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2. Environmental toxicology, an open online textbook

Author

Gestel, C. A. M., Frank G.A.J. Van Belleghem, Den Brink, N. W., Droge, S. T. J., Hamers, T., Hermens, J. L. M., Kraak, M. H. S., Löhr, A. J., Parsons, J. R., Ragas, A. M. J., Straalen, N. M., Vijver, M. G., Department Science, RS-Research Line Resilience (part of LIRS program), and RS-Research Line Learning (part of LIRS program)

Abstract

This open online textbook on Environmental Toxicology aims at covering the field in its full width, including aspects of environmental chemistry, ecotoxicology, toxicology and risk assessment. With that, it will contribute to improving the quality, continuity and transparency of the education in environmental toxicology. We also want to make sure that fundamental insights on fate and effects of chemicals gained in the past are combined with recent approaches of effect assessment and molecular analysis of mechanisms causing toxicity. The book consists of six chapters, with each chapter being divided into several sub-chapters to enable covering all aspects relevant to the topic. All chapters are designed in a modular way, which each module having clear training goals and being flagged with a number of keywords. Most modules have an average length of 1000-2000 words, a limited number of references, and 3-5 figures and/or tables. A few modules are enlighted with short clips, animations or movies to allow better illustration of the theory. The introduction chapter of the book, for instance, contains a short interview with two key experts reflecting on the development of the field over the past 30 years. The book contains tools for self-study and training, like a (limited) number of questions at the end of each module. For the future we foresee the addition of separate exercises and other tools that may help the student in understanding the theory. The open online textbook was developed by a project team consisting of environmental toxicologists and chemists from six Dutch universities, who drafted the outline of the book and identified authors for each module. Each module is authored by one or two members of the project team. When a topic required expertise not present among the project team, an external expert, often from abroad, was asked to write the module. To guarantee the quality of the book, each module was reviewed by at least one of the members of the project team and also by an international reviewer from outside the project team. The project was supervised by an advisory board, a steering committee and educational advisors. The project team served as the editorial board. The publication of this book on an open online publication platform allows free access to anyone. It is also embedded in learning management systems used in university teaching, thereby giving students easy access. The modular composition of the book will allow teachers to design their “own” book by selecting those modules relevant for the class they teach. This will support flexible use of the book. The publication as an open online book will allow for continuous updating, so it can stay on top of new developments in the field. As it stands, about 100 modules have been finalized, another 30 modules are already available in drafts and currently in the process of being reviewed, and some are still in preparation. In spite of the large number of modules, which do provide a good basis for teaching at the bachelor of science level, we realize the book is still not complete. The book needs more advanced modules that would facilitate teaching at the master of science level and higher, as well as widening the number of topics covered. We would also like to include a broader perspective on regulatory issues so the book covers different geographic regions. Therefore, we will continue working on the book, but we also welcome any suggestions for extending the book. We invite colleagues in environmental toxicology and chemistry to take the initiative to write modules on topics still missing.

Published
2019

3. Investigating hydrophilic and electrostatic properties of surfactants using retention on two mixed-mode liquid chromatographic columns

Author

Hammer, J, Haftka, J J-H, Scherpenisse, P, Hermens, J L M, de Voogt, P, Sub IRAS Tox MTX Milieutoxicologie), One Health Toxicologie, One Health Microbieel, dIRAS RA-1, dIRAS RA-I&I RA, Freshwater and Marine Ecology (IBED, FNWI), Sub IRAS Tox MTX Milieutoxicologie), One Health Toxicologie, One Health Microbieel, dIRAS RA-1, and dIRAS RA-I&I RA

Subjects
Anionic surfactants, Static Electricity, Quantitative Structure-Activity Relationship, 010501 environmental sciences, Perfluorinated surfactants, 01 natural sciences, Biochemistry, High-performance liquid chromatography, Physico-chemical parameters, Analytical Chemistry, chemistry.chemical_compound, Surface-Active Agents, Pulmonary surfactant, Phase (matter), Alkyl, Chromatography, High Pressure Liquid, 0105 earth and related environmental sciences, chemistry.chemical_classification, Wax, Chromatography, Hydrophilic interaction chromatography, 010401 analytical chemistry, Organic Chemistry, Nonionic surfactants, Mixed-mode HILIC, General Medicine, 0104 chemical sciences, Ion Exchange, Silanol, Hydrocarbon, chemistry, visual_art, visual_art.visual_art_medium, Mixed-mode WAX, Hydrophobic and Hydrophilic Interactions
Abstract

In environmental risk assessment, it is essential to understand the relationship between molecular structure and fate and toxicity of organic contaminants. For surfactants, physico-chemical parameters which can reflect the interactions that determine surfactant behavior are not well defined and are therefore needed for the development of robust quantitative structure-activity relationships (QSAR). For the present study, we have measured HPLC retention times of several hydrocarbon and perfluorocarbon surfactant groups on a mixed-mode weak anion-exchange (WAX) and mixed-mode hydrophilic interaction liquid chromatography (HILIC) stationary phase. The nonionic alcohol ethoxylates are well retained on the HILIC column. Retention of anionic surfactants on the HILIC column is likely influenced by the degree of hydration of the surfactants and electrostatic repulsion from silanol groups. Less hydrated anionic surfactants (perfluoroalkyl carboxylates, perfluoroalkyl sulfonates and alkyl sulfates) show minimal hydrophilic interaction while other better hydrated anionic surfactants (alkyl carboxylates and alkyl sulfonates) are well retained. The retention mechanism of surfactants on both columns seems to be related to their degree of hydration, albeit expressed in different retention behavior: generally, retention on the WAX phase increases when retention on the HILIC phase decreases, and vice versa. The retention times from both columns were used to calculate retention factors (k’) and these were subsequently used in calculating parameters that reflect the electrostatic property (kAX) and hydrophilic property (kHILIC) that determine the interaction between the hydrophilic part of the surfactant and the stationary phase. In further development of predictive models, we suggest the use of kAX for anionic surfactants and kHILIC for nonionic surfactants.

Published
2018

4. Solubility Constraints on Aquatic Ecotoxicity Testing of Anionic Surfactants

Author

Hammer, J, Tukker, A M, Postma, J F, Haftka, J J-H, Hermens, J L M, de Voogt, P, Kraak, M H S, Hammer, J, Tukker, A M, Postma, J F, Haftka, J J-H, Hermens, J L M, de Voogt, P, and Kraak, M H S

Abstract

In order to develop models that can predict the environmental behavior and effects of chemicals, reliable experimental data are needed. However, for anionic surfactants the number of ecotoxicity studies is still limited. The present study therefore aimed to determine the aquatic ecotoxicity of three classes of anionic surfactants. To this purpose we subjected daphnids (Daphnia magna) for 48 h to alkyl carboxylates (CxCO2-), alkyl sulfonates (CxSO3-), and alkyl sulfates (CxSO4-) with different carbon chain lengths (x). However, all surfactants with x > 11 showed less than 50% immobility at water solubility. Hence, EC50 values for only few surfactants could be gathered: C9CO2- (16 mg L-1), C11CO2- (0.8 mg L-1) and C11SO4- (13.5 mg L-1). Data from these compounds showed an increase in ecotoxicity with a factor 4.5 per addition of a hydrocarbon unit to the alkyl chain, and a factor 20 when replacing the sulfate head group by a carboxylate head group. Unfortunately, we could not test carboxylates with a broader variety of chain lengths because solubility limited the range of chain length that can be tested.

Published
2018

5. Solubility Constraints on Aquatic Ecotoxicity Testing of Anionic Surfactants

Author

Sub IRAS Tox MTX Milieutoxicologie), One Health Toxicologie, dIRAS RA-1, Sub FG Externen, Hammer, J, Tukker, A M, Postma, J F, Haftka, J J-H, Hermens, J L M, de Voogt, P, Kraak, M H S, Sub IRAS Tox MTX Milieutoxicologie), One Health Toxicologie, dIRAS RA-1, Sub FG Externen, Hammer, J, Tukker, A M, Postma, J F, Haftka, J J-H, Hermens, J L M, de Voogt, P, and Kraak, M H S

Published
2018

6. Investigating hydrophilic and electrostatic properties of surfactants using retention on two mixed-mode liquid chromatographic columns

Author

Sub IRAS Tox MTX Milieutoxicologie), One Health Toxicologie, One Health Microbieel, dIRAS RA-1, dIRAS RA-I&I RA, Hammer, J, Haftka, J J-H, Scherpenisse, P, Hermens, J L M, de Voogt, P, Sub IRAS Tox MTX Milieutoxicologie), One Health Toxicologie, One Health Microbieel, dIRAS RA-1, dIRAS RA-I&I RA, Hammer, J, Haftka, J J-H, Scherpenisse, P, Hermens, J L M, and de Voogt, P

Published
2018

7. Predicting the phospholipophilicity of monoprotic positively charged amines

Author

Droge, S T J, Hermens, J L M, Gutsell, S, Rabone, J, Hodges, G, Sub IRAS Tox MTX Milieutoxicologie), dIRAS RA-1, Sub IRAS Tox MTX Milieutoxicologie), and dIRAS RA-1

Subjects
Inorganic chemistry, Ionic bonding, 010501 environmental sciences, Management, Monitoring, Policy and Law, 01 natural sciences, Cations, Environmental Chemistry, Organic chemistry, Amines, Chromatography, High Pressure Liquid, Phospholipids, 0105 earth and related environmental sciences, chemistry.chemical_classification, Chemistry, Bilayer, 010401 analytical chemistry, Public Health, Environmental and Occupational Health, Cationic polymerization, Sorption, Membranes, Artificial, General Medicine, 0104 chemical sciences, Partition coefficient, Quaternary Ammonium Compounds, Hydrocarbon, Polar, Amine gas treating, Adsorption
Abstract

The sorption affinity of eighty-six charged amine structures to phospholipid monolayers (log KIAM) was determined using immobilized artificial membrane high-performance liquid chromatography (IAM-HPLC). The amine compounds covered the most prevalent types of polar groups, widely ranged in structural complexity, and included forty-seven pharmaceuticals, as well as several narcotics and pesticides. Amine type specific corrective increments were used to align log KIAM data with bilayer membrane sorption coefficients (KMW(IAM)). Using predicted sorption affinities of neutral amines, we evaluated the difference (scaling factor ΔMW) with the measured log KMW(IAM) for cationic amines. The ΔMW values were highly variable, ranging from -2.37 to +2.3 log units. For each amine type, polar amines showed lower ΔMW values than hydrocarbon based amines (CxHyN(+)). COSMOmic software was used to directly calculate the partitioning coefficient of ionic structures into a phospholipid bilayer (KDMPC-W,cation), including quaternary ammonium compounds. The resulting root mean square error (RMSE) between log KDMPC-W,cation and log KMW(IAM) was 0.83 for all eighty-six polar amines, and 0.47 for sixty-eight CxHyN(+) amines. The polar amines were then split into five groups depending on polarity and structural complexity, and corrective increments for each group were defined to improve COSMOmic predictions. Excluding only the group with sixteen complex amine structures (≥4 polar groups, Mw > 400, including several macrolide antibiotics), the resulting RMSE for corrected KDMPC-W,cation values improved to 0.45 log units for the remaining set of 138 polar and CxHyN(+) amines.

Published
2017

8. Phospholipophilicity of CxHyN(+) amines: chromatographic descriptors and molecular simulations for understanding partitioning into membranes

Author

Droge, S T J, Hermens, J L M, Rabone, J, Gutsell, S, Hodges, G, Sub IRAS Tox MTX Milieutoxicologie), and dIRAS RA-1

Subjects
Synthetic membrane, 010501 environmental sciences, Management, Monitoring, Policy and Law, Molecular Dynamics Simulation, 01 natural sciences, Cations, Environmental Chemistry, Molecule, Moiety, Amines, Lipid bilayer, Alkyl, Chromatography, High Pressure Liquid, Phospholipids, 0105 earth and related environmental sciences, chemistry.chemical_classification, Chromatography, Chemistry, Bilayer, 010401 analytical chemistry, Cell Membrane, Public Health, Environmental and Occupational Health, Water, Membranes, Artificial, General Medicine, 0104 chemical sciences, Membrane, Amine gas treating, Hydrophobic and Hydrophilic Interactions
Abstract

Using immobilized artificial membrane high-performance liquid chromatography (IAM-HPLC) the sorption affinity of 70 charged amine structures to phospholipids was determined. The amines contained only 1 charged moiety and no other polar groups, the rest of the molecule being aliphatic and/or aromatic hydrocarbon groups. We systematically evaluated the influence of the amine type (1°, 2°, 3° amines and quaternary ammonium), alkyl chain branching, phenyl ring positioning, charge positioning (terminal vs. central in the molecule) on the phospholipid-water partitioning coefficient (KPLIPW). These experimental results were compared with quantum-chemistry based three-dimensional (3D) molecular simulations of the partitioning of charged amines, including the most likely solute conformers, using a hydrated phospholipid bilayer in the COSMOmic module of COSMOtherm software. Both IAM-HPLC retention data and the simulations suggest that the molecular orientation of charged amines at the location in the bilayer with the lowest calculated Gibbs free energy exerts a strong influence over the partitioning within the membrane. The most favourable position of charged amines coincides with the region where the phosphate anions in the phospholipid bilayer are most abundant. Hydrocarbon units oriented in this layer are located more towards the aqueous phase and contribute less to the overall membrane affinity than hydrocarbon units extending into the more hydrophobic core of the bilayer. COSMOmic simulations explain most of the trends between the structural differences observed in IAM-HPLC based KPLIPW. For this set of cationic structures, the mean absolute difference between COSMOmic simulations and IAM-HPLC data, accounting only for amine type corrective increments, is 0.31 log units.

Published
2016

10. Phospholipophilicity of CxHyN(+) amines: chromatographic descriptors and molecular simulations for understanding partitioning into membranes

Author

Sub IRAS Tox MTX Milieutoxicologie), dIRAS RA-1, Droge, S T J|info:eu-repo/dai/nl/304834017, Hermens, J L M|info:eu-repo/dai/nl/069681384, Rabone, J, Gutsell, S, Hodges, G, Sub IRAS Tox MTX Milieutoxicologie), dIRAS RA-1, Droge, S T J|info:eu-repo/dai/nl/304834017, Hermens, J L M|info:eu-repo/dai/nl/069681384, Rabone, J, Gutsell, S, and Hodges, G

Published
2016

11. Abstracts of papers toxicological meeting

Author

Beynen, A. C., Meijer, G. W., Joosten, H. F. P., van Kolfschoten, A. A., Koëter, H. B. W. M., Leegwater, P. C., Hermens, J. L. M., Rauws, A. G., Lumley, C. E., Walker, S. R., Bodar, C. W. M., Voogt, P. A., Wijnne, H., v. d. Zee, A., Zandee, D. I., Boogaard, P. J., Mulder, G. J., Nagelkerke, J. F., Boot, J. H., van Holsteijn, C. W. M., Blaauboer, B. J., Bos, R. P., Theuws, J. L. G., Jongeneelen, F. J., Brouwer, E. J., de Wolff, F. A., Busker, Ruud W., Commandeur, J. N. M., Vermeulen, N. P. E., Coosen, R., Schenk, E., van Leeuwen, F. X. R., Vos, J. G., Peereboom-Stegeman, J. H. J. Copius, van Veen, H., Pertijs, J., Danse, L. H. J. C., de Jong, K., Speijers, G. J. A., de Kom, J. F. M., Edelbroek, P. M., de Jong, E. G., Maes, R. A. A., de Vries, H., van Henegouwen, G. M. J. Beyersbergen, Berkhuysen, M. H. J., Kalloe, P., de Zwaan, A., de Kock, W. Chr, den Besten, P. J., Dogterom, P., Dormans, J. A. M. A., Boere, A. J. F., van Bree, L., Rombout, P. J. A., Evelo, C. T. A., Fijneman, P. H. S., Henderson, P. Th., Goeptar, A. R., Haenen, G. R. M. M., Bast, A., Tai Tin Tsoi, J. N. L., Timmerman, H., Hageman, G., Hermans, R., Kleinjans, J., Herweijer, M. A., Bootsman, T. C., van der Meer, S. G., Planta, R. J., Kappers, Frederike I., Wondergem-van Eijk, Jacqueline A. A. M., Kelder, P. P., de Mol, N. J., Janssen, L. H. M., Kroese, E. D., van de Poll, M. L. M, Meerman, J. H. N., Lock, R. A. C., Verbost, P. M., Flik, G., Bonga, S. E. Wendelaar, Lusthof, K. J., Hennes, W. C., den Hartogh, R., Kietjens, I., Dornans, J., Rombout, P., Schoonderwoerd, S. A., Luijendijk, J. J., van Henegouwen, G. M. J. Beijersbergen, te Koppele, J. M., Coles, B., Ketterer, B., van Ginkel, M. F., van der Voet, G. B., van Pelt, F. N. A. M., olde Meierink, Y. J. M., Weterings, P. J. J. H, van Os, C. H., Verhagen, H., Schutte, B., Reynders, M. M. J., Blijham, G. H., ten Hoor, F., Kleinjans, J. C. S., Wetzer, A. M., Weetink, H., Rietveld, E. C, Seutter-Berlage, F., and van Henegouwen, Gerard M. J. Beijersbergen

Published
1987
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15. Quantifying processes determining the free concentration of phenanthrene in basal cytotoxicity assays

Author

Kramer, N. I., Krismartina, M., Rico-Rico, A., Blaauboer, B. J., Hermens, J. L. M., Kramer, N. I., Krismartina, M., Rico-Rico, A., Blaauboer, B. J., and Hermens, J. L. M.

Abstract

Difficulties may arise when extrapolating in vitro derived toxicity data to in vivo toxicity data because of the high variability and occasional low sensitivity of in vitro results. Differences in the free concentration of a test compound between in vitro and in vivo systems and between different in vitro systems may in part explain this variability and sensitivity difference. The aim of this study was to determine what assay components influence the free concentration of phenanthrene in a Balb/c 3T3 and RTgill-W1 MTT assay. Partition coefficients of phenanthrene to serum, well plate plastic, cells, and headspace were measured and subsequently used to model the free concentration of the compound in vitro. The estimated free concentration was compared to the free concentration measured in the assays (Figure presented) using solid phase microextraction (SPME). Results indicate that the free concentration of phenanthrene, a relatively volatile and hydrophobic compound, is significantly reduced in a typical in vitro setup as it binds to matrices such as serum protein and well plate plastic. A reduction in free concentration due to increasing serum protein levels is accompanied by an increase in the median effect concentration (EC 50) and can be modeled, with the exception of evaporation, using the partition coefficients of the compound to assay components. © 2012 American Chemical Society.

Published
2012

16. Absorption of hydrophobic compounds into the poly(dimethylsiloxane) coating of solid-phase microextraction fibers : high partition coefficients and fluorescence microscopy images

Author

Philipp Mayer, Vaes, W. H. J., Hermens, J. L. M., and Centraal Instituut voor Voedingsonderzoek TNO

Subjects
Nutrition
Abstract

The use of solid-phase microextraction with poly(dimethylsiloxane) (PDMS)-coated glass fibers for the extraction and analysis of hydrophobic organic analytes is increasing. The literature on this topic is characterized by large discrepancies in partition coefficients and an uncertainty of whether highly hydrophobic analytes are retained by absorption into the fiber coating or by adsorption to the fiber surface. We applied a new method, which minimizes the impact of experimental artifacts, to determine PDMS water partition coefficients of 17 hydrophobic analytes including chlorinated benzenes, PCBs, PAHs, and p,p′-DDE. These partition coefficients are several orders of magnitude higher than some reported values. Two observations strongly suggest that the retention of hydrophobic organic substances is governed by partitioning into the PDMS coating. (1) The partition coefficients are proportional with octanol/water partition coefficients. (2) The fluorescence of fluoranthene was observed to be homogeneously distributed within the polymer coating when studied by means of fluorescence microscopy. Implications of these findings for the application of solid-phase microextraction with respect to potential detection limits, with respect to biomimetic extraction, and with respect to measurements in multicompartment systems are discussed. © 2000 American Chemical Society. Chemicals/CAS: baysilon, 63148-62-9; Benzene, 71-43-2; Dimethylpolysiloxanes; p-Aminohippuric Acid, 61-78-9; Polychlorinated Biphenyls; Silicones

Published
2000

17. Effects of solvents and dosing procedure on chemical toxicity in cell-based in vitro assays

Author

Tanneberger, K., Rico-Rico, A., Kramer, N. I., Busser, F. J. M., Hermens, J. L. M., Schirmer, K., Tanneberger, K., Rico-Rico, A., Kramer, N. I., Busser, F. J. M., Hermens, J. L. M., and Schirmer, K.

Abstract

Due to the implementation of new legislation, such as REACh, a dramatic increase of animal use for toxicity testing is expected and the search for alternatives is timely. Cell-based in vitro assays are promising alternatives. However, the behavior of chemicals in these assays is still poorly understood. We set out to quantify the exposure and associated toxicity of chemicals with different physicochemical properties toward a fish gill cell line when different solvents and procedural steps are used to introduce test chemicals to cells. Three chemicals with a range of hydrophobicity and volatility were selected and delivered in three different solvents using two common dosing procedures. Toxicity tests were coupled with chemical analysis to quantify the chemical concentrations within culture wells. The impact of solvents and dosing procedure was greatest for the most volatile and hydrophobic test chemical. We show that certain combinations of the test chemical, solvent, and procedural steps can lead to inhomogeneous distribution of the test chemical and thus differing degrees of bioavailability, resulting in quantitative differences in apparent toxicity. © 2010 American Chemical Society.

Published
2010

18. Phospholipophilicity of CxHyN+ amines: chromatographic descriptors and molecular simulations for understanding partitioning into membranes.

Author

Droge, S. T. J., Hermens, J. L. M., Rabone, J., Gutsell, S., and Hodges, G.

Abstract

Using immobilized artificial membrane high-performance liquid chromatography (IAM-HPLC) the sorption affinity of 70 charged amine structures to phospholipids was determined. The amines contained only 1 charged moiety and no other polar groups, the rest of the molecule being aliphatic and/or aromatic hydrocarbon groups. We systematically evaluated the influence of the amine type (1°, 2°, 3° amines and quaternary ammonium), alkyl chain branching, phenyl ring positioning, charge positioning (terminal vs. central in the molecule) on the phospholipid-water partitioning coefficient (KPLIPW). These experimental results were compared with quantum-chemistry based three-dimensional (3D) molecular simulations of the partitioning of charged amines, including the most likely solute conformers, using a hydrated phospholipid bilayer in the COSMOmic module of COSMOtherm software. Both IAM-HPLC retention data and the simulations suggest that the molecular orientation of charged amines at the location in the bilayer with the lowest calculated Gibbs free energy exerts a strong influence over the partitioning within the membrane. The most favourable position of charged amines coincides with the region where the phosphate anions in the phospholipid bilayer are most abundant. Hydrocarbon units oriented in this layer are located more towards the aqueous phase and contribute less to the overall membrane affinity than hydrocarbon units extending into the more hydrophobic core of the bilayer. COSMOmic simulations explain most of the trends between the structural differences observed in IAM-HPLC based KPLIPW. For this set of cationic structures, the mean absolute difference between COSMOmic simulations and IAM-HPLC data, accounting only for amine type corrective increments, is 0.31 log units. [ABSTRACT FROM AUTHOR]

Published
2016
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19. Plant uptake of LAS and DEHP from sludge amended soil

Author

Lipnick, R. L., Hermens, J. L. M., Jones, K. C., Muir, D. C. G., Grøn, C., Laturnus, F., Mortensen, G. K., Egsgaard, H., Samsøe-Petersen, L., Ambus, Per Lennart, Jensen, E. S., Lipnick, R. L., Hermens, J. L. M., Jones, K. C., Muir, D. C. G., Grøn, C., Laturnus, F., Mortensen, G. K., Egsgaard, H., Samsøe-Petersen, L., Ambus, Per Lennart, and Jensen, E. S.

Published
2001

24. General and Class Specific Models for Prediction of Soil Sorption Using Various Physicochemical Descriptors

Author

Andersson, P. L., Maran, U., Fara, D., Karelson, M., and Hermens, J. L. M.

Abstract

Diverse chemical descriptors were explored for use in QSAR models aimed to screen the soil sorption potential of organic compounds. The descriptors included logP, HyperChem QSARProperties descriptors, a combination of connectivity indices, geometrical, and quantum chemical measures, and two sets from the DRAGON and CODESSA program packages, respectively. Generally, the univariate logP models were capable of capturing most of the variation and give an indication of the sorption potential. The multivariate models required refined variable selection procedures but were shown to include crucial descriptors for modeling compound classes with specific chemical characteristics.

Published
2002
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25. Aqueous Solubility−Molecular Size Relationships:  A Mechanistic Case Study Using C<INF>10</INF>- to C<INF>19</INF>-Alkanes

Author

Tolls, J., Dijk, J. van, Verbruggen, E. J. M., Hermens, J. L. M., Loeprecht, B., and Schuurmann, G.

Abstract

Saturated hydrocarbons are important constituents of petroleum products. Their behavior in water, the most prevalent environmental solvent, is of relevance with regard to environmental partitioning. Due to their negligible attractive interactions with water, they are suitable compounds for a mechanism-based validation of the relationship between molecular size and the solubility in water. To that end, we measured the aqueous solubility of aliphatic and alicyclic hydrocarbons with 10 to 19 carbon atoms employing the slow-stirring experiment. Moreover, we compiled data on molecular weight and molar volume at the boiling point as macroscopic size parameters and calculated quantum-chemical molecular size parameters. The aqueous solubility data span a range from 6 × 10-6 M to 4 × 10-11 M with coefficients of variation of less than 15% except for 2,6,10,14-tetramethylpentadecane (39%). The relationships of the experimentally determined solubility values with the macroscopic reflected the general trend of decreasing solubility with increasing molecular size, but discriminated between n- and branched alkanes. This indicates that these parameters do not reflect the solute−solvent interactions at the microscopic level. Interpretation of the experimentally observed solubility data based on theoretical considerations of the conformation and the constitution of alkanes is consistent with the following overall picture:  For a given n-alkane in aqueous solution, the all-trans conformation is preferred over folded geometries. Within alkanes, molecular size is the primary determinant of their solubility in water, and increasing molecular size results in a decrease in water solubility mainly due to the increased free energy penalty for cavity formation in water. The solvent-accessible molecular volume and surface area appeared to be valid reflections of the molecular size.

Published
2002
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27. Quantitative Structure−Activity Relationships for the Aquatic Toxicity of Polar and Nonpolar Narcotic Pollutants

Author

Ramos, E. Urrestarazu, Vaes, W. H. J., Verhaar, H. J. M., and Hermens, J. L. M.

Abstract

QSARs were developed for the acute toxicity of narcotic pollutants (nonpolar and polar) to the water flea (Daphnia magna), the guppy (Poecilia reticulata), and the pond snail (Lymnaea stagnalis) using hydrophobicity (log KOW) and hydrogen bonding capacity descriptors (Q-, Q+, εHOMO, εLUMO). Toxicity increases with increasing hydrophobicity and to a minor extent with decreasing LUMO energies and increasing absolute charges in the molecule. The models are rationalized by taking into account the composition of biomembranes, into which chemicals must partition for displaying narcosis. The similarity of these results with models for the membrane/water partition coefficients supports the hypothesis that the toxicity of narcotics is directly related to the accumulation in biological membranes. The results indicate that baseline toxicity based on log KOW should be redefined for chemicals for which log KOW is not a good surrogate for partitioning into biological membranes.

Published
1998

28. Solid Phase Microextraction as a Tool To Determine Membrane/Water Partition Coefficients and Bioavailable Concentrations in in Vitro Systems

Author

Vaes, W. H. J., Ramos, E. Urrestarazu, Hamwijk, C., Holsteijn, I. van, Blaauboer, B. J., Seinen, W., Verhaar, H. J. M., and Hermens, J. L. M.

Abstract

Solid phase microextraction (SPME) is an extraction technique that uses a polymer-coated fiber as the extraction device. After extraction, the compound of interest can be desorbed from the fiber and subsequently analyzed by GC or HPLC. One of the properties of SPME is that only the freely dissolved fraction of a chemical is available for partitioning to the extraction device. The method can be applied in a way that small amounts are extracted from the sample, which allows negligible depletion extraction. These two properties make SPME devices particularly suitable for measurements of free concentrations. In toxicological studies the free concentration is considered to be a more relevant parameter, concerning toxic effects, than the nominal concentration that is used most frequently. In the current study, the usefulness of this method to measure phospholipid/water partition coefficients and free concentrations in three different in vitro test systems (rat hepatocytes in primary culture, 9000g and 100000g homogenate fractions of rainbow trout liver) was demonstrated. Results show separate relationships between phospholipid/water and n-octanol/water partition coefficients for a set of polar and nonpolar organic chemicals, respectively. These observations suggest that phospholipid/water partition coefficients may be a more suitable parameter in modeling the kinetic behavior of organic chemicals. Additionally, differences between the nominal and the actual free concentration in in vitro systems are more pronounced for more hydrophobic compounds, as was expected based on theoretical considerations. To our knowledge, the approach presented here is the first analytical method to measure toxicologically relevant concentrations in in vitro test systems in a fast and efficient way.

Published
1997

31. Multiple computer-automated structure evaluation program study of aquatic toxicity 1: guppy

Author

Hermens, J. L. M., Klopman, G., Rosenkranz, H. S., and Saiakhov, R.

Subjects
*COMPUTER simulation, *GUPPIES, *TOXICITY testing
Abstract

An acute fish toxicity model was constructed on the basis of a wide series of experimental data for guppy. The Multiple Computer-Automated Structure Evaluation program was used to construct the model. The created model possesses very good predictive ability. It can correctlypredict acute toxicity for guppy for 80% of compounds with an average error of only 0.63 log unit per median lethal concentration. The importance of the narcosis effect was demonstrated. The main toxicophores, corresponding to polar narcosis and to the reactive chemicals, were identified. [ABSTRACT FROM AUTHOR]

Published
1999

32. Quantitative structure--property relationships for the chemical reactivity of acrylates and methacrylates

Author

Hermens, J. L. M., Freidig, A. P., and Verhaar, H. J. M.

Subjects
*HYDROLYSIS, *METHYL methacrylate
Abstract

Reactivity towards three different nucleophiles was measured for a training set of six acrylates and seven methacrylates. The reactions studied were neutral and base-catalyzed hydrolysis and Michael addition of reduced glutathione (GSH). A linear free energy relationship (LFER) was established for the base-catalyzed hydrolysis rate constants of methacrylates, with the Taft parameter sigma* as single descriptor. The GSH reactivity could be modeled with a partial least square regression (PLS) using four quantum chemical ground state parameters describing the difference in frontier orbital interaction and coulombic forces within the training set. Literature data for GSH reactivity was used to test the applicability of the PLS model. Differences in acute fish toxicity for structurally similar acrylates and methacrylatescould be explained by their different potency as Michael-type acceptors. [ABSTRACT FROM AUTHOR]

Published
1999

33. Estimating impact of humic acid on bioavailability and bioaccumulation of hydrophobic chemicals in guppies using kinetic solid-phase extraction

Author

Hermens, J. L. M., Busser, F. J. M., Garicano, E. A., and Freidig, A. P.

Subjects
*BIOACCUMULATION, *BIOAVAILABILITY, *FISHES, *HUMIC acid
Abstract

Many organic micropollutants show a reduced bioavailability in the presence of dissolved organic matter, which 1, explained by reduction of the freely dissolved aqueous concentration. The partition coefficient between organic matter and the aqueous phase, KDoc, is used to describe the distribution of neutral hydrophobic micropollutants. In the present study, the freely dissolved concentration was measured using partitioning of micropollutants between water and a hydrophobic solid-phase filter disk (C-18 Empore(TM) disk) Slivers of the disk were exposed in aqueous solutions that contained several micropollutants and Aldrich humic acid at different concentrations. Initial uptake rates of the micropollutants from water to disk (k1) were measured to estimate the freely dissolved concentration in the solution. Partition coefficients, KDoc, of tetra- and hexachlorobenzene. pentachloroatil , iodofenphos, and p,p' DDT were calculated. These values were comparable to earlier, published KDoc s toward Aldrich humic 1C)d In a validation experiment, the uptake rates of three chlorobenzenes in guppy (Poecilia reticulata) were measured In the absence I and presence of humic acids. The lowering of the uptake rates in guppy was correctly predicted with the KDoc values from the Empore disk experiment These findings suggest that the proposed method to measure the freely dissolved concentration is a valid tool to predict the bioavailability of hydrophobic compounds in the aqueous environment. [ABSTRACT FROM AUTHOR]

Published
1998

34. A novel approach for dissolving chemicals with low aqueous solubility: generator disk in the headspace

Author

Hermens, J. L. M., Verhaar, H. J. M., Vaes, W. H. J., and Ramos, E. Urrestarazu

Subjects
*CHEMISTRY, *DDT (Insecticide), *MATHEMATICAL analysis, *POLLUTION, *POLYCHLORINATED biphenyls
Abstract

In this communication a novel approach of preparing solutions of chemicals in water with a low solubility is presented. The method consists of loading a C18 coated Empore(tm) disk withthe chemical of interest, followed by desorption of the chemical into the water through the vapor phase. [ABSTRACT FROM AUTHOR]

Published
1997

35. Estimating total body residues and baseline toxicity of complex organic mixtures in effluents and surface waters

Author

Hermens, J. L. M., van deGuchte, C., van Duyn, P., van Leeuwen, C.J., van Loon, W. M. G. M., Verwoerd, M. E., and Wijnker, F. G.

Subjects
*BIOACCUMULATION, *ENVIRONMENTAL chemistry
Abstract

Recently, a new procedure was developed to estimate total body residues (TBRs) in biota after exposure to complex mixtures of organic chemicals in water. The procedure is based on a simulation of bioconcentration using a hydrophobic phase and on the measurement of total molar concentrations on this hydrophobic phase via vapor pressure osmometry and gas chromatography-mass spectrometry. In this paper, the results of the application of this procedure to effluents and surface water are presented. Estimated TBRs (TBRests) give informationon the potential total bioaccumulation of complex mixtures. Moreover, using these estimated total body burdens, baseline toxicity effectscan be predicted, including the contributions of chemicals with specific modes of action to the overall baseline toxicity. The advantage of the parameter TBRest is that it determines total molar concentrations of organic chemicals, including those chemicals that are usually not measured because they cannot be identified or because their concentrations are below the detection limits of individual compounds. [ABSTRACT FROM AUTHOR]

Published
1997

42. Exposure Modelling

Author

Van De Meent, D., De Bruijn, J. H. M., De Leeuw, F. A. A. M., De Nijs, A. C. M., Jager, D. T., Vermeire, T. G., van Leeuwen, C. J., editor, and Hermens, J. L. M., editor

Published
1995
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49. Predicting the phospholipophilicity of monoprotic positively charged amines.

Author

Droge ST, Hermens JL, Gutsell S, Rabone J, and Hodges G

Subjects
Adsorption, Cations, Chromatography, High Pressure Liquid, Membranes, Artificial, Quaternary Ammonium Compounds, Amines chemistry, Phospholipids chemistry
Abstract

The sorption affinity of eighty-six charged amine structures to phospholipid monolayers (log K IAM ) was determined using immobilized artificial membrane high-performance liquid chromatography (IAM-HPLC). The amine compounds covered the most prevalent types of polar groups, widely ranged in structural complexity, and included forty-seven pharmaceuticals, as well as several narcotics and pesticides. Amine type specific corrective increments were used to align log K IAM data with bilayer membrane sorption coefficients (K MW (IAM)). Using predicted sorption affinities of neutral amines, we evaluated the difference (scaling factor Δ MW ) with the measured log K MW (IAM) for cationic amines. The Δ MW values were highly variable, ranging from -2.37 to +2.3 log units. For each amine type, polar amines showed lower Δ MW values than hydrocarbon based amines (C x H y N + ). COSMOmic software was used to directly calculate the partitioning coefficient of ionic structures into a phospholipid bilayer (K DMPC-W,cation ), including quaternary ammonium compounds. The resulting root mean square error (RMSE) between log K DMPC-W,cation and log K MW (IAM) was 0.83 for all eighty-six polar amines, and 0.47 for sixty-eight C x H y N + amines. The polar amines were then split into five groups depending on polarity and structural complexity, and corrective increments for each group were defined to improve COSMOmic predictions. Excluding only the group with sixteen complex amine structures (≥4 polar groups, M w > 400, including several macrolide antibiotics), the resulting RMSE for corrected K DMPC-W,cation values improved to 0.45 log units for the remaining set of 138 polar and C x H y N + amines.

Published
2017
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50. Solid phase microextraction as a tool to predict internal concentrations of soil contaminants in terrestrial organisms after exposure to a laboratory standard soil.

Author

van der Wal L, van Gestel CA, and Hermens JL

Subjects
Animals, Chemistry Techniques, Analytical methods, Chlorobenzenes chemistry, Dimethylpolysiloxanes chemistry, Environmental Exposure, Silicones chemistry, Soil analysis, Chlorobenzenes analysis, Chlorobenzenes metabolism, Oligochaeta metabolism, Soil Pollutants analysis, Soil Pollutants metabolism
Abstract

Uptake and accumulation of three chlorobenzenes was studied in both biota (Enchytraeus crypticus) and 30 mum polydimethylsiloxane (PDMS) solid phase microextraction (SPME) fibers after exposure to spiked OECD soil. The OECD soil was spiked with three different concentrations of all contaminants. Uptake of all three chlorobenzenes in E. crypticus was fast and steady state levels were reached within 2-4 days. Also in the PDMS-SPME fibers uptake was very fast for all three compounds, with steady state levels reached after 1 day. Comparison of steady state levels in biota and in the PDMS-SPME fibers showed a relationship which was consistent over the range of concentrations of chlorobenzenes in soil and the difference in logKow. This shows that measuring the concentrations of hydrophobic chemicals in a hydrophobic phase such as PDMS can be used as a simple tool to estimate internal concentrations of these chemicals in biota exposed to complex matrices such as soil.

Published
2004
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