plastics and are often used in sunscreens, cosmetics, paint, and food packaging. BUVSs can negatively affect aquatic wildlife when released into the environment via plastic degradation. In this review, we summarize the distribution of BUVSs globally and discuss neurotoxicological endpoints measured in fish to understand how these plastic additives can affect the neurological health of teleost fishes. BUVSs have been detected in aquatic environments at concentrations ranging from 0.05 up to 99,200 ng/L. Studies show that BUVSs affect behavioral responses and acetylcholinesterase activity, indicators of neurotoxicity. Our computational analysis using transcriptome data suggests certain pathways associated with neurodegeneration are responsive to exposure to BUVSs, like "Complement Activation in Alzheimer's Disease". Based on our review, we identify some research needs for future investigations: (1) molecular studies in the central nervous system to define precise mechanisms of neurotoxicity; (2) a wider range of tests for assessing aberrant behaviors given that BUVSs can affect the activity of larval zebrafish; and (3) histopathology of the nervous system to accompany biochemical analyses. These data are expected to enhance understanding of the neurotoxicity potential of benzotriazoles and other plastic additives.

Benzotriazole Ultraviolet Stabilizers (BUVSs) as Potential Protein Kinase Antagonists in Rice

The ubiquitous occurrence of benzotriazole ultraviolet stabilizers (BUVSs) in the environment and organisms has warned of their potential ecological and health risks. Studies showed that some BUVSs exerted immune and chronic toxicities to animals by disturbing signaling transduction, yet limited research has investigated the toxic effects on crop plants and the underlying mechanisms of signaling regulation. Herein, a laboratory-controlled hydroponic experiment was conducted on rice to explore the phytotoxicity of BUVSs by integrating conventional biochemical experiments, transcriptomic analysis, competitive sorption assays, and computational studies. The results showed that BUVSs inhibited the growth of rice by 6.30-20.4% by excessively opening the leaf stomas, resulting in increased transpiration. BUVSs interrupted the transduction of abscisic acid (ABA) signal through competitively binding to Ca2+-dependent protein kinase (CDPK), weakening the CDPK phosphorylation and further inhibiting the downstream signaling. As structural analogues of ATP, BUVSs acted as potential ABA signaling antagonists, leading to physiological dysfunction in mediating stomatal closure under stresses. This is the first comprehensive study elucidating the effects of BUVSs on the function of key proteins and the associated signaling transduction in plants and providing insightful information for the risk evaluation and control of BUVSs.

Nontarget Screening and Fate of Emerging Per- and Polyfluoroalkyl Substances in Wastewater Treatment Plants in Tianjin, China

Wastewater treatment plants (WWTPs) are typical point sources of per- and polyfluoroalkyl substances (PFAS) released into the environment. The suspect and nontarget screening based on gas chromatography or liquid chromatography-high resolution mass spectrometry were performed on atmosphere, wastewater, and sludge samples collected from two WWTPs in Tianjin to discover emerging PFAS and their fate in this study. A total of 40 PFAS (14 neutral and 26 ionic) and 64 PFAS were identified in the atmosphere and wastewater/sludge, respectively, among which 5 short-chain perfluoroalkyl sulfonamide derivatives, 4 ionic PFAS, and 15 aqueous film-forming foam-related cationic or zwitterionic PFAS have rarely or never been reported in WWTPs in China. Active air sampling is more conducive to the enrichment of emerging PFAS, while passive sampling is inclined to leave out some ultrashort-chain PFAS or unstable transformation intermediates. Moreover, most precursors and intermediates could be enriched in the atmosphere at night, while the PFAS associated with aerosols with high water content or particles enter the atmosphere easily during the day. Although most emerging PFAS could not be eliminated efficiently in conventional treatment units, deep bed filtration and advanced oxidation processes could partly remove some emerging precursors.

Embryonic Exposure to UV-328 Impairs the Cell Cycle in Zebrafish (Danio rerio) by Inhibiting the p38 MAPK/p53/Gadd45a Signaling Pathway

The benzotriazole UV stabilizer UV-328 is well known for its potent antioxidative properties; however, there are concerns about how it may affect signaling nodes and lead to negative consequences. This study identified the key signaling cascades involved in oxidative stress in zebrafish (Danio rerio) larvae and evaluated the cell cycle arrests and associated developmental alternations. Exposure to UV-328 at 0.25, 0.50, 1.00, 2.00, and 4.00 μg/L downregulated gene expression associated with oxidative stress (cat, gpx, gst, and sod) and apoptosis (caspase-3, caspase-6, caspase-8, and caspase-9) at 3 days postfertilization (dpf). The transcriptome aberration in zebrafish with disrupted p38 mitogen-activated protein kinase (MAPK) cascades was validated based on decreased mRNA expressions of p38 MAPK (0.36-fold), p53 (0.33-fold), and growth arrest and DNA damage-inducible protein 45 α (Gadd45a) (0.52-fold) after a 3- and 14-day exposure alongside a correspondingly decreased protein expression. The percentage of cells in the Gap 1 (G1) phase increased from 69.60% to a maximum of 77.07% (p < 0.05) in the 3 dpf embryos. UV-328 inhibited the p38 MAPK/p53/Gadd45a regulatory circuit but promoted G1 phase cell cycle arrest, abnormally accelerating the embryo hatching and heart rate. This study provided mechanistic insights that enrich the risk profiles of UV-328.

Comparative toxicogenomics of benzotriazole ultraviolet stabilizers at environmental concentrations in Asian clam (Corbicula fluminea): Insight into molecular networks and behavior

Benzotriazole ultraviolet stabilizers (BUVSs) are widespread emerging pollutants, which can pose exposure risks to benthic organisms. However, the toxicity and mechanisms of BUVSs congeners in benthic clams are far from elucidated. In this study, Asian clams (Corbicula fluminea) were exposed to one of UV-234, UV-326, UV-329, or UV-P at environmentally relevant levels (0.1, 1, and 10 μg/L) for 21 days. Filtration rate (FR) was increased in clams exposed to all BUVSs and there were notable histopathologic changes, including irregular digestive lumen, lipid droplet vacuolation, and degraded epithelial cells. To determine the molecular underpinnings following BUVSs exposure, the transcriptome responses in digestive glands were compared. Differentially expressed genes shared among BUVSs treatments were associated with focal adhesion, TNF-α/NF-κB proinflammatory pathways, and apoptosis. Following this, biochemical analysis of biomarkers related to apoptosis were conducted to further validate response. Exposure to BUVSs inhibited anti-oxidant enzyme activity and induced oxidative stress. Heat shock proteins were also triggered with exposure, and there was an induction of caspase-3 and caspase-9 activity. Molecular responses were not identical in the digestive gland of C. fluminea when comparing responses to BUVSs; nevertheless conserved mechanism (impairment of the oxidative defense system, immune system disruption, and induction of apoptosis) among BUVSs congeners was noted. This study provides novel insight into the toxicity and hazards of BUVSs in benthic organisms.