1
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Teuschler LK, Hertzberg RC, McDonald A, Sey YM, Simmons JE. Evaluation of a Proportional Response Addition Approach to Mixture Risk Assessment and Predictive Toxicology Using Data on Four Trihalomethanes from the U.S. EPA's Multiple-Purpose Design Study. Toxics 2024; 12:240. [PMID: 38668462 PMCID: PMC11053411 DOI: 10.3390/toxics12040240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/16/2024] [Accepted: 03/19/2024] [Indexed: 04/29/2024]
Abstract
In this study, proportional response addition (Prop-RA), a model for predicting response from chemical mixture exposure, is demonstrated and evaluated by statistically analyzing data on all possible binary combinations of the four regulated trihalomethanes (THMs). These THMs were the subject of a multipurpose toxicology study specifically designed to evaluate Prop-RA. The experimental design used a set of doses common to all components and mixtures, providing hepatotoxicity data on the four single THMs and the binary combinations. In Prop-RA, the contribution of each component to mixture toxicity is proportional to its fraction in the mixture based on its response at the total mixture dose. The primary analysis consisted of 160 evaluations. Statistically significant departures from the Prop-RA prediction were found for seven evaluations, with three predications that were greater than and four that were less than the predicted response; interaction magnitudes (n-fold difference in response vs. prediction) ranged from 1.3 to 1.4 for the former and 2.6 to 3.8 for the latter. These predictions support the idea that Prop-RA works best with chemicals where the effective dose ranges overlap. Prop-RA does not assume the similarity of toxic action or independence, but it can be applied to a mixture of components that affect the same organ/system, with perhaps unknown toxic modes of action.
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Affiliation(s)
| | | | - Anthony McDonald
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Yusupha Mahtarr Sey
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jane Ellen Simmons
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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2
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Hester K, Kirrane E, Anderson T, Kulikowski N, Simmons JE, Lehmann DM. Environmental exposure to metals and the development of tauopathies, synucleinopathies, and TDP-43 proteinopathies: A systematic evidence map protocol. Environ Int 2022; 169:107528. [PMID: 36183491 DOI: 10.1016/j.envint.2022.107528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 08/22/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis are incurable and expected to increase in prevalence in the upcoming decades. Environmental exposure to metals has been suggested as a contributing factor to the development of neurodegenerative disease. This systematic evidence map will identify and characterize the epidemiological and experimental data available on the intersection of eighteen metals of environmental concern (i.e., aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, mercury, nickel, palladium, radium, silver, vanadium, and zinc) and three neurodegenerative disease clusters (i.e., tauopathies, synucleinopathies, and TDP-43 proteinopathies). We aim to describe the type and amount of evidence available (or lack thereof) for each metal and neurodegenerative disease combination and highlight important knowledge gaps and knowledge clusters for future research. METHODS We will conduct a thorough search using two databases (MEDLINE and Web of Science Core Collection) and grey literature resources. Pre-defined criteria have been developed to identify studies which evaluate at least one of the selected metals and neurodegenerative disease-relevant outcomes (e.g., neuropathology, cognitive function, motor function, disease mortality). At each phase of review, studies will be evaluated by two reviewers. Studies determined to be relevant will be extracted for population, exposure, and outcome information. We will conduct a narrative review of the included studies, and the extracted data will be available in a database hosted on Tableau Public. CONCLUSION This protocol documents the decisions made a priori to data collection regarding these objectives.
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Affiliation(s)
- Kirstin Hester
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Ellen Kirrane
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Timothy Anderson
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Hazardous Pollutant Assessment & Systems Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Nichole Kulikowski
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Jane Ellen Simmons
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - David M Lehmann
- Center for Public Health and Environmental Assessment, Health and Environmental Effects Division, Integrated Health Assessment Branch, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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3
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Rooney J, Wehmas LC, Ryan N, Chorley BN, Hester SD, Kenyon EM, Schmid JE, George BJ, Hughes MF, Sey YM, Tennant AH, Simmons JE, Wood CE, Corton JC. Genomic comparisons between hepatocarcinogenic and non-hepatocarcinogenic organophosphate insecticides in the mouse liver. Toxicology 2022; 465:153046. [PMID: 34813904 DOI: 10.1016/j.tox.2021.153046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 11/12/2021] [Accepted: 11/17/2021] [Indexed: 11/27/2022]
Abstract
Short-term biomarkers of toxicity have an increasingly important role in the screening and prioritization of new chemicals. In this study, we examined early indicators of liver toxicity for three reference organophosphate (OP) chemicals, which are among the most widely used insecticides in the world. The OP methidathion was previously shown to increase the incidence of liver toxicity, including hepatocellular tumors, in male mice. To provide insights into the adverse outcome pathway (AOP) that underlies these tumors, effects of methidathion in the male mouse liver were examined after 7 and 28 day exposures and compared to those of two other OPs that either do not increase (fenthion) or possibly suppress liver cancer (parathion) in mice. None of the chemicals caused increases in liver weight/body weight or histopathological changes in the liver. Parathion decreased liver cell proliferation after 7 and 28 days while the other chemicals had no effects. There was no evidence for hepatotoxicity in any of the treatment groups. Full-genome microarray analysis of the livers from the 7 and 28 day treatments demonstrated that methidathion and fenthion regulated a large number of overlapping genes, while parathion regulated a unique set of genes. Examination of cytochrome P450 enzyme activities and use of predictive gene expression biomarkers found no consistent evidence for activation of AhR, CAR, PXR, or PPARα. Parathion suppressed the male-specific gene expression pattern through STAT5b, similar to genetic and dietary conditions that decrease liver tumor incidence in mice. Overall, these findings indicate that methidathion causes liver cancer by a mechanism that does not involve common mechanisms of liver cancer induction.
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Affiliation(s)
- John Rooney
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at US EPA, Office of Research and Development, Center for Computational Toxicology and Exposure (formerly NHEERL), Research Triangle Park, NC, 27711, United States; National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - Leah C Wehmas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Natalia Ryan
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at US EPA, Office of Research and Development, Center for Computational Toxicology and Exposure (formerly NHEERL), Research Triangle Park, NC, 27711, United States; National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - Brian N Chorley
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Susan D Hester
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Elaina M Kenyon
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Judith E Schmid
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - Barbara Jane George
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Michael F Hughes
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Yusupha M Sey
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Alan H Tennant
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Jane Ellen Simmons
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
| | - Charles E Wood
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States(3).
| | - J Christopher Corton
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States.
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4
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George BJ, Thomas KW, Simmons JE. Response to Comment on "Censoring Trace-Level Environmental Data: Statistical Analysis Considerations to Limit Bias". Environ Sci Technol 2021; 55:15556-15557. [PMID: 34704749 PMCID: PMC8796121 DOI: 10.1021/acs.est.1c06431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Barbara Jane George
- Address correspondence to Barbara Jane George,
Center for Public Health and Environmental Assessment, Office of Research and
Development, U.S. EPA, Research Triangle Park, North Carolina 27711, United
States. Telephone: (919) 541-4551.
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George BJ, Gains-Germain L, Broms K, Black K, Furman M, Hays MD, Thomas KW, Simmons JE. Censoring Trace-Level Environmental Data: Statistical Analysis Considerations to Limit Bias. Environ Sci Technol 2021; 55:3786-3795. [PMID: 33625843 PMCID: PMC8224532 DOI: 10.1021/acs.est.0c02256] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Trace-level environmental data typically include values near or below detection and quantitation thresholds where health effects may result from low-concentration exposures to one chemical over time or to multiple chemicals. In a cook stove case study, bias in dibenzo[a,h]anthracene concentration means and standard deviations (SDs) was assessed following censoring at thresholds for selected analysis approaches: substituting threshold/2, maximum likelihood estimation, robust regression on order statistics, Kaplan-Meier, and omitting censored observations. Means and SDs for gas chromatography-mass spectrometry-determined concentrations were calculated after censoring at detection and calibration thresholds, 17% and 55% of the data, respectively. Threshold/2 substitution was the least biased. Measurement values were subsequently simulated from two log-normal distributions at two sample sizes. Means and SDs were calculated for 30%, 50%, and 80% censoring levels and compared to known distribution counterparts. Simulation results illustrated (1) threshold/2 substitution to be inferior to modern after-censoring statistical approaches and (2) all after-censoring approaches to be inferior to including all measurement data in analysis. Additionally, differences in stove-specific group means were tested for uncensored samples and after censoring. Group differences of means tests varied depending on censoring and distributional decisions. Investigators should guard against censoring-related bias from (explicit or implicit) distributional and analysis approach decisions.
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Affiliation(s)
- Barbara Jane George
- Center for Public Health and Environmental Assessment,
Office of Research and Development, U.S. EPA, Research Triangle Park, North Carolina
27711, United States
| | | | - Kristin Broms
- Neptune and Company, Inc., Lakewood, Colorado 80215, United
States
| | - Kelly Black
- Neptune and Company, Inc., Lakewood, Colorado 80215, United
States
| | - Marschall Furman
- Oak Ridge Institute for Science and Education (ORISE)
Research Participant at U.S. EPA, Office of Research and Development, Center for
Public Health and Environmental Assessment, Research Triangle Park, North Carolina
27711, United States
| | - Michael D. Hays
- Center for Environmental Measurement and Modeling, Office
of Research and Development, U.S. EPA, Research Triangle Park, North Carolina 27711,
United States
| | - Kent W. Thomas
- Center for Public Health and Environmental Assessment,
Office of Research and Development, U.S. EPA, Research Triangle Park, North Carolina
27711, United States
| | - Jane Ellen Simmons
- Center for Public Health and Environmental Assessment,
Office of Research and Development, U.S. EPA, Research Triangle Park, North Carolina
27711, United States
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6
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Feder PI, Aume LL, Triplett CA, Simmons JE, Narotsky MG. Analysis of proportional data in reproductive and developmental toxicity studies: Comparison of sensitivities of logit transformation, arcsine square root transformation, and nonparametric analysis. Birth Defects Res 2020; 112:1260-1272. [PMID: 32735073 DOI: 10.1002/bdr2.1755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 11/12/2022]
Abstract
BACKGROUND In developmental and reproductive toxicity studies, analysis of litter-based binary endpoints (e.g., incidence of malformed fetuses) is complex in that littermates often are not entirely independent of one another. It is well established that the litter, not the individual fetus, is the proper independent experimental unit in statistical analysis. Accordingly, analysis is often based on the proportion affected per litter and the litter proportions are analyzed as continuous data. Because these proportional data generally do not meet assumptions of symmetry or normality, data are typically analyzed by nonparametric methods, arcsine square root transformation, or logit transformation. METHODS We conducted power calculations to compare different approaches (nonparametric, arcsine square root-transformed, logit-transformed, untransformed) for analyzing litter-based proportional data. A reproductive toxicity study with a control and one treated group provided data for two endpoints: prenatal loss, and fertility by in utero insemination (IUI). Type 1 error and power were estimated by 10,000 simulations based on two-sample one-tailed t tests with varying numbers of litters per group. To further compare the different approaches, we conducted additional analyses with shifted mean proportions to produce illustrative scenarios. RESULTS Analyses based on logit-transformed proportions had greater power than those based on untransformed or arcsine square root-transformed proportions, or nonparametric procedures. CONCLUSION The logit transformation is preferred to the other approaches considered when making inferences concerning litter-based proportional endpoints, particularly with skewed distributions. The improved performance of the logit transformation becomes increasingly pronounced as the response proportions are increasingly close to the boundaries of the parameter space.
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Affiliation(s)
- Paul I Feder
- Battelle Memorial Institute, Columbus, Ohio, USA
| | - Laura L Aume
- Battelle Memorial Institute, Columbus, Ohio, USA
| | | | - Jane Ellen Simmons
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Research Triangle Park, North Carolina, USA
| | - Michael G Narotsky
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Research Triangle Park, North Carolina, USA
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7
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Evans MV, Eklund CR, Williams DN, Sey YM, Simmons JE. Global optimization of the Michaelis-Menten parameters using physiologically-based pharmacokinetic (PBPK) modeling and chloroform vapor uptake data in F344 rats. Inhal Toxicol 2020; 32:97-109. [PMID: 32241199 DOI: 10.1080/08958378.2020.1742818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Objective: To quantify metabolism, a physiologically based pharmacokinetic (PBPK) model for a volatile compound can be calibrated with the closed chamber (i.e. vapor uptake) inhalation data. Here, we introduce global optimization as a novel component of the predictive process and use it to illustrate a procedure for metabolic parameter estimation.Materials and methods: Male F344 rats were exposed in vapor uptake chambers to initial concentrations of 100, 500, 1000, and 3000 ppm chloroform. Chamber time-course data from these experiments, in combination with optimization using a chemical-specific PBPK model, were used to estimate Michaelis-Menten metabolic constants. Matlab® simulation software was used to integrate the mass balance equations and to perform the global optimizations using MEIGO (MEtaheuristics for systems biology and bIoinformatics Global Optimization - Version 64 bit, R2016A), a toolbox written for Matlab®. The cost function used the chamber time-course data and least squares to minimize the difference between data and simulation values.Results and discussion: The final values estimated for Vmax (maximum metabolic rate) and Km (affinity constant) were 1.2 mg/h and a range between 0.0005 and 0.6 mg/L, respectively. Also, cost function plots were used to analyze the dose-dependent capacity to estimate Vmax and Km within the experimental range used. Sensitivity analysis was used to assess identifiability for both parameters and show these kinetic data may not be sufficient to identify Km.Conclusion: In summary, this work should help toxicologists interested in optimization techniques understand the overall process employed when calibrating metabolic parameters in a PBPK model with inhalation data.
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Affiliation(s)
- Marina V Evans
- ORD, National Health and Environmental Effects Research Laboratory, ISTD, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Christopher R Eklund
- ORD, National Health and Environmental Effects Research Laboratory, ISTD, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - David N Williams
- ORISE, Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Yusupha M Sey
- ORD, National Health and Environmental Effects Research Laboratory, ISTD, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Jane Ellen Simmons
- ORD, National Health and Environmental Effects Research Laboratory, ISTD, US Environmental Protection Agency, Research Triangle Park, NC, USA
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8
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Berninger JP, DeMarini DM, Warren SH, Simmons JE, Wilson VS, Conley JM, Armstrong MD, Iwanowicz LR, Kolpin DW, Kuivila KM, Reilly TJ, Romanok KM, Villeneuve DL, Bradley PM. Predictive Analysis Using Chemical-Gene Interaction Networks Consistent with Observed Endocrine Activity and Mutagenicity of U.S. Streams. Environ Sci Technol 2019; 53:8611-8620. [PMID: 31287672 PMCID: PMC6770991 DOI: 10.1021/acs.est.9b02990] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In a recent U.S. Geological Survey/U.S. Environmental Protection Agency study assessing more than 700 organic compounds in 38 streams, in vitro assays indicated generally low estrogen, androgen, and glucocorticoid receptor activities, with 13 surface waters with 17β-estradiol-equivalent (E2Eq) activities greater than a 1-ng/L estimated effects-based trigger value for estrogenic effects in male fish. Among the 36 samples assayed for mutagenicity in the Salmonella bioassay (reported here), 25% had low mutagenic activity and 75% were not mutagenic. Endocrine and mutagenic activities of the water samples were well correlated with each other and with the total number and cumulative concentrations of detected chemical contaminants. To test the predictive utility of knowledge-base-leveraging approaches, site-specific predicted chemical-gene (pCGA) and predicted analogous pathway-linked (pPLA) association networks identified in the Comparative Toxicogenomics Database were compared with observed endocrine/mutagenic bioactivities. We evaluated pCGA/pPLA patterns among sites by cluster analysis and principal component analysis and grouped the pPLA into broad mode-of-action classes. Measured E2eq and mutagenic activities correlated well with predicted pathways. The pPLA analysis also revealed correlations with signaling, metabolic, and regulatory groups, suggesting that other effects pathways may be associated with chemical contaminants in these waters and indicating the need for broader bioassay coverage to assess potential adverse impacts.
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Affiliation(s)
- Jason P. Berninger
- Columbia Environmental Research Center, U.S. Geological Survey, Columbia, Missouri 65201, United States
| | - David M. DeMarini
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Sarah H. Warren
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Vickie S. Wilson
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Justin M. Conley
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Mikayla D. Armstrong
- Department of Environmental Science and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Luke R. Iwanowicz
- Leetown Science Center, U.S. Geological Survey, Kearneysville, West Virginia 25430, United States
| | - Dana W. Kolpin
- Central Midwest Water Science Center, U.S. Geological Survey, Iowa City, Iowa 52240, United States
| | - Kathryn M. Kuivila
- Oregon Water Science Center, U.S. Geological Survey, Portland, Oregon 97201, United States
| | - Timothy J. Reilly
- New Jersey Water Science Center, U.S. Geological Survey, Lawrenceville, New Jersey 08648, United States
| | - Kristin M. Romanok
- New Jersey Water Science Center, U.S. Geological Survey, Lawrenceville, New Jersey 08648, United States
| | - Daniel L. Villeneuve
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Duluth, Minnesota 55804, United States
| | - Paul M. Bradley
- South Atlantic Water Science Center, U.S. Geological Survey, Columbia, South Carolina 29210, United States
- Corresponding author: Phone 803-727-9046;
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Boone JS, Vigo C, Boone T, Byrne C, Ferrario J, Benson R, Donohue J, Simmons JE, Kolpin DW, Furlong ET, Glassmeyer ST. Per- and polyfluoroalkyl substances in source and treated drinking waters of the United States. Sci Total Environ 2019; 653:359-369. [PMID: 30412881 PMCID: PMC6996027 DOI: 10.1016/j.scitotenv.2018.10.245] [Citation(s) in RCA: 117] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 04/15/2023]
Abstract
Contaminants of emerging concern (CECs), including per- and polyfluoroalkyl substances (PFAS), are of interest to regulators, water treatment utilities, the general public and scientists. This study measured 17 PFAS in source and treated water from 25 drinking water treatment plants (DWTPs) as part of a broader study of CECs in drinking water across the United States. PFAS were quantitatively detected in all 50 samples, with summed concentrations of the 17 PFAS ranging from <1 ng/L to 1102 ng/L. The median total PFAS concentration was 21.4 ng/L in the source water and 19.5 ng/L in the treated drinking water. Comparing the total PFAS concentration in source and treated water at each location, only five locations demonstrated statistically significant differences (i.e. P < 0.05) between the source and treated water. When the perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) concentrations in the treated drinking water are compared to the existing US Environmental Protection Agency's PFOA and PFOS drinking water heath advisory of 70 ng/L for each chemical or their sum one DWTP exceeded the threshold. Six of the 25 DWTPs were along two large rivers. The DWTPs within each of the river systems had specific PFAS profiles, with the three DWTPs from one river being dominated by PFOA, while three DWTPs on the second river were dominated by perfluorobutyric acid (PFBA).
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Affiliation(s)
- J Scott Boone
- US Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Stennis Space Center, MS 39529, United States of America.
| | - Craig Vigo
- US Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Stennis Space Center, MS 39529, United States of America.
| | - Tripp Boone
- US Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Stennis Space Center, MS 39529, United States of America.
| | - Christian Byrne
- US Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Stennis Space Center, MS 39529, United States of America
| | - Joseph Ferrario
- US Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Stennis Space Center, MS 39529, United States of America
| | - Robert Benson
- USEPA Region 8, 1595 Wynkoop St., Mail Code: 8WP-S, Denver, CO 80202-1129, United States of America.
| | - Joyce Donohue
- USEPA, Office of Water, Office of Science and Technology, William Jefferson Clinton Building, 1200 Pennsylvania Avenue, N. W., Washington, DC 20460, United States of America.
| | - Jane Ellen Simmons
- USEPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711, United States of America.
| | - Dana W Kolpin
- U.S. Geological Survey, Central Midwest Water Science Center, 400 S. Clinton St., Iowa City, IA 52240, United States of America.
| | - Edward T Furlong
- U.S. Geological Survey, National Water Quality Laboratory, PO Box 25585, Building 95, Denver Federal Center, Denver, CO 80225-0046, United States of America.
| | - Susan T Glassmeyer
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, United States of America.
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Postigo C, DeMarini DM, Armstrong MD, Liberatore HK, Lamann K, Kimura SY, Cuthbertson AA, Warren SH, Richardson SD, McDonald T, Sey YM, Ackerson NOB, Duirk SE, Simmons JE. Chlorination of Source Water Containing Iodinated X-ray Contrast Media: Mutagenicity and Identification of New Iodinated Disinfection Byproducts. Environ Sci Technol 2018; 52:13047-13056. [PMID: 30339747 PMCID: PMC6369525 DOI: 10.1021/acs.est.8b04625] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Iodinated contrast media (ICM) are nonmutagenic agents administered for X-ray imaging of soft tissues. ICM can reach μg/L levels in surface waters because they are administered in high doses, excreted largely unmetabolized, and poorly removed by wastewater treatment. Iodinated disinfection byproducts (I-DBPs) are highly genotoxic and have been reported in disinfected waters containing ICM. We assessed the mutagenicity in Salmonella of extracts of chlorinated source water containing one of four ICM (iopamidol, iopromide, iohexol, and diatrizoate). We quantified 21 regulated and nonregulated DBPs and 11 target I-DBPs and conducted a nontarget, comprehensive broad-screen identification of I-DBPs. We detected one new iodomethane (trichloroiodomethane), three new iodoacids (dichloroiodoacetic acid, chlorodiiodoacetic acid, bromochloroiodoacetic acid), and two new nitrogenous I-DBPs (iodoacetonitrile and chloroiodoacetonitrile). Their formation depended on the presence of iopamidol as the iodine source; identities were confirmed with authentic standards when available. This is the first identification in simulated drinking water of chloroiodoacetonitrile and iodoacetonitrile, the latter of which is highly cytotoxic and genotoxic in mammalian cells. Iopamidol (5 μM) altered the concentrations and relative distribution of several DBP classes, increasing total haloacetonitriles by >10-fold. Chlorination of ICM-containing source water increased I-DBP concentrations but not mutagenicity, indicating that such I-DBPs were either not mutagenic or at concentrations too low to affect mutagenicity.
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Affiliation(s)
- Cristina Postigo
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Box 7050, SE-750 07 Uppsala, Sweden
- Corresponding author: CP: Phone +34-93-400-6100;
| | - David M. DeMarini
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Mikayla D. Armstrong
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Hannah K. Liberatore
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, South Carolina 29208, United States
| | - Karsten Lamann
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, South Carolina 29208, United States
| | - Susana Y. Kimura
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, South Carolina 29208, United States
| | - Amy A. Cuthbertson
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, South Carolina 29208, United States
| | - Sarah H. Warren
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Susan D. Richardson
- Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, South Carolina 29208, United States
| | - Tony McDonald
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Yusupha M. Sey
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Nana Osei B. Ackerson
- Department of Civil Engineering, University of Akron, Akron, Ohio 44235, United States
| | - Stephen E. Duirk
- Department of Civil Engineering, University of Akron, Akron, Ohio 44235, United States
| | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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11
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Rooney JP, Ryan N, Chorley BN, Hester SD, Kenyon EM, Schmid JE, George BJ, Hughes MF, Sey YM, Tennant A, MacMillan DK, Simmons JE, McQueen CA, Pandiri A, Wood CE, Corton JC. From the Cover: Genomic Effects of Androstenedione and Sex-Specific Liver Cancer Susceptibility in Mice. Toxicol Sci 2018; 160:15-29. [PMID: 28973534 DOI: 10.1093/toxsci/kfx153] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Current strategies for predicting carcinogenic mode of action for nongenotoxic chemicals are based on identification of early key events in toxicity pathways. The goal of this study was to evaluate short-term key event indicators resulting from exposure to androstenedione (A4), an androgen receptor agonist and known liver carcinogen in mice. Liver cancer is more prevalent in men compared with women, but androgen-related pathways underlying this sex difference have not been clearly identified. Short-term hepatic effects of A4 were compared with reference agonists of the estrogen receptor (ethinyl estradiol, EE) and glucocorticoid receptor (prednisone, PRED). Male B6C3F1 mice were exposed for 7 or 28 days to A4, EE, or PRED. EE increased and PRED suppressed hepatocyte proliferation, while A4 had no detectable effects. In a microarray analysis, EE and PRED altered >3000 and >670 genes, respectively, in a dose-dependent manner, whereas A4 did not significantly alter any genes. Gene expression was subsequently examined in archival liver samples from male and female B6C3F1 mice exposed to A4 for 90 days. A4 altered more genes in females than males and did not alter expression of genes linked to activation of the mitogenic xenobiotic receptors AhR, CAR, and PPARα in either sex. A gene expression biomarker was used to show that in female mice, the high dose of A4 activated the growth hormone-regulated transcription factor STAT5b, which controls sexually dimorphic gene expression in the liver. These findings suggest that A4 induces subtle age-related effects on STAT5b signaling that may contribute to the higher risk of liver cancer in males compared with females.
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Affiliation(s)
- John P Rooney
- Office of Research and Development, Oak Ridge Institute for Science and Education (ORISE).,Integrated Systems Toxicology Division
| | - Natalia Ryan
- Office of Research and Development, Oak Ridge Institute for Science and Education (ORISE).,Integrated Systems Toxicology Division
| | | | | | | | | | | | | | | | | | | | | | - Charlene A McQueen
- Office of the Director, National Health and Environmental Effects Research Laboratory (NHEERL), U.S. EPA, Research Triangle Park, North Carolina, 27711
| | - Arun Pandiri
- National Toxicology Program, Research Triangle Park, North Carolina, 27711
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12
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Wambaugh JF, Hughes MF, Ring CL, MacMillan DK, Ford J, Fennell TR, Black SR, Snyder RW, Sipes NS, Wetmore BA, Westerhout J, Setzer RW, Pearce RG, Simmons JE, Thomas RS. Evaluating In Vitro-In Vivo Extrapolation of Toxicokinetics. Toxicol Sci 2018; 163:152-169. [PMID: 29385628 PMCID: PMC5920326 DOI: 10.1093/toxsci/kfy020] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Prioritizing the risk posed by thousands of chemicals potentially present in the environment requires exposure, toxicity, and toxicokinetic (TK) data, which are often unavailable. Relatively high throughput, in vitro TK (HTTK) assays and in vitro-to-in vivo extrapolation (IVIVE) methods have been developed to predict TK, but most of the in vivo TK data available to benchmark these methods are from pharmaceuticals. Here we report on new, in vivo rat TK experiments for 26 non-pharmaceutical chemicals with environmental relevance. Both intravenous and oral dosing were used to calculate bioavailability. These chemicals, and an additional 19 chemicals (including some pharmaceuticals) from previously published in vivo rat studies, were systematically analyzed to estimate in vivo TK parameters (e.g., volume of distribution [Vd], elimination rate). For each of the chemicals, rat-specific HTTK data were available and key TK predictions were examined: oral bioavailability, clearance, Vd, and uncertainty. For the non-pharmaceutical chemicals, predictions for bioavailability were not effective. While no pharmaceutical was absorbed at less than 10%, the fraction bioavailable for non-pharmaceutical chemicals was as low as 0.3%. Total clearance was generally more under-estimated for nonpharmaceuticals and Vd methods calibrated to pharmaceuticals may not be appropriate for other chemicals. However, the steady-state, peak, and time-integrated plasma concentrations of nonpharmaceuticals were predicted with reasonable accuracy. The plasma concentration predictions improved when experimental measurements of bioavailability were incorporated. In summary, HTTK and IVIVE methods are adequately robust to be applied to high throughput in vitro toxicity screening data of environmentally relevant chemicals for prioritizing based on human health risks.
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Affiliation(s)
| | - Michael F Hughes
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Caroline L Ring
- National Center for Computational Toxicology
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831
| | - Denise K MacMillan
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Jermaine Ford
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | | | - Sherry R Black
- RTI International, Research Triangle Park, North Carolina
| | | | - Nisha S Sipes
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27717
| | - Barbara A Wetmore
- National Exposure Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Joost Westerhout
- The Netherlands Organisation for Applied Scientific Research (TNO), AJ Zeist 3700, The Netherlands
| | | | - Robert G Pearce
- National Center for Computational Toxicology
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831
| | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Glassmeyer ST, Furlong ET, Kolpin DW, Batt AL, Benson R, Boone JS, Conerly O, Donohue MJ, King DN, Kostich MS, Mash HE, Pfaller SL, Schenck KM, Simmons JE, Varughese EA, Vesper SJ, Villegas EN, Wilson VS. Nationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States. Sci Total Environ 2017; 581-582:909-922. [PMID: 28024752 PMCID: PMC7017586 DOI: 10.1016/j.scitotenv.2016.12.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 05/18/2023]
Abstract
When chemical or microbial contaminants are assessed for potential effect or possible regulation in ambient and drinking waters, a critical first step is determining if the contaminants occur and if they are at concentrations that may cause human or ecological health concerns. To this end, source and treated drinking water samples from 29 drinking water treatment plants (DWTPs) were analyzed as part of a two-phase study to determine whether chemical and microbial constituents, many of which are considered contaminants of emerging concern, were detectable in the waters. Of the 84 chemicals monitored in the 9 Phase I DWTPs, 27 were detected at least once in the source water, and 21 were detected at least once in treated drinking water. In Phase II, which was a broader and more comprehensive assessment, 247 chemical and microbial analytes were measured in 25 DWTPs, with 148 detected at least once in the source water, and 121 detected at least once in the treated drinking water. The frequency of detection was often related to the analyte's contaminant class, as pharmaceuticals and anthropogenic waste indicators tended to be infrequently detected and more easily removed during treatment, while per and polyfluoroalkyl substances and inorganic constituents were both more frequently detected and, overall, more resistant to treatment. The data collected as part of this project will be used to help inform evaluation of unregulated contaminants in surface water, groundwater, and drinking water.
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Affiliation(s)
- Susan T Glassmeyer
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Edward T Furlong
- USGS, National Water Quality Laboratory, Denver Federal Center, Bldg 95, Denver, CO 80225, United States.
| | - Dana W Kolpin
- USGS, 400 S. Clinton St, Rm 269 Federal Building, Iowa City, IA 52240, United States.
| | - Angela L Batt
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Robert Benson
- USEPA, Region 8, 1595 Wynkoop St., Mail Code: 8P-W, Denver, CO 80202-1129, United States.
| | - J Scott Boone
- USEPA, Office of Chemical Safety and Pollution Prevention, Stennis Space Center, MS, United States.
| | - Octavia Conerly
- USEPA, Office of Water, Office of Science and Technology, William Jefferson Clinton Building, 1200 Pennsylvania Avenue, N. W., Mail Code: 4304T, Washington, DC 20460, United States.
| | - Maura J Donohue
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Dawn N King
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Mitchell S Kostich
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Heath E Mash
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Stacy L Pfaller
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Kathleen M Schenck
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Jane Ellen Simmons
- USEPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711, United States.
| | - Eunice A Varughese
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Stephen J Vesper
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Eric N Villegas
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, United States.
| | - Vickie S Wilson
- USEPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC 27711, United States.
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15
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Benson R, Conerly OD, Sander W, Batt AL, Boone JS, Furlong ET, Glassmeyer ST, Kolpin DW, Mash HE, Schenck KM, Simmons JE. Human health screening and public health significance of contaminants of emerging concern detected in public water supplies. Sci Total Environ 2017; 579:1643-1648. [PMID: 28040195 PMCID: PMC6277017 DOI: 10.1016/j.scitotenv.2016.03.146] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/09/2016] [Accepted: 03/20/2016] [Indexed: 05/20/2023]
Abstract
The source water and treated drinking water from twenty five drinking water treatment plants (DWTPs) across the United States were sampled in 2010-2012. Samples were analyzed for 247 contaminants using 15 chemical and microbiological methods. Most of these contaminants are not regulated currently either in drinking water or in discharges to ambient water by the U. S. Environmental Protection Agency (USEPA) or other U.S. regulatory agencies. This analysis shows that there is little public health concern for most of the contaminants detected in treated water from the 25 DWTPs participating in this study. For vanadium, the calculated Margin of Exposure (MOE) was less than the screening MOE in two DWTPs. For silicon, the calculated MOE was less than the screening MOE in one DWTP. Additional study, for example a national survey may be needed to determine the number of people ingesting vanadium and silicon above a level of concern. In addition, the concentrations of lithium found in treated water from several DWTPs are within the range previous research has suggested to have a human health effect. Additional investigation of this issue is necessary. Finally, new toxicological data suggest that exposure to manganese at levels in public water supplies may present a public health concern which will require a robust assessment of this information.
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Affiliation(s)
- Robert Benson
- USEPA Region 8, 1595 Wynkoop, Denver, CO 80202, United States.
| | - Octavia D Conerly
- USEPA, Office of Water, Office of Science and Technology, William Jefferson Clinton Building, 1200 Pennsylvania Ave, NW, Washington, DC 20460, United States.
| | - William Sander
- American Association for the Advancement of Science (AAAS) and Technology Policy Fellow hosted, USEPA, Office of Water, Office of Science and Technology, William Jefferson Clinton Building, 1200 Pennsylvania Ave, NW, Washington, DC 20460, United States.
| | - Angela L Batt
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W Martin Luther King Dr., Cincinnati, OH 45268, United States.
| | - J Scott Boone
- USEPA, Office of Chemical Safety and Pollution Prevention, Stennis Space Port, MS, United States.
| | - Edward T Furlong
- USGS, National Water Quality Laboratory, PO Box 25585, Building 95, Denver Federal Center, Denver, CO 80225, United States.
| | - Susan T Glassmeyer
- USEPA, Office of Research and Development, National Exposure Research Laboratory, 26 W Martin Luther King Dr., Cincinnati, OH 45268, United States.
| | - Dana W Kolpin
- USGS, Iowa Water Science Center, PO Box 1230, Iowa City, IA 52244, United States.
| | - Heath E Mash
- USEPA, Office of Research and Development, National Risk Management Research Laboratory, 26 W Martin Luther King Dr., Cincinnati, OH 45268, United States.
| | - Kathleen M Schenck
- USEPA, Office of Research and Development, National Risk Management Research Laboratory, 26 W Martin Luther King Dr., Cincinnati, OH 45268, United States.
| | - Jane Ellen Simmons
- USEPA, Office of Research and Development, National Health and Environmental Effects Research Division, 109 T.W. Alexander Dr., Research Triangle Park, NC 27709, United States.
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16
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Jeong CH, Postigo C, Richardson SD, Simmons JE, Kimura SY, Mariñas BJ, Barcelo D, Liang P, Wagner ED, Plewa MJ. Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water. Environ Sci Technol 2015; 49:13749-59. [PMID: 25942416 PMCID: PMC4791037 DOI: 10.1021/es506358x] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The introduction of drinking water disinfection greatly reduced waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water leads to an unintended consequence, the formation of drinking water disinfection byproducts (DBPs). The haloacetaldehydes (HALs) are the third largest group by weight of identified DBPs in drinking water. The primary objective of this study was to analyze the occurrence and comparative toxicity of the emerging HAL DBPs. A new HAL DBP, iodoacetaldehyde (IAL) was identified. This study provided the first systematic, quantitative comparison of HAL toxicity in Chinese hamster ovary cells. The rank order of HAL cytotoxicity is tribromoacetaldehyde (TBAL) ≈ chloroacetaldehyde (CAL) > dibromoacetaldehyde (DBAL) ≈ bromochloroacetaldehyde (BCAL) ≈ dibromochloroacetaldehyde (DBCAL) > IAL > bromoacetaldehyde (BAL) ≈ bromodichloroacetaldehyde (BDCAL) > dichloroacetaldehyde (DCAL) > trichloroacetaldehyde (TCAL). The HALs were highly cytotoxic compared to other DBP chemical classes. The rank order of HAL genotoxicity is DBAL > CAL ≈ DBCAL > TBAL ≈ BAL > BDCAL>BCAL ≈ DCAL>IAL. TCAL was not genotoxic. Because of their toxicity and abundance, further research is needed to investigate their mode of action to protect the public health and the environment.
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Affiliation(s)
- Clara H. Jeong
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Safe Global Water Institute and the Science and Technology Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Cristina Postigo
- Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Barcelona 08034, Spain
| | - Susan D. Richardson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
| | - Susana Y. Kimura
- Department of Civil and Environmental Engineering and
- Safe Global Water Institute and the Science and Technology Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Benito J. Mariñas
- Department of Civil and Environmental Engineering and
- Safe Global Water Institute and the Science and Technology Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Damia Barcelo
- Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Barcelona 08034, Spain
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, 17003 Girona, Girona, Spain
| | - Pei Liang
- Department of Chemistry, Central China Normal University, Wuhan, Hubei 430079, P.R China
| | - Elizabeth D. Wagner
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Safe Global Water Institute and the Science and Technology Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
| | - Michael J. Plewa
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Safe Global Water Institute and the Science and Technology Center of Advanced Materials for the Purification of Water with Systems, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
- Corresponding Author: Phone: 217-333-3614.
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17
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Lake AD, Wood CE, Bhat VS, Chorley BN, Carswell GK, Sey YM, Kenyon EM, Padnos B, Moore TM, Tennant AH, Schmid JE, George BJ, Ross DG, Hughes MF, Corton JC, Simmons JE, McQueen CA, Hester SD. Dose and Effect Thresholds for Early Key Events in a PPARα-Mediated Mode of Action. Toxicol Sci 2015; 149:312-25. [PMID: 26519955 DOI: 10.1093/toxsci/kfv236] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Current strategies for predicting adverse health outcomes of environmental chemicals are centered on early key events in toxicity pathways. However, quantitative relationships between early molecular changes in a given pathway and later health effects are often poorly defined. The goal of this study was to evaluate short-term key event indicators using qualitative and quantitative methods in an established pathway of mouse liver tumorigenesis mediated by peroxisome proliferator-activated receptor alpha (PPARα). Male B6C3F1 mice were exposed for 7 days to di (2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), and n-butyl benzyl phthalate (BBP), which vary in PPARα activity and liver tumorigenicity. Each phthalate increased expression of select PPARα target genes at 7 days, while only DEHP significantly increased liver cell proliferation labeling index (LI). Transcriptional benchmark dose (BMDT) estimates for dose-related genomic markers stratified phthalates according to hypothetical tumorigenic potencies, unlike BMDs for non-genomic endpoints (relative liver weights or proliferation). The 7-day BMDT values for Acot1 as a surrogate measure for PPARα activation were 29, 370, and 676 mg/kg/day for DEHP, DNOP, and BBP, respectively, distinguishing DEHP (liver tumor BMD of 35 mg/kg/day) from non-tumorigenic DNOP and BBP. Effect thresholds were generated using linear regression of DEHP effects at 7 days and 2-year tumor incidence values to anchor early response molecular indicators and a later phenotypic outcome. Thresholds varied widely by marker, from 2-fold (Pdk4 and proliferation LI) to 30-fold (Acot1) induction to reach hypothetical tumorigenic expression levels. These findings highlight key issues in defining thresholds for biological adversity based on molecular changes.
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Affiliation(s)
- April D Lake
- *Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina 27599; Oak Ridge Institute for Science and Education (ORISE) participant at the National Health and Environmental Effects Research Laboratory (NHEERL), Office of Research and Development (ORD), U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711; Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Charles E Wood
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | | | - Brian N Chorley
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Gleta K Carswell
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Yusupha M Sey
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Elaina M Kenyon
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Beth Padnos
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Tanya M Moore
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Alan H Tennant
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | | | - Barbara Jane George
- Office of the Associate Director for Health, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - David G Ross
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Michael F Hughes
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - J Christopher Corton
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Jane Ellen Simmons
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Charlene A McQueen
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711
| | - Susan D Hester
- Integrated Systems Toxicology Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina 27711;
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Narotsky MG, Klinefelter GR, Goldman JM, DeAngelo AB, Best DS, McDonald A, Strader LF, Murr AS, Suarez JD, George MH, Hunter ES, Simmons JE. Reproductive toxicity of a mixture of regulated drinking-water disinfection by-products in a multigenerational rat bioassay. Environ Health Perspect 2015; 123:564-70. [PMID: 25695961 PMCID: PMC4455591 DOI: 10.1289/ehp.1408579] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 02/12/2015] [Indexed: 05/21/2023]
Abstract
BACKGROUND Trihalomethanes (THMs) and haloacetic acids (HAAs) are regulated disinfection by-products (DBPs); their joint reproductive toxicity in drinking water is unknown. OBJECTIVE We aimed to evaluate a drinking water mixture of the four regulated THMs and five regulated HAAs in a multigenerational reproductive toxicity bioassay. METHODS Sprague-Dawley rats were exposed (parental, F1, and F2 generations) from gestation day 0 of the parental generation to postnatal day (PND) 6 of the F2 generation to a realistically proportioned mixture of THMs and HAAs at 0, 500×, 1,000×, or 2,000× of the U.S. Environmental Protection Agency's maximum contaminant levels (MCLs). RESULTS Maternal water consumption was reduced at ≥ 1,000×; body weights were reduced at 2,000×. Prenatal and postnatal survival were unaffected. F1 pup weights were unaffected at birth but reduced at 2,000× on PND6 and at ≥ 1,000× on PND21. Postweaning F1 body weights were reduced at 2,000×, and water consumption was reduced at ≥ 500×. Males at 2,000× had a small but significantly increased incidence of retained nipples and compromised sperm motility. Onset of puberty was delayed at 1,000× and 2,000×. F1 estrous cycles and fertility were unaffected, and F2 litters showed no effects on pup weight or survival. Histologically, P0 (parental) dams had nephropathy and adrenal cortical pathology at 2,000×. CONCLUSIONS A mixture of regulated DBPs at up to 2,000× the MCLs had no adverse effects on fertility, pregnancy maintenance, prenatal survival, postnatal survival, or birth weights. Delayed puberty at ≥ 1,000× may have been secondary to reduced water consumption. Male nipple retention and compromised sperm motility at 2,000× may have been secondary to reduced body weights.
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Affiliation(s)
- Michael G Narotsky
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
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George BJ, Sobus JR, Phelps LP, Rashleigh B, Simmons JE, Hines RN. Raising the bar for reproducible science at the U.S. Environmental Protection Agency Office of Research and Development. Toxicol Sci 2015; 145:16-22. [PMID: 25795653 PMCID: PMC4408961 DOI: 10.1093/toxsci/kfv020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Considerable concern has been raised regarding research reproducibility both within and outside the scientific community. Several factors possibly contribute to a lack of reproducibility, including a failure to adequately employ statistical considerations during study design, bias in sample selection or subject recruitment, errors in developing data inclusion/exclusion criteria, and flawed statistical analysis. To address some of these issues, several publishers have developed checklists that authors must complete. Others have either enhanced statistical expertise on existing editorial boards, or formed distinct statistics editorial boards. Although the U.S. Environmental Protection Agency, Office of Research and Development, already has a strong Quality Assurance Program, an initiative was undertaken to further strengthen statistics consideration and other factors in study design and also to ensure these same factors are evaluated during the review and approval of study protocols. To raise awareness of the importance of statistical issues and provide a forum for robust discussion, a Community of Practice for Statistics was formed in January 2014. In addition, three working groups were established to develop a series of questions or criteria that should be considered when designing or reviewing experimental, observational, or modeling focused research. This article describes the process used to develop these study design guidance documents, their contents, how they are being employed by the Agency’s research enterprise, and expected benefits to Agency science. The process and guidance documents presented here may be of utility for any research enterprise interested in enhancing the reproducibility of its science.
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Affiliation(s)
- Barbara Jane George
- *US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; US Environmental Protection Agency, Office of Research and Development, Office of the Science Advisor, Research Triangle Park, North Carolina 27711; and US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island 02882
| | - Jon R Sobus
- *US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; US Environmental Protection Agency, Office of Research and Development, Office of the Science Advisor, Research Triangle Park, North Carolina 27711; and US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island 02882
| | - Lara P Phelps
- *US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; US Environmental Protection Agency, Office of Research and Development, Office of the Science Advisor, Research Triangle Park, North Carolina 27711; and US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island 02882
| | - Brenda Rashleigh
- *US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; US Environmental Protection Agency, Office of Research and Development, Office of the Science Advisor, Research Triangle Park, North Carolina 27711; and US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island 02882
| | - Jane Ellen Simmons
- *US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; US Environmental Protection Agency, Office of Research and Development, Office of the Science Advisor, Research Triangle Park, North Carolina 27711; and US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island 02882
| | - Ronald N Hines
- *US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; US Environmental Protection Agency, Office of Research and Development, Office of the Science Advisor, Research Triangle Park, North Carolina 27711; and US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Narragansett, Rhode Island 02882
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Postigo C, Jeong CH, Richardson SD, Wagner ED, Plewa MJ, Simmons JE, Barceló D. Analysis, Occurrence, and Toxicity of Haloacetaldehydes in Drinking Waters: Iodoacetaldehyde as an Emerging Disinfection By-Product. ACS Symposium Series 2015. [DOI: 10.1021/bk-2015-1190.ch002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Cristina Postigo
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
| | - Clara H. Jeong
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
| | - Susan D. Richardson
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
| | - Elizabeth D. Wagner
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
| | - Michael J. Plewa
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
| | - Jane Ellen Simmons
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
| | - Damià Barceló
- Department of Environmental Chemistry, Institute for Environmental Assessment and WaterResearch, (IDAEA-CSIC), Carrer Jordi Girona 18-26, 08034, Barcelona, Spain
- Department of Crop Sciences and the Center of Advanced Materials for the Purification of Water with Systems, Safe Global Water Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry and Biochemistry, University of South Carolina, JM Palms Centre for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States
- National Health and Environmental Effects Research Laboratory, (NHEERL-U.S. EPA), 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
- Catalan Institute for Water Research (ICRA), Parc Científic i Tecnològic de la Universitat de Girona, Edifici H2O, Carrer d’Emili Grahit, 101, 17003 Girona, Spain
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Lehmann GM, Verner MA, Luukinen B, Henning C, Assimon SA, LaKind JS, McLanahan ED, Phillips LJ, Davis MH, Powers CM, Hines EP, Haddad S, Longnecker MP, Poulsen MT, Farrer DG, Marchitti SA, Tan YM, Swartout JC, Sagiv SK, Welsh C, Campbell JL, Foster WG, Yang RS, Fenton SE, Tornero-Velez R, Francis BM, Barnett JB, El-Masri HA, Simmons JE. Improving the risk assessment of lipophilic persistent environmental chemicals in breast milk. Crit Rev Toxicol 2014; 44:600-17. [PMID: 25068490 PMCID: PMC4115797 DOI: 10.3109/10408444.2014.926306] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lipophilic persistent environmental chemicals (LPECs) have the potential to accumulate within a woman's body lipids over the course of many years prior to pregnancy, to partition into human milk, and to transfer to infants upon breastfeeding. As a result of this accumulation and partitioning, a breastfeeding infant's intake of these LPECs may be much greater than his/her mother's average daily exposure. Because the developmental period sets the stage for lifelong health, it is important to be able to accurately assess chemical exposures in early life. In many cases, current human health risk assessment methods do not account for differences between maternal and infant exposures to LPECs or for lifestage-specific effects of exposure to these chemicals. Because of their persistence and accumulation in body lipids and partitioning into breast milk, LPECs present unique challenges for each component of the human health risk assessment process, including hazard identification, dose-response assessment, and exposure assessment. Specific biological modeling approaches are available to support both dose-response and exposure assessment for lactational exposures to LPECs. Yet, lack of data limits the application of these approaches. The goal of this review is to outline the available approaches and to identify key issues that, if addressed, could improve efforts to apply these approaches to risk assessment of lactational exposure to these chemicals.
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Affiliation(s)
- Geniece M. Lehmann
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | - Marc-André Verner
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, US
| | | | - Cara Henning
- ICF International, Research Triangle Park, NC, US
| | - Sue Anne Assimon
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD, US
| | - Judy S. LaKind
- LaKind Associates, LLC, Catonsville, MD, US
- University of Maryland School of Medicine, Baltimore, MD, US
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, US
| | - Eva D. McLanahan
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | - Linda J. Phillips
- Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, US
| | - Matthew H. Davis
- Office of Children’s Health Protection, U.S. Environmental Protection Agency, Washington, DC, US
| | - Christina M. Powers
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | - Erin P. Hines
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | - Sami Haddad
- Department of Environmental Health and Occupational Health, IRSPUM (Université de Montréal Public Health Research Institute), Université de Montréal, Montreal, Quebec, Canada
| | - Matthew P. Longnecker
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, US
| | | | | | - Satori A. Marchitti
- Office of Research and Development, U.S. Environmental Protection Agency, Athens, GA, US
| | - Yu-Mei Tan
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | - Jeffrey C. Swartout
- Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, OH, US
| | - Sharon K. Sagiv
- Department of Environmental Health, Boston University School of Public Health, Boston, MA, US
| | - Clement Welsh
- Division of Toxicology and Human Health Sciences, Agency for Toxic Substances and Disease Registry, Atlanta, GA, US
| | - Jerry L. Campbell
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC, US
| | - Warren G. Foster
- Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada
| | - Raymond S.H. Yang
- Quantitative and Computational Toxicology Group, Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, US
| | - Suzanne E. Fenton
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, US
| | - Rogelio Tornero-Velez
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | | | - John B. Barnett
- Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Morgantown, WV, US
| | - Hisham A. El-Masri
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
| | - Jane Ellen Simmons
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, US
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Lyon BA, Milsk RY, DeAngelo AB, Simmons JE, Moyer MP, Weinberg HS. Integrated chemical and toxicological investigation of UV-chlorine/chloramine drinking water treatment. Environ Sci Technol 2014; 48:6743-53. [PMID: 24840005 DOI: 10.1021/es501412n] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
As the use of alternative drinking water treatment increases, it is important to understand potential public health implications associated with these processes. The objective of this study was to evaluate the formation of disinfection byproducts (DBPs) and cytotoxicity of natural organic matter (NOM) concentrates treated with chlorine, chloramine, and medium pressure ultraviolet (UV) irradiation followed by chlorine or chloramine, with and without nitrate or iodide spiking. The use of concentrated NOM conserved volatile DBPs and allowed for direct analysis of the treated water. Treatment with UV prior to chlorine in ambient (unspiked) samples did not affect cytotoxicity as measured using an in vitro normal human colon cell (NCM460) assay, compared to chlorination alone when toxicity is expressed on the basis of dissolved organic carbon (DOC). Nitrate-spiked UV+chlorine treatment produced greater cytotoxicity than nitrate-spiked chlorine alone or ambient UV+chlorine samples, on both a DOC and total organic halogen basis. Samples treated with UV+chloramine were more cytotoxic than those treated with only chloramine using either dose metric. This study demonstrated the combination of cytotoxicity and DBP measurements for process evaluation in drinking water treatment. The results highlight the importance of dose metric when considering the relative toxicity of complex DBP mixtures formed under different disinfection scenarios.
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Affiliation(s)
- Bonnie A Lyon
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , 146A Rosenau Hall, Chapel Hill, North Carolina 27599, United States
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Hertzberg RC, Pan Y, Li R, Haber LT, Lyles RH, Herr DW, Moser VC, Simmons JE. A four-step approach to evaluate mixtures for consistency with dose addition. Toxicology 2013; 313:134-44. [DOI: 10.1016/j.tox.2012.10.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 10/07/2012] [Accepted: 10/08/2012] [Indexed: 12/01/2022]
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Rider CV, Boekelheide K, Catlin N, Gordon CJ, Morata T, Selgrade MK, Sexton K, Simmons JE. Cumulative risk: toxicity and interactions of physical and chemical stressors. Toxicol Sci 2013; 137:3-11. [PMID: 24154487 DOI: 10.1093/toxsci/kft228] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent efforts to update cumulative risk assessment procedures to incorporate nonchemical stressors ranging from physical to psychosocial reflect increased interest in consideration of the totality of variables affecting human health and the growing desire to develop community-based risk assessment methods. A key roadblock is the uncertainty as to how nonchemical stressors behave in relationship to chemical stressors. Physical stressors offer a reasonable starting place for measuring the effects of nonchemical stressors and their modulation of chemical effects (and vice versa), as they clearly differ from chemical stressors; and "doses" of many physical stressors are more easily quantifiable than those of psychosocial stressors. There is a commonly held belief that virtually nothing is known about the impact of nonchemical stressors on chemically mediated toxicity or the joint impact of coexposure to chemical and nonchemical stressors. Although this is generally true, there are several instances where a substantial body of evidence exists. A workshop titled "Cumulative Risk: Toxicity and Interactions of Physical and Chemical Stressors" held at the 2013 Society of Toxicology Annual Meeting provided a forum for discussion of research addressing the toxicity of physical stressors and what is known about their interactions with chemical stressors, both in terms of exposure and effects. Physical stressors including sunlight, heat, radiation, infectious disease, and noise were discussed in reference to identifying pathways of interaction with chemical stressors, data gaps, and suggestions for future incorporation into cumulative risk assessments.
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Affiliation(s)
- Cynthia V Rider
- * Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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Narotsky MG, Klinefelter GR, Goldman JM, Best DS, McDonald A, Strader LF, Suarez JD, Murr AS, Thillainadarajah I, Hunter ES, Richardson SD, Speth TF, Miltner RJ, Pressman JG, Teuschler LK, Rice GE, Moser VC, Luebke RW, Simmons JE. Comprehensive assessment of a chlorinated drinking water concentrate in a rat multigenerational reproductive toxicity study. Environ Sci Technol 2013; 47:10653-10659. [PMID: 23909560 DOI: 10.1021/es402646c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Some epidemiological studies report associations between drinking water disinfection byproducts (DBPs) and adverse reproductive/developmental effects, e.g., low birth weight, spontaneous abortion, stillbirth, and birth defects. Using a multigenerational rat bioassay, we evaluated an environmentally relevant "whole" mixture of DBPs representative of chlorinated drinking water, including unidentified DBPs as well as realistic proportions of known DBPs at low-toxicity concentrations. Source water from a water utility was concentrated 136-fold, chlorinated, and provided as drinking water to Sprague-Dawley rats. Timed-pregnant females (P0 generation) were exposed during gestation and lactation. Weanlings (F1 generation) continued exposures and were bred to produce an F2 generation. Large sample sizes enhanced statistical power, particularly for pup weight and prenatal loss. No adverse effects were observed for pup weight, prenatal loss, pregnancy rate, gestation length, puberty onset in males, growth, estrous cycles, hormone levels, immunological end points, and most neurobehavioral end points. Significant, albeit slight, effects included delayed puberty for F1 females, reduced caput epidydimal sperm counts in F1 adult males, and increased incidences of thyroid follicular cell hypertrophy in adult females. These results highlight areas for future research, while the largely negative findings, particularly for pup weight and prenatal loss, are notable.
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Affiliation(s)
- Michael G Narotsky
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency , Research Triangle Park, North Carolina 27711, United States
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Slone EJ, Teuschler LK, Aume LL, Narotsky MG, Simmons JE, Lordo RA, Rice GE. Estimation of individual rodent water consumption from group consumption data for gestation, lactation, and postweaning life stages using linear regression models. ILAR J 2013; 53:E99-112. [PMID: 23382274 DOI: 10.1093/ilar.53.1.99] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In rodent bioassays where chemicals are administered in the drinking water, water consumption data for individual animals are needed to estimate chemical exposures accurately. If multiple animals share a common water source, as occurs in some studies, only the total amount of drinking water consumed by all animals utilizing the common source is directly measurable, and water consumption rates for individual animals are not available. In the Four Lab Study of the US Environmental Protection Agency, which included a multigenerational rodent bioassay, a complex mixture of drinking water disinfection by-products was delivered to multiple Sprague-Dawley rats from a common drinking water container. To estimate disinfection by-product mixture exposure for each animal, authors developed four log-linear regression models to allocate water consumption among rats sharing a common water container. The four models represented three animal lifestages: Gestation, Lactation, and Postweaning, with separate Postweaning models for male and female. Authors used data from six Sprague-Dawley rat bioassays to develop these models from available individual cage data for the Postweaning models, and available individual animal data for the Gestation and Lactation models. The r(2) values for the model fits were good, ranging from 0.67 to 0.92. The Gestation and Lactation models were generally quite accurate in predicting average daily water consumption whereas the Postweaning models were less robust. These models can be generalized for use in other reproductive and developmental bioassays where common water sources are used and data on the explanatory variables are available.
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Moser VC, Padilla S, Simmons JE, Haber LT, Hertzberg RC. Impact of chemical proportions on the acute neurotoxicity of a mixture of seven carbamates in preweanling and adult rats. Toxicol Sci 2012; 129:126-34. [PMID: 22649187 DOI: 10.1093/toxsci/kfs190] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Statistical design and environmental relevance are important aspects of studies of chemical mixtures, such as pesticides. We used a dose-additivity model to test experimentally the default assumptions of dose additivity for two mixtures of seven N-methylcarbamates (carbaryl, carbofuran, formetanate, methomyl, methiocarb, oxamyl, and propoxur). The best-fitting models were selected for the single-chemical dose-response data and used to develop a combined prediction model, which was then compared with the experimental mixture data. We evaluated behavioral (motor activity) and cholinesterase (ChE)-inhibitory (brain, red blood cells) outcomes at the time of peak acute effects following oral gavage in adult and preweanling (17 days old) Long-Evans male rats. The mixtures varied only in their mixing ratios. In the relative potency mixture, proportions of each carbamate were set at equitoxic component doses. A California environmental mixture was based on the 2005 sales of each carbamate in California. In adult rats, the relative potency mixture showed dose additivity for red blood cell ChE and motor activity, and brain ChE inhibition showed a modest greater-than additive (synergistic) response, but only at a middle dose. In rat pups, the relative potency mixture was either dose-additive (brain ChE inhibition, motor activity) or slightly less-than additive (red blood cell ChE inhibition). On the other hand, at both ages, the environmental mixture showed greater-than additive responses on all three endpoints, with significant deviations from predicted at most to all doses tested. Thus, we observed different interactive properties for different mixing ratios of these chemicals. These approaches for studying pesticide mixtures can improve evaluations of potential toxicity under varying experimental conditions that may mimic human exposures.
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Affiliation(s)
- Virginia C Moser
- Toxicity Assessment Division, US EPA, Research Triangle Park, North Carolina 27711, USA.
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Narotsky MG, Pressman JG, Miltner RJ, Speth TF, Teuschler LK, Rice GE, Richardson SD, Best DS, McDonald A, Hunter ES, Simmons JE. Developmental Toxicity Evaluations of Whole Mixtures of Disinfection By-products using Concentrated Drinking Water in Rats: Gestational and Lactational Effects of Sulfate and Sodium. ACTA ACUST UNITED AC 2012; 95:202-12. [DOI: 10.1002/bdrb.21004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/19/2011] [Indexed: 11/11/2022]
Affiliation(s)
- Michael G. Narotsky
- National Health and Environmental Effects Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Research Triangle Park; North Carolina
| | - Jonathan G. Pressman
- National Risk Management Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Cincinnati; Ohio
| | - Richard J. Miltner
- National Risk Management Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Cincinnati; Ohio
| | - Thomas F. Speth
- National Risk Management Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Cincinnati; Ohio
| | - Linda K. Teuschler
- National Center for Environmental Assessment; Office of Research and Development; U.S. Environmental Protection Agency; Cincinnati; Ohio
| | - Glenn E. Rice
- National Center for Environmental Assessment; Office of Research and Development; U.S. Environmental Protection Agency; Cincinnati; Ohio
| | - Susan D. Richardson
- National Exposure Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Athens; Georgia
| | - Deborah S. Best
- National Health and Environmental Effects Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Research Triangle Park; North Carolina
| | - Anthony McDonald
- National Health and Environmental Effects Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Research Triangle Park; North Carolina
| | - E. Sidney Hunter
- National Health and Environmental Effects Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Research Triangle Park; North Carolina
| | - Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory; Office of Research and Development; U.S. Environmental Protection Agency; Research Triangle Park; North Carolina
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Rider CV, Dourson ML, Hertzberg RC, Mumtaz MM, Price PS, Simmons JE. Incorporating nonchemical stressors into cumulative risk assessments. Toxicol Sci 2012; 127:10-7. [PMID: 22345310 DOI: 10.1093/toxsci/kfs088] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The role of nonchemical stressors in modulating the human health risk associated with chemical exposures is an area of increasing attention. On 9 March 2011, a workshop titled "Approaches for Incorporating Nonchemical Stressors into Cumulative Risk Assessment" took place during the 50th Anniversary Annual Society of Toxicology Meeting in Washington D.C. Objectives of the workshop included describing the current state of the science from various perspectives (i.e., regulatory, exposure, modeling, and risk assessment) and presenting expert opinions on currently available methods for incorporating nonchemical stressors into cumulative risk assessments. Herein, distinct frameworks for characterizing exposure to, joint effects of, and risk associated with chemical and nonchemical stressors are discussed.
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Affiliation(s)
- Cynthia V Rider
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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Colman J, Rice GE, Wright JM, Hunter ES, Teuschler LK, Lipscomb JC, Hertzberg RC, Simmons JE, Fransen M, Osier M, Narotsky MG. Identification of developmentally toxic drinking water disinfection byproducts and evaluation of data relevant to mode of action. Toxicol Appl Pharmacol 2011; 254:100-26. [DOI: 10.1016/j.taap.2011.02.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 04/22/2010] [Accepted: 04/22/2010] [Indexed: 12/26/2022]
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Plewa MJ, Simmons JE, Richardson SD, Wagner ED. Mammalian cell cytotoxicity and genotoxicity of the haloacetic acids, a major class of drinking water disinfection by-products. Environ Mol Mutagen 2010; 51:871-8. [PMID: 20839218 DOI: 10.1002/em.20585] [Citation(s) in RCA: 212] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The haloacetic acids (HAAs) are disinfection by-products (DBPs) that are formed during the disinfection of drinking water, wastewaters and recreational pool waters. Currently, five HAAs [bromoacetic acid (BAA), dibromoacetic acid (DBAA), chloroacetic acid (CAA), dichloroacetic acid (DCAA), and trichloroacetic acid (TCAA); designated as HAA5] are regulated by the U.S. EPA, at a maximum contaminant level of 60 μg/L for the sum of BAA, DBAA, CAA, DCAA, and TCAA. We present a comparative systematic analysis of chronic cytotoxicity and acute genomic DNA damaging capacity of 12 individual HAAs in mammalian cells. In addition to the HAA5, we analyzed iodoacetic acid (IAA), diiodoacetic acid (DiAA), bromoiodoacetic acid (BIAA), tribromoacetic acid (TBAA), chlorodibromoacetic acid (CDBAA), bromodichloroacetic acid (BDCAA), and bromochloroacetic acid (BCAA). Their rank order of chronic cytotoxicity in Chinese hamster ovary cells was IAA > BAA > TBAA > CDBAA > DIAA > DBAA > BDCAA > BCAA > CAA > BIAA > TCAA > DCAA. The rank order for genotoxicity was IAA > BAA > CAA > DBAA > DIAA > TBAA > BCAA > BIAA > CDBAA. DCAA, TCAA, and BDCAA were not genotoxic. The trend for both cytotoxicity and genotoxicity is iodinated HAAs > brominated HAAs > chlorinated HAAs. The use of alternative disinfectants other than chlorine generates new DBPs and alters their distribution. Systematic, comparative, in vitro toxicological data provides the water supply community with information to consider when employing alternatives to chlorine disinfection. In addition, these data aid in prioritizing DBPs and their related compounds for future in vivo toxicological studies and risk assessment.
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Affiliation(s)
- Michael J Plewa
- Department of Crop Sciences, College of Agricultural, Consumer and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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Pressman JG, Richardson SD, Speth TF, Miltner RJ, Narotsky MG, Hunter ES, Rice GE, Teuschler LK, McDonald A, Parvez S, Krasner SW, Weinberg HS, McKague AB, Parrett CJ, Bodin N, Chinn R, Lee CFT, Simmons JE. Concentration, chlorination, and chemical analysis of drinking water for disinfection byproduct mixtures health effects research: U.S. EPA's Four Lab Study. Environ Sci Technol 2010; 44:7184-92. [PMID: 20496936 DOI: 10.1021/es9039314] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The U.S. Environmental Protection Agency's "Four Lab Study" involved participation of researchers from four national Laboratories and Centers of the Office of Research and Development along with collaborators from the water industry and academia. The study evaluated toxicological effects of complex disinfection byproduct (DBP) mixtures, with an emphasis on reproductive and developmental effects that have been associated with DBP exposures in some human epidemiologic studies. This paper describes a new procedure for producing chlorinated drinking water concentrate for animal toxicology experiments, comprehensive identification of >100 DBPs, and quantification of 75 priority and regulated DBPs. In the research reported herein, complex mixtures of DBPs were produced by concentrating a natural source water with reverse osmosis membranes, followed by addition of bromide and treatment with chlorine. By concentrating natural organic matter in the source water first and disinfecting with chlorine afterward, DBPs (including volatiles and semivolatiles) were formed and maintained in a water matrix suitable for animal studies. DBP levels in the chlorinated concentrate compared well to those from EPA's Information Collection Rule (ICR) and a nationwide study of priority unregulated DBPs when normalized by total organic carbon (TOC). DBPs were relatively stable over the course of the animal studies (125 days) with multiple chlorination events (every 5-14 days), and a significant portion of total organic halogen was accounted for through a comprehensive identification approach. DBPs quantified included regulated DBPs, priority unregulated DBPs, and additional DBPs targeted by the ICR. Many DBPs are reported for the first time, including previously undetected and unreported haloacids and haloamides. The new concentration procedure not only produced a concentrated drinking water suitable for animal experiments, but also provided a greater TOC concentration factor (136×), enhancing the detection of trace DBPs that are often below detection using conventional approaches.
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Affiliation(s)
- Jonathan G Pressman
- National Risk Management Research Laboratory, US EPA, Cincinnati, Ohio 45268, USA
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Narotsky MG, Best DS, McDonald A, Godin EA, Hunter ES, Simmons JE. Pregnancy loss and eye malformations in offspring of F344 rats following gestational exposure to mixtures of regulated trihalomethanes and haloacetic acids. Reprod Toxicol 2010; 31:59-65. [PMID: 20850520 DOI: 10.1016/j.reprotox.2010.08.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 08/09/2010] [Accepted: 08/25/2010] [Indexed: 11/24/2022]
Abstract
Chlorination of drinking water yields hundreds of disinfection by-products (DBPs). Among the DBPs, four trihalomethanes (THMs; chloroform, bromodichloromethane, chlorodibromomethane, bromoform) and five haloacetic acids (HAAs; chloroacetic, dichloroacetic, trichloroacetic, bromoacetic, and dibromoacetic acid) are U.S. EPA regulated. We assessed the combined toxicity of these DBPs. F344 rats were treated with mixtures of the four THMs (THM4), the five HAAs (HAA5), or nine DBPs (DBP9; THM4+HAA5). Mixtures were administered in 10% Alkamuls(®) EL-620 daily by gavage on gestation days 6-20. Litters were examined postnatally. All three mixtures caused pregnancy loss at ≥ 613 μmol/kg/day. In surviving litters, resorption rates were increased in groups receiving HAA5 at 615 μmol/kg/day and DBP9 at 307 μmol/kg/day. HAA5 caused eye malformations (anophthalmia, microphthalmia) at ≥ 308 μmol/kg/day. Thus, both HAAs and THMs contributed to DBP9-induced pregnancy loss. The presence of THMs in the full mixture, however, appeared to reduce the incidence of HAA-induced eye defects.
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Affiliation(s)
- Michael G Narotsky
- Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, ORD, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Mcdonald A, Killough P, Puckett E, Best DS, Simmons JE, Pressman JG, Narotsky MG. A novel water delivery system for administering volatile chemicals while minimizing chemical waste in rodent toxicity studies. Lab Anim 2010; 44:66-8. [DOI: 10.1258/la.2009.009066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Rodent toxicity studies typically use water bottles to administer test chemicals via drinking water. However, water bottles provide inconsistent exposure of volatile chemicals due to varying headspace, and lead to excessive waste of test material. To refine drinking water toxicity studies in rodents by enhancing sample quality and consistency, and minimizing waste, we designed and implemented a novel water delivery system that keeps the water chilled, headspace free and protected from light. Materials used were resistant to chemical interaction. In this gravity-fed system, a 6-L Teflon® water bag, stored in a polystyrene cooler on the cage rack, was connected to a stainless steel manifold delivering water to five cages via specialized drinking valves. Due to the absence of headspace in the water bag, this system allows consistent exposure of volatile chemicals. In addition, small diameter tubing throughout the system reduces the amount of test material residing in the system and minimizes chemical waste.
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Affiliation(s)
| | - P Killough
- Animal Resources and Research Services Team; Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - E Puckett
- Animal Resources and Research Services Team; Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - D S Best
- Water Supply and Water Resources Division, National Risk Management Research Laboratory, ORD, US Environmental Protection Agency, Cincinnati, OH 45268, USA
| | | | - J G Pressman
- Animal Resources and Research Services Team; Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - M G Narotsky
- Water Supply and Water Resources Division, National Risk Management Research Laboratory, ORD, US Environmental Protection Agency, Cincinnati, OH 45268, USA
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35
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El-Masri HA, Dowd S, Pegram RA, Harrison R, Yavanhxay SJ, Simmons JE, Evans M. Development of an inhalation physiologically based pharmacokinetic (PBPK) model for 2,2, 4-trimethylpentane (TMP) in male Long-Evans rats using gas uptake experiments. Inhal Toxicol 2009; 21:1176-85. [DOI: 10.3109/08958370903005751] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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El-Masri HA, Dowd S, Pegram RA, Harrison R, Yavanhxay SJ, Simmons JE, Evans M. Development of an inhalation physiologically based pharmacokinetic (PBPK) model for 2,2, 4-trimethylpentane (TMP) in male Long-Evans rats using gas uptake experiments. Inhal Toxicol 2009. [DOI: 10.1080/08958370903005751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Robinson BL, Guinnup DE, Andrews JE, Allis JW, McDonald A, Seely JC, Mohin TJ, Simmons JE. Hepatic and Renal Assessment of Acute Exposure to Inhaled Epichlorohydrin: Toxicological Evaluation and Exposure Modeling. Inhal Toxicol 2008. [DOI: 10.3109/08958379509029099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Richardson SD, Thruston AD, Krasner SW, Weinberg HS, Miltner RJ, Schenck KM, Narotsky MG, McKague AB, Simmons JE. Integrated disinfection by-products mixtures research: comprehensive characterization of water concentrates prepared from chlorinated and ozonated/postchlorinated drinking water. J Toxicol Environ Health A 2008; 71:1165-1186. [PMID: 18636390 DOI: 10.1080/15287390802182417] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This article describes the disinfection by-product (DBP) characterization portion of a series of experiments designed for comprehensive chemical and toxicological evaluation of two drinking-water concentrates containing highly complex mixtures of DBPs. This project, called the Four Lab Study, involved the participation of scientists from four laboratories and centers of the U.S. Environmental Protection Agency (EPA) Office of Research and Development, along with collaborators from the water industry and academia, and addressed toxicologic effects of complex DBP mixtures, with an emphasis on reproductive and developmental effects that are associated with DBP exposures in epidemiologic studies. Complex mixtures of DBPs from two different disinfection schemes (chlorination and ozonation/postchlorination) were concentrated successfully, while maintaining a water matrix suitable for animal studies. An array of chlorinated/brominated/iodinated DBPs was created. The DBPs were relatively stable over the course of the animal experiments, and a significant portion of the halogenated DBPs formed in the drinking water was accounted for through a comprehensive qualitative and quantitative identification approach. DBPs quantified included priority DBPs that are not regulated but have been predicted to produce adverse health effects, as well as those currently regulated in the United States and those targeted during implementation of the Information Collection Rule. New by-products were also reported for the first time. These included previously undetected and unreported bromo- and chloroacids, iodinated compounds, bromo- and iodophenols, and bromoalkyltins.
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Affiliation(s)
- Susan D Richardson
- Office of Research and Development, U.S. Environmental Protection Agency, National Exposure Research Laboratory, Athens, Georgia 30605, USA.
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39
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Claxton LD, Pegram R, Schenck KM, Simmons JE, Warren SH. Integrated disinfection by-products research: salmonella mutagenicity of water concentrates disinfected by chlorination and ozonation/postchlorination. J Toxicol Environ Health A 2008; 71:1187-1194. [PMID: 18636391 DOI: 10.1080/15287390802182508] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Although chemical disinfection of drinking water is a highly protective public health practice, the disinfection process is known to produce toxic contaminants. Epidemiological studies associate chlorinated drinking water with quantitatively increased risks of rectal, kidney, and bladder cancer. One study found a significant exposure-response association between water mutagenicity and relative risk for bladder and kidney cancer. A number of studies found that several types of disinfection processes increase the level of mutagens detected by the Salmonella assay. As part of a comprehensive study to examine chlorinated and ozonated/postchlorinated drinking water for toxicological contaminants, the Salmonella mutagenicity assay was used to screen both volatile and nonvolatile organic components. The assay also compared the use of reverse osmosis and XAD resin procedures for concentrating the nonvolatile components. Companion papers provide the results from other toxicological assays and chemical analysis of the drinking water samples. The volatile components of the ozonated/postchlorinated and chlorinated water samples and a trihalomethane mixture were mutagenic to a Salmonella tester strain transfected with a rat theta-class glutathione S-transferase and predominantly nonmutagenic in the control strain. In this study, the nonvolatile XAD concentrate of the untreated water possessed a low level of mutagenic activity. However, compared to the levels of mutagenicity in the finished water XAD concentrates, the contribution from the settled source water was minimal. The mutagenicity seen in the reverse osmosis concentrates was < 50% of that seen in the XAD concentrates. Overall, mutagenic responses were similar to those observed in other North American studies and provide evidence that the pilot plant produced disinfection by-products similar to that seen in other studies.
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Affiliation(s)
- Larry D Claxton
- Environmental Carcinogenesis Division, National Health and Environmental Effects Research Laboratory (NHEERL), U.S. EPA, Research Triangle Park, North Carolina 27709, USA.
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Miltner RJ, Speth TF, Richardson SD, Krasner SW, Weinberg HS, Simmons JE. Integrated disinfection by-products mixtures research: disinfection of drinking waters by chlorination and ozonation/postchlorination treatment scenarios. J Toxicol Environ Health A 2008; 71:1133-1148. [PMID: 18636388 DOI: 10.1080/15287390802182060] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This article describes disinfection of the same source water by two commonly used disinfection treatment scenarios for purposes of subsequent concentration, chemical analysis, and toxicological evaluation. Accompanying articles in this issue of the Journal of Toxicology and Environmental Health describe concentration of these finished waters by reverse osmosis techniques, chemical characterization of the resulting disinfection by-product (DBP) concentrates, in vivo and in vitro toxicological results, and risk assessment methods developed to analyze data from this project. This project, called the "Four Lab Study," involved participation of scientists from four laboratories/centers of the U.S. Environmental Protection Agency Office of Research and Development as well as extramural collaborators from the water industry and academia. One of the two finished waters was prepared by conventional treatment and disinfected by chlorination. The other finished water was also prepared by conventional treatment and disinfected by ozonation followed by chlorination (ozonation/postchlorination). Chlorination conditions of dose, time and temperature were similar for both treatment scenarios, allowing for a comparison. Both finished waters had acceptably low levels of particulates and bacteria, representative pH and chlorine levels, and contained numerous DBP. Known effects of ozonation were observed in that, relative to the water that was chlorinated only, the ozonated/postchlorinated water had lower concentrations of total organic halogen, trihalomethanes (THM), haloacetic acids (HAA), and higher concentrations of bromate, and aldehydes.
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Affiliation(s)
- Richard J Miltner
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA.
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Simmons JE, Richardson SD, Teuschler LK, Miltner RJ, Speth TF, Schenck KM, Hunter ES, Rice G. Research issues underlying the four-lab study: integrated disinfection by-products mixtures research. J Toxicol Environ Health A 2008; 71:1125-1132. [PMID: 18636387 DOI: 10.1080/15287390802181906] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Chemical disinfection of drinking water is a major public health triumph of the 20th century, resulting in significant decreases in morbidity and mortality from waterborne diseases. Disinfection by-products (DBP) are chemicals formed by the reaction of oxidizing disinfectants with inorganic and organic materials in the source water. To address potential health concerns that cannot be answered directly by toxicological research on individual DBPs or defined DBP mixtures, scientists residing within the various organizations of the U.S. Environmental Protection Agency's Office of Research and Development (the National Health and Environmental Effects Research Laboratory, the National Risk Management Research Laboratory, the National Exposure Research Laboratory, and the National Center for Environmental Assessment) engaged in joint investigation of environmentally realistic complex mixtures of DBP. Research on complex mixtures of DBP is motivated by three factors: (a) DBP exposure is ubiquitous to all segments of the population; (b) some positive epidemiologic studies are suggestive of potential developmental, reproductive, or carcinogenic health effects in humans exposed to DBP; and (c) significant amounts of the material that makes up the total organic halide portion of the DBP have not been identified. The goal of the Integrated Disinfection Byproducts Mixtures Research Project (the 4Lab Study) is provision of sound, defensible, experimental data on environmentally relevant mixtures of DBP and an improved estimation of the potential health risks associated with exposure to the mixtures of DBP formed during disinfection of drinking water. A phased research plan was developed and implemented. The present series of articles provides the results from the first series of experiments.
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Affiliation(s)
- Jane Ellen Simmons
- National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA.
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Crosby LM, Simmons JE, Ward WO, Moore TM, Morgan KT, Deangelo AB. Integrated disinfection by-products (DBP) mixtures research: gene expression alterations in primary rat hepatocyte cultures exposed to DBP mixtures formed by chlorination and ozonation/postchlorination. J Toxicol Environ Health A 2008; 71:1195-1215. [PMID: 18636392 DOI: 10.1080/15287390802182581] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Large-scale differential gene expression analysis was used to examine the biological effects of disinfected surface waters on cultured rat hepatocytes. Source water from East Fork Lake (Harsha Lake), a reservoir on the Little Miami River in Ohio, was spiked with iodide and bromide and disinfected by chlorination or ozonation/postchlorination. The chlorinated and ozonated/postchlorinated waters were concentrated, respectively, 136- and 124-fold (full strength) by reverse-osmosis membrane techniques. Volatile disinfection by-products (DBP) lost during concentration were restored to the extent possible. Primary rat hepatocytes were exposed to either full-strength or 1:10 or 1:20 dilutions of the concentrates for 24 h and assayed for cytotoxicity and gene expression alterations. The full-strength concentrates were cytotoxic, whereas the diluted samples exhibited no detectable cytotoxicity. Differential gene expression analysis provided evidence for the underlying causes of the severe cytotoxicity observed in rat hepatocytes treated with the full-strength ozonation/postchlorination concentrate (e.g., cell cycle arrest, metabolic stasis, oxidative stress). Many gene expression responses were shared among the hepatocyte cultures treated with dilutions of the ozonation/ postchlorination and chlorination concentrates. The shift in the character of the response between the full-strength concentrates and the diluted samples indicated a threshold for toxicity. A small subset of gene expression changes was identified that was observed in the response of hepatocytes to peroxisome proliferators, phthalate esters, and haloacetic acids, suggesting a peroxisome proliferative response.
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Affiliation(s)
- Lynn M Crosby
- U.S. Environmental Protection Agency/University of North Carolina-Chapel Hill Cooperative Training Program, Research Triangle Park, North Carolina 27711, USA
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Narotsky MG, Best DS, Rogers EH, McDonald A, Sey YM, Simmons JE. Integrated disinfection by-products mixtures research: assessment of developmental toxicity in Sprague-Dawley rats exposed to concentrates of water disinfected by chlorination and ozonation/postchlorination. J Toxicol Environ Health A 2008; 71:1216-1221. [PMID: 18636393 DOI: 10.1080/15287390802182623] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Epidemiological and animal toxicity studies have raised concerns regarding possible adverse health effects of disinfection by-products (DBPs) found in drinking water. The classes and concentrations of DBPs are influenced by the choice of disinfection process (e.g., chlorination, ozonation) as well as source water characteristics (e.g., pH, total organic carbon, bromide content). Disinfected waters were found to contain more than 500 compounds, many of which remain unidentified. Therefore, a "whole-mixture" approach was used to evaluate the toxic potential of alternative disinfection scenarios. An in vivo developmental toxicity screen was used to evaluate the adverse developmental effects of the complex mixtures produced by two different disinfection processes. Water was obtained from East Fork Lake, Ohio; spiked with iodide and bromide; and disinfected either by chlorination or by ozonation/postchlorination, producing finished drinking water suitable for human consumption. These waters were concentrated approximately 130-fold by reverse osmosis membrane techniques. To the extent possible, volatile DBPs lost in the concentration process were spiked back into the concentrates. These concentrates were then provided as drinking water to Sprague-Dawley rats on gestation days 6-16; controls received boiled, distilled, deionized water. The dams (19-20 per group) were allowed to deliver and their litters were examined on postnatal days (PD) 1 and 6. All dams delivered normally, with parturition occurring significantly earlier in the ozonation/postchlorination group. However, no effects on prenatal survival, postnatal survival, or pup weight were evident. Skeletal examination of the PD-6 pups also revealed no treatment effects. Thus, approximately 130-fold higher concentrates of both ozonated/postchlorinated and chlorinated water appeared to exert no adverse developmental effects in this study.
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Affiliation(s)
- Michael G Narotsky
- Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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Rice G, Teuschler LK, Speth TF, Richardson SD, Miltner RJ, Schenck KM, Gennings C, Hunter ES, Narotsky MG, Simmons JE. Integrated disinfection by-products research: assessing reproductive and developmental risks posed by complex disinfection by-product mixtures. J Toxicol Environ Health A 2008; 71:1222-1234. [PMID: 18636394 DOI: 10.1080/15287390802182649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This article presents a toxicologically-based risk assessment strategy for identifying the individual components or fractions of a complex mixture that are associated with its toxicity. The strategy relies on conventional component-based mixtures risk approaches such as dose addition, response addition, and analyses of interactions. Developmental toxicity data from two drinking-water concentrates containing disinfection by-products (DBP) mixtures were used to illustrate the strategy. The results of this study showed that future studies of DBP concentrates using the Chernoff-Kavlock bioassay need to consider evaluating DBP that are concentrated more than 130-fold and using a rat strain that is more sensitive to chemically-induced pregnancy loss than Sprague-Dawley rats. The results support the planned experimental design of a multigeneration reproductive and developmental study of DBP concentrates. Finally, this article discusses the need for a systematic evaluation of DBP concentrates obtained from multiple source waters and treatment types. The development of such a database could be useful in evaluating whether a specific DBP concentrate is sufficiently similar to tested combinations of source waters and treatment alternatives so that health risks for the former may be estimated using data on the latter.
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Affiliation(s)
- Glenn Rice
- U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, USA.
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Speth TF, Miltner RJ, Richardson SD, Simmons JE. Integrated disinfection by-products mixtures research: concentration by reverse osmosis membrane techniques of disinfection by-products from water disinfected by chlorination and ozonation/postchlorination. J Toxicol Environ Health A 2008; 71:1149-1164. [PMID: 18636389 DOI: 10.1080/15287390802182219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
To conduct the health-effect studies described in subsequent articles in this series, concentrated aqueous mixtures of disinfection by-products were required for the two water treatment trains described in the preceding article (Miltner et al., 2008). To accomplish this, the finished drinking waters from each treatment train were sent through cation-exchange resin columns to remove hardness and free chlorine. Reverse osmosis membranes were then used to concentrate approximately 2400 L of each finished water down to approximately 18 L. The resulting volumetric concentration factors for the chlorinated and ozonated/postchlorinated waters were 136- and 124-fold, respectively. The concentrates were spiked with select disinfection by-products (DBPs) that were lost during the concentration effort. The results, along with the rationale for choosing the method of concentration, are presented. After reintroduction of a select list of lost DBPs, the concentration methodology used herein was able to produce concentrates that retained large percentages of the DBPs that were in the initial finished drinking waters. Further, the distributions of the DBPs in the concentrates matched those found in the finished drinking waters.
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Affiliation(s)
- Thomas F Speth
- U.S. Environmental Protection Agency, National Risk Management Research Laboratory, Cincinnati, Ohio 45268, USA.
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Stork LG, Gennings C, Carter WH, Johnson RE, Mays DP, Simmons JE, Wagner ED, Plewa MJ. Testing for additivity in chemical mixtures using a fixed-ratio ray design and statistical equivalence testing methods. JABES 2007. [DOI: 10.1198/108571107x249816] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gennings C, Carter WH, Carchman RA, DeVito MJ, Simmons JE, Crofton KM. The impact of exposure to a mixture of eighteen polyhalogenated aromatic hydrocarbons on thyroid function: Estimation of an interaction threshold. JABES 2007. [DOI: 10.1198/108571107x176727] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mason AM, Borgert CJ, Bus JS, Moiz Mumtaz M, Simmons JE, Sipes IG. Improving the scientific foundation for mixtures joint toxicity and risk assessment: contributions from the SOT mixtures project--introduction. Toxicol Appl Pharmacol 2007; 223:99-103. [PMID: 17434550 DOI: 10.1016/j.taap.2007.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 12/04/2006] [Accepted: 02/16/2007] [Indexed: 10/23/2022]
Abstract
Risk assessments are enhanced when policy and other decision-makers have access to experimental science designed to specifically inform key policy questions. Currently, our scientific understanding and science policy for environmental mixtures are based largely on extrapolating from and combining data in the observable range of single chemical toxicity to lower environmental concentrations and composition, i.e., using higher dose data to extrapolate and predict lower dose toxicity. There is a growing consensus that the default assumptions underlying those mixtures risk assessments that are conducted in the absence of actual mixtures data rest on an inadequate scientific database. Future scientific research should both build upon the current science and advance toxicology into largely uncharted territory. More precise approaches to better characterize toxicity of mixtures are needed. The Society of Toxicology (SOT) sponsored a series of panels, seminars, and workshops to help catalyze and improve the design and conduct of experimental toxicological research to better inform risk assessors and decision makers. This paper summarizes the activities of the SOT Mixtures Program and serves as the introductory paper to a series of articles in this issue, which hope to inspire innovative research and challenge the status quo.
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Affiliation(s)
- Ann M Mason
- Chlorine Chemistry Division of the American Chemistry Council, Arlington, Virginia, USA.
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Abstract
The estimation of risk following exposure to mixtures is an important feature of pesticide risk assessment. Also of concern is the potential for increased sensitivity of the young to pesticide toxicity. We have conducted interaction studies using a mixture of five organophosphorus (OP) pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion) in both adult (published previously) and preweanling rats using a fixed-ratio ray design. In the present study, cholinesterase inhibition and behavioral changes (motor activity, gait, and tail-pinch response) were measured in 17-day-old Long-Evans male rats following acute exposure to the OPs. The ratio of pesticides in the mixture reflected the relative dietary exposure estimates projected by the U.S. Environmental Protection Agency Dietary Exposure Evaluation Model. Dose-response data were collected for each OP alone, which were used (alone or in conjunction with the mixture data) to build an additivity model to predict the effects of the pesticide mixture along a ray of increasing total doses, using the same fixed ratio of components. The mixture data (full ray) were similarly modeled and statistically compared to the additivity model along the ray. Since malathion has been shown to produce synergistic interactions with certain OPs, it was of interest to evaluate the influence of malathion in this study. A second pesticide mixture, without malathion (reduced ray), was tested using the same dose levels of the remaining four OPs. Analysis of the full ray revealed significant greater-than-additive responses for all endpoints. The magnitude of this shift ranged from two- to threefold for estimates of the ED(20) and ED(50). The deviation from additivity was also detected in the reduced ray for all but two endpoints (motor activity and tail-pinch response); however, for all endpoints, the reduced ray was significantly different from the full ray. Thus, greater-than-additive responses were detected in preweanling rats with this OP mixture, and this effect can only partially be attributed to the malathion in the mixture.
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Affiliation(s)
- Virginia C Moser
- Neurotoxicology Division, 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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Abstract
Traditional factorial designs for evaluating interactions among chemicals in a mixture may be prohibitive when the number of chemicals is large. Using a mixture of chemicals with a fixed ratio (mixture ray) results in an economical design that allows estimation of additivity or nonadditive interaction for a mixture of interest. This methodology is extended easily to a mixture with a large number of chemicals. Optimal experimental conditions can be chosen that result in increased power to detect departures from additivity. Although these designs are used widely for linear models, optimal designs for nonlinear threshold models are less well known. In the present work, the use of D-optimal designs is demonstrated for nonlinear threshold models applied to a fixed-ratio mixture ray. For a fixed sample size, this design criterion selects the experimental doses and number of subjects per dose level that result in minimum variance of the model parameters and thus increased power to detect departures from additivity. An optimal design is illustrated for a 2:1 ratio (chlorpyrifos:carbaryl) mixture experiment. For this example, and in general, the optimal designs for the nonlinear threshold model depend on prior specification of the slope and dose threshold parameters. Use of a D-optimal criterion produces experimental designs with increased power, whereas standard nonoptimal designs with equally spaced dose groups may result in low power if the active range or threshold is missed.
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Affiliation(s)
- Todd Coffey
- Department of Biostatistics, Virginia Commonwealth University, Richmond, 23298, USA
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