Experimental and theoretical insights into photochemical transformation kinetics and mechanisms of aqueous propylparaben and risk assessment of its degradation products

An, Taicheng; Fang, Hansun; Li, Guiying; Wang, Shilong; Yao, Shun

doi:10.1002/etc.2632

Cited by 25 publications

(8 citation statements)

References 39 publications

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“…The particles were left in contact with P. phosphoreum 502 for 15 min before luminescence measurement. 29 To study whether the NP toxicity only involved ROS-induced damage, the concentration of the metal oxide NPs was selected to exclude toxicity induced by the release of metal ions. Two different exposure procedures involving the metal oxides and bacteria were performed ( Figure S3): (1) Traditional toxicity test: 20 mL of dispersed NP suspensions and 500 μL of P. phosphoreum 502 were mixed, allowed to rest for 15 min, and then exposed to UV light.…”

Section: •−mentioning

confidence: 99%

Quantitative Analysis of Reactive Oxygen Species Photogenerated on Metal Oxide Nanoparticles and Their Bacteria Toxicity: The Role of Superoxide Radicals

Wang

Zhao

et al. 2017

Environ. Sci. Technol.

169

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Ecotoxicity of engineered nanoparticles (NPs) has become the focus of considerable attention because of their wide applications. Reactive oxygen species (ROS) play important roles in the toxicity mechanisms of engineered metal oxide NPs. This work aimed to understand quantitatively the contribution of photogenerated ROS on metal oxide NPs to their toxicity. The dynamic generation of O 2•− , • OH, and H 2 O 2 in aqueous suspensions of photoilluminated metal oxide nano-and bulk particles (TiO 2 , ZnO, V 2 O 5 , CeO 2 , Fe 2 O 3 , and Al 2 O 3 ) was measured by a continuous-flow chemiluminescence (CFCL) detection system. Superoxides were generated on all six nanoparticles as well as bulk TiO 2 and ZnO, with nano TiO 2 producing the highest concentration (180 nM). Hydroxyl radicals were detected on both nano-and bulk TiO 2 and ZnO, whereas H 2 O 2 was detected only on TiO 2 and ZnO nanoparticles. The generation of ROS can in general be interpreted by the electronic structures and surface defects of the NPs and the ROS redox potentials. Furthermore, acute toxicity of the six metal oxide particles to a luminescent bacterium, P. phosphoreum 502 was assessed after photoillumination. The toxicity effect was attributed to the long-lived O 2 •− radicals on the nanoparticlce, and its potency follows the order of TiO 2 > ZnO > V 2 O 5 > Fe 2 O 3 > CeO 2 > Al 2 O 3 , which is the same as the order of the O 2•− concentration measured by CFCL. Our work revealed quantitatively the important role superoxide radicals play in the toxicity of various metal oxide nanoparticles after photoillumination.

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Section: •−mentioning

confidence: 99%

Quantitative Analysis of Reactive Oxygen Species Photogenerated on Metal Oxide Nanoparticles and Their Bacteria Toxicity: The Role of Superoxide Radicals

Wang

Zhao

et al. 2017

Environ. Sci. Technol.

169

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“…For the toxicity bioassay with P. phosphoreum , the assays were carried out according to the standardized GB/T 15441‐1995, and the standard procedure was employed to reconstitute the bacteria, using sodium chloride solution. Luminescence was determined with a Luminometer DXY‐3 (Institute of Soil Science, Chinese Academy of Sciences), and toxicity was determined after 15‐min incubation . The S. capricornutum bioassay was carried out according to the Organisation for Economic Co‐operation and Development guideline for algal growth inhibition test 201, and the algal biomass at different exposure times was measured by manual cell counting using a microscope.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, chromophoric DOM may play a significant role in the photochemical transformation of organic pollutants, especially emerging organic contaminants, depending on the magnitude of these 2 factors . Furthermore, photochemical degradation of organics does not guarantee complete decontamination because of toxic product formation . As such, identifying photochemical degradation intermediates and evaluating treated solution ecotoxicity are necessary because despite low concentrations, some synergistic or antagonistic effects may occur in photoproduct mixtures .…”

Section: Introductionmentioning

confidence: 99%

Indirect photochemical transformations of acyclovir and penciclovir in aquatic environments increase ecological risk

et al. 2016

Enviro Toxic and Chemistry

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Acyclovir and penciclovir, 2 antiviral drugs, are increasingly detected in aquatic environments. The present study explores the natural photochemical transformation mechanisms and fate of these drugs, examining direct and indirect photochemical transformation under simulated sunlight irradiation. The 2 antiviral drugs are photostable under certain conditions but significantly degrade in the presence of chromophoric dissolved organic matter (DOM). The degradation rate associated with the drugs' indirect photochemical transformation scaled with chromophoric DOM concentration. Quenchers and sensitizers were used to identify indirect photochemical transformation mechanism. Results suggested that both pharmaceuticals could be transformed by reacting with 1 O 2 , • OH, and excited chromophoric DOM. The 1 O 2 played an important role in indirect photochemical transformation. Furthermore, the reaction kinetics between their substructural molecules, guanine, isocytosine, and imidazole, with different reactive oxygen species were evaluated to determine which substrate functionalities were most susceptible to singlet oxygenation. Imidazole was identified as the reaction site for 1 O 2 , and preliminary 1 O 2 oxidation mechanisms were further evaluated based on liquid chromatographic-tandem mass spectrometric results. Finally, aquatic ecotoxicity assessment of phototransformed solutions revealed that the degradation of acyclovir and penciclovir may not ultimately diminish environmental risk because of either formation of more toxic intermediates than parent pharmaceuticals or some synergistic effects existing between the intermediates. Environ Toxicol Chem 2016;35:584-592. # 2015 SETAC

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“…Further, the respective contribution rate was obtained to analyze the role of the main active species during (A) (B) (C) photodegradation. Special experiments with various scavengers, including p-BQ, FFA, isopropanol, triethanolamine, MeCN, acetone, and different gas saturation (air and N 2 ), were designed to identify the main reactive species generated during the photodegradation of CAL (An et al 2014). As shown in Figure 6, the degradation rate of CAL was accelerated under nitrogen and acetone but slowed down under other quenching conditions.…”

Section: Skin Irritation Eye Irritationmentioning

confidence: 99%

Insights into the Photodegradation of the Contact Allergen Fragrance Cinnamyl Alcohol: Kinetics, Mechanism, and Toxicity

Gao

Luo

et al. 2021

Enviro Toxic and Chemistry

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Fragrances can cause general health issues, and special concerns exist surrounding the issue of skin safety. Cinnamyl alcohol (CAL) is a frequent fragrance contact allergen that has various toxic effects on indiscriminate animals. In the present study, the photodegradation transformation mechanism of CAL and toxicity evolution during this process were examined. The results showed that CAL (50 μM) can be completely degraded after 90-min ultraviolet (UV) irradiation with a degradation rate of 0.086 min -1 . Increased toxicity on bioluminescent bacteria was observed during this process, with lethality increasing from 10.6% (0 min) to 50.2% (90 min) under UV light irradiation. Further, the photodegradation mechanisms of CAL were explored to find the reason behind the increased toxicity observed. Laser flash photolysis and quenching experiments showed that O 2•-, 1 O 2 , and • OH were mainly responsible for CAL photodegradation, together with 3 CAL* and e aq -. The 5 main photodegradation products were cinnamyl aldehyde, benzaldehyde, benzenepropanal, cinnamic acid, and toluene, as identified using gas chromatography-mass spectrometry and liquid chromatography-quadrupole-time-offlight-mass spectrometry. Once exposed to air, CAL was found to be easily oxidized to cinnamyl aldehyde and subsequently to cinnamic acid by O 2 •-or 1 O 2 -mediated pathways, leading to increased toxicity. Benzaldehyde exhibited bioreactive toxicity, increasing the toxicity through • OH-mediated pathways. Theoretical prediction of skin irritation indicated that cinnamyl aldehyde (0.83), benzenepropanal (0.69), cinnamyl aldehyde (0.69), and benzaldehyde (0.70) were higher than CAL (0.63), which may cause a profound impact on an individual's health and well-being. Overall, the present study advances the understanding of the photodegradation processes and health impacts of fragrance ingredients.

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Experimental and theoretical insights into photochemical transformation kinetics and mechanisms of aqueous propylparaben and risk assessment of its degradation products

Cited by 25 publications

References 39 publications

Quantitative Analysis of Reactive Oxygen Species Photogenerated on Metal Oxide Nanoparticles and Their Bacteria Toxicity: The Role of Superoxide Radicals

Quantitative Analysis of Reactive Oxygen Species Photogenerated on Metal Oxide Nanoparticles and Their Bacteria Toxicity: The Role of Superoxide Radicals

Indirect photochemical transformations of acyclovir and penciclovir in aquatic environments increase ecological risk

Insights into the Photodegradation of the Contact Allergen Fragrance Cinnamyl Alcohol: Kinetics, Mechanism, and Toxicity

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