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Jalili-Jahani N, Fatehi A, Zeraatkar E. PLS and N-PLS based MIA-QSPR modeling of the photodegradation half-lives for polychlorinated biphenyl congeners. RSC Adv 2020; 10:33753-33761. [PMID: 35519039 PMCID: PMC9056733 DOI: 10.1039/d0ra05231k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 07/27/2020] [Indexed: 11/21/2022] Open
Abstract
Multivariate image analysis as a useful tool in environmental risk assessment studies.
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Affiliation(s)
| | - Azadeh Fatehi
- Green Land Shiraz Eksir Chemical and Agricultural Industries Company
- Shiraz
- Iran
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2
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Gutiérrez-Hernández RF, Bello-Mendoza R, Hernández-Ramírez A, Malo EA, Nájera-Aguilar HA. Photo-assisted electrochemical degradation of polychlorinated biphenyls with boron-doped diamond electrodes. ENVIRONMENTAL TECHNOLOGY 2019; 40:1-10. [PMID: 28876166 DOI: 10.1080/09593330.2017.1375999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 08/25/2017] [Indexed: 06/07/2023]
Abstract
The capacity of the photo electro-Fenton (PEF) process to degrade a mixture of seven polychlorinated biphenyl (PCB) congeners was studied. Boron-doped diamond (BDD) sheets were used as anode and cathode in the experimental electrolytic cell that contained Na2SO4 0.05 M at pH 3 as supporting electrolyte for the electro generation of H2O2 at the cathode. The effects of UV light intensity (254 and 365 nm), current density (8, 16 and 24 mA cm-2) and ferrous ion dosage (0.1, 0.2 and 0.3 mM) on PCB (C0 = 50 μg L-1) degradation were evaluated. The highest level of PCB degradation (97%) was achieved with 16 mA cm-2 of current density, 0.1 mM of ferrous ion and UV light at 365 nm as irradiation source after 6 h of reaction. PCB28, PCB52 and PCB101 were not detected after 0.5, 1.5 and 3 h of reaction, respectively. The degradation of PCB138, PCB153, PCB180 and PCB209 was also high (>95%). The PEF system outperformed other oxidation processes (electro-Fenton, anodic oxidation, Fenton, photo-Fenton and UV photolysis) in terms of reaction rate and degradation efficiency. These results demonstrate for the first time the degradation of PCB209, the most highly chlorinated PCB congener, by an advanced electrochemical oxidation process.
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Affiliation(s)
- Rubén F Gutiérrez-Hernández
- a Departamento de Ingeniería Química y Bioquímica , Instituto Tecnológico de Tapachula , Tapachula , Mexico
- b El Colegio de la Frontera Sur , Tapachula , Mexico
| | - Ricardo Bello-Mendoza
- b El Colegio de la Frontera Sur , Tapachula , Mexico
- c Department of Civil and Natural Resources Engineering , University of Canterbury , Christchurch , New Zealand
| | | | - Edi A Malo
- b El Colegio de la Frontera Sur , Tapachula , Mexico
| | - Hugo A Nájera-Aguilar
- e Escuela de Ingeniería Ambiental , Universidad de Ciencias y Artes de Chiapas , Tuxtla Gutiérrez , Mexico
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Tetz LM, Kamau PW, Cheng AA, Meeker JD, Loch-Caruso R. Troubleshooting the dichlorofluorescein assay to avoid artifacts in measurement of toxicant-stimulated cellular production of reactive oxidant species. J Pharmacol Toxicol Methods 2013; 67:56-60. [PMID: 23380227 DOI: 10.1016/j.vascn.2013.01.195] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 01/08/2013] [Accepted: 01/24/2013] [Indexed: 10/27/2022]
Abstract
INTRODUCTION The dichlorofluorescein (DCF) assay is a popular method for measuring cellular reactive oxidant species (ROS). Although caveats have been reported with the DCF assay and other compounds, the potential for artifactual results due to cell-free interactions between the DCF compound and toxicants has hardly been explored. We evaluated the utility of the DCF assay for measuring ROS generation by the toxicants mono-(2-ethylhexyl) phthalate (MEHP), and tetrabromobisphenol A (TBBPA). METHODS DCF fluorescence was measured spectrofluorometrically after a 1-h incubation of toxicants with 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate (carboxy-H2DCFDA). MEHP was incubated with carboxy-H2DCFDA in cell-free solutions of Hank's buffered salt solution (HBSS), or in Royal Park Memorial Institute (RPMI) medium with or without fetal bovine serum. TBBPA was incubated with carboxy-H2DCFDA in cell-free HBSS and with human trophoblast cells (HTR8/SVneo cells). RESULTS MEHP did not increase fluorescence in solutions of carboxy-H2DCFDA in HBSS or RPMI medium without serum. However, MEHP (90 and 180μM) increased DCF fluorescence in cell-free RPMI medium containing serum. Furthermore, serum-free and cell-free HBSS containing 25μM TBBPA exhibited concentration-dependent increased fluorescence with 5-100μM carboxy-H2DCFDA (p<0.05), but not 1μM carboxy-H2DCFDA. In addition, we observed increased fluorescence in HTR8/SVneo cell cultures exposed to TBBPA (0.5-25μM) (p<0.05), as we had observed in cell-free buffer. DISCUSSION MEHP demonstrated an interaction with serum in cell-free generation of DCF fluorescence, whereas TBBPA facilitated conversion of carboxy-H2DCFDA to the fluorescent DCF moiety in the absence of serum. Because TBBPA increased fluorescence in the absence of cells, the increased DCF fluorescence observed with TBBPA in the presence of cells cannot be attributed to cellular ROS and may, instead, be the result of chemical activation of carboxy-H2DCFDA to the fluorescent DCF moiety. These data illustrate the importance of including cell-free controls when using the DCF assay to study toxicant-stimulated cellular production of ROS.
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Affiliation(s)
- Lauren M Tetz
- Environmental Health Sciences Department, University of Michigan School of Public Health, Ann Arbor, MI 48109-2029, USA.
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Yu DN, Macawile MCA, Abella LC, Gallardo SM. Degradation of polychlorinated biphenyls in aqueous solutions after UV-peroxide treatment: focus on toxicity of effluent to primary producers. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2011; 74:1607-1614. [PMID: 21531462 DOI: 10.1016/j.ecoenv.2011.04.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/05/2011] [Accepted: 04/15/2011] [Indexed: 05/30/2023]
Abstract
The combination of UV irradiation and hydrogen peroxide (UV-H(2)O(2)) was shown to be effective in treating water spiked with 2,2',4,4',5,5'-hexachlorobipheny (PCB 153), reducing its concentration by as much as 98%. To test the toxicity of the effluent, bioassays involving three species of primary producers were performed. Results showed the effluent exerting an adverse effect on the algae Scenedesmus bijugatus and the duckweed Lemna paucicostata. On the other hand, exposure of the mungbean Vigna radiata to the effluent revealed mostly no statistically significant adverse effect or growth stimulation. This suggested that on an exposure period of 96 h, higher forms of chlorophyll-bearing species such as plants are relatively unaffected by trace concentrations of PCBs and degradation products, while less differentiated species like algae and duckweeds are vulnerable.
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Affiliation(s)
- Dennis N Yu
- Chemical Engineering Department, De La Salle University - Manila, 2401 Taft Avenue, Malate, Manila 1004, Philippines.
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Han SK, Bilski P, Karriker B, Sik RH, Chignell CF. Oxidation of flame retardant tetrabromobisphenol A by singlet oxygen. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:166-72. [PMID: 18350892 PMCID: PMC2376276 DOI: 10.1021/es071800d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Wide use of flame retardants can pose an environmental hazard, and it is of interest to investigate how they may degrade. We report here that 3,3',5,5'-tetrabromobisphenol A (TBBPA) is subject to photosensitized oxidation involving singlet molecular oxygen ((1)O2). By using visible light and rose bengal or methylene blue as 102 photosensitizers, we have found that TBBPA is a 102 quencher. The quenching rate constant, k(q), depends on TBBPA ionization (pK = 7.4). In acetonitrile, where TBBPA is undissociated, the kq value is 6.1 x 10(5) M(-1) s(-1) for a TBBPA monomer and decreases to 2.9 x 10(4) M(-1) s(-1) for TBBPA dimers and/or aggregates. TBBPA dissociates in aqueous solutions, and its kq value is 1.44 x 10(9) M(-1) s(-1) in alkaline solution, decreasing to 3.9 x 10(8) M(-1) s(-1) at pH 7.2. The strong 102 quenching by TBBPA anion initiates an efficient oxidation of TBBPA, which results in oxygen consumption in aqueous micellar (e.g., Triton X-100) solutions containing photosensitizer. This oxygen consumption is mediated by transient radical species, which we detected by using EPR spectroscopy. We observed two major radicals and one minor radical generated from TBBPA by reaction with 102 at pH 10. One was identified as the 2,6-dibromo-p-benzosemiquinone radical (a2H = 2.36 G, g = 2.0056). A second radical (aH = 2.10 G, g = 2.0055) could not be identified butwas probably a 2,6-dibromo-p-benzosemiquinone radical containing an EPR-silent substituent at the 3-position. Spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DPMO) showed that other minor radicals (hydroxyl, carbon-centered) are also generated during the reaction of TBBPA with (1)O2. The photosensitized production of radicals and oxygen consumption were completely inhibited by the azide anion, an efficient physical (1)O2 quencher. Because TBBPA is a stable compound that at neutral pH does not absorb much of the atmosphere-filtered solar radiation, its photosensitized oxidation by (1)O2 may be the key reaction initiating or mediating TBBPA degradation in the natural environment.
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Affiliation(s)
- S K Han
- Department of Marine Environmental Engineering, Mokpo National Maritime University, 571-2 Chukkyo-dong, Mokpo 530-729, South Korea
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Niu JF, Yang ZF, Shen ZY, Wang LL. QSPRs for the prediction of photodegradation half-life of PCBs in n-hexane. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2006; 17:173-82. [PMID: 16644556 DOI: 10.1080/10659360600636170] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
By partial least squares (PLS) regression analysis, a quantitative structure-property relationship (QSPR) model was developed for photodegradation half-life (t1/2) of polychlorinated biphenyls (PCBs) in n-hexane solution under UV irradiation. Quantum chemical descriptors computed by PM3 Hamiltonian were used as predictor variables. The cross-validated value for the optimal QSPR model was 0.589, indicating good predictive capability for log t1/2 values of PCBs in n-hexane. The QSPR results show that standard heat of formation (DeltaHf), total energy (TE), and molecular weight (Mw) have dominant effect on t1/2 values of PCBs in n-hexane. Increasing DeltaHf and TE values or decreasing Mw values of the PCBs leads to decrease of log t1/2 values. In addition, increasing the largest negative atomic charge on a carbon atom and dipole moment of the PCBs leads to decrease of log t1/2 values.
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Affiliation(s)
- J F Niu
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, P. R. China.
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Qin HF, Bao HY, Liu AD, Hou XG. Photodegradation of 4-Chlorobiphenyl in Hexane by UV Irradiation. CHINESE J CHEM 2006. [DOI: 10.1002/cjoc.200690068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Eriksson J, Rahm S, Green N, Bergman A, Jakobsson E. Photochemical transformations of tetrabromobisphenol A and related phenols in water. CHEMOSPHERE 2004; 54:117-126. [PMID: 14559264 DOI: 10.1016/s0045-6535(03)00704-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A method was developed for studies of the phototransformation at UV irradiation of aqueous solutions of tetrabromobisphenol A (TBBPA), tribromobisphenol A (TriBBPA), tetrachlorobisphenol A (TCBPA), 2,4-dichlorophenol at various pHs as well as 2-chlorophenol, 2-bromophenol, 3,4-dichlorophenol and bisphenol A at pH 11. The absorbance spectra of the compounds and the emission spectra of the light-source were determined and used to calculate disappearance quantum yields of the photochemical reactions that were taking place. No major differences between the disappearance quantum yields of TBBPA and TCBPA were observed at pH 10, while the disappearance quantum yield of TriBBPA was approximately two times higher. The rate of decomposition of TBBPA was six times higher at pH 8 than at pH 6. Identification of the degradation products of TBBPA and TriBBPA, by GC-MS analysis and by comparison to synthesised reference compounds, indicated that TBBPA and TriBBPA decompose via different mechanisms. Three isopropylphenol derivatives; 4-isopropyl-2,6-dibromophenol, 4-isopropylene-2,6-dibromophenol and 4-(2-hydroxyisopropyl)-2,6-dibromophenol, were identified as major degradation products of TBBPA while the major degradation product of TriBBPA was tentatively identified as 2-(2,4-cyclopentadienyl)-2-(3,5-dibromo-4-hydroxyphenyl)propane.
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Affiliation(s)
- Johan Eriksson
- Departments of Environmental Chemistry and Structural Chemistry, Stockholm University, SE-106 91, Sweden.
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Chang FC, Chiu TC, Yen JH, Wang YS. Dechlorination pathways of ortho-substituted PCBs by UV irradiation in n-hexane and their correlation to the charge distribution on carbon atom. CHEMOSPHERE 2003; 51:775-784. [PMID: 12668036 DOI: 10.1016/s0045-6535(03)00003-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The photodegradations of 22 individual polychlorinated biphenyl (PCB) congeners (including 21 non-coplanar ortho substituted and one non-ortho substituted) by irradiation with ultraviolet lamp in n-hexane solution were studied. Photoproducts were identified by matching their retention times and mass spectra with those of authentic standards. PCB congener with less than two chlorides was photodegraded within half an hour, if more than three chlorine on ring, the photodechlorination time for PCB needs one and half hours or more, sometimes even longer than 15 h. The half-life of PCB degradation by photodechlorination was much shorter than that by anaerobic biological dechlorination. Charge distribution on carbon atom combined with the monitoring products of individual PCB congeners were used to deduce the photodegradation pathways. The higher the charge distribution for carbon to which chlorine is attached, the easier for photodechlorination to occur. A lot of chlorine atoms attached PCB, the dechlorination was found to occur prior to the carbon with higher charge distribution at the benzene ring with more chlorine atoms attached.
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Affiliation(s)
- Fang Cheng Chang
- Department of Agricultural Chemistry, National Taiwan University, 1, sec. 4, Roosevelt Road, 10617, Taipei, Taiwan
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Anitescu G, Tavlarides LL. Methanol as a Cosolvent and Rate-Enhancer for the Oxidation Kinetics of 3,3‘,4,4‘-Tetrachlorobiphenyl Decomposition in Supercritical Water. Ind Eng Chem Res 2002. [DOI: 10.1021/ie0103714] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gheorghe Anitescu
- Department of Chemical Engineering and Materials Science, Syracuse University, Syracuse, New York 13244
| | - Lawrence L. Tavlarides
- Department of Chemical Engineering and Materials Science, Syracuse University, Syracuse, New York 13244
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Yao Y, Kakimoto K, Ogawa HI, Kato Y, Kadokami K, Shinohara R. Further study on the photochemistry of non-ortho substituted PCBs by UV irradiation in alkaline 2-propanol. CHEMOSPHERE 2000; 40:951-956. [PMID: 10739031 DOI: 10.1016/s0045-6535(99)00338-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The photochemical behaviors of six non-ortho substituted PCB congeners, i.e., 3,4-DiCB, 3,5-DiCB, 3,3',5-TriCB, 3,4,5-TriCB, 3,3',4,5-TetraCB, and 3,4,4',5-TetraCB, irradiated at 254 nm in alkaline 2-propanol were investigated. Besides the determination of the photodechlorination pathways of these compounds, the presence of photorearrangement was observed in the case of 3, 4-DiCB with its products being identified. The results indicate that dechlorination is much more important than rearrangement during the process of PCB photolysis.
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Affiliation(s)
- Y Yao
- Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, Tobata, Kitakyushu, Japan.
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