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Scholz S, Nichols JW, Escher BI, Ankley GT, Altenburger R, Blackwell B, Brack W, Burkhard L, Collette TW, Doering JA, Ekman D, Fay K, Fischer F, Hackermüller J, Hoffman JC, Lai C, Leuthold D, Martinovic-Weigelt D, Reemtsma T, Pollesch N, Schroeder A, Schüürmann G, von Bergen M. The Eco-Exposome Concept: Supporting an Integrated Assessment of Mixtures of Environmental Chemicals. Environ Toxicol Chem 2022; 41:30-45. [PMID: 34714945 PMCID: PMC9104394 DOI: 10.1002/etc.5242] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/20/2021] [Accepted: 10/26/2021] [Indexed: 05/04/2023]
Abstract
Organisms are exposed to ever-changing complex mixtures of chemicals over the course of their lifetime. The need to more comprehensively describe this exposure and relate it to adverse health effects has led to formulation of the exposome concept in human toxicology. Whether this concept has utility in the context of environmental hazard and risk assessment has not been discussed in detail. In this Critical Perspective, we propose-by analogy to the human exposome-to define the eco-exposome as the totality of the internal exposure (anthropogenic and natural chemicals, their biotransformation products or adducts, and endogenous signaling molecules that may be sensitive to an anthropogenic chemical exposure) over the lifetime of an ecologically relevant organism. We describe how targeted and nontargeted chemical analyses and bioassays can be employed to characterize this exposure and discuss how the adverse outcome pathway concept could be used to link this exposure to adverse effects. Available methods, their limitations, and/or requirement for improvements for practical application of the eco-exposome concept are discussed. Even though analysis of the eco-exposome can be resource-intensive and challenging, new approaches and technologies make this assessment increasingly feasible. Furthermore, an improved understanding of mechanistic relationships between external chemical exposure(s), internal chemical exposure(s), and biological effects could result in the development of proxies, that is, relatively simple chemical and biological measurements that could be used to complement internal exposure assessment or infer the internal exposure when it is difficult to measure. Environ Toxicol Chem 2022;41:30-45. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Stefan Scholz
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
- Address correspondence to
| | - John W. Nichols
- Office of Research and Development, Great Lakes Ecology and Toxicology Division, US Environmental Protection Agency, Duluth, Minnesota
| | - Beate I. Escher
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
- Environmental Toxicology, Center for Applied Geoscience, Eberhard Karls University Tubingen, Tubingen, Germany
| | - Gerald T. Ankley
- Office of Research and Development, Great Lakes Ecology and Toxicology Division, US Environmental Protection Agency, Duluth, Minnesota
| | - Rolf Altenburger
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
- Institute for Environmental Research, Biologie V, RWTH Aachen University, Aachen, Germany
| | - Brett Blackwell
- Office of Research and Development, Great Lakes Ecology and Toxicology Division, US Environmental Protection Agency, Duluth, Minnesota
| | - Werner Brack
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
- Department of Evolutionary Ecology and Environmental Toxicology, Faculty of Biological Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Lawrence Burkhard
- Office of Research and Development, Great Lakes Ecology and Toxicology Division, US Environmental Protection Agency, Duluth, Minnesota
| | - Timothy W. Collette
- Office of Research and Development, Ecosystem Processes Division, US Environmental Protection Agency, Athens, Georgia
| | - Jon A. Doering
- National Research Council, US Environmental Protection Agency, Duluth, Minnesota
| | - Drew Ekman
- Office of Research and Development, Ecosystem Processes Division, US Environmental Protection Agency, Athens, Georgia
| | - Kellie Fay
- Office of Pollution Prevention and Toxics, Risk Assessment Division, US Environmental Protection Agency, Washington, DC
| | - Fabian Fischer
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
| | | | - Joel C. Hoffman
- Office of Research and Development, Great Lakes Ecology and Toxicology Division, US Environmental Protection Agency, Duluth, Minnesota
| | - Chih Lai
- College of Arts and Sciences, University of Saint Thomas, St. Paul, Minnesota, USA
| | - David Leuthold
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
| | | | | | - Nathan Pollesch
- Office of Research and Development, Great Lakes Ecology and Toxicology Division, US Environmental Protection Agency, Duluth, Minnesota
| | | | - Gerrit Schüürmann
- Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany
- Institute of Organic Chemistry, Technische Universitat Bergakademie Freiberg, Freiberg, Germany
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Huang W, Bencic DC, Flick RL, Nacci DE, Clark BW, Burkhard L, Lahren T, Biales AD. Characterization of the Fundulus heteroclitus embryo transcriptional response and development of a gene expression-based fingerprint of exposure for the alternative flame retardant, TBPH (bis (2-ethylhexyl)-tetrabromophthalate). Environ Pollut 2019; 247:696-705. [PMID: 30721860 PMCID: PMC7495336 DOI: 10.1016/j.envpol.2019.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/18/2018] [Accepted: 01/03/2019] [Indexed: 05/07/2023]
Abstract
Although alternative Flame Retardant (FR) chemicals are expected to be safer than the legacy FRs they replace, their risks to human health and the environment are often poorly characterized. This study used a small volume, fish embryo system to reveal potential mechanisms of action and diagnostic exposure patterns for TBPH (bis (2-ethylhexyl)-tetrabromophthalate), a component of several widely-used commercial products. Two different concentration of TBPH were applied to sensitive early life stages of an ecologically important test species, Fundulus heteroclitus (Atlantic killifish), with a well-annotated genome. Exposed fish embryos were sampled for transcriptomics or chemical analysis of parent compound and primary metabolite or observed for development and survival through larval stage. Global transcript profiling using RNA-seq was conducted (n = 16 per treatment) to provide a non-targeted and statistically robust approach to characterize TBPH gene expression patterns. Transcriptomic analysis revealed a dose-response in the expression of genes associated with a surprisingly limited number of biological pathways, but included the aryl hydrocarbon receptor signal transduction pathway, which is known to respond to several toxicologically-important chemical classes. A transcriptional fingerprint using Random Forests was developed that was able to perfectly discriminate exposed vs. non-exposed individuals in test sets. These results suggest that TBPH has a relatively low potential for developmental toxicity (at least in fishes), despite concerns related to its structural similarities to endocrine disrupting chemicals and that the early life stage Fundulus system may provide a convenient test system for exposure characterization. More broadly, this study advances the usefulness of a biological testing and analysis system utilizing non-targeted transcriptomics profiling and early developmental endpoints that complements current screening methods to characterize chemicals of ecological and human health concern.
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Affiliation(s)
- Weichun Huang
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - David C Bencic
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - Robert L Flick
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - Diane E Nacci
- U.S. EPA National Health and Environmental Effects Research Laboratory, 27 Tarzwell Drive Narragansett, RI, 02882, USA
| | - Bryan W Clark
- U.S. EPA National Health and Environmental Effects Research Laboratory, 27 Tarzwell Drive Narragansett, RI, 02882, USA
| | - Lawrence Burkhard
- U.S. EPA National Health and Environmental Effects Research Laboratory, 6201 Congdon Boulevard, Duluth, MN, 55804, USA
| | - Tylor Lahren
- U.S. EPA National Health and Environmental Effects Research Laboratory, 6201 Congdon Boulevard, Duluth, MN, 55804, USA
| | - Adam D Biales
- U.S. EPA Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA.
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