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vom Saal FS, Antoniou M, Belcher SM, Bergman A, Bhandari RK, Birnbaum LS, Cohen A, Collins TJ, Demeneix B, Fine AM, Flaws JA, Gayrard V, Goodson WH, Gore AC, Heindel JJ, Hunt PA, Iguchi T, Kassotis CD, Kortenkamp A, Mesnage R, Muncke J, Myers JP, Nadal A, Newbold RR, Padmanabhan V, Palanza P, Palma Z, Parmigiani S, Patrick L, Prins GS, Rosenfeld CS, Skakkebaek NE, Sonnenschein C, Soto AM, Swan SH, Taylor JA, Toutain PL, von Hippel FA, Welshons WV, Zalko D, Zoeller RT. The Conflict between Regulatory Agencies over the 20,000-Fold Lowering of the Tolerable Daily Intake (TDI) for Bisphenol A (BPA) by the European Food Safety Authority (EFSA). ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:45001. [PMID: 38592230 PMCID: PMC11003459 DOI: 10.1289/ehp13812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 04/10/2024]
Abstract
BACKGROUND The European Food Safety Authority (EFSA) recommended lowering their estimated tolerable daily intake (TDI) for bisphenol A (BPA) 20,000-fold to 0.2 ng / kg body weight ( BW ) / day . BPA is an extensively studied high production volume endocrine disrupting chemical (EDC) associated with a vast array of diseases. Prior risk assessments of BPA by EFSA as well as the US Food and Drug Administration (FDA) have relied on industry-funded studies conducted under good laboratory practice protocols (GLP) requiring guideline end points and detailed record keeping, while also claiming to examine (but rejecting) thousands of published findings by academic scientists. Guideline protocols initially formalized in the mid-twentieth century are still used by many regulatory agencies. EFSA used a 21st century approach in its reassessment of BPA and conducted a transparent, but time-limited, systematic review that included both guideline and academic research. The German Federal Institute for Risk Assessment (BfR) opposed EFSA's revision of the TDI for BPA. OBJECTIVES We identify the flaws in the assumptions that the German BfR, as well as the FDA, have used to justify maintaining the TDI for BPA at levels above what a vast amount of academic research shows to cause harm. We argue that regulatory agencies need to incorporate 21st century science into chemical hazard identifications using the CLARITY-BPA (Consortium Linking Academic and Regulatory Insights on BPA Toxicity) nonguideline academic studies in a collaborative government-academic program model. DISCUSSION We strongly endorse EFSA's revised TDI for BPA and support the European Commission's (EC) apparent acceptance of this updated BPA risk assessment. We discuss challenges to current chemical risk assessment assumptions about EDCs that need to be addressed by regulatory agencies to, in our opinion, become truly protective of public health. Addressing these challenges will hopefully result in BPA, and eventually other structurally similar bisphenols (called regrettable substitutions) for which there are known adverse effects, being eliminated from all food-related and many other uses in the EU and elsewhere. https://doi.org/10.1289/EHP13812.
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Affiliation(s)
- Frederick S. vom Saal
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Michael Antoniou
- Department of Medical and Molecular Genetics, King’s College London School of Medicine, London, UK
| | - Scott M. Belcher
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Ake Bergman
- Department of Environmental Science (ACES), Stockholm University, Stockholm, Sweden
| | - Ramji K. Bhandari
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Linda S. Birnbaum
- Scientist Emeritus and Former Director, National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, North Carolina, USA
- Scholar in Residence, Duke University, Durham, North Carolina, USA
| | - Aly Cohen
- Integrative Rheumatology Associates, Princeton, New Jersey, USA
| | - Terrence J. Collins
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Barbara Demeneix
- Comparative Physiology Laboratory, Natural History Museum, Paris, France
| | - Anne Marie Fine
- Environmental Medicine Education International, Mancos, Colorado, USA
| | - Jodi A. Flaws
- Department of Comparative Biosciences, University of Illinois Urbana—Champaign, Urbana-Champaign, Illinois, USA
| | - Veronique Gayrard
- ToxAlim (Research Centre in Food Toxicology), University of Toulouse, Toulouse, France
| | - William H. Goodson
- California Pacific Medical Center Research Institute, San Francisco, California, USA
| | - Andrea C. Gore
- Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, Texas, USA
| | - Jerrold J. Heindel
- Healthy Environment and Endocrine Disruptor Strategies, Raleigh, North Carolina, USA
| | - Patricia A. Hunt
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, Washington, USA
| | - Taisen Iguchi
- Graduate School of Nanobioscience, Yokohama City University, Yokohama, Japan
| | - Christopher D. Kassotis
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan, USA
- Department of Pharmacology, Wayne State University, Detroit, Michigan, USA
| | - Andreas Kortenkamp
- Centre for Pollution Research and Policy, Brunel University London, Uxbridge, UK
| | - Robin Mesnage
- Department of Medical and Molecular Genetics, King’s College London School of Medicine, London, UK
| | - Jane Muncke
- Food Packaging Forum Foundation, Zurich, Switzerland
| | | | - Angel Nadal
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE) and CIBERDEM, Miguel Hernandez University of Elche, Elche, Alicante, Spain
| | - Retha R. Newbold
- Scientist Emeritus, NTP, NIEHS, Research Triangle Park, North Carolina, USA
| | - Vasantha Padmanabhan
- Department of Pediatrics, Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA
| | - Paola Palanza
- Unit of Neuroscience, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | | | - Stefano Parmigiani
- Unit of Evolutionary and Functional Biology, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Lyn Patrick
- Environmental Medicine Education International, Mancos, Colorado, USA
| | - Gail S. Prins
- Department of Urology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Cheryl S. Rosenfeld
- Biomedical Sciences, Thompson Center for Autism and Neurobehavioral Disorders, University of Missouri—Columbia, Columbia, Missouri, USA
- MU Institute of Data Science and Informatics, University of Missouri—Columbia, Columbia, Missouri, USA
| | - Niels E. Skakkebaek
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Carlos Sonnenschein
- Department of Immunology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Ana M. Soto
- Department of Immunology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Shanna H. Swan
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Julia A. Taylor
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, USA
| | - Pierre-Louis Toutain
- Royal Veterinary College, University of London, London, UK
- NTHERES, INRAE, ENVT, Université de Toulouse, Toulouse, France
| | - Frank A. von Hippel
- Department of Community, Environment & Policy, University of Arizona, Tucson, Arizona, USA
| | - Wade V. Welshons
- Department of Biomedical Sciences, University of Missouri—Columbia, Columbia, Missouri, USA
| | - Daniel Zalko
- ToxAlim (Research Centre in Food Toxicology), University of Toulouse, Toulouse, France
| | - R. Thomas Zoeller
- Department of Biology, University of Massachusetts, Amherst, Massachusetts, USA
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2
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Gray LE, Conley JM, Bursian SJ. Dose Addition Models Accurately Predict the Subacute Effects of a Mixture of Perfluorooctane Sulfonate and Perfluorooctanoic Acid on Japanese Quail (Coturnix japonica) Chick Mortality. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2024; 43:97-104. [PMID: 37753878 DOI: 10.1002/etc.5758] [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: 07/06/2023] [Revised: 08/03/2023] [Accepted: 09/26/2023] [Indexed: 09/28/2023]
Abstract
Biomonitoring data have consistently demonstrated that fish, wildlife, and humans are exposed to multiple per- and polyfluoroalkyl substances (PFAS) in drinking water and foods. Despite ubiquitous exposure to mixtures of PFAS, there is a lack of in vivo PFAS mixture research that addresses whether these chemicals act in a cumulative, dose-additive (DA) manner or whether they behave independently. For this reason, there is a critical need for mixtures studies designed to evaluate the cumulative toxicity and potential chemical interactions to support the assessment of human and ecological risks and also to define appropriate regulatory actions. Our primary objective was to evaluate the previously published Japanese quail chick mortality concentration-response data for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and the mixture of PFOS + PFOA and to use statistical modeling to determine whether the effects of the mixtures were accurately predicted by either DA or response addition modeling. In addition, we wanted to compare different DA models to determine whether one model produced more accurate predictions than the others. Our results support the hypothesis of cumulative effects on shared endpoints from PFOA and PFOS co-exposure and DA approaches for predictive estimates of cumulative effects. Given the limited number of in vivo studies that have been executed with enough individual PFAS and PFAS mixture concentration-response data to test the hypothesis of DA for PFAS mixtures, this re-analysis of the data is an important contribution to our understanding of how PFAS mixtures act. The analysis will provide support for regulatory agencies as they begin to implement PFAS cumulative hazard assessments in higher vertebrates. Environ Toxicol Chem 2024;43:97-104. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- L Earl Gray
- US Environmental Protection Agency, Office of Research & Development, Center for Public Health and Environmental Assessment, Office of Research & Development, US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Justin M Conley
- US Environmental Protection Agency, Office of Research & Development, Center for Public Health and Environmental Assessment, Office of Research & Development, US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Steven J Bursian
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
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3
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Zhang H, Kato D, Ihara MO, Jürgens MD, Johnson AC, Chen J, Tanaka H, Ihara M. Biological-Activity-Based Prioritization of Antidepressants in Wastewater in England and Japan. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:6444-6454. [PMID: 37022287 DOI: 10.1021/acs.est.2c08380] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Antidepressants are one of the most commonly prescribed pharmaceuticals. Although they have been frequently detected in aquatic environments around the globe, little is known regarding their adverse effects on humans and aquatic organisms. Recently, an in vitro monoamine transporter inhibition assay was developed to detect transporter-inhibitory activities of antidepressants in wastewater in Japan. However, it was unclear which antidepressants were responsible for transporter-inhibitory activities in wastewater. Herein, the per capita consumption of 32 antidepressants, their excretion of unchanged parent compounds, per capita water consumption, removal rate during wastewater treatment processes, and potency values from the monoamine transporter inhibition assay were used to prioritize antidepressants of concern in effluent wastewater in England and Japan. In both countries, sertraline and O-desmethylvenlafaxine had the highest contribution to inhibitory activities against the human serotonin transporter (hSERT) and zebrafish SERT (zSERT), respectively. It was found that the antidepressants inhibited the zSERT more strongly than the hSERT. The inhibitory activities found against the zSERT in wastewater in England and Japan were higher than thresholds for abnormal behavior in fish. The antidepressants prioritized in this study provide insight into launching environmental monitoring and ecotoxicological studies of antidepressants.
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Affiliation(s)
- Han Zhang
- Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian Key Laboratory on Chemicals Risk Control and Pollution Prevention Technology, School of Environmental Science and Technology, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Daisuke Kato
- Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan
| | - Mariko O Ihara
- Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan
| | - Monika D Jürgens
- Centre for Ecology and Hydrology, Wallingford, Oxfordshire OX10 8BB, U.K
| | - Andrew C Johnson
- Centre for Ecology and Hydrology, Wallingford, Oxfordshire OX10 8BB, U.K
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian Key Laboratory on Chemicals Risk Control and Pollution Prevention Technology, School of Environmental Science and Technology, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Hiroaki Tanaka
- Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan
| | - Masaru Ihara
- Research Center for Environmental Quality Management, Kyoto University, 1-2 Yumihama, Otsu, Shiga 520-0811, Japan
- Faculty of Agriculture and Marine Science, Kochi University, 200 Monobe-Otsu, Nankoku City, Kochi 783-8502, Japan
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Bajard L, Adamovsky O, Audouze K, Baken K, Barouki R, Beltman JB, Beronius A, Bonefeld-Jørgensen EC, Cano-Sancho G, de Baat ML, Di Tillio F, Fernández MF, FitzGerald RE, Gundacker C, Hernández AF, Hilscherova K, Karakitsios S, Kuchovska E, Long M, Luijten M, Majid S, Marx-Stoelting P, Mustieles V, Negi CK, Sarigiannis D, Scholz S, Sovadinova I, Stierum R, Tanabe S, Tollefsen KE, van den Brand AD, Vogs C, Wielsøe M, Wittwehr C, Blaha L. Application of AOPs to assist regulatory assessment of chemical risks - Case studies, needs and recommendations. ENVIRONMENTAL RESEARCH 2023; 217:114650. [PMID: 36309218 PMCID: PMC9850416 DOI: 10.1016/j.envres.2022.114650] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 05/06/2023]
Abstract
While human regulatory risk assessment (RA) still largely relies on animal studies, new approach methodologies (NAMs) based on in vitro, in silico or non-mammalian alternative models are increasingly used to evaluate chemical hazards. Moreover, human epidemiological studies with biomarkers of effect (BoE) also play an invaluable role in identifying health effects associated with chemical exposures. To move towards the next generation risk assessment (NGRA), it is therefore crucial to establish bridges between NAMs and standard approaches, and to establish processes for increasing mechanistically-based biological plausibility in human studies. The Adverse Outcome Pathway (AOP) framework constitutes an important tool to address these needs but, despite a significant increase in knowledge and awareness, the use of AOPs in chemical RA remains limited. The objective of this paper is to address issues related to using AOPs in a regulatory context from various perspectives as it was discussed in a workshop organized within the European Union partnerships HBM4EU and PARC in spring 2022. The paper presents examples where the AOP framework has been proven useful for the human RA process, particularly in hazard prioritization and characterization, in integrated approaches to testing and assessment (IATA), and in the identification and validation of BoE in epidemiological studies. Nevertheless, several limitations were identified that hinder the optimal usability and acceptance of AOPs by the regulatory community including the lack of quantitative information on response-response relationships and of efficient ways to map chemical data (exposure and toxicity) onto AOPs. The paper summarizes suggestions, ongoing initiatives and third-party tools that may help to overcome these obstacles and thus assure better implementation of AOPs in the NGRA.
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Affiliation(s)
- Lola Bajard
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Ondrej Adamovsky
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Karine Audouze
- Université Paris Cité, T3S, Inserm UMR S-1124, F-75006 Paris, France
| | - Kirsten Baken
- Unit Health, Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, Belgium
| | - Robert Barouki
- Université Paris Cité, T3S, Inserm UMR S-1124, F-75006 Paris, France
| | - Joost B Beltman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Anna Beronius
- Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, Solna, Sweden
| | - Eva Cecilie Bonefeld-Jørgensen
- Centre for Arctic Health & Molecular Epidemiology, Department of Public Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus, Denmark; Greenland Centre for Health Research, University of Greenland, Manutooq 1, 3905 Nuussuaq, Greenland
| | | | - Milo L de Baat
- KWR Water Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, the Netherlands
| | - Filippo Di Tillio
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, Netherlands
| | - Mariana F Fernández
- Center for Biomedical Research (CIBM) & School of Medicine, University of Granada, 18016 Granada, Spain; Instituto de Investigación Biosanitaria (ibs. GRANADA), 18012, Granada, Spain; Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain
| | - Rex E FitzGerald
- Swiss Centre for Applied Human Toxicology SCAHT, University of Basel, Missionsstrasse 64, CH-4055 Basel, Switzerland
| | - Claudia Gundacker
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria
| | - Antonio F Hernández
- Instituto de Investigación Biosanitaria (ibs. GRANADA), 18012, Granada, Spain; Department of Legal Medicine and Toxicology, University of Granada School of Medicine, Avda. de la Investigación, 11, 18016, Granada, Spain; Consortium for Biomedical Research in Epidemiology & Public Health, CIBERESP, Madrid, Spain
| | - Klara Hilscherova
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Spyros Karakitsios
- Environmental Engineering Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece; HERACLES Research Centre on the Exposome and Health, Center for Interdisciplinary Research and Innovation, Thessaloniki, Greece
| | - Eliska Kuchovska
- IUF-Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Manhai Long
- Centre for Arctic Health & Molecular Epidemiology, Department of Public Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus, Denmark
| | - Mirjam Luijten
- National Institute for Public Health and the Environment (RIVM), Centre for Health Protection, Bilthoven, the Netherlands
| | - Sanah Majid
- KWR Water Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, the Netherlands
| | - Philip Marx-Stoelting
- German Federal Institute for Risk Assessment, Dept. Pesticides Safety, Berlin, Germany
| | - Vicente Mustieles
- Center for Biomedical Research (CIBM) & School of Medicine, University of Granada, 18016 Granada, Spain; Instituto de Investigación Biosanitaria (ibs. GRANADA), 18012, Granada, Spain; Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain
| | - Chander K Negi
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Dimosthenis Sarigiannis
- Environmental Engineering Laboratory, Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece; HERACLES Research Centre on the Exposome and Health, Center for Interdisciplinary Research and Innovation, Thessaloniki, Greece
| | - Stefan Scholz
- UFZ Helmholtz Center for Environmental Research, Dept Bioanalyt Ecotoxicol, D-04318 Leipzig, Germany
| | - Iva Sovadinova
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Rob Stierum
- Netherlands Organisation for Applied Scientific Research, Risk Analysis for Products in Development, Utrecht, the Netherlands
| | - Shihori Tanabe
- Division of Risk Assessment, Center for Biological Safety and Research, National Institute of Health Sciences, Kawasaki, Japan
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen, Oslo, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management (MINA), Norway
| | - Annick D van den Brand
- Institute for Public Health and the Environment (RIVM), Centre for Nutrition, Prevention and Health Services, 3720 BA Bilthoven, the Netherlands
| | - Carolina Vogs
- Institute of Environmental Medicine, Karolinska Institutet, Nobels väg 13, Solna, Sweden; Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Maria Wielsøe
- Centre for Arctic Health & Molecular Epidemiology, Department of Public Health, Aarhus University, Bartholins Allé 2, 8000 Aarhus, Denmark
| | | | - Ludek Blaha
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic.
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5
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Conley JM, Lambright CS, Evans N, Medlock-Kakaley E, Dixon A, Hill D, McCord J, Strynar MJ, Ford J, Gray LE. Cumulative maternal and neonatal effects of combined exposure to a mixture of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) during pregnancy in the Sprague-Dawley rat. ENVIRONMENT INTERNATIONAL 2022; 170:107631. [PMID: 36402036 PMCID: PMC9944680 DOI: 10.1016/j.envint.2022.107631] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/29/2022] [Accepted: 11/10/2022] [Indexed: 05/10/2023]
Abstract
Globally, biomonitoring data demonstrate virtually all humans carry residues of multiple per- and polyfluoroalkyl substances (PFAS). Despite pervasive co-exposure, limited mixtures-based in vivo PFAS toxicity research has been conducted. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are commonly detected PFAS in human and environmental samples and both produce adverse effects in laboratory animal studies, including maternal and offspring effects when orally administered during pregnancy and lactation. To evaluate the effects of combined exposure to PFOA and PFOS, we orally exposed pregnant Sprague-Dawley rats from gestation day 8 (GD8) to postnatal day 2 (PND2) to PFOA (10-250 mg/kg/d) or PFOS (0.1-5 mg/kg/d) individually to characterize effects and dose response curve parameters, followed by a variable-ratio mixture experiment with a constant dose of PFOS (2 mg/kg/d) mixed with increasing doses of PFOA (3-80 mg/kg/d). The mixture study design was intended to: 1) shift the PFOA dose response curves for endpoints shared with PFOS, 2) allow comparison of dose addition (DA) and response addition (RA) model predictions, 3) conduct relative potency factor (RPF) analysis for multiple endpoints, and 4) avoid overt maternal toxicity. Maternal serum and liver concentrations of PFOA and PFOS were consistent between the individual chemical and mixture experiments. Combined exposure with PFOS significantly shifted the PFOA dose response curves towards effects at lower doses compared to PFOA-only exposure for multiple endpoints and these effects were well predicted by dose addition. For endpoints amenable to mixture model analyses, DA produced equivalent or better estimates of observed data than RA. All endpoints evaluated were accurately predicted by RPF and DA approaches except for maternal gestational weight gain, which produced less-than-additive results in the mixture. Data support the hypothesis of cumulative effects on shared endpoints from PFOA and PFOS co-exposure and dose additive approaches for predictive estimates of mixture effects.
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Affiliation(s)
- Justin M Conley
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Christy S Lambright
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Nicola Evans
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Elizabeth Medlock-Kakaley
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Aaron Dixon
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Donna Hill
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - James McCord
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Environmental Measurement and Modeling, Research Triangle Park, NC, USA.
| | - Mark J Strynar
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Environmental Measurement and Modeling, Research Triangle Park, NC, USA.
| | - Jermaine Ford
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Computational Toxicology and Exposure, Research Triangle Park, NC, USA.
| | - L Earl Gray
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
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