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Hu H, Ma P, Li H, You J. Determining buffering capacity of polydimethylsiloxane-based passive dosing for hydrophobic organic compounds in large-volume bioassays. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169710. [PMID: 38184249 DOI: 10.1016/j.scitotenv.2023.169710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/25/2023] [Accepted: 12/25/2023] [Indexed: 01/08/2024]
Abstract
Polydimethylsiloxane (PDMS) is the most widely used material for passive dosing. However, the ability of PDMS to maintain constant water concentrations of chemicals in large-volume bioassays was insufficiently investigated. In this study, we proposed a kinetic-based method to determine the buffering capacity of PDMS for maintaining constant water concentrations of hydrophobic organic contaminants (HOCs) in large-volume bioassays. A good correlation between log Kow and PDMS-water partitioning coefficients (log KPW) was observed for HOCs with log Kow values ranging from 3.30 to 7.42. For low-molecular-weight HOCs, volatile loss was identified as the primary cause of unstable water concentrations in passive dosing systems. Slow desorption from PDMS resulted in a reduction of water concentrations for high-molecular-weight HOCs. The volume ratio of PDMS to water (RV) was the key factor controlling buffering capacity. As such, buffering capacity was defined as the minimum RV required to maintain 90% of the initial water concentration and was determined to be 0.0076-0.032 for six representative HOCs. Finally, passive dosing with an RV of 0.014 was validated to effectively maintain water concentrations of phenanthrene in 2-L and 96-h toxicity tests with adult mosquitofish. By determining buffering capacity of PDMS, this study recommended specific RV values for cost-efficient implementation of passive dosing approaches in aquatic toxicology, particularly in large-volume bioassays.
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Affiliation(s)
- Hao Hu
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
| | - Ping Ma
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China; Department of Eco-engineering, Guangdong Eco-Engineering Polytechnic, Guangzhou 510520, China
| | - Huizhen Li
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China.
| | - Jing You
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China
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2
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Ruan T, Li P, Wang H, Li T, Jiang G. Identification and Prioritization of Environmental Organic Pollutants: From an Analytical and Toxicological Perspective. Chem Rev 2023; 123:10584-10640. [PMID: 37531601 DOI: 10.1021/acs.chemrev.3c00056] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
Exposure to environmental organic pollutants has triggered significant ecological impacts and adverse health outcomes, which have been received substantial and increasing attention. The contribution of unidentified chemical components is considered as the most significant knowledge gap in understanding the combined effects of pollutant mixtures. To address this issue, remarkable analytical breakthroughs have recently been made. In this review, the basic principles on recognition of environmental organic pollutants are overviewed. Complementary analytical methodologies (i.e., quantitative structure-activity relationship prediction, mass spectrometric nontarget screening, and effect-directed analysis) and experimental platforms are briefly described. The stages of technique development and/or essential parts of the analytical workflow for each of the methodologies are then reviewed. Finally, plausible technique paths and applications of the future nontarget screening methods, interdisciplinary techniques for achieving toxicant identification, and burgeoning strategies on risk assessment of chemical cocktails are discussed.
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Affiliation(s)
- Ting Ruan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pengyang Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haotian Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tingyu Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Luo YS, Chen Z, Hsieh NH, Lin TE. Chemical and biological assessments of environmental mixtures: A review of current trends, advances, and future perspectives. JOURNAL OF HAZARDOUS MATERIALS 2022; 432:128658. [PMID: 35290896 DOI: 10.1016/j.jhazmat.2022.128658] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/21/2022] [Accepted: 03/07/2022] [Indexed: 05/28/2023]
Abstract
Considering the chemical complexity and toxicity data gaps of environmental mixtures, most studies evaluate the chemical risk individually. However, humans are usually exposed to a cocktail of chemicals in real life. Mixture health assessment remains to be a research area having significant knowledge gaps. Characterization of chemical composition and bioactivity/toxicity are the two critical aspects of mixture health assessments. This review seeks to introduce the recent progress and tools for the chemical and biological characterization of environmental mixtures. The state-of-the-art techniques include the sampling, extraction, rapid detection methods, and the in vitro, in vivo, and in silico approaches to generate the toxicity data of an environmental mixture. Application of these novel methods, or new approach methodologies (NAMs), has increased the throughput of generating chemical and toxicity data for mixtures and thus refined the mixture health assessment. Combined with computational methods, the chemical and biological information would shed light on identifying the bioactive/toxic components in an environmental mixture.
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Affiliation(s)
- Yu-Syuan Luo
- Institute of Food Safety and Health, College of Public Health, National Taiwan University, Taipei City, Taiwan.
| | - Zunwei Chen
- Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Nan-Hung Hsieh
- Interdisciplinary Faculty of Toxicology and Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Tzu-En Lin
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
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4
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Smith KEC, Jeong Y. Passive Sampling and Dosing of Aquatic Organic Contaminant Mixtures for Ecotoxicological Analyses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9538-9547. [PMID: 33749267 DOI: 10.1021/acs.est.0c08067] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Toxicity results from exposure to mixtures of organic contaminants. Assessing this using ecotoxicity bioassays involves sampling of the environmental mixture and then introducing this into the test. The first step is accounting for the bioavailable levels of all mixture constituents. Passive sampling specifically targets these bioavailable fractions but the sampler-accumulated mixture varies with the compound and sampler properties as well as time. The second step involves reproducing and maintaining the sampled mixture constituents in the bioassay. Passive sampler extraction and spiking always leads to a skewed mixture profile in the test. Alternatively, the recovered passive samplers might be directly used in passive dosing mode. Here, the reproduced contaminant mixture depends on whether kinetic or equilibrium sampling applies. These concepts were tested for determining the combined toxicity of laboratory and field mixtures of aquatic contaminants in the Microtox and ER-Calux bioassays. Aqueous sample extraction and spiking, passive sampler extraction and spiking, and passive sampling and dosing were compared for first sampling and then introducing mixtures in toxicity bioassays. The analytical and toxicity results show that the correct way to first sample the bioavailable mixture profile, and then to reproduce and maintain this in the toxicity test, is by combining equilibrium passive sampling and dosing.
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Affiliation(s)
- Kilian E C Smith
- Environmental Safety Group, KIST Europe, Korea Institute of Science and Technology, Campus E 7.1, Saarbrücken, Germany
| | - Yoonah Jeong
- Environmental Safety Group, KIST Europe, Korea Institute of Science and Technology, Campus E 7.1, Saarbrücken, Germany
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Chapman FM, Sparham C, Hastie C, Sanders DJ, van Egmond R, Chapman KE, Doak SH, Scott AD, Jenkins GJS. Comparison of passive-dosed and solvent spiked exposures of pro-carcinogen, benzo[a]pyrene, to human lymphoblastoid cell line, MCL-5. Toxicol In Vitro 2020; 67:104905. [PMID: 32497684 DOI: 10.1016/j.tiv.2020.104905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/26/2020] [Accepted: 05/28/2020] [Indexed: 11/17/2022]
Abstract
Genotoxicity testing methods in vitro provide a means to predict the DNA damaging effects of chemicals on human cells. This is hindered in the case of hydrophobic test compounds, however, which will partition to in vitro components such as plastic-ware and medium proteins, in preference to the aqueous phase of the exposure medium. This affects the freely available test chemical concentration, and as this freely dissolved aqueous concentration is that bioavailable to cells, it is important to define and maintain this exposure. Passive dosing promises to have an advantage over traditional 'solvent spiking' exposure methods and involves the establishment and maintenance of known chemical concentrations in the in vitro medium, and therefore aqueous phase. Passive dosing was applied in a novel format to expose the MCL-5 human lymphoblastoid cell line to the pro-carcinogen, benzo[a]pyrene (B[a]P) and was compared to solvent (dimethyl sulphoxide) spiked B[a]P exposures over 48 h. Passive dosing induced greater changes, at lower concentrations, to micronucleus frequency, p21 mRNA expression, cell cycle abnormalities, and cell and nuclear morphology. This was attributed to a maintained, definable, free chemical concentration using passive dosing and the presence or absence of solvent, and highlights the influence of exposure choice on genotoxic outcomes.
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Affiliation(s)
- Fiona M Chapman
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK.
| | - Chris Sparham
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Colin Hastie
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - David J Sanders
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Roger van Egmond
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Katherine E Chapman
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK
| | - Shareen H Doak
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK
| | - Andrew D Scott
- Safety and Environmental Assurance Centre, Unilever, Colworth House, Sharnbrook, Bedford MK44 1LQ, UK
| | - Gareth J S Jenkins
- In Vitro Toxicology Group, Institute of Life Science 1, Swansea University Medical School, Singleton Campus, Swansea SA2 8PP, UK
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Stibany F, Ewald F, Miller I, Hollert H, Schäffer A. Improving the reliability of aquatic toxicity testing of hydrophobic chemicals via equilibrium passive dosing - A multiple trophic level case study on bromochlorophene. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 584-585:96-104. [PMID: 28142058 DOI: 10.1016/j.scitotenv.2017.01.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/13/2017] [Accepted: 01/13/2017] [Indexed: 04/15/2023]
Abstract
The main objective of the present study was to improve the reliability and practicability of aquatic toxicity testing of hydrophobic chemicals based upon the model substance bromochlorophene (BCP). Therefore, we adapted a passive dosing format to test the toxicity of BCP at different concentrations and in multiple test systems with aquatic organisms of various trophic levels. At the same time, the method allowed for the accurate determination of exposure concentrations (i.e., in the presence of exposed organisms; Ctest) and freely dissolved concentrations (i.e., without organisms present; Cfree) of BCP in all tested media. We report on the joint adaptation of three ecotoxicity tests - algal growth inhibition, Daphnia magna immobilization, and fish-embryo toxicity - to a silicone O-ring based equilibrium passive dosing format. Effect concentrations derived by passive dosing methods were compared with corresponding effect concentrations derived by standard co-solvent setups. The passive dosing format led to EC50-values in the lower μgL-1 range for algae, daphnids, and fish embryos, whereas increased effect concentrations were measured in the co-solvent setups for algae and daphnids. This effect once more shows that passive dosing might offer advantages over standard methods like co-solvent setups when it comes to a reliable risk assessment of hydrophobic substances. The presented passive dosing setup offers a facilitated, practical, and repeatable way to test hydrophobic chemicals on their toxicity to aquatic organisms, and is an ideal basis for the detailed investigation of this important group of chemicals.
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Affiliation(s)
- Felix Stibany
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - Franziska Ewald
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Ina Miller
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Henner Hollert
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Andreas Schäffer
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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Heger S, Bluhm K, Brendt J, Mayer P, Anders N, Schäffer A, Seiler TB, Hollert H. Microscale In Vitro Assays for the Investigation of Neutral Red Retention and Ethoxyresorufin-O-Deethylase of Biofuels and Fossil Fuels. PLoS One 2016; 11:e0163862. [PMID: 27684069 PMCID: PMC5042516 DOI: 10.1371/journal.pone.0163862] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 09/15/2016] [Indexed: 11/21/2022] Open
Abstract
Only few information on the potential toxic effectiveness of biofuels are available. Due to increasing worldwide demand for energy and fuels during the past decades, biofuels are considered as a promising alternative for fossil fuels in the transport sector. Hence, more information on their hazard potentials are required to understand the toxicological impact of biofuels on the environment. In the German Cluster of Excellence "Tailor-made Fuels from Biomass" design processes for economical, sustainable and environmentally friendly biofuels are investigated. In an unique and interdisciplinary approach, ecotoxicological methods are applied to gain information on potential adverse environmental effects of biofuels at an early phase of their development. In the present study, three potential biofuels, ethyl levulinate, 2-methyltetrahydrofuran and 2-methylfuran were tested. Furthermore, we investigated a fossil gasoline fuel, a fossil diesel fuel and an established biodiesel. Two in vitro bioassays, one for assessing cytotoxicity and one for aryl hydrocarbon receptor agonism, so called dioxin-like activity, as measured by Ethoxyresorufin-O-Deethylase, were applied using the permanent fish liver cell line RTL-W1 (Oncorhynchus mykiss). The special properties of these fuel samples required modifications of the test design. Points that had to be addressed were high substance volatility, material compatibility and low solubility. For testing of gasoline, diesel and biodiesel, water accommodated fractions and a passive dosing approach were tested to address the high hydrophobicity and low solubility of these complex mixtures. Further work has to focus on an improvement of the chemical analyses of the fuel samples to allow a better comparison of any effects of fossil fuels and biofuels.
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Affiliation(s)
- Sebastian Heger
- RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Aachen, Germany
| | - Kerstin Bluhm
- RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Aachen, Germany
| | - Julia Brendt
- RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Aachen, Germany
| | - Philipp Mayer
- Technical University of Denmark, Department of Environmental Engineering, Kongens Lyngby, Denmark
| | - Nico Anders
- RWTH Aachen University, Chemical Engineering, Enzyme Process Technology, Aachen, Germany
| | - Andreas Schäffer
- RWTH Aachen University, Institute for Environmental Research, Chair of Environmental Biology and Chemodynamcis, Aachen, Germany
- Chongqing University, College of Resources and Environmental Science, Chongqing, China
- Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing, China
| | - Thomas-Benjamin Seiler
- RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Aachen, Germany
| | - Henner Hollert
- RWTH Aachen University, Institute for Environmental Research, Department of Ecosystem Analysis, Aachen, Germany
- Chongqing University, College of Resources and Environmental Science, Chongqing, China
- Nanjing University, State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing, China
- Tongji University, College of Environmental Science and Engineering and State Key Laboratory of Pollution Control and Resource Reuse, Shanghai, China
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8
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Fischer F, Böhm L, Höss S, Möhlenkamp C, Claus E, Düring RA, Schäfer S. Passive Dosing in Chronic Toxicity Tests with the Nematode Caenorhabditis elegans. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9708-9716. [PMID: 27494096 DOI: 10.1021/acs.est.6b02956] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In chronic toxicity tests with Caenorhabditis elegans, it is necessary to feed the nematode with bacteria, which reduces the freely dissolved concentration (Cfree) of hydrophobic organic chemicals (HOCs), leading to poorly defined exposure with conventional dosing procedures. We examined the efficacy of passive dosing of polycyclic aromatic hydrocarbons (PAHs) using silicone O-rings to control exposure during C. elegans toxicity testing and compared the results to those obtained with solvent spiking. Solid-phase microextraction and liquid-liquid extraction were used to measure Cfree and the chemicals taken up via ingestion. During toxicity testing, Cfree decreased by up to 89% after solvent spiking but remained constant with passive dosing. This led to a higher apparent toxicity on C. elegans exposed by passive dosing than by solvent spiking. With increasing bacterial cell densities, Cfree of solvent-spiked PAHs decreased while being maintained constant with passive dosing. This resulted in lower apparent toxicity under solvent spiking but an increased apparent toxicity with passive dosing, probably as a result of the higher chemical uptake rate via food (CUfood). Our results demonstrate the utility of passive dosing to control Cfree in routine chronic toxicity testing of HOCs. Moreover, both chemical uptake from water or via food ingestion can be controlled, thus enabling the discrimination of different uptake routes in chronic toxicity studies.
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Affiliation(s)
- Fabian Fischer
- German Federal Institute of Hydrology (BfG) , Am Mainzer Tor 1, 56068 Koblenz, Germany
- Institute of Soil Science and Soil Conservation, Research Center for BioSystems, Land Use, and Nutrition (iFZ), Justus Liebig University Giessen , Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Leonard Böhm
- Institute of Soil Science and Soil Conservation, Research Center for BioSystems, Land Use, and Nutrition (iFZ), Justus Liebig University Giessen , Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | | | - Christel Möhlenkamp
- German Federal Institute of Hydrology (BfG) , Am Mainzer Tor 1, 56068 Koblenz, Germany
| | - Evelyn Claus
- German Federal Institute of Hydrology (BfG) , Am Mainzer Tor 1, 56068 Koblenz, Germany
| | - Rolf-Alexander Düring
- Institute of Soil Science and Soil Conservation, Research Center for BioSystems, Land Use, and Nutrition (iFZ), Justus Liebig University Giessen , Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Sabine Schäfer
- German Federal Institute of Hydrology (BfG) , Am Mainzer Tor 1, 56068 Koblenz, Germany
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9
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Defining and Controlling Exposure During In Vitro Toxicity Testing and the Potential of Passive Dosing. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 157:263-292. [DOI: 10.1007/10_2015_5017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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10
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Smith KEC, Jeong Y, Kim J. Passive dosing versus solvent spiking for controlling and maintaining hydrophobic organic compound exposure in the Microtox® assay. CHEMOSPHERE 2015; 139:174-180. [PMID: 26117202 DOI: 10.1016/j.chemosphere.2015.06.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/12/2015] [Accepted: 06/10/2015] [Indexed: 06/04/2023]
Abstract
Microbial toxicity bioassays such as the Microtox® test are ubiquitously applied to measure the toxicity of chemicals and environmental samples. In many ways their operation is conducive to the testing of organic chemicals. They are of short duration, use glass cuvettes and take place at reduced temperatures in medium lacking sorbing components. All of these are expected to reduce sorptive and volatile losses, but particularly for hydrophobic organics the role of such losses in determining the bioassay response remains unclear. This study determined the response of the Microtox® test when using solvent spiking compared to passive dosing for introducing the model hydrophobic compounds acenaphthene, phenanthrene, fluoranthene and benzo(a)pyrene. Compared to solvent spiking, the apparent sensitivity of the Microtox® test with passive dosing was 3.4 and 12.4 times higher for acenaphthene and phenanthrene, respectively. Furthermore, fluoranthene only gave a consistent response with passive dosing. Benzo(a)pyrene did not result in a response with either spiking or passive dosing even at aqueous solubility. Such differences in the apparent sensitivity of the Microtox® test can be traced back to the precise definition of the dissolved exposure concentrations and the buffering of losses with passive dosing. This highlights the importance of exposure control even in simple and short-term microbial bioassays such as the Microtox® test.
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Affiliation(s)
- Kilian E C Smith
- Korea Institute of Science and Technology, Campus E 7.1, Universität des Saarlandes, Saarbrücken, Germany.
| | - Yoonah Jeong
- Korea Institute of Science and Technology, Campus E 7.1, Universität des Saarlandes, Saarbrücken, Germany
| | - Jongwoon Kim
- Korea Institute of Science and Technology, Campus E 7.1, Universität des Saarlandes, Saarbrücken, Germany
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11
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Gilbert D, Mayer P, Pedersen M, Vinggaard AM. Endocrine activity of persistent organic pollutants accumulated in human silicone implants--Dosing in vitro assays by partitioning from silicone. ENVIRONMENT INTERNATIONAL 2015; 84:107-114. [PMID: 26264162 DOI: 10.1016/j.envint.2015.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/28/2015] [Accepted: 07/04/2015] [Indexed: 06/04/2023]
Abstract
Persistent organic pollutants (POPs) accumulated in human tissues may pose a risk for human health by interfering with the endocrine system. This study establishes a new link between actual human internal POP levels and the endocrine active dose in vitro, applying partitioning-controlled dosing from silicone to the H295R steroidogenesis assay: (1) Measured concentrations of POPs in silicone breast implants were taken from a recent study and silicone disks were loaded according to these measurements. (2) Silicone disks were transferred into H295R cell culture plates in order to control exposure of the adrenal cells by equilibrium partitioning. (3) Hormone production of the adrenal cells was measured as toxicity endpoint. 4-Nonylphenol was used for method development, and the new dosing method was compared to conventional solvent-dosing. The two dosing modes yielded similar dose-dependent hormonal responses of H295R cells. However, with the partitioning-controlled freely dissolved concentrations (Cfree) as dose metrics, dose-response curves were left-shifted by two orders of magnitude relative to spiked concentrations. Partitioning-controlled dosing of POPs resulted in up to 2-fold increases in progestagen and corticosteroid levels at Cfree of individual POPs in or below the femtomolar range. Silicone acted not only as source of the POPs but also as a sorption sink for lipophilic hormones, stimulating the cellular hormone production. Methodologically, the study showed that silicone can be used as reference partitioning phase to transfer in vivo exposure in humans (silicone implants) to in vitro assays (partition-controlled dosing). The main finding was that POPs at the levels at which they are found in humans can interfere with steroidogenesis in a human adrenocortical cell line.
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Affiliation(s)
- Dorothea Gilbert
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark; Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Philipp Mayer
- Department of Environmental Engineering, DTU Environment, Technical University of Denmark, Miljøvej 113, DK-2800 Kgs. Lyngby, Denmark
| | - Mikael Pedersen
- Division of Food Chemistry, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark
| | - Anne Marie Vinggaard
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 Søborg, Denmark.
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12
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Claessens M, Monteyne E, Wille K, Vanhaecke L, Roose P, Janssen CR. Passive sampling reversed: coupling passive field sampling with passive lab dosing to assess the ecotoxicity of mixtures present in the marine environment. MARINE POLLUTION BULLETIN 2015; 93:9-19. [PMID: 25752535 DOI: 10.1016/j.marpolbul.2015.02.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/16/2015] [Accepted: 02/19/2015] [Indexed: 06/04/2023]
Abstract
This study presents a new approach in aquatic toxicity testing combining passive sampling and passive dosing. Polydimethylsiloxane sheets were used to sample contaminant mixtures in the marine environment. These sheets were subsequently transferred to ecotoxicological test medium in which the sampled contaminant mixtures were released through passive dosing. 4 out of 17 of these mixtures caused severe effects in a growth inhibition assay with a marine diatom. These effects could not be explained by the presence of compounds detected in the sampling area and were most likely attributable to unmeasured compounds absorbed to the passive samplers during field deployment. The findings of this study indicate that linking passive sampling in the field to passive dosing in laboratory ecotoxicity tests provides a practical and complimentary approach for assessing the toxicity of hydrophobic contaminant mixtures that mimics realistic environmental exposures. Limitations and opportunities for future improvements are presented.
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Affiliation(s)
- Michiel Claessens
- Ghent University, Faculty of Bioscience Engineering, Laboratory of Environmental Toxicology and Aquatic Ecology, J. Plateaustraat 22, B-9000 Ghent, Belgium.
| | - Els Monteyne
- Royal Belgian Institute of Natural Sciences, Management Unit of the North Sea Mathematical Model, 2e en 23e Linieregimentsplein, B-8400 Oostende, Belgium
| | - Klaas Wille
- Ghent University, Faculty of Veterinary Medicine, Research Group of Veterinary Public Health and Zoonoses, Laboratory of Chemical Analysis, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Lynn Vanhaecke
- Ghent University, Faculty of Veterinary Medicine, Research Group of Veterinary Public Health and Zoonoses, Laboratory of Chemical Analysis, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Patrick Roose
- Royal Belgian Institute of Natural Sciences, Management Unit of the North Sea Mathematical Model, 2e en 23e Linieregimentsplein, B-8400 Oostende, Belgium
| | - Colin R Janssen
- Ghent University, Faculty of Bioscience Engineering, Laboratory of Environmental Toxicology and Aquatic Ecology, J. Plateaustraat 22, B-9000 Ghent, Belgium
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Differential immunomodulatory responses to nine polycyclic aromatic hydrocarbons applied by passive dosing. Toxicol In Vitro 2015; 29:345-51. [DOI: 10.1016/j.tiv.2014.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 11/09/2014] [Accepted: 11/18/2014] [Indexed: 01/02/2023]
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Hultman MT, Rundberget JT, Tollefsen KE. Evaluation of the sensitivity, responsiveness and reproducibility of primary rainbow trout hepatocyte vitellogenin expression as a screening assay for estrogen mimics. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 159:233-244. [PMID: 25560651 DOI: 10.1016/j.aquatox.2014.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/11/2014] [Accepted: 12/14/2014] [Indexed: 06/04/2023]
Abstract
Vitellogenin (Vtg) induction in primary fish hepatocytes has been proposed as an in vitro screening assay for ER agonists and antagonists, but has not yet been used extensively as a high-throughput screening tool due to poor reproducibility, sensitivity and overall feasibility. The present work has evaluated the role of seasonal variation, normalization, optimal culture and assay conditions on the sensitivity, responsiveness and reproducibility of in vitro vtg gene mRNA and protein expression in rainbow trout (Oncorhynchus mykiss) primary hepatocytes using the xenoestrogen 17α-ethynylestradiol (EE2) as a test chemical. The results show that primary hepatocytes display a relatively high individual and seasonal variation in both Vtg mRNA and protein induction potential, although less variance was observed in assay sensitivity. Data normalization of assay response to maximum (3 nM EE2) and minimum (DMSO) Vtg production dramatically reduced this variance and led to improved assay reproducibility. A time-dependent response was observed both for mRNA and protein expression, reaching maximum Vtg induction after 96 h of exposure, although reproducible concentration response curves for both Vtg mRNA and protein could be obtained already after 48 h. A need for chemical re-exposure of the hepatocytes was identified to be important for sustaining exposure concentrations in extended studies (>48 h), whereas different plate formats (96, 24 or 6 wells) did not affect the bioassay performance. In conclusion, standardization of hepatocyte bioassay and test conditions as well as data-normalization procedures are proposed to be instrumental for more consistent and comparable results in future use of this in vitro assay.
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Affiliation(s)
- Maria T Hultman
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo, Norway; Faculty of Environmental Science & Technology, Department for Environmental Sciences, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås, Norway.
| | - Jan Thomas Rundberget
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo, Norway
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 Oslo, Norway; Faculty of Environmental Science & Technology, Department for Environmental Sciences, Norwegian University of Life Sciences (NMBU), Post Box 5003, N-1432 Ås, Norway
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Booij P, Sjollema SB, Leonards PEG, de Voogt P, Stroomberg GJ, Vethaak AD, Lamoree MH. Extraction tools for identification of chemical contaminants in estuarine and coastal waters to determine toxic pressure on primary producers. CHEMOSPHERE 2013; 93:107-114. [PMID: 23751123 DOI: 10.1016/j.chemosphere.2013.04.095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/24/2013] [Accepted: 04/29/2013] [Indexed: 06/02/2023]
Abstract
The extent to which chemical stressors affect primary producers in estuarine and coastal waters is largely unknown. However, given the large number of legacy pollutants and chemicals of emerging concern present in the environment, this is an important and relevant issue that requires further study. The purpose of our study was to extract and identify compounds which are inhibitors of photosystem II activity in microalgae from estuarine and coastal waters. Field sampling was conducted in the Western Scheldt estuary (Hansweert, The Netherlands). We compared four different commonly used extraction methods: passive sampling with silicone rubber sheets, polar organic integrative samplers (POCIS) and spot water sampling using two different solid phase extraction (SPE) cartridges. Toxic effects of extracts prepared from spot water samples and passive samplers were determined in the Pulse Amplitude Modulation (PAM) fluorometry bioassay. With target chemical analysis using LC-MS and GC-MS, a set of PAHs, PCBs and pesticides was determined in field samples. These compound classes are listed as priority substances for the marine environment by the OSPAR convention. In addition, recovery experiments with both SPE cartridges were performed to evaluate the extraction suitability of these methods. Passive sampling using silicone rubber sheets and POCIS can be applied to determine compounds with different structures and polarities for further identification and determination of toxic pressure on primary producers. The added value of SPE lies in its suitability for quantitative analysis; calibration of passive samplers still needs further investigation for quantification of field concentrations of contaminants.
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Affiliation(s)
- Petra Booij
- Institute for Environmental Studies, VU University, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands.
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Smith KEC, Heringa MB, Uytewaal M, Mayer P. The dosing determines mutagenicity of hydrophobic compounds in the Ames II assay with metabolic transformation: passive dosing versus solvent spiking. Mutat Res 2012; 750:12-8. [PMID: 22989744 DOI: 10.1016/j.mrgentox.2012.07.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 06/15/2012] [Accepted: 07/25/2012] [Indexed: 11/20/2022]
Abstract
The Ames II bacterial mutagenicity assay is a new version of the standard Ames test for screening chemicals for genotoxic activity. However, the use of plastic micro-titer plates has drawbacks in the case of testing hydrophobic mutagens, since sorptive and other losses make it difficult to control and define the exposure concentrations, and they reduce availability for bacterial uptake or to the S9 enzymes. With passive dosing, a biocompatible polymer such as silicone is loaded with the test compound and acts as a partitioning source. It compensates for any losses and results in stable freely dissolved concentrations. Passive dosing using silicone O-rings was applied in the Ames II assay to measure PAH mutagenicity in strains TA98 and TAMix - a mixture of six different bacterial strains detecting six different base-pair substitutions - after metabolic activation by S9. Initially, 10 PAHs were tested with passive dosing from saturated O-rings, aiming at levels in the test medium close to aqueous solubility. Fluoranthene, pyrene and benzo(a)pyrene were mutagenic in both TA98 and TAMix, whereas benz(a)anthracene was mutagenic in TA98 only. The concentration-dependent mutagenic activity of benzo(a)pyrene was then compared for passive dosing and solvent spiking. With spiking, nominal concentrations greatly exceeded aqueous solubility before mutagenicity was observed, due to sorptive losses and limiting dissolution kinetics. In contrast, the passive dosing concentration-response curves were more reproducible, and shifted towards lower concentrations by several orders of magnitude. This study raises fundamental questions about how to introduce hydrophobic test substances in the Ames II assay with biotransformation, since the measured mutagenicity not only depends on the compound potency but also on its supply, sorption and consumption during the assay.
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Affiliation(s)
- Kilian E C Smith
- Department of Environmental Science, Aarhus University, Roskilde, Denmark.
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