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Lendor S, Olkowicz M, Boyaci E, Yu M, Diwan M, Hamani C, Palmer M, Reyes-Garcés N, Gómez-Ríos GA, Pawliszyn J. Investigation of Early Death-Induced Changes in Rat Brain by Solid Phase Microextraction via Untargeted High Resolution Mass Spectrometry: In Vivo versus Postmortem Comparative Study. ACS Chem Neurosci 2020; 11:1827-1840. [PMID: 32407623 DOI: 10.1021/acschemneuro.0c00270] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Analysis of brain samples obtained postmortem remains a standard approach in neuroscience, despite often being suboptimal for inferring roles of small molecules in the pathophysiology of brain diseases. Sample collection and preservation further hinders conclusive interpretation of biomarker analysis in autopsy samples. We investigate purely death-induced changes affecting rat hippocampus in the first hour of postmortem interval (PMI) by means of untargeted liquid chromatography-mass spectrometry-based metabolomics. The unique possibility of sampling the same brain area of each animal both in vivo and postmortem was enabled by employing solid phase microextraction (SPME) probes. Four millimeter probes coated with mixed mode extraction phase were used to sample awake, freely roaming animals, with 2 more sampling events performed after death. Significant changes in brain neurochemistry were found to occur as soon as 30 min after death, further progressing with increasing PMI, evidenced by relative changes in levels of metabolites and lipids. These included species from several distinct groups, which can be classified as engaged in energy metabolism-related processes, signal transduction, neurotransmission, or inflammatory response. Additionally, we perform thorough analysis of interindividual variability in response to death, which provides insights into how this aspect can obscure conclusions drawn from an untargeted study at single metabolite and pathway level. The results suggest high demand for systematic studies examining the PMI time course with in vivo sampling as a starting point to eliminate artifacts in the form of neurochemical changes assumed to occur in vivo.
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Affiliation(s)
- Sofia Lendor
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - Mariola Olkowicz
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - Ezel Boyaci
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - Miao Yu
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - Mustansir Diwan
- Neuroimaging Research Section, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Clement Hamani
- Neuroimaging Research Section, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Michael Palmer
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - Nathaly Reyes-Garcés
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - German Augusto Gómez-Ríos
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
| | - Janusz Pawliszyn
- Department of Chemistry, University of Waterloo, 200 University Avenue, Waterloo, Ontario N2L 3G1, Canada
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Improving in vitro to in vivo extrapolation by incorporating toxicokinetic measurements: A case study of lindane-induced neurotoxicity. Toxicol Appl Pharmacol 2015; 283:9-19. [DOI: 10.1016/j.taap.2014.11.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/16/2014] [Accepted: 11/17/2014] [Indexed: 11/20/2022]
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Abraham MH, Gola JMR, Ibrahim A, Acree WE, Liu X. The prediction of blood-tissue partitions, water-skin partitions and skin permeation for agrochemicals. PEST MANAGEMENT SCIENCE 2014; 70:1130-1137. [PMID: 24085512 DOI: 10.1002/ps.3658] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 09/03/2013] [Accepted: 09/30/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND There is considerable interest in the blood-tissue distribution of agrochemicals, and a number of researchers have developed experimental methods for in vitro distribution. These methods involve the determination of saline-blood and saline-tissue partitions; not only are they indirect, but they do not yield the required in vivo distribution. RESULTS The authors set out equations for gas-tissue and blood-tissue distribution, for partition from water into skin and for permeation from water through human skin. Together with Abraham descriptors for the agrochemicals, these equations can be used to predict values for all of these processes. The present predictions compare favourably with experimental in vivo blood-tissue distribution where available. The predictions require no more than simple arithmetic. CONCLUSIONS The present method represents a much easier and much more economic way of estimating blood-tissue partitions than the method that uses saline-blood and saline-tissue partitions. It has the added advantages of yielding the required in vivo partitions and being easily extended to the prediction of partition of agrochemicals from water into skin and permeation from water through skin.
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Tissue-to-blood distribution coefficients in the rat: Utility for estimation of the volume of distribution in man. Eur J Pharm Sci 2013; 50:526-43. [DOI: 10.1016/j.ejps.2013.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 07/03/2013] [Accepted: 08/13/2013] [Indexed: 12/21/2022]
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Kuo DTF, Di Toro DM. Biotransformation model of neutral and weakly polar organic compounds in fish incorporating internal partitioning. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2013; 32:1873-1881. [PMID: 23625748 DOI: 10.1002/etc.2259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 03/29/2013] [Accepted: 04/22/2013] [Indexed: 06/02/2023]
Abstract
A model for whole-body in vivo biotransformation of neutral and weakly polar organic chemicals in fish is presented. It considers internal chemical partitioning and uses Abraham solvation parameters as reactivity descriptors. It assumes that only chemicals freely dissolved in the body fluid may bind with enzymes and subsequently undergo biotransformation reactions. Consequently, the whole-body biotransformation rate of a chemical is retarded by the extent of its distribution in different biological compartments. Using a randomly generated training set (n = 64), the biotransformation model is found to be: log (HLφfish ) = 2.2 (±0.3)B - 2.1 (±0.2)V - 0.6 (±0.3) (root mean square error of prediction [RMSE] = 0.71), where HL is the whole-body biotransformation half-life in days, φfish is the freely dissolved fraction in body fluid, and B and V are the chemical's H-bond acceptance capacity and molecular volume. Abraham-type linear free energy equations were also developed for lipid-water (Klipidw ) and protein-water (Kprotw ) partition coefficients needed for the computation of φfish from independent determinations. These were found to be 1) log Klipidw = 0.77E - 1.10S - 0.47A - 3.52B + 3.37V + 0.84 (in Lwat /kglipid ; n = 248, RMSE = 0.57) and 2) log Kprotw = 0.74E - 0.37S - 0.13A - 1.37B + 1.06V - 0.88 (in Lwat /kgprot ; n = 69, RMSE = 0.38), where E, S, and A quantify dispersive/polarization, dipolar, and H-bond-donating interactions, respectively. The biotransformation model performs well in the validation of HL (n = 424, RMSE = 0.71). The predicted rate constants do not exceed the transport limit due to circulatory flow. Furthermore, the model adequately captures variation in biotransformation rate between chemicals with varying log octanol-water partitioning coefficient, B, and V and exhibits high degree of independence from the choice of training chemicals. The present study suggests a new framework for modeling chemical reactivity in biological systems.
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Affiliation(s)
- Dave T F Kuo
- Civil and Environmental Engineering Department, University of Delaware, Newark, Delaware, USA.
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Gouliarmou V, Smith KEC, de Jonge LW, Mayer P. Measuring Binding and Speciation of Hydrophobic Organic Chemicals at Controlled Freely Dissolved Concentrations and without Phase Separation. Anal Chem 2012; 84:1601-8. [DOI: 10.1021/ac2028497] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Varvara Gouliarmou
- Department
of Environmental
Science, Aarhus University, P.O. Box 358,
4000 Roskilde, Denmark
| | - Kilian E. C. Smith
- Department
of Environmental
Science, Aarhus University, P.O. Box 358,
4000 Roskilde, Denmark
| | - Lis Wollesen de Jonge
- Department of Agroecology and
Environment, Aarhus University, P.O. Box
50, 8830 Tjele, Denmark
| | - Philipp Mayer
- Department
of Environmental
Science, Aarhus University, P.O. Box 358,
4000 Roskilde, Denmark
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7
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Tremblay RT, Kim D, Fisher JW. Determination of tissue to blood partition coefficients for nonvolatile herbicides, insecticides, and fungicides using negligible depletion solid-phase microextraction (nd-SPME) and ultrafiltration. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2012; 75:288-298. [PMID: 22409491 DOI: 10.1080/15287394.2012.652059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Partition coefficients (PCs) are used in physiologically based pharmacokinetic (PBPK) models to estimate the free concentration of a chemical in specific blood or organs. Biological PC(tissue:blood) (tissue to blood) values were determined for a series of nonvolatile herbicides, insecticides, and fungicides in liver, brain, skin, fat, kidneys, and muscle of male Sprague-Dawley rats using two different analytical methods. The free phase concentration (in phosphate-buffered saline) of a given chemical was measured in the presence and absence of tissue (including blood) and used to calculate the PC, defined as the ratio of the concentration of the chemical in saline to the concentration in the tissue. PCs were determined for 13 compounds with aqueous solubility ranging from 20 to 4100 mg/L, molecular weights from 187.3 to 342.2 g/mol, and log K (ow) values from -0.18 to 3.9. An ultrafiltration high-performance liquid chromatography (HPLC) method was implemented for compounds with log K (ow) near 0.1 or less and a negligible depletion solid-phase microextraction (nd-SPME) method for compounds with higher log K (ow). PC(tissue:saline) coefficients of variation were 0.13 (n = 3 compounds) on average for the HPLC method and 0.29 (n = 10 compounds) for the nd-SPME method. Presented here is one of the most comprehensive data sets of biological partition coefficients for herbicides, insecticides, and fungicides.
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Affiliation(s)
- Raphaël T Tremblay
- Interdisciplinary Toxicology Program, University of Georgia, Athens, Georgia, USA.
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Park TJ, Kim YS, Hwang T, Govindaiah P, Choi SW, Kim E, Won K, Lee SH, Kim JH. Preparation and characterization of heparinized multi-walled carbon nanotubes. Process Biochem 2012. [DOI: 10.1016/j.procbio.2011.10.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Jahnke A, Mayer P, Adolfsson-Erici M, McLachlan MS. Equilibrium sampling of environmental pollutants in fish: comparison with lipid-normalized concentrations and homogenization effects on chemical activity. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:1515-1521. [PMID: 21437939 DOI: 10.1002/etc.534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 12/24/2010] [Accepted: 02/07/2011] [Indexed: 05/30/2023]
Abstract
Equilibrium sampling of organic pollutants into the silicone polydimethylsiloxane (PDMS) has recently been applied in biological tissues including fish. Pollutant concentrations in PDMS can then be multiplied with lipid/PDMS distribution coefficients (D(Lipid,PDMS) ) to obtain concentrations in fish lipids. In the present study, PDMS thin films were used for equilibrium sampling of polychlorinated biphenyls (PCBs) in intact tissue of two eels and one salmon. A classical exhaustive extraction technique to determine lipid-normalized PCB concentrations, which assigns the body burden of the chemical to the lipid fraction of the fish, was additionally applied. Lipid-based PCB concentrations obtained by equilibrium sampling were 85 to 106% (Norwegian Atlantic salmon), 108 to 128% (Baltic Sea eel), and 51 to 83% (Finnish lake eel) of those determined using total extraction. This supports the validity of the equilibrium sampling technique, while at the same time confirming that the fugacity capacity of these lipid-rich tissues for PCBs was dominated by the lipid fraction. Equilibrium sampling was also applied to homogenates of the same fish tissues. The PCB concentrations in the PDMS were 1.2 to 2.0 times higher in the homogenates (statistically significant in 18 of 21 cases, p < 0.05), indicating that homogenization increased the chemical activity of the PCBs and decreased the fugacity capacity of the tissue. This observation has implications for equilibrium sampling and partition coefficients determined using tissue homogenates.
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Affiliation(s)
- Annika Jahnke
- Department of Applied Environmental Science, Stockholm University, Stockholm, Sweden.
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Escher BI, Cowan-Ellsberry CE, Dyer S, Embry MR, Erhardt S, Halder M, Kwon JH, Johanning K, Oosterwijk MTT, Rutishauser S, Segner H, Nichols J. Protein and lipid binding parameters in rainbow trout (Oncorhynchus mykiss) blood and liver fractions to extrapolate from an in vitro metabolic degradation assay to in vivo bioaccumulation potential of hydrophobic organic chemicals. Chem Res Toxicol 2011; 24:1134-43. [PMID: 21604782 DOI: 10.1021/tx200114y] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binding of hydrophobic chemicals to colloids such as proteins or lipids is difficult to measure using classical microdialysis methods due to low aqueous concentrations, adsorption to dialysis membranes and test vessels, and slow kinetics of equilibration. Here, we employed a three-phase partitioning system where silicone (polydimethylsiloxane, PDMS) serves as a third phase to determine partitioning between water and colloids and acts at the same time as a dosing device for hydrophobic chemicals. The applicability of this method was demonstrated with bovine serum albumin (BSA). Measured binding constants (K(BSAw)) for chlorpyrifos, methoxychlor, nonylphenol, and pyrene were in good agreement with an established quantitative structure-activity relationship (QSAR). A fifth compound, fluoxypyr-methyl-heptyl ester, was excluded from the analysis because of apparent abiotic degradation. The PDMS depletion method was then used to determine partition coefficients for test chemicals in rainbow trout (Oncorhynchus mykiss) liver S9 fractions (K(S9w)) and blood plasma (K(bloodw)). Measured K(S9w) and K(bloodw) values were consistent with predictions obtained using a mass-balance model that employs the octanol-water partition coefficient (K(ow)) as a surrogate for lipid partitioning and K(BSAw) to represent protein binding. For each compound, K(bloodw) was substantially greater than K(S9w), primarily because blood contains more lipid than liver S9 fractions (1.84% of wet weight vs 0.051%). Measured liver S9 and blood plasma binding parameters were subsequently implemented in an in vitro to in vivo extrapolation model to link the in vitro liver S9 metabolic degradation assay to in vivo metabolism in fish. Apparent volumes of distribution (V(d)) calculated from the experimental data were similar to literature estimates. However, the calculated binding ratios (f(u)) used to relate in vitro metabolic clearance to clearance by the intact liver were 10 to 100 times lower than values used in previous modeling efforts. Bioconcentration factors (BCF) predicted using the experimental binding data were substantially higher than the predicted values obtained in earlier studies and correlated poorly with measured BCF values in fish. One possible explanation for this finding is that chemicals bound to proteins can desorb rapidly and thus contribute to metabolic turnover of the chemicals. This hypothesis remains to be investigated in future studies, ideally with chemicals of higher hydrophobicity.
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Affiliation(s)
- Beate I Escher
- The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 39 Kessels Road, Brisbane, Qld 4108, Australia.
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Adler S, Basketter D, Creton S, Pelkonen O, van Benthem J, Zuang V, Andersen KE, Angers-Loustau A, Aptula A, Bal-Price A, Benfenati E, Bernauer U, Bessems J, Bois FY, Boobis A, Brandon E, Bremer S, Broschard T, Casati S, Coecke S, Corvi R, Cronin M, Daston G, Dekant W, Felter S, Grignard E, Gundert-Remy U, Heinonen T, Kimber I, Kleinjans J, Komulainen H, Kreiling R, Kreysa J, Leite SB, Loizou G, Maxwell G, Mazzatorta P, Munn S, Pfuhler S, Phrakonkham P, Piersma A, Poth A, Prieto P, Repetto G, Rogiers V, Schoeters G, Schwarz M, Serafimova R, Tähti H, Testai E, van Delft J, van Loveren H, Vinken M, Worth A, Zaldivar JM. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010. Arch Toxicol 2011; 85:367-485. [PMID: 21533817 DOI: 10.1007/s00204-011-0693-2] [Citation(s) in RCA: 358] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/03/2011] [Indexed: 01/09/2023]
Abstract
The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated.
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Affiliation(s)
- Sarah Adler
- Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET), Federal Institute for Risk Assessment (BfR), Berlin, Germany
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12
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Joshi G, Tremblay RT, Martin SA, Fisher JW. Partition coefficients for nonane and its isomers in the rat. Toxicol Mech Methods 2010; 20:594-9. [DOI: 10.3109/15376516.2010.518175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Automated solid-phase microextraction and thin-film microextraction for high-throughput analysis of biological fluids and ligand–receptor binding studies. Nat Protoc 2010; 5:140-61. [DOI: 10.1038/nprot.2009.180] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Vuckovic D, Pawliszyn J. Automated study of ligand–receptor binding using solid-phase microextraction. J Pharm Biomed Anal 2009; 50:550-5. [DOI: 10.1016/j.jpba.2008.08.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/14/2008] [Accepted: 08/21/2008] [Indexed: 11/28/2022]
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Poerschmann J, Trommler U, Nyplova P, Morgenstern P, Górecki T. Complexation-flocculation of organic contaminants by the application of oxyhumolite-based humic organic matter. CHEMOSPHERE 2008; 70:1228-37. [PMID: 17868769 DOI: 10.1016/j.chemosphere.2007.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 07/30/2007] [Accepted: 08/02/2007] [Indexed: 05/17/2023]
Abstract
Control of hazardous organic micropollutants is a challenging water quality issue. Dissolved humic organic matter (DOM) isolated from oxyhumolite coal mined in Bohemia was investigated as a complexation agent to remove polycyclic aromatic hydrocarbons (PAHs) and functionalized phenols from water by a two-stage process involving complexation and flocculation. After the formation of humic-contaminant complexes, ferric salts were added resulting in the precipitation and flocculation of the DOM and the associated pollutants. Flocculation experiments with ferric ion coagulants indicated that precipitation of oxyhumolite DOM together with the complexed contaminants occurred at lower ferric ion concentrations than with the reference DOM in acidic environments (pH approximately 3.5). The complexation-flocculation removal rates for non-reactive PAHs characterized by small localization energies of pi-electrons correlated well with the complexation constants. On the other hand, the combined complexation-flocculation removal rates for activated PAHs including trans-stilbene, anthracene and 9-methyl anthracene, as well as functionalized polar phenols, were higher than predicted from the complexation coefficients. Methodological studies revealed for the first time that the ferric ion coagulant contributed to enhanced removal rates, most probably due to ferric ion-catalyzed pollutant degradation resulting in oxidized products.
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Affiliation(s)
- Juergen Poerschmann
- Department of Environmental Technology, UFZ-Helmholtz Centre for Environmental Research Leipzig-Halle Ltd., Permoserstr. 15, 04318 Leipzig, Germany.
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16
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Coecke S, Blaauboer BJ, Elaut G, Freeman S, Freidig A, Gensmantel N, Hoet P, Kapoulas VM, Ladstetter B, Langley G, Leahy D, Mannens G, Meneguz A, Monshouwer M, Nemery B, Pelkonen O, Pfaller W, Prieto P, Proctor N, Rogiers V, Rostami-Hodjegan A, Sabbioni E, Steiling W, van de Sandt JJM. Toxicokinetics and metabolism. Altern Lab Anim 2005; 33 Suppl 1:147-75. [PMID: 16194147 DOI: 10.1177/026119290503301s15] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Sandra Coecke
- ECVAM, Institute for Health and Consumer Protection, European Commission Joint Research Centre, 21020 Ispra (VA), Italy
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Lee S, Gan J, Liu WP, Anderson MA. Evaluation of Kd underestimation using solid phase microextraction. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:5597-5602. [PMID: 14717169 DOI: 10.1021/es0344563] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Many important environmental pollutants are strongly adsorbing hydrophobic compounds. Because of their potential to adsorb to dissolved organic matter (DOM), their partition coefficient Kd may be underestimated by the conventional approach due to incomplete phase separation. In this study, solid-phase microextraction (SPME) was compared with liquid-liquid partition (LLP) for measuring Kd of bifenthrin and permethrin isomers on sediments. Due to its selective detection of the freely dissolved concentration, SPME gave Kd values 0.6-4.4-fold greater than those obtained by LLP in creek and field sediments and 3.6-21.7-fold greater in nursery runoff sediments. Underestimation by the conventional method was attributed to adsorption to DOM that was not excluded from the aqueous phase by centrifugation. The degree of underestimation was dependent on the source and amount of DOM and may be generally significant for compounds that have DOM adsorption coefficient (KDOM) > 10(4). This study provides evidence that the existing Kd values for many hydrophobic pollutants may be underestimated, and SPME may be a viable, efficacious tool for evaluating the underestimation.
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Affiliation(s)
- S Lee
- Department of Environmental Sciences, University of California, Riverside, California 92507, USA
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Heringa M, Hermens J. Measurement of free concentrations using negligible depletion-solid phase microextraction (nd-SPME). Trends Analyt Chem 2003. [DOI: 10.1016/s0165-9936(03)01006-9] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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