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Carlin DJ, Rider CV. Combined Exposures and Mixtures Research: An Enduring NIEHS Priority. ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:75001. [PMID: 38968090 PMCID: PMC11225971 DOI: 10.1289/ehp14340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 04/25/2024] [Accepted: 06/12/2024] [Indexed: 07/07/2024]
Abstract
BACKGROUND The National Institute of Environmental Health Sciences (NIEHS) continues to prioritize research to better understand the health effects resulting from exposure to mixtures of chemical and nonchemical stressors. Mixtures research activities over the last decade were informed by expert input during the development and deliberations of the 2011 NIEHS Workshop "Advancing Research on Mixtures: New Perspectives and Approaches for Predicting Adverse Human Health Effects." NIEHS mixtures research efforts since then have focused on key themes including a) prioritizing mixtures for study, b) translating mixtures data from in vitro and in vivo studies, c) developing cross-disciplinary collaborations, d) informing component-based and whole-mixture assessment approaches, e) developing sufficient similarity methods to compare across complex mixtures, f) using systems-based approaches to evaluate mixtures, and g) focusing on management and integration of mixtures-related data. OBJECTIVES We aimed to describe NIEHS driven research on mixtures and combined exposures over the last decade and present areas for future attention. RESULTS Intramural and extramural mixtures research projects have incorporated a diverse array of chemicals (e.g., polycyclic aromatic hydrocarbons, botanicals, personal care products, wildfire emissions) and nonchemical stressors (e.g., socioeconomic factors, social adversity) and have focused on many diseases (e.g., breast cancer, atherosclerosis, immune disruption). We have made significant progress in certain areas, such as developing statistical methods for evaluating multiple chemical associations in epidemiology and building translational mixtures projects that include both in vitro and in vivo models. DISCUSSION Moving forward, additional work is needed to improve mixtures data integration, elucidate interactions between chemical and nonchemical stressors, and resolve the geospatial and temporal nature of mixture exposures. Continued mixtures research will be critical to informing cumulative impact assessments and addressing complex challenges, such as environmental justice and climate change. https://doi.org/10.1289/EHP14340.
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Affiliation(s)
- Danielle J. Carlin
- Division of Extramural Research and Training, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Cynthia V. Rider
- Division of Translational Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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Rager JE, Rider CV. Wrangling Whole Mixtures Risk Assessment: Recent Advances in Determining Sufficient Similarity. CURRENT OPINION IN TOXICOLOGY 2023; 35:100417. [PMID: 37790747 PMCID: PMC10545370 DOI: 10.1016/j.cotox.2023.100417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Human health risk assessments for complex mixtures can address real-world exposures and protect public health. While risk assessors typically prefer whole mixture approaches over component-based approaches, data from the precise exposure of interest are often unavailable and surrogate data from a sufficiently similar mixture(s) are required. This review describes recent advances in determining sufficient similarity of whole, complex mixtures spanning the comparison of chemical features, bioactivity profiles, and statistical evaluation to determine "thresholds of similarity". Case studies, including water disinfection byproducts, botanical ingredients, and wildfire emissions, are used to highlight tools and methods. Limitations to application of sufficient similarity in risk-based decision making are reviewed and recommendations presented for developing best practice guidelines.
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Affiliation(s)
- Julia E. Rager
- The Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill
| | - Cynthia V. Rider
- Division of Translational Toxicology, National Institute of Environmental Health Sciences
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Koval LE, Carberry CK, Kim YH, McDermott E, Hartwell H, Jaspers I, Gilmour MI, Rager JE. Wildfire Variable Toxicity: Identifying Biomass Smoke Exposure Groupings through Transcriptomic Similarity Scoring. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17131-17142. [PMID: 36399130 PMCID: PMC10777820 DOI: 10.1021/acs.est.2c06043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The prevalence of wildfires continues to grow globally with exposures resulting in increased disease risk. Characterizing these health risks remains difficult due to the wide landscape of exposures that can result from different burn conditions and fuel types. This study tested the hypothesis that biomass smoke exposures from variable fuels and combustion conditions group together based on similar transcriptional response profiles, informing which wildfire-relevant exposures may be considered as a group for health risk evaluations. Mice (female CD-1) were exposed via oropharyngeal aspiration to equal mass biomass smoke condensates produced from flaming or smoldering burns of eucalyptus, peat, pine, pine needles, or red oak species. Lung transcriptomic signatures were used to calculate transcriptomic similarity scores across exposures, which informed exposure groupings. Exposures from flaming peat, flaming eucalyptus, and smoldering eucalyptus induced the greatest responses, with flaming peat grouping with the pro-inflammatory agent lipopolysaccharide. Smoldering red oak and smoldering peat induced the least transcriptomic response. Groupings paralleled pulmonary toxicity markers, though they were better substantiated by higher data dimensionality and resolution provided through -omic-based evaluation. Interestingly, groupings based on smoke chemistry signatures differed from transcriptomic/toxicity-based groupings. Wildfire-relevant exposure groupings yield insights into risk assessment strategies to ultimately protect public health.
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Affiliation(s)
- Lauren E Koval
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
| | - Celeste K Carberry
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
| | - Yong Ho Kim
- The Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, The University of North Carolina, Chapel Hill, North Carolina27599, United States
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, Durham, North Carolina27711, United States
| | - Elena McDermott
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
| | - Hadley Hartwell
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
| | - Ilona Jaspers
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, The University of North Carolina, Chapel Hill, North Carolina27599, United States
- Curriculum in Toxicology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina27599, United States
- Department of Pediatrics, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
| | - M Ian Gilmour
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, Durham, North Carolina27711, United States
| | - Julia E Rager
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina27599, United States
- The Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, The University of North Carolina, Chapel Hill, North Carolina27599, United States
- Curriculum in Toxicology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina27599, United States
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Rivera BN, Ghetu CC, Chang Y, Truong L, Tanguay RL, Anderson KA, Tilton SC. Leveraging Multiple Data Streams for Prioritization of Mixtures for Hazard Characterization. TOXICS 2022; 10:651. [PMID: 36355943 PMCID: PMC9699527 DOI: 10.3390/toxics10110651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
There is a growing need to establish alternative approaches for mixture safety assessment of polycyclic aromatic hydrocarbons (PAHs). Due to limitations with current component-based approaches, and the lack of established methods for using whole mixtures, a promising alternative is to use sufficiently similar mixtures; although, an established framework is lacking. In this study, several approaches are explored to form sufficiently similar mixtures. Multiple data streams including environmental concentrations and empirically and predicted toxicity data for cancer and non-cancer endpoints were used to prioritize chemical components for mixture formations. Air samplers were analyzed for unsubstituted and alkylated PAHs. A synthetic mixture of identified PAHs was created (Creosote-Fire Mix). Existing toxicity values and chemical concentrations were incorporated to identify hazardous components in the Creosote-Fire Mix. Sufficiently similar mixtures of the Creosote-Fire Mix were formed based on (1) relative abundance; (2) toxicity values; and (3) a combination approach incorporating toxicity and abundance. Hazard characterization of these mixtures was performed using high-throughput screening in primary normal human bronchial epithelium (NHBE) and zebrafish. Differences in chemical composition and potency were observed between mixture formation approaches. The toxicity-based approach (Tox Mix) was the most potent mixture in both models. The combination approach (Weighted-Tox Mix) was determined to be the ideal approach due its ability to prioritize chemicals with high exposure and hazard potential.
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Roell K, Koval LE, Boyles R, Patlewicz G, Ring C, Rider CV, Ward-Caviness C, Reif DM, Jaspers I, Fry RC, Rager JE. Development of the InTelligence And Machine LEarning (TAME) Toolkit for Introductory Data Science, Chemical-Biological Analyses, Predictive Modeling, and Database Mining for Environmental Health Research. FRONTIERS IN TOXICOLOGY 2022; 4:893924. [PMID: 35812168 PMCID: PMC9257219 DOI: 10.3389/ftox.2022.893924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/30/2022] [Indexed: 01/09/2023] Open
Abstract
Research in environmental health is becoming increasingly reliant upon data science and computational methods that can more efficiently extract information from complex datasets. Data science and computational methods can be leveraged to better identify relationships between exposures to stressors in the environment and human disease outcomes, representing critical information needed to protect and improve global public health. Still, there remains a critical gap surrounding the training of researchers on these in silico methods. We aimed to address this gap by developing the inTelligence And Machine lEarning (TAME) Toolkit, promoting trainee-driven data generation, management, and analysis methods to “TAME” data in environmental health studies. Training modules were developed to provide applications-driven examples of data organization and analysis methods that can be used to address environmental health questions. Target audiences for these modules include students, post-baccalaureate and post-doctorate trainees, and professionals that are interested in expanding their skillset to include recent advances in data analysis methods relevant to environmental health, toxicology, exposure science, epidemiology, and bioinformatics/cheminformatics. Modules were developed by study coauthors using annotated script and were organized into three chapters within a GitHub Bookdown site. The first chapter of modules focuses on introductory data science, which includes the following topics: setting up R/RStudio and coding in the R environment; data organization basics; finding and visualizing data trends; high-dimensional data visualizations; and Findability, Accessibility, Interoperability, and Reusability (FAIR) data management practices. The second chapter of modules incorporates chemical-biological analyses and predictive modeling, spanning the following methods: dose-response modeling; machine learning and predictive modeling; mixtures analyses; -omics analyses; toxicokinetic modeling; and read-across toxicity predictions. The last chapter of modules was organized to provide examples on environmental health database mining and integration, including chemical exposure, health outcome, and environmental justice indicators. Training modules and associated data are publicly available online (https://uncsrp.github.io/Data-Analysis-Training-Modules/). Together, this resource provides unique opportunities to obtain introductory-level training on current data analysis methods applicable to 21st century science and environmental health.
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Affiliation(s)
- Kyle Roell
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Lauren E. Koval
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Rebecca Boyles
- Research Computing, RTI International, Durham, NC, United States
| | - Grace Patlewicz
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Durham, NC, United States
| | - Caroline Ring
- Center for Computational Toxicology and Exposure, US Environmental Protection Agency, Durham, NC, United States
| | - Cynthia V. Rider
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, NC, United States
| | - Cavin Ward-Caviness
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Chapel Hill, NC, United States
| | - David M. Reif
- Bioinformatics Research Center, Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States
| | - Ilona Jaspers
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Curriculum in Toxicology and Environmental Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
- Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
- Department of Pediatrics, Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Rebecca C. Fry
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Curriculum in Toxicology and Environmental Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Julia E. Rager
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Curriculum in Toxicology and Environmental Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
- Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
- *Correspondence: Julia E. Rager,
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Chen M, Wei D, Wang F, Yin J, Li M, Du Y. Bioassay- and QSAR-based screening of toxic transformation products and their formation under chlorination treatment on levofloxacin. JOURNAL OF HAZARDOUS MATERIALS 2021; 414:125495. [PMID: 33662790 DOI: 10.1016/j.jhazmat.2021.125495] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 02/10/2021] [Accepted: 02/21/2021] [Indexed: 06/12/2023]
Abstract
Levofloxacin (LEV) is a broad-spectrum quinolone antibiotic and widely used for human and veterinary treatment. Overuse of LEV leads to its frequent occurrence in the water environment. In this study, the transformation characteristics of LEV in water during the simulated chlorination disinfection treatment were explored. Fifteen major transformation products (TPs) of LEV were identified, and their plausible formation pathways were proposed. The reaction pathways were strongly dependent on pH condition, and LEV removal was relevant to free available chlorine (FAC) dose. Antibacterial activity of chlorination system was dramatically declined when FAC was more than 3-equivalent (eq) due to the elimination of antibacterial related functional groups. Genotoxicity of chlorination system increased more than 3 times at 0.5-eq of FAC and then decreased with increasing FAC dose, which were in accordance with the relative concentration of toxic TPs estimated by QSAR model. These results implied that the combination of bioassay, QSAR computation and chemical analysis would be an efficient method to screen toxic TPs under chlorination treatment. It is anticipated that the results of this study can provide reference for optimizing operational parameters for water disinfection treatment, and for scientifically evaluating the potential risk of quinolone antibiotics.
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Affiliation(s)
- Miao Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Dongbin Wei
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Feipeng Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Junxia Yin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Min Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China; North Minzu University, Yinchuan, Ningxia 750021, PR China
| | - Yuguo Du
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
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7
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Evlampidou I, Font-Ribera L, Rojas-Rueda D, Gracia-Lavedan E, Costet N, Pearce N, Vineis P, Jaakkola JJ, Delloye F, Makris KC, Stephanou EG, Kargaki S, Kozisek F, Sigsgaard T, Hansen B, Schullehner J, Nahkur R, Galey C, Zwiener C, Vargha M, Righi E, Aggazzotti G, Kalnina G, Grazuleviciene R, Polanska K, Gubkova D, Bitenc K, Goslan EH, Kogevinas M, Villanueva CM. Trihalomethanes in Drinking Water and Bladder Cancer Burden in the European Union. ENVIRONMENTAL HEALTH PERSPECTIVES 2020; 128:17001. [PMID: 31939704 PMCID: PMC7015561 DOI: 10.1289/ehp4495] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 05/19/2023]
Abstract
BACKGROUND Trihalomethanes (THMs) are widespread disinfection by-products (DBPs) in drinking water, and long-term exposure has been consistently associated with increased bladder cancer risk. OBJECTIVE We assessed THM levels in drinking water in the European Union as a marker of DBP exposure and estimated the attributable burden of bladder cancer. METHODS We collected recent annual mean THM levels in municipal drinking water in 28 European countries (EU28) from routine monitoring records. We estimated a linear exposure-response function for average residential THM levels and bladder cancer by pooling data from studies included in the largest international pooled analysis published to date in order to estimate odds ratios (ORs) for bladder cancer associated with the mean THM level in each country (relative to no exposure), population-attributable fraction (PAF), and number of attributable bladder cancer cases in different scenarios using incidence rates and population from the Global Burden of Disease study of 2016. RESULTS We obtained 2005-2018 THM data from EU26, covering 75% of the population. Data coverage and accuracy were heterogeneous among countries. The estimated population-weighted mean THM level was 11.7μg/L [standard deviation (SD) of 11.2]. The estimated bladder cancer PAF was 4.9% [95% confidence interval (CI): 2.5, 7.1] overall (range: 0-23%), accounting for 6,561 (95% CI: 3,389, 9,537) bladder cancer cases per year. Denmark and the Netherlands had the lowest PAF (0.0% each), while Cyprus (23.2%), Malta (17.9%), and Ireland (17.2%) had the highest among EU26. In the scenario where no country would exceed the current EU mean, 2,868 (95% CI: 1,522, 4,060; 43%) annual attributable bladder cancer cases could potentially be avoided. DISCUSSION Efforts have been made to reduce THM levels in the European Union. However, assuming a causal association, current levels in certain countries still could lead to a considerable burden of bladder cancer that could potentially be avoided by optimizing water treatment, disinfection, and distribution practices, among other possible measures. https://doi.org/10.1289/EHP4495.
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Affiliation(s)
- Iro Evlampidou
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
| | - Laia Font-Ribera
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - David Rojas-Rueda
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
| | - Esther Gracia-Lavedan
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
| | - Nathalie Costet
- Université de Rennes, Institut national de la santé et de la recherche médicale (Inserm), École des hautes études en santé publique (EHESP), Rennes, France
| | - Neil Pearce
- London School of Hygiene & Tropical Medicine, London, UK
| | | | - Jouni J.K. Jaakkola
- Center for Environmental and Respiratory Health Research (CERH), University of Oulu, Oulu, Finland
| | - Francis Delloye
- Service Public de Wallonie, Direction générale de l’Agriculture, des Ressources naturelles et de l’Environnement, Département de l'Environnement et de l’Eau, Jambes, Belgium
| | - Konstantinos C. Makris
- Water and Health Laboratory, Cyprus International Institute for Environmental and Public Health, Cyprus University of Technology, Limassol, Cyprus
| | - Euripides G. Stephanou
- Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, Heraklion, Greece
- The Cyprus Institute, Aglantzia-Nicosia, Cyprus
| | - Sophia Kargaki
- Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, Heraklion, Greece
| | | | - Torben Sigsgaard
- Department of Public Health, Section for Environment, Occupation & Health, Aarhus University, Aarhus, Denmark
| | - Birgitte Hansen
- Geological Survey of Denmark and Greenland (GEUS), Aarhus, Denmark
| | - Jörg Schullehner
- Geological Survey of Denmark and Greenland (GEUS), Aarhus, Denmark
- National Centre for Register-based Research, Aarhus University, Aarhus, Denmark
| | - Ramon Nahkur
- Public Health Department, Estonian Ministry of Social Affairs, Tallinn, Estonia
| | - Catherine Galey
- Santé Publique France (French National Public Health Agency), Saint-Maurice, France
| | - Christian Zwiener
- Environmental Analytical Chemistry, Center for Applied Geosciences (ZAG), Eberhard-Karls-University Tuebingen, Tuebingen, Germany
| | - Marta Vargha
- National Public Health Center, Budapest, Hungary
| | - Elena Righi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Gabriella Aggazzotti
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Gunda Kalnina
- Public Health Division, Ministry of Health of the Republic Latvia, Health Inspectorate, Riga, Latvia
| | - Regina Grazuleviciene
- Department of Environmental Sciences, Faculty of Natural Sciences, Vytautas Magnus University, Kaunas, Lithuania
| | - Kinga Polanska
- Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland
| | - Dasa Gubkova
- Public Health Authority of the Slovak Republic, Bratislava, Slovak Republic
| | | | - Emma H. Goslan
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedford, UK
| | - Manolis Kogevinas
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
| | - Cristina M. Villanueva
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiologia y Salud Pública (CIBERESP), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain
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8
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How similar is similar enough? A sufficient similarity case study with Ginkgo biloba extract. Food Chem Toxicol 2018; 118:328-339. [PMID: 29752982 DOI: 10.1016/j.fct.2018.05.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/04/2018] [Accepted: 05/06/2018] [Indexed: 12/20/2022]
Abstract
Botanical dietary supplements are complex mixtures that can be highly variable in composition and quality, making safety evaluation difficult. A key challenge is determining how diverse products in the marketplace relate to chemically and toxicologically characterized reference samples (i.e., how similar must a product be in order to be well-represented by the tested reference sample?). Ginkgo biloba extract (GBE) was used as a case study to develop and evaluate approaches for determining sufficient similarity. Multiple GBE extracts were evaluated for chemical and biological-response similarity. Chemical similarity was assessed using untargeted and targeted chemistry approaches. Biological similarity was evaluated using in vitro liver models and short-term rodent studies. Statistical and data visualization methods were then used to make decisions about the similarity of products to the reference sample. A majority of the 26 GBE samples tested (62%) were consistently determined to be sufficiently similar to the reference sample, while 27% were different from the reference GBE, and 12% were either similar or different depending on the method used. This case study demonstrated that approaches to evaluate sufficient similarity allow for critical evaluation of complex mixtures so that safety data from the tested reference can be applied to untested materials.
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9
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Parvez S, Rice GE, Teuschler LK, Simmons JE, Speth TF, Richardson SD, Miltner RJ, Hunter ES, Pressman JG, Strader LF, Klinefelter GR, Goldman JM, Narotsky MG. Method to assess component contribution to toxicity of complex mixtures: Assessment of puberty acquisition in rats exposed to disinfection byproducts. J Environ Sci (China) 2017; 58:311-321. [PMID: 28774622 PMCID: PMC8343928 DOI: 10.1016/j.jes.2017.05.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/19/2017] [Accepted: 05/31/2017] [Indexed: 05/04/2023]
Abstract
A method based on regression modeling was developed to discern the contribution of component chemicals to the toxicity of highly complex, environmentally realistic mixtures of disinfection byproducts (DBPs). Chemical disinfection of drinking water forms DBP mixtures. Because of concerns about possible reproductive and developmental toxicity, a whole mixture (WM) of DBPs produced by chlorination of a water concentrate was administered as drinking water to Sprague-Dawley (S-D) rats in a multigenerational study. Age of puberty acquisition, i.e., preputial separation (PPS) and vaginal opening (VO), was examined in male and female offspring, respectively. When compared to controls, a slight, but statistically significant delay in puberty acquisition was observed in females but not in males. WM-induced differences in the age at puberty acquisition were compared to those reported in S-D rats administered either a defined mixture (DM) of nine regulated DBPs or individual DBPs. Regression models were developed using individual animal data on age at PPS or VO from the DM study. Puberty acquisition data reported in the WM and individual DBP studies were then compared with the DM models. The delay in puberty acquisition observed in the WM-treated female rats could not be distinguished from delays predicted by the DM regression model, suggesting that the nine regulated DBPs in the DM might account for much of the delay observed in the WM. This method is applicable to mixtures of other types of chemicals and other endpoints.
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Affiliation(s)
- Shahid Parvez
- Indiana University Richard M. Fairbanks School of Public Health, Department of Environmental Health Sciences, IUPUI Campus, Indianapolis, IN 46202, USA
| | - Glenn E Rice
- National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
| | | | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Thomas F Speth
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Susan D Richardson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA
| | - Richard J Miltner
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - E Sidney Hunter
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jonathan G Pressman
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Lillian F Strader
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Gary R Klinefelter
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jerome M Goldman
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Michael G Narotsky
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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10
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Hrudey SE, Backer LC, Humpage AR, Krasner SW, Michaud DS, Moore LE, Singer PC, Stanford BD. Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2015; 18:213-41. [PMID: 26309063 PMCID: PMC4642182 DOI: 10.1080/10937404.2015.1067661] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Exposure to chlorination disinfection by-products (CxDBPs) is prevalent in populations using chlorination-based methods to disinfect public water supplies. Multifaceted research has been directed for decades to identify, characterize, and understand the toxicology of these compounds, control and minimize their formation, and conduct epidemiologic studies related to exposure. Urinary bladder cancer has been the health risk most consistently associated with CxDBPs in epidemiologic studies. An international workshop was held to (1) discuss the qualitative strengths and limitations that inform the association between bladder cancer and CxDBPs in the context of possible causation, (2) identify knowledge gaps for this topic in relation to chlorine/chloramine-based disinfection practice(s) in the United States, and (3) assess the evidence for informing risk management. Epidemiological evidence linking exposures to CxDBPs in drinking water to human bladder cancer risk provides insight into causality. However, because of imprecise, inaccurate, or incomplete estimation of CxDBPs levels in epidemiologic studies, translation from hazard identification directly to risk management and regulatory policy for CxDBPs can be challenging. Quantitative risk estimates derived from toxicological risk assessment for CxDBPs currently cannot be reconciled with those from epidemiologic studies, notwithstanding the complexities involved, making regulatory interpretation difficult. Evidence presented here has both strengths and limitations that require additional studies to resolve and improve the understanding of exposure response relationships. Replication of epidemiologic findings in independent populations with further elaboration of exposure assessment is needed to strengthen the knowledge base needed to better inform effective regulatory approaches.
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Affiliation(s)
- Steve E. Hrudey
- Environmental and Analytical Toxicology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | | | | | - Stuart W. Krasner
- Metropolitan Water District of Southern California, Los Angeles, California, USA
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11
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Marshall S, Gennings C, Teuschler LK, Stork LG, Tornero-Velez R, Crofton KM, Rice GE. An empirical approach to sufficient similarity: combining exposure data and mixtures toxicology data. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2013; 33:1582-95. [PMID: 23398277 PMCID: PMC3776008 DOI: 10.1111/risa.12015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
When assessing risks posed by environmental chemical mixtures, whole mixture approaches are preferred to component approaches. When toxicological data on whole mixtures as they occur in the environment are not available, Environmental Protection Agency guidance states that toxicity data from a mixture considered "sufficiently similar" to the environmental mixture can serve as a surrogate. We propose a novel method to examine whether mixtures are sufficiently similar, when exposure data and mixture toxicity study data from at least one representative mixture are available. We define sufficient similarity using equivalence testing methodology comparing the distance between benchmark dose estimates for mixtures in both data-rich and data-poor cases. We construct a "similar mixtures risk indicator"(SMRI) (analogous to the hazard index) on sufficiently similar mixtures linking exposure data with mixtures toxicology data. The methods are illustrated using pyrethroid mixtures occurrence data collected in child care centers (CCC) and dose-response data examining acute neurobehavioral effects of pyrethroid mixtures in rats. Our method shows that the mixtures from 90% of the CCCs were sufficiently similar to the dose-response study mixture. Using exposure estimates for a hypothetical child, the 95th percentile of the (weighted) SMRI for these sufficiently similar mixtures was 0.20 (i.e., where SMRI <1, less concern; >1, more concern).
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Affiliation(s)
| | - Chris Gennings
- Department of Biostatistics, Virginia Commonwealth University, Richmond, VA
| | | | | | | | - Kevin M. Crofton
- National Health and Environmental Effects Research Labs, Office of Research and Development, U.S. EPA, Research Triangle Park, NC
| | - Glenn E. Rice
- National Center for Environmental Assessment, U.S. EPA, Cincinnati, OH
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12
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Feder PI, Hertzberg RC. Assessing the mammalian toxicity of high-boiling point petroleum substances. Regul Toxicol Pharmacol 2013; 67:S1-3. [PMID: 23954515 DOI: 10.1016/j.yrtph.2013.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Tsai SS, Chiu HF, Yang CY. Trihalomethanes in drinking water and the risk of death from esophageal cancer: does hardness in drinking water matter? JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2013; 76:120-130. [PMID: 23294300 DOI: 10.1080/15287394.2013.738410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The objectives of this study were to (1) examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of esophageal cancer occurrence and (2) determine whether calcium (Ca) and magnesium (Mg) levels in drinking water modify the effects of TTHM on risk to develop esophageal cancer. A matched case-control study was used to investigate the relationship between the risk of death attributed to esophageal cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All esophageal cancer deaths in the 53 municipalities from 2006 through 2010 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from Taiwan Environmental Protection Administration. Information on the levels of Ca and Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM, Ca, and Mg exposure via drinking water. Relative to individuals whose TTHM exposure level <4.9 ppb, the adjusted odds ratio (OR) with 95% confidence interval (CI) for esophageal cancer was 1.02 (0.84-1.23) for individuals who resided in municipalities served by drinking water with a TTHM exposure ≥4.9 ppb. There was evidence of an interaction between drinking-water TTHM levels and low Ca and Mg intake. Our findings showed that the correlation between TTHM exposure and risk of esophageal cancer development was influenced by Ca and Mg levels in drinking water. This is the first study to report effect modification by Ca and Mg intake from drinking water on the correlation between TTHM exposure and risk of esophageal cancer occurrence. Increased knowledge of the interaction between Ca, Mg, and TTHM in reducing risk of esophageal cancer development will aid in public policymaking and standard setting for drinking water.
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Affiliation(s)
- Shang-Shyue Tsai
- Department of Health Care Administration, I-Shou University, Kaohsiung, Taiwan
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14
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Carlin DJ, Rider CV, Woychik R, Birnbaum LS. Unraveling the health effects of environmental mixtures: an NIEHS priority. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:A6-8. [PMID: 23409283 PMCID: PMC3553446 DOI: 10.1289/ehp.1206182] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
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15
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Pressman JG, McCurry DL, Parvez S, Rice GE, Teuschler LK, Miltner RJ, Speth TF. Disinfection byproduct formation in reverse-osmosis concentrated and lyophilized natural organic matter from a drinking water source. WATER RESEARCH 2012; 46:5343-5354. [PMID: 22846256 DOI: 10.1016/j.watres.2012.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 04/10/2012] [Accepted: 07/11/2012] [Indexed: 06/01/2023]
Abstract
Drinking water treatment and disinfection byproduct (DBP) research can be complicated by natural organic matter (NOM) temporal variability. NOM preservation by lyophilization (freeze-drying) has been long practiced to address this issue; however, its applicability for drinking water research has been limited because the selected NOM sources are atypical of most drinking water sources. The purpose of this research was to demonstrate that reconstituted NOM from a lyophilized reverse-osmosis (RO) concentrate of a typical drinking water source closely represents DBP formation in the original NOM. A preliminary experiment assessed DBP formation kinetics and yields in concentrated NOM, which demonstrated that chlorine decays faster in concentrate, in some cases leading to altered DBP speciation. Potential changes in NOM reactivity caused by lyophilization were evaluated by chlorination of lyophilized and reconstituted NOM, its parent RO concentrate, and the source water. Bromide lost during RO concentration was replaced by adding potassium bromide prior to chlorination. Although total measured DBP formation tended to decrease slightly and unidentified halogenated organic formation tended to increase slightly as a result of RO concentration, the changes associated with lyophilization were minor. In lyophilized NOM reconstituted back to source water TOC levels and then chlorinated, the concentrations of 19 of 21 measured DBPs, constituting 96% of the total identified DBP mass, were statistically indistinguishable from those in the chlorinated source water. Furthermore, the concentrations of 16 of 21 DBPs in lyophilized NOM reconstituted back to the RO concentrate TOC levels, constituting 86% DBP mass, were statistically indistinguishable from those in the RO concentrate. This study suggests that lyophilization can be used to preserve concentrated NOM without substantially altering the precursors to DBP formation.
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Affiliation(s)
- Jonathan G Pressman
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA.
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16
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Assessing the risk of ballast water treatment to human health. Regul Toxicol Pharmacol 2012; 62:513-22. [DOI: 10.1016/j.yrtph.2011.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 10/31/2011] [Accepted: 11/07/2011] [Indexed: 11/23/2022]
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17
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Silva ZI, Rebelo MH, Silva MM, Alves AM, Cabral MDC, Almeida AC, Aguiar FR, de Oliveira AL, Nogueira AC, Pinhal HR, Aguiar PM, Cardoso AS. Trihalomethanes in Lisbon indoor swimming pools: occurrence, determining factors, and health risk classification. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2012; 75:878-892. [PMID: 22788374 DOI: 10.1080/15287394.2012.690706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Characterization of water quality from indoor swimming pools, using chorine-based disinfection techniques, was performed during a 6-mo period to study the occurrence, distribution, and concentration factors of trihalomethanes (THM). Several parameters such as levels of water THM, water and air chloroform, water bromodichloromethane (BDCM), water dibromochloromethane (DBCM), water bromoform (BF), free residual chlorine (FrCl), pH, water and air temperature, and permanganate water oxidizability (PWO) were determined in each pool during that period. Chloroform (CF(W)) was the THM detected at higher concentrations in all pools, followed by BDCM, DBCM, and BF detected at 99, 34, and 6% of the samples, respectively. Water THM concentrations ranged from 10.1 to 155 μg/L, with 6.5% of the samples presenting values above 100 μg/L (parametric value established in Portuguese law DL 306/2007). In this study, air chloroform (CF(Air)) concentrations ranged from 45 to 373 μg/m³ with 24% of the samples presenting values above 136 μg/m³ (considered high exposure value). Several significant correlations were observed between total THM and other parameters, namely, CF(W), CF(Air), FrCl, water temperature (T(W)), and PWO. These correlations indicate that FrCl, T(W) and PWO are parameters that influence THM formation. The exposure criterion established for water THM enabled the inclusion of 67% of Lisbon pools in the high exposure group, which reinforces the need for an improvement in pool water quality.
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Affiliation(s)
- Zelinda Isabel Silva
- Water and Soil Unit, Environmental Health Department, Portuguese National Health Institute Doutor Ricardo Jorge (INSA), Lisbon, Portugal
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18
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Prospective power calculations for the Four Lab study of a multigenerational reproductive/developmental toxicity rodent bioassay using a complex mixture of disinfection by-products in the low-response region. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2011; 8:4082-101. [PMID: 22073030 PMCID: PMC3210599 DOI: 10.3390/ijerph8104082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 09/21/2011] [Accepted: 09/30/2011] [Indexed: 11/17/2022]
Abstract
In complex mixture toxicology, there is growing emphasis on testing environmentally representative doses that improve the relevance of results for health risk assessment, but are typically much lower than those used in traditional toxicology studies. Traditional experimental designs with typical sample sizes may have insufficient statistical power to detect effects caused by environmentally relevant doses. Proper study design, with adequate statistical power, is critical to ensuring that experimental results are useful for environmental health risk assessment. Studies with environmentally realistic complex mixtures have practical constraints on sample concentration factor and sample volume as well as the number of animals that can be accommodated. This article describes methodology for calculation of statistical power for non-independent observations for a multigenerational rodent reproductive/developmental bioassay. The use of the methodology is illustrated using the U.S. EPA's Four Lab study in which rodents were exposed to chlorinated water concentrates containing complex mixtures of drinking water disinfection by-products. Possible experimental designs included two single-block designs and a two-block design. Considering the possible study designs and constraints, a design of two blocks of 100 females with a 40:60 ratio of control:treated animals and a significance level of 0.05 yielded maximum prospective power (~90%) to detect pup weight decreases, while providing the most power to detect increased prenatal loss.
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19
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Kuo HW, Peng CY, Feng A, Wu TN, Yang CY. Magnesium in drinking water modifies the association between trihalomethanes and the risk of death from colon cancer. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:392-403. [PMID: 21271439 DOI: 10.1080/15287394.2011.538836] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The objectives of this study were to (1) examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and death attributed to colon cancer and (2) determine whether magnesium (Mg) levels in drinking water modify the effects of TTHM on risk of colon cancer development. A matched case-control study was used to investigate the relationship between the risk of death attributed to colon cancer and exposure to total trihalomethanes (TTHM) in drinking water in 53 municipalities in Taiwan. All colon cancer deaths of the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from Taiwan Environmental Protection Administration. Information on the levels of Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM and Mg exposure via drinking water. Relative to individuals whose TTHM exposure levels were <4.9 ppb, the adjusted odds ration (OR) (with 95% confidence interval [CI]) for colon cancer was 1.14 (1.01-1.28) for individuals who had resided in municipalities served by drinking water with a TTHM exposure≥4.9 ppb. Evidence of an interaction between drinking-water TTHM and Mg intake via drinking water was noted. This is the first study to report an effect modification by Mg intake from drinking water in association between TTHM exposure and risk of colon cancer occurrence. Better knowledge of this modifying factor will help in public policymaking and setting health standards.
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Affiliation(s)
- Hsin-Wei Kuo
- Institute of Occupational Safety and Health, College of Health Sciences, Kaohsiung Medical University, and Department of Internal Medicine, Yuan's General Hospital, Kaohsiung, Taiwan
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20
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Francis RA, Vanbriesen JM, Small MJ. Bayesian statistical modeling of disinfection byproduct (DBP) bromine incorporation in the ICR database. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:1232-1239. [PMID: 20095529 DOI: 10.1021/es9028606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Statistical models are developed for bromine incorporation in the trihalomethane (THM), trihaloacetic acids (THAA), dihaloacetic acid (DHAA), and dihaloacetonitrile (DHAN) subclasses of disinfection byproducts (DBPs) using distribution system samples from plants applying only free chlorine as a primary or residual disinfectant in the Information Collection Rule (ICR) database. The objective of this study is to characterize the effect of water quality conditions before, during, and post-treatment on distribution system bromine incorporation into DBP mixtures. Bayesian Markov Chain Monte Carlo (MCMC) methods are used to model individual DBP concentrations and estimate the coefficients of the linear models used to predict the bromine incorporation fraction for distribution system DBP mixtures in each of the four priority DBP classes. The bromine incorporation models achieve good agreement with the data. The most important predictors of bromine incorporation fraction across DBP classes are alkalinity, specific UV absorption (SUVA), and the bromide to total organic carbon ratio (Br:TOC) at the first point of chlorine addition. Free chlorine residual in the distribution system, distribution system residence time, distribution system pH, turbidity, and temperature only slightly influence bromine incorporation. The bromide to applied chlorine (Br:Cl) ratio is not a significant predictor of the bromine incorporation fraction (BIF) in any of the four classes studied. These results indicate that removal of natural organic matter and the location of chlorine addition are important treatment decisions that have substantial implications for bromine incorporation into disinfection byproduct in drinking waters.
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Affiliation(s)
- Royce A Francis
- Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
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21
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Buteau S, Valcke M. Probabilistic human health risk assessment for quarterly exposure to high chloroform concentrations in drinking-water distribution network of the Province of Quebec, Canada. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2010; 73:1626-1644. [PMID: 20967676 DOI: 10.1080/15287394.2010.501718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Because quarterly concentrations of total trihalomethanes (THM) exceeding the 80 μg/L guideline are often tolerated by the public health authorities of the Province of Quebec (Canada), this study examined whether quarterly episodes of high concentrations of THM may pose a risk to the health of its population. Using Monte Carlo simulations, a probabilistic risk assessment was performed for infants (0-<6 mo), toddlers (6 mo-<5 yr) and adults (≥20 yr). Multiroute exposure including ingestion of drinking water as well as inhalation and dermal exposure while showering or bathing was considered. The resulting absorbed doses were compared to short-term reference values for chloroform, used as surrogate for THM, by calculating risk quotients (RQ). On the basis of THM concentrations values in Quebec's drinking water distribution systems during the months of July to October and exceeding the guideline value (>80 μg/L), the 95th percentile value of RQ were 0.65, 0.46, and 0.24 for infants, toddlers, and adults, respectively. Back-calculation allowed determining that a chloroform concentration of 330 μg/L would result in RQ ≤ 1 for 99% of infants, the subgroup considered the most susceptible among the general population. Overall, this study showed that episodes of high THM concentration encountered in Quebec drinking-water distribution network need not be considered as an immediate health concern for the general population. However, these results should not be interpreted as an authorization to exceed the 80 μg/L standard but rather as a risk management tool for public health authorities.
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Affiliation(s)
- Stephane Buteau
- Institut national de santé publique du Québec, Montréal, Québec, Canada
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22
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Kuo HW, Chen PS, Ho SC, Wang LY, Yang CY. Trihalomethanes in drinking water and the risk of death from rectal cancer: does hardness in drinking water matter? JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2010; 73:807-818. [PMID: 20391122 DOI: 10.1080/15287391003689267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The objectives of this study were (1) to examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of rectal cancer development and (2) to determine whether calcium (Ca) and magnesium (Mg) levels in drinking water might modify the effects of TTHM on risk of developing rectal cancer. A matched cancer case-control study was used to investigate the relationship between the risk of death attributed to rectal cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All rectal cancer deaths in the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from the Taiwan Environmental Protection Administration. Information on the levels of Ca and Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM, Ca, and Mg exposure via drinking water. Relative to individuals whose TTHM exposure level was <4.9 ppb, the adjusted OR (95% CI) for rectal cancer occurrence was 1.04 (0.88-1.22) for individuals who resided in municipalities served by drinking water with a TTHM exposure >or=4.9 ppb. There was no evidence of an interaction of drinking-water TTHM levels with low Ca intake via drinking water. However, evidence of an interaction was noted between drinking-water TTHM concentrations and Mg intake via drinking water. Our findings showed that the correlation between TTHM exposure and risk of rectal cancer is influenced by Mg in drinking water. Increased knowledge of the interaction between Mg and TTHM in reducing rectal cancer risk will aid in public policymaking and standard setting.
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Affiliation(s)
- Hsin-Wei Kuo
- Institute of Occupational Safety and Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan
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23
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Feder PI, Ma ZJ, Bull RJ, Teuschler LK, Schenck KM, Simmons JE, Rice G. Evaluating sufficient similarity for disinfection by-product (DBP) mixtures: multivariate statistical procedures. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:468-481. [PMID: 19267308 DOI: 10.1080/15287390802608965] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
For evaluation of the adverse health effects associated with exposures to complex chemical mixtures in the environment, the U.S. Environmental Protection Agency (EPA) (2000) states, "if no data are available on the mixture of concern, but health effects data are available on a similar mixture ... a decision must be made whether the mixture on which health effects are available is 'sufficiently' similar to the mixture of concern to permit a risk assessment." This article provides a detailed discussion of statistical considerations for evaluation of the similarity of mixtures. Multivariate statistical procedures are suggested to determine whether individual samples of drinking-water disinfection by-products (DBPs) vary significantly from a group of samples that are considered to be similar. The application of principal components analysis to (1) reduce the dimensionality of the vectors of water samples and (2) permit visualization and statistical comparisons in lower dimensional space is suggested. Formal analysis of variance tests of homogeneity are illustrated. These multivariate statistical procedures are applied to a data set describing samples from multiple water treatment plants. Essential data required for carrying out sensitive analyses include (1) identification and measurement of toxicologically sensitive process input and output characteristics, and (2) estimates of variability within the data to construct statistically efficient estimates and tests.
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Affiliation(s)
- Paul I Feder
- Battelle, Statistics and Information Analysis, Columbus, Ohio 43201-2693, USA.
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24
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Rice GE, Teuschler LK, Bull RJ, Simmons JE, Feder PI. Evaluating the similarity of complex drinking-water disinfection by-product mixtures: overview of the issues. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:429-436. [PMID: 19267305 DOI: 10.1080/15287390802608890] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Humans are exposed daily to complex mixtures of environmental chemical contaminants, which arise as releases from sources such as engineering procedures, degradation processes, and emissions from mobile or stationary sources. When dose-response data are available for the actual environmental mixture to which individuals are exposed (i.e., the mixture of concern), these data provide the best information for dose-response assessment of the mixture. When suitable data on the mixture itself are not available, surrogate data might be used from a sufficiently similar mixture or a group of similar mixtures. Consequently, the determination of whether the mixture of concern is "sufficiently similar" to a tested mixture or a group of tested mixtures is central to the use of whole mixture methods. This article provides an overview for a series of companion articles whose purpose is to develop a set of biostatistical, chemical, and toxicological criteria and approaches for evaluating the similarity of drinking-water disinfection by-product (DBPs) complex mixtures. Together, the five articles in this series serve as a case study whose techniques will be relevant to assessing similarity for other classes of complex mixtures of environmental chemicals. Schenck et al. (2009) describe the chemistry and mutagenicity of a set of DBP mixtures concentrated from five different drinking-water treatment plants. Bull et al. (2009a, 2009b) describe how the variables that impact the formation of DBP affect the chemical composition and, subsequently, the expected toxicity of the mixture. Feder et al. (2009a, 2009b) evaluate the similarity of DBP mixture concentrates by applying two biostatistical approaches, principal components analysis, and a nonparametric "bootstrap" analysis. Important factors for determining sufficient similarity of DBP mixtures found in this research include disinfectant used; source water characteristics, including the concentrations of bromide and total organic carbon; concentrations and proportions of individual DBPs with known toxicity data on the same endpoint; magnitude of the unidentified fraction of total organic halides; similar toxicity outcomes for whole mixture testing (e.g., mutagenicity); and summary chemical measures such as total trihalomethanes, total haloacetic acids, total haloacetonitriles, and the levels of bromide incorporation in the DBP classes.
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Affiliation(s)
- Glenn E Rice
- U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA.
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Bull RJ, Rice G, Teuschler L, Feder P. Chemical measures of similarity among disinfection by-product mixtures. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:482-493. [PMID: 19267309 DOI: 10.1080/15287390802608973] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
There are few measures that can be used to distinguish among mixtures of disinfection by-products (DBPs) produced in the chlorination or chloramination of drinking water. Objective measures of similarities among DBP mixtures would greatly simplify judgments about the risk that may be associated with exposure to DBPs in a given water supply. Major by-products of chlorination/chloramination include the trihalomethanes (THMs) and haloacetic acids (HAAs), which are routinely measured for compliance to regulations. A key question is whether measurement of similar amounts of these DBPs is indicative of the myriad other DBPs that are known to be produced. This article utilized data from a survey of 35 utilities in the United States that included several additional parameters, including members of the haloacetonitrile, trihaloacetaldehyde, and halopropanone classes. Based upon the distribution of bromine in the THM class, the concentrations of unmeasured brominated and bromochlorinated compounds could be determined. This allowed determination of whether measures of the THM and/or HAA classes reflected the amounts of these less abundant classes. Variations in relative yields among DBP classes were observed with water source type and with whether chlorine or chloramine was used as the disinfectant. However, most of the variability was attributable to geographic location. The relative abundance of brominated by-products also varied among water sources. Recent documentation that potent by-products, such as nitrosamines, are selectively produced in particular water systems and preferentially with chloramination indicates that more measures of individual DBP are needed to evaluate similarity among DBPs mixtures.
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Feder PI, Ma ZJ, Bull RJ, Teuschler LK, Rice G. Evaluating sufficient similarity for drinking-water disinfection by-product (DBP) mixtures with bootstrap hypothesis test procedures. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:494-504. [PMID: 19267310 DOI: 10.1080/15287390802608981] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In chemical mixtures risk assessment, the use of dose-response data developed for one mixture to estimate risk posed by a second mixture depends on whether the two mixtures are sufficiently similar. While evaluations of similarity may be made using qualitative judgments, this article uses nonparametric statistical methods based on the "bootstrap" resampling technique to address the question of similarity among mixtures of chemical disinfectant by-products (DBP) in drinking water. The bootstrap resampling technique is a general-purpose, computer-intensive approach to statistical inference that substitutes empirical sampling for theoretically based parametric mathematical modeling. Nonparametric, bootstrap-based inference involves fewer assumptions than parametric normal theory based inference. The bootstrap procedure is appropriate, at least in an asymptotic sense, whether or not the parametric, distributional assumptions hold, even approximately. The statistical analysis procedures in this article are initially illustrated with data from 5 water treatment plants (Schenck et al., 2009), and then extended using data developed from a study of 35 drinking-water utilities (U.S. EPA/AMWA, 1989), which permits inclusion of a greater number of water constituents and increased structure in the statistical models.
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Affiliation(s)
- Paul I Feder
- Battelle, Statistics and Information Analysis, Columbus, Ohio 43201-2693, USA.
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