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Carlson LM, Christensen K, Sagiv SK, Rajan P, Klocke CR, Lein PJ, Coffman E, Shaffer RM, Yost EE, Arzuaga X, Factor-Litvak P, Sergeev A, Toborek M, Bloom MS, Trgovcich J, Jusko TA, Robertson L, Meeker JD, Keating AF, Blain R, Silva RA, Snow S, Lin C, Shipkowski K, Ingle B, Lehmann GM. A systematic evidence map for the evaluation of noncancer health effects and exposures to polychlorinated biphenyl mixtures. Environ Res 2023; 220:115148. [PMID: 36580985 PMCID: PMC10013199 DOI: 10.1016/j.envres.2022.115148] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/12/2022] [Accepted: 12/22/2022] [Indexed: 06/17/2023]
Abstract
Assessing health outcomes associated with exposure to polychlorinated biphenyls (PCBs) is important given their persistent and ubiquitous nature. PCBs are classified as a Group 1 carcinogen, but the full range of potential noncancer health effects from exposure to PCBs has not been systematically summarized and evaluated. We used systematic review methods to identify and screen the literature using combined manual review and machine learning approaches. A protocol was developed that describes the literature search strategy and Populations, Exposures, Comparators, and Outcomes (PECO) criteria used to facilitate subsequent screening and categorization of literature into a systematic evidence map of PCB exposure and noncancer health endpoints across 15 organs/systems. A comprehensive literature search yielded 62,599 records. After electronic prioritization steps, 17,037 studies were manually screened at the title and abstract level. An additional 900 studies identified by experts or supplemental searches were also included. After full-text screening of 3889 references, 1586 studies met the PECO criteria. Relevant study details such as the endpoints assessed, exposure duration, and species were extracted into literature summary tables. This review compiles and organizes the human and mammalian studies from these tables into an evidence map for noncancer health endpoints and PCB mixture exposure to identify areas of robust research as well as areas of uncertainty that would benefit from future investigation. Summary data are available online as interactive visuals with downloadable metadata. Sufficient research is available to inform PCB hazard assessments for most organs/systems, but the amount of data to inform associations with specific endpoints differs. Furthermore, despite many years of research, sparse data exist for inhalation and dermal exposures, which are highly relevant human exposure routes. This evidence map provides a foundation for future systematic reviews and noncancer hazard assessments of PCB mixtures and for strategic planning of research to inform areas of greater uncertainty.
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Affiliation(s)
- Laura M Carlson
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
| | - Krista Christensen
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
| | - Sharon K Sagiv
- Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA.
| | | | - Carolyn R Klocke
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, Davis, CA, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis School of Veterinary Medicine, Davis, CA, USA.
| | - Evan Coffman
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
| | - Rachel M Shaffer
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
| | - Erin E Yost
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
| | - Xabier Arzuaga
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
| | - Pam Factor-Litvak
- Mailman School of Public Health, Columbia University, New York, NY, USA.
| | | | | | | | | | - Todd A Jusko
- University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
| | | | | | - Aileen F Keating
- Department of Animal Science, Iowa State University, Ames, IA, USA.
| | | | | | | | | | - Kelly Shipkowski
- ICF, Fairfax, VA, Currently at National Institute of Environmental Health Sciences, USA.
| | - Brandall Ingle
- ICF, Fairfax, VA, Currently at US Environmental Protection Agency, USA.
| | - Geniece M Lehmann
- Office of Research and Development, Center for Public Health and Environmental Assessment, US Environmental Protection Agency, USA.
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2
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Kapraun DF, Schlosser PM, Nylander-French LA, Kim D, Yost EE, Druwe IL. A Physiologically Based Pharmacokinetic Model for Naphthalene With Inhalation and Skin Routes of Exposure. Toxicol Sci 2021; 177:377-391. [PMID: 32687177 DOI: 10.1093/toxsci/kfaa117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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
Naphthalene, a volatile organic compound present in moth repellants and petroleum-based fuels, has been shown to induce toxicity in mice and rats during chronic inhalation exposures. Although simpler default methods exist for extrapolating toxicity points of departure from animals to humans, using a physiologically based pharmacokinetic (PBPK) model to perform such extrapolations is generally preferred. Confidence in PBPK models increases when they have been validated using both animal and human in vivo pharmacokinetic (PK) data. A published inhalation PBPK model for naphthalene was previously shown to predict rodent PK data well, so we sought to evaluate this model using human PK data. The most reliable human data available come from a controlled skin exposure study, but the inhalation PBPK model does not include a skin exposure route; therefore, we extended the model by incorporating compartments representing the stratum corneum and the viable epidermis and parameters that determine absorption and rate of transport through the skin. The human data revealed measurable blood concentrations of naphthalene present in the subjects prior to skin exposure, so we also introduced a continuous dose-rate parameter to account for these baseline blood concentration levels. We calibrated the three new parameters in the modified PBPK model using data from the controlled skin exposure study but did not modify values for any other parameters. Model predictions then fell within a factor of 2 of most (96%) of the human PK observations, demonstrating that this model can accurately predict internal doses of naphthalene and is thus a viable tool for use in human health risk assessment.
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Affiliation(s)
- Dustin F Kapraun
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina 27711
| | - Paul M Schlosser
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina 27711
| | - Leena A Nylander-French
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - David Kim
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Erin E Yost
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina 27711
| | - Ingrid L Druwe
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina 27711
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Yost EE, Galizia A, Kapraun DF, Persad AS, Vulimiri SV, Angrish M, Lee JS, Druwe IL. Health Effects of Naphthalene Exposure: A Systematic Evidence Map and Analysis of Potential Considerations for Dose-Response Evaluation. Environ Health Perspect 2021; 129:76002. [PMID: 34251878 PMCID: PMC8274693 DOI: 10.1289/ehp7381] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 05/19/2023]
Abstract
BACKGROUND Naphthalene is a polycyclic aromatic hydrocarbon that has been associated with health effects, including cancer. As the state of the science on naphthalene toxicity continues to evolve, updated toxicity reference value(s) may be required to support human health risk assessment. OBJECTIVES We present a systematic evidence map of studies that could be used to derive toxicity reference value(s) for naphthalene. METHODS Human and animal health effect studies and physiologically based pharmacokinetic (PBPK) models were identified from a literature search based on populations, exposures, comparators, and outcomes (PECO) criteria. Human and animal studies meeting PECO criteria were refined to a smaller subset considered most informative for deriving chronic reference value(s), which are preferred for assessing risk to the general public. This subset was evaluated for risk of bias and sensitivity, and the suitability of each study for dose-response analysis was qualitatively assessed. Lowest observed adverse effect levels (LOAELs) were extracted and summarized. Other potentially relevant studies (e.g., mechanistic and toxicokinetic studies) were tracked as supplemental information but not evaluated further. Existing reference values for naphthalene are also summarized. RESULTS We identified 26 epidemiology studies and 16 animal studies that were considered most informative for further analysis. Eleven PBPK models were identified. The available epidemiology studies generally had significant risk of bias and/or sensitivity concerns and were mostly found to have low suitability for dose-response analysis due to the nature of the exposure measurements. The animal studies had fewer risk of bias and sensitivity concerns and were mostly found to be suitable for dose-response analysis. CONCLUSION Although both epidemiological and animal studies of naphthalene provide weight of evidence for hazard identification, the available animal studies appear more suitable for reference value derivation. PBPK models and mechanistic and toxicokinetic data can be applied to extrapolate these animal data to humans, considering mode of action and interspecies metabolic differences. https://doi.org/10.1289/EHP7381.
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Affiliation(s)
- Erin E. Yost
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Audrey Galizia
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Dustin F. Kapraun
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Amanda S. Persad
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Suryanarayana V. Vulimiri
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Michelle Angrish
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Janice S. Lee
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
| | - Ingrid L. Druwe
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Washington, District of Columbia, USA
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Radke EG, Yost EE, Roth N, Sathyanarayana S, Whaley P. Application of US EPA IRIS systematic review methods to the health effects of phthalates: Lessons learned and path forward. Environ Int 2020; 145:105820. [PMID: 33081976 DOI: 10.1016/j.envint.2020.105820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 05/17/2020] [Indexed: 05/21/2023]
Affiliation(s)
- Elizabeth G Radke
- US EPA Center for Public Health and Environmental Assessment, Washington, DC, United States.
| | - Erin E Yost
- US EPA Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States
| | - Nicolas Roth
- Swiss Centre for Applied Human Toxicology, University of Basel, Basel, Switzerland
| | - Sheela Sathyanarayana
- University of Washington and Seattle Children's Research Institute, Seattle, WA, United States
| | - Paul Whaley
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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Weaver JA, Beverly BEJ, Keshava N, Mudipalli A, Arzuaga X, Cai C, Hotchkiss AK, Makris SL, Yost EE. Hazards of diethyl phthalate (DEP) exposure: A systematic review of animal toxicology studies. Environ Int 2020; 145:105848. [PMID: 32958228 PMCID: PMC7995140 DOI: 10.1016/j.envint.2020.105848] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [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] [Received: 10/16/2019] [Revised: 05/05/2020] [Accepted: 05/06/2020] [Indexed: 05/18/2023]
Abstract
BACKGROUND Diethyl phthalate (DEP) is widely used in many commercially available products including plastics and personal care products. DEP has generally not been found to share the antiandrogenic mode of action that is common among other types of phthalates, but there is emerging evidence that DEP may be associated with other types of health effects. OBJECTIVE To inform chemical risk assessment, we performed a systematic review to identify and characterize outcomes within six broad hazard categories (male reproductive, female reproductive, developmental, liver, kidney, and cancer) following exposure of nonhuman mammalian animals to DEP or its primary metabolite, monoethyl phthalate (MEP). METHODS A literature search was conducted in online scientific databases (PubMed, Web of Science, Toxline, Toxcenter) and Toxic Substances Control Act Submissions, augmented by review of online regulatory sources as well as forward and backward searches. Studies were selected for inclusion using PECO (Population, Exposure, Comparator, Outcome) criteria. Studies were evaluated using criteria defined a priori for reporting quality, risk of bias, and sensitivity using a domain-based approach. Evidence was synthesized by outcome and life stage of exposure, and strength of evidence was summarized into categories of robust, moderate, slight, indeterminate, or compelling evidence of no effect, using a structured framework. RESULTS Thirty-four experimental studies in animals were included in this analysis. Although no effects on androgen-dependent male reproductive development were observed following gestational exposure to DEP, there was evidence including effects on sperm following peripubertal and adult exposures, and the overall evidence for male reproductive effects was considered moderate. There was moderate evidence that DEP exposure can lead to developmental effects, with the major effect being reduced postnatal growth following gestational or early postnatal exposure; this generally occurred at doses associated with maternal effects, consistent with the observation that DEP is not a potent developmental toxicant. The evidence for liver effects was considered moderate based on consistent changes in relative liver weight at higher dose levels; histopathological and biochemical changes indicative of hepatic effects were also observed, but primarily in studies that had significant concerns for risk of bias and sensitivity. The evidence for female reproductive effects was considered slight based on few reports of statistically significant effects on maternal body weight gain, organ weight changes, and pregnancy outcomes. Evidence for cancer and effects on kidney were judged to be indeterminate based on limited evidence (i.e., a single two-year cancer bioassay) and inconsistent findings, respectively. CONCLUSIONS These results suggest that DEP exposure may induce androgen-independent male reproductive toxicity (i.e., sperm effects) as well as developmental toxicity and hepatic effects, with some evidence of female reproductive toxicity. More research is warranted to fully evaluate these outcomes and strengthen confidence in this database.
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Affiliation(s)
- James A Weaver
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States
| | - Brandiese E J Beverly
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States
| | - Nagalakshmi Keshava
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States
| | - Anuradha Mudipalli
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States
| | - Xabier Arzuaga
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Washington, DC, United States
| | - Christine Cai
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Washington, DC, United States
| | - Andrew K Hotchkiss
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States
| | - Susan L Makris
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Washington, DC, United States
| | - Erin E Yost
- U.S. Environmental Protection Agency, Center for Public Health and Environmental Assessment, Research Triangle Park, NC, United States.
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Arzuaga X, Walker T, Yost EE, Radke EG, Hotchkiss AK. Use of the Adverse Outcome Pathway (AOP) framework to evaluate species concordance and human relevance of Dibutyl phthalate (DBP)-induced male reproductive toxicity. Reprod Toxicol 2019; 96:445-458. [PMID: 31260805 PMCID: PMC10067323 DOI: 10.1016/j.reprotox.2019.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [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: 02/16/2019] [Revised: 06/05/2019] [Accepted: 06/25/2019] [Indexed: 12/14/2022]
Abstract
Dibutyl phthalate (DBP) is a phthalate ester used as a plasticizer, and solvent. Studies using rats consistently report that DBP exposure disrupts normal development of the male reproductive system in part via inhibition of androgen synthesis. However, studies using xenograft models report that in human fetal testis DBP exposure is unlikely to impair testosterone synthesis. These results question the validity of the rat model for assessment of male reproductive effects caused by DBP. The Adverse Outcome Pathway (AOP) framework was used to evaluate the available evidence for DBP-induced toxicity to the male reproductive system. Three relevant biological elements were identified: 1) fetal rats are more sensitive than other rodents and human fetal xenografts to DBP-induced anti-androgenic effects, 2) DBP-induced androgen-independent adverse outcomes are conserved amongst different mammalian models and human fetal testis xenografts, and 3) DBP-induced anti-androgenic effects are conserved in different mammalian species when exposure occurs during postnatal life stages.
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Affiliation(s)
- Xabier Arzuaga
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America.
| | - Teneille Walker
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
| | - Erin E Yost
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
| | - Elizabeth G Radke
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
| | - Andrew K Hotchkiss
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
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Arzuaga X, Smith MT, Gibbons CF, Skakkebæk NE, Yost EE, Beverly BEJ, Hotchkiss AK, Hauser R, Pagani RL, Schrader SM, Zeise L, Prins GS. Proposed Key Characteristics of Male Reproductive Toxicants as an Approach for Organizing and Evaluating Mechanistic Evidence in Human Health Hazard Assessments. Environ Health Perspect 2019; 127:65001. [PMID: 31199676 PMCID: PMC6792367 DOI: 10.1289/ehp5045] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/22/2019] [Accepted: 05/30/2019] [Indexed: 05/20/2023]
Abstract
BACKGROUND Assessing chemicals for their potential to cause male reproductive toxicity involves the evaluation of evidence obtained from experimental, epidemiological, and mechanistic studies. Although mechanistic evidence plays an important role in hazard identification and evidence integration, the process of identifying, screening and analyzing mechanistic studies and outcomes is a challenging exercise due to the diversity of research models and methods and the variety of known and proposed pathways for chemical-induced toxicity. Ten key characteristics of carcinogens provide a valuable tool for organizing and assessing chemical-specific data by potential mechanisms for cancer-causing agents. However, such an approach has not yet been developed for noncancer adverse outcomes. OBJECTIVES The objective in this study was to identify a set of key characteristics that are frequently exhibited by exogenous agents that cause male reproductive toxicity and that could be applied for identifying, organizing, and summarizing mechanistic evidence related to this outcome. DISCUSSION The identification of eight key characteristics of male reproductive toxicants was based on a survey of known male reproductive toxicants and established mechanisms and pathways of toxicity. The eight key characteristics can provide a basis for the systematic, transparent, and objective organization of mechanistic evidence relevant to chemical-induced effects on the male reproductive system. https://doi.org/10.1289/EHP5045.
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Affiliation(s)
- Xabier Arzuaga
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington, DC, USA
| | - Martyn T. Smith
- University of California, Berkeley, School of Public Health, Berkeley, California, USA
| | - Catherine F. Gibbons
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington, DC, USA
| | - Niels E. Skakkebæk
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Erin E. Yost
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Brandiese E. J. Beverly
- Office of Health Assessment and Translation, National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Andrew K. Hotchkiss
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Russ Hauser
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Rodrigo L. Pagani
- Department of Urology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Steven M. Schrader
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA (retired)
| | - Lauren Zeise
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Sacramento, California, USA
| | - Gail S. Prins
- Department of Urology, University of Illinois at Chicago, Chicago, Illinois, USA
- School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA
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8
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Yost EE, Euling SY, Weaver JA, Beverly BEJ, Keshava N, Mudipalli A, Arzuaga X, Blessinger T, Dishaw L, Hotchkiss A, Makris SL. Hazards of diisobutyl phthalate (DIBP) exposure: A systematic review of animal toxicology studies. Environ Int 2019; 125:579-594. [PMID: 30591249 PMCID: PMC8596331 DOI: 10.1016/j.envint.2018.09.038] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/30/2018] [Accepted: 09/23/2018] [Indexed: 05/19/2023]
Abstract
BACKGROUND Biomonitoring studies indicate a trend towards increased human exposure to diisobutyl phthalate (DIBP), a replacement for dibutyl phthalate (DBP). Recent reviews have found DIBP to be a male reproductive toxicant, but have not evaluated other hazards of DIBP exposure. OBJECTIVE To inform chemical risk assessment, we performed a systematic review to identify and characterize outcomes within six broad hazard categories (male reproductive, female reproductive, developmental, liver, kidney, and cancer) following exposure of nonhuman mammalian animals to DIBP or the primary metabolite, monoisobutyl phthalate (MIBP). METHODS A literature search was conducted in four online scientific databases [PubMed, Web of Science, Toxline, and Toxic Substances Control Act Test Submissions 2.0 (TSCATS2)], and augmented by review of regulatory sources as well as forward and backward searches. Studies were identified for inclusion based on defined PECO (Population, Exposure, Comparator, Outcome) criteria. Studies were evaluated using criteria defined a priori for reporting quality, risk of bias, and sensitivity using a domain-based approach. Evidence was synthesized by outcome and life stage of exposure, and strength of evidence was summarized into categories of robust, moderate, slight, indeterminate, or compelling evidence of no effect, using a structured framework. RESULTS Nineteen toxicological studies in rats or mice met the inclusion criteria. There was robust evidence that DIBP causes male reproductive toxicity. Male rats and mice exposed to DIBP during gestation had decreased testosterone and adverse effects on sperm or testicular histology, with additional phthalate syndrome effects observed in male rats. There was also evidence of androgen-dependent and -independent male reproductive effects in rats and mice following peripubertal or young adult exposure to DIBP or MIBP, but confidence was reduced because of concerns over risk of bias and sensitivity in the available studies. There was also robust evidence that DIBP causes developmental toxicity; specifically, increased post-implantation loss and decreased pre- and postnatal growth. For other hazards, evidence was limited by the small number of studies, experimental designs that were suboptimal for evaluating outcomes, and study evaluation concerns such as incomplete reporting of methods and results. There was slight evidence for female reproductive toxicity and effects on liver, and indeterminate evidence for effects on kidney and cancer. CONCLUSION Results support DIBP as a children's health concern and indicate that male reproductive and developmental toxicities are hazards of DIBP exposure, with some evidence for female reproductive and liver toxicity. Data gaps include the need for more studies on male reproductive effects following postnatal and adult exposure, and studies to characterize potential hormonal mechanisms in females.
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Affiliation(s)
- Erin E Yost
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America.
| | - Susan Y Euling
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
| | - James A Weaver
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
| | - Brandiese E J Beverly
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
| | - Nagalakshmi Keshava
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
| | - Anuradha Mudipalli
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
| | - Xabier Arzuaga
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
| | - Todd Blessinger
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
| | - Laura Dishaw
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
| | - Andrew Hotchkiss
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, United States of America
| | - Susan L Makris
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States of America
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9
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Lee B, Kullman SW, Yost EE, Worley-Davis L, Reckhow KH. An object-oriented Bayesian network approach for establishing swine manure-borne natural estrogenic compounds budget. Sci Total Environ 2018; 639:815-825. [PMID: 29803052 PMCID: PMC8033785 DOI: 10.1016/j.scitotenv.2018.05.209] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 06/08/2023]
Abstract
A facility-wide estrogen budget model was developed to assess the excretion of natural estrogens by swine in a commercial swine farrowing concentrated animal feeding operations (CAFO) in North Carolina, using an object-oriented Bayesian network (OOBN) approach. The OOBN model is the combination of twelve objects of Bayesian network models, which characterize the estrogen budget flows based on the sow reproductive cycle (i.e., pre-estrus, estrus, and lactation) for the three natural estrogen types [estrone (E1), 17β-estradiol (E2), and estriol (E3)] within each barn. This OOBN model provides a mechanism to quantify the levels of the natural estrogens and their probabilistic distributions with regard to estrogen type, waste sources such as urine, feces, and recycling lagoon slurry, and animal reproductive status. Moreover, the OOBN model allows us to assess the overall contribution of natural estrogen compounds from each operational unit of the CAFO, while accounting for the uncertainties. Results from the OOBN model indicate a rank order of lactating sows > gestating sows > breeding sows in terms of contribution of estrogen loads to the total natural estrogen budget. As to estrogen type, E1 was found as the major estrogen metabolite with the summed concentrations of urine, feces, and flushing slurry wastes exceeding 3000 ng/l > 90% of the time. As to waste sources, the flushing slurry waste was found to be a major contributor of the estrogen budget compared with urine and feces wastes from barn animals.
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Affiliation(s)
- Boknam Lee
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
| | - Seth W Kullman
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA
| | - Erin E Yost
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA
| | - Lynn Worley-Davis
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA
| | - Kenneth H Reckhow
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
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Lee B, Kullman SW, Yost EE, Meyer MT, Worley-Davis L, Michael Williams C, Reckhow KH. Corrigendum to "Predicting characteristics of rainfall driven estrogen runoff and transport from swine AFO spray fields" [Sci. Total Environ. 532 (2015) 571-580]. Sci Total Environ 2018; 628-629:1460. [PMID: 30045565 DOI: 10.1016/j.scitotenv.2018.02.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Affiliation(s)
- Boknam Lee
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
| | - Seth W Kullman
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA
| | - Erin E Yost
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA
| | - Michael T Meyer
- Organic Geochemistry Research Laboratory, U.S. Geological Survey (USGS), Lawrence, KS 66049, USA
| | - Lynn Worley-Davis
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA
| | - C Michael Williams
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA
| | - Kenneth H Reckhow
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
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11
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Burgoon LD, Druwe IL, Painter K, Yost EE. Using In Vitro High-Throughput Screening Data for Predicting Benzo[k]Fluoranthene Human Health Hazards. Risk Anal 2017; 37:280-290. [PMID: 27088631 DOI: 10.1111/risa.12613] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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: 04/29/2015] [Revised: 01/07/2016] [Accepted: 02/10/2016] [Indexed: 05/24/2023]
Abstract
Today there are more than 80,000 chemicals in commerce and the environment. The potential human health risks are unknown for the vast majority of these chemicals as they lack human health risk assessments, toxicity reference values, and risk screening values. We aim to use computational toxicology and quantitative high-throughput screening (qHTS) technologies to fill these data gaps, and begin to prioritize these chemicals for additional assessment. In this pilot, we demonstrate how we were able to identify that benzo[k]fluoranthene may induce DNA damage and steatosis using qHTS data and two separate adverse outcome pathways (AOPs). We also demonstrate how bootstrap natural spline-based meta-regression can be used to integrate data across multiple assay replicates to generate a concentration-response curve. We used this analysis to calculate an in vitro point of departure of 0.751 μM and risk-specific in vitro concentrations of 0.29 μM and 0.28 μM for 1:1,000 and 1:10,000 risk, respectively, for DNA damage. Based on the available evidence, and considering that only a single HSD17B4 assay is available, we have low overall confidence in the steatosis hazard identification. This case study suggests that coupling qHTS assays with AOPs and ontologies will facilitate hazard identification. Combining this with quantitative evidence integration methods, such as bootstrap meta-regression, may allow risk assessors to identify points of departure and risk-specific internal/in vitro concentrations. These results are sufficient to prioritize the chemicals; however, in the longer term we will need to estimate external doses for risk screening purposes, such as through margin of exposure methods.
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Affiliation(s)
- Lyle D Burgoon
- U.S. Army Engineer Research and Development Center, Research Triangle Park, NC, USA
| | - Ingrid L Druwe
- Oak Ridge Institute for Science and Education assigned to the U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, USA
| | - Kyle Painter
- Oak Ridge Institute for Science and Education assigned to the U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, USA
| | - Erin E Yost
- Oak Ridge Institute for Science and Education assigned to the U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC, USA
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12
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Yost EE, Stanek J, Burgoon LD. A decision analysis framework for estimating the potential hazards for drinking water resources of chemicals used in hydraulic fracturing fluids. Sci Total Environ 2017; 574:1544-1558. [PMID: 27666475 PMCID: PMC5776703 DOI: 10.1016/j.scitotenv.2016.08.167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [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: 06/23/2016] [Revised: 08/22/2016] [Accepted: 08/22/2016] [Indexed: 05/27/2023]
Abstract
Despite growing concerns over the potential for hydraulic fracturing to impact drinking water resources, there are limited data available to identify chemicals used in hydraulic fracturing fluids that may pose public health concerns. In an effort to explore these potential hazards, a multi-criteria decision analysis (MCDA) framework was employed to analyze and rank selected subsets of these chemicals by integrating data on toxicity, frequency of use, and physicochemical properties that describe transport in water. Data used in this analysis were obtained from publicly available databases compiled by the United States Environmental Protection Agency (EPA) as part of a larger study on the potential impacts of hydraulic fracturing on drinking water. Starting with nationwide hydraulic fracturing chemical usage data from EPA's analysis of the FracFocus Chemical Disclosure Registry 1.0, MCDAs were performed on chemicals that had either noncancer toxicity values (n=37) or cancer-specific toxicity values (n=10). The noncancer MCDA was then repeated for subsets of chemicals reported in three representative states (Texas, n=31; Pennsylvania, n=18; and North Dakota, n=20). Within each MCDA, chemicals received scores based on relative toxicity, relative frequency of use, and physicochemical properties (mobility in water, volatility, persistence). Results show a relative ranking of these chemicals based on hazard potential, and provide preliminary insight into chemicals that may be more likely than others to impact drinking water resources. Comparison of nationwide versus state-specific analyses indicates regional differences in the chemicals that may be of more concern to drinking water resources, although many chemicals were commonly used and received similar overall hazard rankings. Several chemicals highlighted by these MCDAs have been reported in groundwater near areas of hydraulic fracturing activity. This approach is intended as a preliminary analysis, and represents one possible method for integrating data to explore potential public health impacts.
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Affiliation(s)
- Erin E Yost
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park, NC, United States
| | - John Stanek
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park, NC, United States
| | - Lyle D Burgoon
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park, NC, United States.
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13
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Pow CSL, Yost EE, Aday DD, Kullman SW. Sharing the Roles: An Assessment of Japanese Medaka Estrogen Receptors in Vitellogenin Induction. Environ Sci Technol 2016; 50:8886-8895. [PMID: 27391190 PMCID: PMC5443407 DOI: 10.1021/acs.est.6b01968] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 06/06/2023]
Abstract
Teleost fish express at least three estrogen receptor (ER) subtypes. To date, however, the individual role of these ER subtypes in regulating expression of estrogen responsive genes remains ambiguous. Here, we investigate putative roles of three ER subtypes in Japanese medaka (Oryzias latipes), using vitellogenin (VTG) I and II as model genes. We identify specific ligand/receptor/promoter dynamics, using transient transactivation assays that incorporate luciferase reporters comprising 3kb promoter/enhancer regions of medaka VTGI and VTGII genes. Four steroidal estrogens (17β-estradiol, estrone, estriol, and 17α-estradiol) were tested in these assays. Results indicate that all three medaka ERs (mERs) are capable of initiating transactivation of both VTG I and II, with ERβ2 exhibiting greatest activity. Promoter deletion analysis suggests that ligand-specific receptor transactivation and utilization of regional-specific estrogen response elements may be associated with differential activities of each medaka ER. Further, cluster analysis of in vivo gene expression and in vitro transactivation suggests that all three ER subtypes putatively play a role in up-regulation of VTG. Results illustrate that preferential ligand/receptor/promoter interactions may have direct implications for VTG gene expression and other ER-mediated regulatory functions that are relevant to the risk assessment of estrogenic compounds.
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Affiliation(s)
- Crystal S.D. Lee Pow
- North Carolina State University, Department of Biological Sciences, Environmental and Molecular Toxicology Program, 850 Main Campus Drive, Raleigh, NC 27606, United States
| | - Erin E. Yost
- North Carolina State University, Department of Biological Sciences, Environmental and Molecular Toxicology Program, 850 Main Campus Drive, Raleigh, NC 27606, United States
| | - D. Derek Aday
- North Carolina State University, Department of Applied Ecology, 127 David Clark Labs, Raleigh, NC 27695, United States
| | - Seth W. Kullman
- North Carolina State University, Department of Biological Sciences, Environmental and Molecular Toxicology Program, 850 Main Campus Drive, Raleigh, NC 27606, United States
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14
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Yost EE, Stanek J, DeWoskin RS, Burgoon LD. Estimating the Potential Toxicity of Chemicals Associated with Hydraulic Fracturing Operations Using Quantitative Structure-Activity Relationship Modeling. Environ Sci Technol 2016; 50:7732-42. [PMID: 27172125 DOI: 10.1021/acs.est.5b05327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The United States Environmental Protection Agency (EPA) identified 1173 chemicals associated with hydraulic fracturing fluids, flowback, or produced water, of which 1026 (87%) lack chronic oral toxicity values for human health assessments. To facilitate the ranking and prioritization of chemicals that lack toxicity values, it may be useful to employ toxicity estimates from quantitative structure-activity relationship (QSAR) models. Here we describe an approach for applying the results of a QSAR model from the TOPKAT program suite, which provides estimates of the rat chronic oral lowest-observed-adverse-effect level (LOAEL). Of the 1173 chemicals, TOPKAT was able to generate LOAEL estimates for 515 (44%). To address the uncertainty associated with these estimates, we assigned qualitative confidence scores (high, medium, or low) to each TOPKAT LOAEL estimate, and found 481 to be high-confidence. For 48 chemicals that had both a high-confidence TOPKAT LOAEL estimate and a chronic oral reference dose from EPA's Integrated Risk Information System (IRIS) database, Spearman rank correlation identified 68% agreement between the two values (permutation p-value =1 × 10(-11)). These results provide support for the use of TOPKAT LOAEL estimates in identifying and prioritizing potentially hazardous chemicals. High-confidence TOPKAT LOAEL estimates were available for 389 of 1026 hydraulic fracturing-related chemicals that lack chronic oral RfVs and OSFs from EPA-identified sources, including a subset of chemicals that are frequently used in hydraulic fracturing fluids.
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Affiliation(s)
- Erin E Yost
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park 27711, North Carolina, United States
| | - John Stanek
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park 27711, North Carolina, United States
| | - Robert S DeWoskin
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park 27711, North Carolina, United States
| | - Lyle D Burgoon
- United States Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park 27711, North Carolina, United States
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15
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Yost EE, Stanek J, DeWoskin RS, Burgoon LD. Overview of Chronic Oral Toxicity Values for Chemicals Present in Hydraulic Fracturing Fluids, Flowback, and Produced Waters. Environ Sci Technol 2016; 50:4788-97. [PMID: 27050380 DOI: 10.1021/acs.est.5b04645] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Concerns have been raised about potential public health effects that may arise if hydraulic fracturing-related chemicals were to impact drinking water resources. This study presents an overview of the chronic oral toxicity values-specifically, chronic oral reference values (RfVs) for noncancer effects, and oral slope factors (OSFs) for cancer-that are available for a list of 1173 chemicals that the United States (U.S.) Environmental Protection Agency (EPA) identified as being associated with hydraulic fracturing, including 1076 chemicals used in hydraulic fracturing fluids and 134 chemicals detected in flowback or produced waters from hydraulically fractured wells. The EPA compiled RfVs and OSFs using six governmental and intergovernmental data sources. Ninety (8%) of the 1076 chemicals reported in hydraulic fracturing fluids and 83 (62%) of the 134 chemicals reported in flowback/produced water had a chronic oral RfV or OSF available from one or more of the six sources. Furthermore, of the 36 chemicals reported in hydraulic fracturing fluids in at least 10% of wells nationwide (identified from EPA's analysis of the FracFocus Chemical Disclosure Registry 1.0), 8 chemicals (22%) had an available chronic oral RfV. The lack of chronic oral RfVs and OSFs for the majority of these chemicals highlights the significant knowledge gap that exists to assess the potential human health hazards associated with hydraulic fracturing.
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Affiliation(s)
- Erin E Yost
- Oak Ridge Institute for Science and Education (ORISE) Research Participation Program and §Office of Research and Development, United States Environmental Protection Agency, National Center for Environmental Assessment , Research Triangle Park, North Carolina 27711, United States
| | - John Stanek
- Oak Ridge Institute for Science and Education (ORISE) Research Participation Program and §Office of Research and Development, United States Environmental Protection Agency, National Center for Environmental Assessment , Research Triangle Park, North Carolina 27711, United States
| | - Robert S DeWoskin
- Oak Ridge Institute for Science and Education (ORISE) Research Participation Program and §Office of Research and Development, United States Environmental Protection Agency, National Center for Environmental Assessment , Research Triangle Park, North Carolina 27711, United States
| | - Lyle D Burgoon
- Oak Ridge Institute for Science and Education (ORISE) Research Participation Program and §Office of Research and Development, United States Environmental Protection Agency, National Center for Environmental Assessment , Research Triangle Park, North Carolina 27711, United States
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16
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Lee B, Kullman SW, Yost EE, Meyer MT, Worley-Davis L, Williams CM, Reckhow KH. Predicting characteristics of rainfall driven estrogen runoff and transport from swine AFO spray fields. Sci Total Environ 2015; 532:571-580. [PMID: 26102057 PMCID: PMC5428992 DOI: 10.1016/j.scitotenv.2015.06.051] [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] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/11/2015] [Accepted: 06/11/2015] [Indexed: 06/04/2023]
Abstract
Animal feeding operations (AFOs) have been implicated as potentially major sources of estrogenic contaminants into the aquatic environment due to the relatively minimal treatment of waste and potential mobilization and transport of waste components from spray fields. In this study a Bayesian network (BN) model was developed to inform management decisions and better predict the transport and fate of natural steroidal estrogens from these sites. The developed BN model integrates processes of surface runoff and sediment loss with the modified universal soil loss equation (MUSLE) and the soil conservation service curve number (SCS-CN) runoff model. What-if scenario simulations of lagoon slurry wastes to the spray fields were conducted for the most abundant natural estrogen estrone (E1) observed in the system. It was found that E1 attenuated significantly after 2 months following waste slurry application in both spring and summer seasons, with the overall attenuation rate predicted to be higher in the summer compared to the spring. Using simulations of rainfall events in conjunction with waste slurry application rates, it was predicted that the magnitude of E1 runoff loss is significantly higher in the spring as compared to the summer months, primarily due to spray field crop management plans. Our what-if scenario analyses suggest that planting Bermuda grass in the spray fields is likely to reduce runoff losses of natural estrogens near the water bodies and ecosystems, as compared to planting of soybeans.
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Affiliation(s)
- Boknam Lee
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
| | - Seth W Kullman
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA
| | - Erin E Yost
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695, USA
| | - Michael T Meyer
- Organic Geochemistry Research Laboratory, U.S. Geological Survey (USGS), Lawrence, KS 66049, USA
| | - Lynn Worley-Davis
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA
| | - C Michael Williams
- Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC 27695, USA
| | - Kenneth H Reckhow
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
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17
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Yost EE, Meyer MT, Dietze JE, Williams CM, Worley-Davis L, Lee B, Kullman SW. Transport of steroid hormones, phytoestrogens, and estrogenic activity across a swine lagoon/sprayfield system. Environ Sci Technol 2014; 48:11600-9. [PMID: 25148584 PMCID: PMC5428989 DOI: 10.1021/es5025806] [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] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The inflow, transformation, and attenuation of natural steroid hormones and phytoestrogens and estrogenic activity were assessed across the lagoon/sprayfield system of a prototypical commercial swine sow operation. Free and conjugated steroid hormones (estrogens, androgens, and progesterone) were detected in urine and feces of sows across reproductive stages, with progesterone being the most abundant steroid hormone. Excreta also contained phytoestrogens indicative of a soy-based diet, particularly, daidzein, genistein, and equol. During storage in barn pits and the anaerobic lagoon, conjugated hormones dissipated, and androgens and progesterone were attenuated. Estrone and equol persisted along the waste disposal route. Following application of lagoon slurry to agricultural soils, all analytes exhibited attenuation within 2 days. However, analytes including estrone, androstenedione, progesterone, and equol remained detectable in soil at 2 months postapplication. Estrogenic activity in the yeast estrogen screen and T47D-KBluc in vitro bioassays generally tracked well with analyte concentrations. Estrone was found to be the greatest contributor to estrogenic activity across all sample types. This investigation encompasses the most comprehensive suite of natural hormone and phytoestrogen analytes examined to date across a livestock lagoon/sprayfield and provides global insight into the fate of these analytes in this widely used waste management system.
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Affiliation(s)
- Erin E Yost
- Department of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University , Raleigh, North Carolina, United States
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18
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Yost EE, Lee Pow C, Hawkins MB, Kullman SW. Bridging the gap from screening assays to estrogenic effects in fish: potential roles of multiple estrogen receptor subtypes. Environ Sci Technol 2014; 48:5211-9. [PMID: 24422420 PMCID: PMC4014147 DOI: 10.1021/es404093n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This study seeks to delineate the ligand interactions that drive biomarker induction in fish exposed to estrogenic pollutants and provide a case study on the capacity of human (h) estrogen receptor (ER)-based in vitro screening assays to predict estrogenic effects in aquatic species. Adult male Japanese medaka (Oryzias latipes) were exposed to solutions of singular steroidal estrogens or to the estrogenic extract of an anaerobic swine waste lagoon. All exposure concentrations were calibrated to be equipotent based on the yeast estrogen screen (YES), which reports activation of hERα. These exposures elicited significantly different magnitudes of hepatic vitellogenin and choriogenin gene induction in the male medaka. Effects of the same YES-calibrated solutions in the T47D-KBluc assay, which reports activation of hERα and hERβ, generally recapitulated observations in medaka. Using competitive ligand binding assays, it was found that the magnitude of vitellogenin/choriogenin induction by different estrogenic ligands correlated positively with preferential binding affinity for medaka ERβ subtypes, which are highly expressed in male medaka liver prior to estrogen exposure. Results support emerging evidence that ERβ subtypes are critically involved in the teleost estrogenic response, with the ERα:ERβ ratio being of particular importance. Accordingly, incorporation of multiple ER subtypes into estrogen screening protocols may increase predictive value for the risk assessment of aquatic systems, including complex estrogenic mixtures.
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Affiliation(s)
- Erin E. Yost
- Department
of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, 850 Main Campus Drive, Raleigh, North Carolina 27606, United States
| | - Crystal Lee Pow
- Department
of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, 850 Main Campus Drive, Raleigh, North Carolina 27606, United States
| | - Mary Beth Hawkins
- Department
of Biological Sciences, North Carolina State
University, Campus Box 7617, Raleigh, North Carolina 27695, United States
| | - Seth W. Kullman
- Department
of Biological Sciences, Program in Environmental and Molecular Toxicology, North Carolina State University, 850 Main Campus Drive, Raleigh, North Carolina 27606, United States
- Phone: (919) 515-4378. Fax: (919) 515-7169. E-mail:
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19
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Yost EE, Meyer M, Dietze JE, Meissner BM, Worley-Davis L, Williams CM, Lee B, Kullman SW. Comprehensive assessment of hormones, phytoestrogens, and estrogenic activity in an anaerobic swine waste lagoon. Environ Sci Technol 2013; 47:13781-90. [PMID: 24144340 PMCID: PMC3854839 DOI: 10.1021/es4026408] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 10/17/2013] [Accepted: 10/21/2013] [Indexed: 05/19/2023]
Abstract
In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were more abundant than androgens or progesterone, with estrone being the predominant estrogen species. Conjugated hormones were detected only at low levels. The isoflavone metabolite equol was by far the predominant phytoestrogen species, with daidzein, genistein, formononetin, and coumestrol present at lower levels. Phytoestrogens were often more abundant than steroidal estrogens, but contributed minimally toward total estrogenic activity. Analytes were significantly elevated in the solid phases of the lagoon; although low observed log KOC values suggest enhanced solubility in the aqueous phase, perhaps due to dissolved or colloidal organic carbon. The association with the solid phase, as well as recalcitrance of analytes to anaerobic degradation, results in a markedly elevated load of analytes and estrogenic activity within lagoon sludge. Overall, findings emphasize the importance of adsorption and transformation processes in governing the fate of these compounds in lagoon waste, which is ultimately used for broadcast application as a fertilizer.
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Affiliation(s)
- Erin E. Yost
- Department
of Biological Sciences, Environmental and Molecular Toxicology, North Carolina State University, 850 Main Campus Drive, Raleigh, North Carolina 27695, United States
| | - Michael
T. Meyer
- Organic
Geochemistry Research Laboratory, U.S. Geological
Survey, 4821 Quail Crest
Place, Lawrence, Kansas 66049, United States
| | - Julie E. Dietze
- Organic
Geochemistry Research Laboratory, U.S. Geological
Survey, 4821 Quail Crest
Place, Lawrence, Kansas 66049, United States
| | - Benjamin M. Meissner
- Organic
Geochemistry Research Laboratory, U.S. Geological
Survey, 4821 Quail Crest
Place, Lawrence, Kansas 66049, United States
| | - Lynn Worley-Davis
- Prestage
Department of Poultry Science, North Carolina
State University, 2711
Founders Drive, Raleigh, North Carolina 27695, United States
| | - C. Michael Williams
- Prestage
Department of Poultry Science, North Carolina
State University, 2711
Founders Drive, Raleigh, North Carolina 27695, United States
| | - Boknam Lee
- Nicholas
School of the Environment, Duke University, 450 Research Drive, Durham, North Carolina 27705, United States
| | - Seth W. Kullman
- Department
of Biological Sciences, Environmental and Molecular Toxicology, North Carolina State University, 850 Main Campus Drive, Raleigh, North Carolina 27695, United States
- Phone: (919) 515-4378. Fax: (919) 515-7169. E-mail:
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20
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Sumpter LR, Inayat MS, Yost EE, Duvall W, Hagan E, Mayhew CN, Elford HL, Gallicchio VS. In vivo examination of hydroxyurea and the novel ribonucleotide reductase inhibitors trimidox and didox in combination with the reverse transcriptase inhibitor abacavir: suppression of retrovirus-induced immunodeficiency disease. Antiviral Res 2004; 62:111-20. [PMID: 15130534 DOI: 10.1016/j.antiviral.2003.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Accepted: 11/10/2003] [Indexed: 10/26/2022]
Abstract
Inhibition of ribonucleotide reductase (RR) has gained attention as a potential strategy for HIV-1 therapy through the success of hydroxyurea (HU) to potentiate the activity of the nucleoside reverse transcriptase inhibitor (NRTI) didanosine (ddI) in clinical trials. However, the use of HU has been limited by its development of hematopoietic toxicity. In this study, the novel RR inhibitors didox (DX; 3,4-dihydroxybenzohydroxamic acid), and trimidox (TX; 3,4,5-trihydroxybenzamidoxime) were evaluated along with HU for anti-retroviral efficacy in LPBM5-induced retro-viral disease (MAIDS) both as monotherapeutic regimens and in combination with the guanine containing NRTI abacavir (ABC). Anti-retroviral drug efficacy was determined by measuring inhibition of splenomegaly, hypergammaglobulinemia, and splenic levels of proviral DNA. In this study, all RRIs tested showed the ability to improve the efficacy of ABC in the MAIDS model by reducing splenomegaly, hypergammaglobulinemia, and splenic proviral DNA levels.
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Affiliation(s)
- L Ryan Sumpter
- Department of Clinical Sciences, University of Kentucky Medical Center, CHS Building, 900 South Limestone Street, Lexington, KY 40536, USA
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