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Sun S, Jiang J, Zhao H, Wan H, Qu B. Photochemical reaction of tricresyl phosphate (TCP) in aqueous solution: Influencing factors and photolysis products. CHEMOSPHERE 2020; 241:124971. [PMID: 31590024 DOI: 10.1016/j.chemosphere.2019.124971] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/17/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Organophosphate triesters (OPEs) have caused great concern as a class of emerging environmental contaminants due to their widespread use and their toxicity to organisms. However, the phototransformation behavior of OPE is still not fully understood, which is important for understanding their environmental fate. In the present study, the photodegradation of tricresyl phosphate (TCP), one of the most widely detected OPEs in aqueous environments, was investigated including the direct photolysis and in the presence of several natural water factors, NO2-, Fe3+ and humic acid. The degradation process followed the pseudo-first-order kinetics, with rate constant increasing slightly with increasing initial TCP concentration. The presence of NO2- and Fe3+ was observed to promote the photochemical loss of TCP, while humic acid played a negative role on TCP transformation. Electron spin resonance (EPR) analysis showed that carbon-centered radical was produced in the photolysis process of TCP, and hydroxyl radical contributed to the promotion of rate constant for Fe3+ and NO2-. Four photolysis products were tentatively identified by HPLC-LTQ-Orbitrap MS analysis, and the possible degradation pathways of TCP were proposed. These findings provide a meaningful reference for the fate and transformation of OPEs in natural water.
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Affiliation(s)
- Shibin Sun
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Jingqiu Jiang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Hongxia Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
| | - Huihui Wan
- College of Chemical Engineering, Analytical Center, Dalian University of Technology, Dalian, 116024, China
| | - Baocheng Qu
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, 116024, China.
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Li Y, Chen R, He J, Ma H, Zhao F, Tao S, Liu J, Hu J. Triphenyl Phosphate at Environmental Levels Retarded Ovary Development and Reduced Egg Production in Japanese Medaka ( Oryzias latipes). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14709-14715. [PMID: 31751126 DOI: 10.1021/acs.est.9b05669] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Since triphenyl phosphate (TPhP) elicits both antiestrogenic activities via blocking the estrogen receptor (ER) and estrogenic activity by elevating 17β-estradiol (17β-E2) synthesis, its adverse effect on female reproduction is uncertain. In this study, we exposed Japanese medaka to TPhP at 131, 363, and 1773 ng/L for 100 days following hatching. TPhP significantly induced ovary retardation in all exposure groups (incidence: from 11.9 to 37.8%) and reduced egg production by 38.9 and 50.9% in the 363 and 1773 ng/L exposure groups, respectively. Vitellogenin (vtg) transcription was significantly downregulated by 35.4-57.4% after TPhP exposure, explaining the ovary retardation. Considering that 17β-E2 was only significantly decreased in the 1773 ng/L exposure group, ER antagonism could be the dominant contributor to the inhibition of vtg transcription and female reproductive toxicity of TPhP. As 4-hydroxyphenyl diphenyl phosphate, a metabolite of TPhP, was detected in livers with similar concentration [68.4-1237 ng/g lipid weight (lw)] to that of TPhP (485-1594 ng/g lw) and elicited medaka ER antagonistic activity (50% inhibitory concentration = 78.1 μM), TPhP and its metabolite should both contribute to the reproductive inhibition. We demonstrate that TPhP at environmentally relevant concentrations is toxic to female reproduction, which poses an ecological risk to wild fish at the population level.
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Affiliation(s)
- Yu Li
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Ruichao Chen
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Jianwu He
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Haojia Ma
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Fanrong Zhao
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Shu Tao
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Junfeng Liu
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
| | - Jianying Hu
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences , Peking University , Beijing 100871 , China
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53
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Zhang J, Yang Y, Liu W, Schlenk D, Liu J. Glucocorticoid and mineralocorticoid receptors and corticosteroid homeostasis are potential targets for endocrine-disrupting chemicals. ENVIRONMENT INTERNATIONAL 2019; 133:105133. [PMID: 31520960 DOI: 10.1016/j.envint.2019.105133] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/19/2019] [Accepted: 08/26/2019] [Indexed: 05/16/2023]
Abstract
Endocrine-disrupting chemicals (EDCs) have received significant concern, since they ubiquitously exist in the environment and are able to induce adverse health effects on human and wildlife. Increasing evidence shows that the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), members of the steroid receptor subfamily, are potential targets for EDCs. GR and MR mediate the actions of glucocorticoids and mineralocorticoids, respectively, which are two main classes of corticosteroids involved in many physiological processes. The effects of EDCs on the homeostasis of these two classes of corticosteroids have also gained more attention recently. This review summarized the effects of environmental GR/MR ligands on receptor activity, and disruption of corticosteroid homeostasis. More than 130 chemicals classified into 7 main categories were reviewed, including metals, metalloids, pesticides, bisphenol analogues, flame retardants, other industrial chemicals and pharmaceuticals. The mechanisms by which EDCs interfere with GR/MR activity are primarily involved in ligand-receptor binding, nuclear translocation of the receptor complex, DNA-receptor binding, and changes in the expression of endogenous GR/MR genes. Besides directly interfering with receptors, enzyme-catalyzed synthesis and prereceptor regulation pathways of corticosteroids are also important targets for EDCs. The collected evidence suggests that corticosteroids and their receptors should be considered as potential targets for safety assessment of EDCs. The recognition of relevant xenobiotics and their underlying mechanisms of action is still a challenge in this emerging field of research.
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Affiliation(s)
- Jianyun Zhang
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Department of Public Health, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Ye Yang
- Institute of Hygiene, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China
| | - Weiping Liu
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Daniel Schlenk
- Department of Environmental Sciences, University of California, Riverside, 900 University Avenue, Riverside, CA 92521, United States
| | - Jing Liu
- MOE Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
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Fujino C, Watanabe Y, Sanoh S, Hattori S, Nakajima H, Uramaru N, Kojima H, Yoshinari K, Ohta S, Kitamura S. Comparative study of the effect of 17 parabens on PXR-, CAR- and PPARα-mediated transcriptional activation. Food Chem Toxicol 2019; 133:110792. [DOI: 10.1016/j.fct.2019.110792] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/27/2019] [Accepted: 08/23/2019] [Indexed: 12/24/2022]
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Hou R, Luo X, Liu C, Zhou L, Wen J, Yuan Y. Enhanced degradation of triphenyl phosphate (TPHP) in bioelectrochemical systems: Kinetics, pathway and degradation mechanisms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:113040. [PMID: 31421579 DOI: 10.1016/j.envpol.2019.113040] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Triphenyl phosphate (TPHP) is one of the major organophosphate esters (OPEs) with increasing consumption. Considering its largely distribution and high toxicity in aquatic environment, it is important to explore an efficient treatment for TPHP. This study aimed to investigate the accelerated degradation of TPHP in a three-electrode single chamber bioelectrochemical system (BES). Significant increase of degradation efficiency of TPHP in the BES was observed compared with open circuit and abiotic controls. The one-order degradation rates of TPHP (1.5 mg L-1) were increased with elevating sodium acetate concentrations and showed the highest value (0.054 ± 0.010 h-1) in 1.0 g L-1 of sodium acetate. This result indicated bacterial metabolism of TPHP was enhanced by the application of micro-electrical field and addition acetate as co-substrates. TPHP could be degraded into diphenyl phosphate (DPHP), hydroxyl triphenyl phosphate (OH-TPHP) and three byproducts. DPHP was the most accumulated degradation product in BES, which accounted more than 35.5% of the initial TPHP. The composition of bacterial community in BES electrode was affected by the acclimation by TPHP, with the most dominant bacteria of Azospirillum, Petrimonas, Pseudomonas and Geobacter at the genera level. Moreover, it was found that the acute toxic effect of TPHP to Vibrio fischeri was largely removed after the treatment, which revealed that BES is a promising technology to remove TPHP threaten in aquatic environment.
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Affiliation(s)
- Rui Hou
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaoshan Luo
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Chuangchuang Liu
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Lihua Zhou
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China
| | - Junlin Wen
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Yong Yuan
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.
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56
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Kang H, Lee J, Lee JP, Choi K. Urinary metabolites of organophosphate esters (OPEs) are associated with chronic kidney disease in the general US population, NHANES 2013-2014. ENVIRONMENT INTERNATIONAL 2019; 131:105034. [PMID: 31374441 DOI: 10.1016/j.envint.2019.105034] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/16/2019] [Accepted: 07/16/2019] [Indexed: 06/10/2023]
Abstract
Organophosphate esters (OPEs) have been widely used in building materials and consumer products as flame retardants and plasticizers. In vitro studies have suggested adverse effects of OPEs on the kidney. Despite accumulating evidence indicating widespread exposure to OPEs, their association with renal function in humans has not been evaluated. This study aims to investigate the association between OPEs exposure and chronic kidney disease (CKD) among the general US adult population by employing data from the US National Health and Nutrition Examination Survey (NHANES) 2013-2014. Among 1578 adults who were not currently pregnant, the associations of the urinary OPE metabolites with two CKD-related parameters, i.e., estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR), and CKD were assessed. To account for urine dilution, in addition to conventional creatinine-adjustment, covariate-adjusted creatinine standardization, which controls for potential confounding by kidney function, was employed. Multi-pollutant models were also constructed to verify the associations observed in the models on individual OPE metabolites. The urinary bis(2-chloroethyl) phosphate (BCEP) level was negatively associated with eGFR only with the covariate-adjusted standardization method, but not with the conventional creatinine adjustment. In addition, both bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) and di-n-butyl phosphate (DNBP) were positively associated with the ACR, regardless of methods of urine dilution adjustment. These three compounds were also associated with CKD. Following adjusting urine dilution with the covariate-adjusted standardization method, the association became more evident. Moreover, similar results were observed in the secondary analysis with the multi-pollutant models. Among the US general population, several OPEs were identified as potential chemical determinants of CKD. Experimental studies are warranted to understand the potential mechanisms underlying this observation.
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Affiliation(s)
- Habyeong Kang
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea
| | - Jeonghwan Lee
- Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Republic of Korea
| | - Jung Pyo Lee
- Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Republic of Korea; Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Kyungho Choi
- Department of Environmental Health Sciences, School of Public Health, Seoul National University, Seoul, Republic of Korea; Institute of Health and Environmental, Seoul National University, Seoul, Republic of Korea.
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57
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Serra H, Scholze M, Altenburger R, Busch W, Budzinski H, Brion F, Aït-Aïssa S. Combined effects of environmental xeno-estrogens within multi-component mixtures: Comparison of in vitro human- and zebrafish-based estrogenicity bioassays. CHEMOSPHERE 2019; 227:334-344. [PMID: 30999174 DOI: 10.1016/j.chemosphere.2019.04.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/07/2019] [Accepted: 04/08/2019] [Indexed: 05/15/2023]
Abstract
Some recent studies showed that in vitro bioassays based on fish or human estrogen receptor (ER) activation may have distinct responses to environmental samples, highlighting the need to better understand bioassay-specific ER response to environmental mixtures. For this purpose, we investigated a 12-compound mixture in two mixture ratios (M1 and M2) on zebrafish (zf) liver cells stably expressing zfERα (ZELHα cells) or zfERβ2 (ZELHβ2 cells) and on human ER-reporter gene (MELN) cells. The mixture included the well-known ER ligands bisphenol A (BPA) and genistein (GEN), and other compounds representatives of a freshwater background contamination. In this context, the study aimed at assessing the robustness of concentration addition (CA) model and the potential confounding influence of other chemicals by testing subgroups of ER activators, ER inhibitors or ER activators and inhibitors combined. Individual chemical testing showed a higher prevalence of ER inhibitors in zebrafish than human cells (e.g. propiconazole), and some chemicals inhibited zfER but activated hER response (e.g. benzo(a)pyrene, triphenylphosphate). The estrogenic activity of M1 and M2 was well predicted by CA in MELN cells, whereas it was significantly lower than predicted in ZELHβ2 cells, contrasting with the additive effects observed for BPA and GEN binary mixtures. When testing the subgroups of ER activators and inhibitors combined, the deviation from additivity in ZELHβ2 cells was caused by zebrafish-specific inhibiting chemicals. This study provides novel information on the ability of environmental pollutants to interfere with zfER signalling and shows that non-estrogenic chemicals can influence the response to a mixture of xeno-estrogens in a bioassay-specific manner.
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Affiliation(s)
- Hélène Serra
- Institut National de l'Environnement Industriel et des risques (INERIS), Unité Ecotoxicologie in vitro et in vivo, UMR-I 02 SEBIO, 60550, Verneuil-en-Halatte, France; UMR-CNRS EPOC/LPTC, Université de Bordeaux, Talence, France
| | | | - Rolf Altenburger
- UFZ- Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Wibke Busch
- UFZ- Helmholtz Centre for Environmental Research, Leipzig, Germany
| | | | - François Brion
- Institut National de l'Environnement Industriel et des risques (INERIS), Unité Ecotoxicologie in vitro et in vivo, UMR-I 02 SEBIO, 60550, Verneuil-en-Halatte, France
| | - Selim Aït-Aïssa
- Institut National de l'Environnement Industriel et des risques (INERIS), Unité Ecotoxicologie in vitro et in vivo, UMR-I 02 SEBIO, 60550, Verneuil-en-Halatte, France.
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58
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Hou R, Yuan S, Feng C, Xu Y, Rao K, Wang Z. Toxicokinetic patterns, metabolites formation and distribution in various tissues of the Chinese rare minnow (Gobiocypris rarus) exposed to tri(2‑butoxyethyl) phosphate (TBOEP) and tri-n-butyl phosphate (TNBP). THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 668:806-814. [PMID: 30870749 DOI: 10.1016/j.scitotenv.2019.03.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/02/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
Alkylated organophosphate esters (alkyl-OPEs) are widely used and extensively detected in aquatic organisms. This work investigated the tissue-specific toxicokinetics of two common alkyl-OPEs, tri(2‑butoxyethyl) phosphate (TBOEP) and tri‑n‑butyl phosphate (TNBP) in Chinese rare minnow (Gobiocypris rarus) through a 50 day uptake and depuration experiment. The tissue-specific bioconcentration factor (BCF) values for the two alkyl-OPEs ranged from 1 to 30 L/kg wet weight (ww), with the kidney and ovary as the tissues with the highest accumulation. The tissue BCFs only exhibited a significant correlation with lipid contents only in storage tissues (i.e., muscle, brain, ovary and testis), indicating that lipids might not be the major contributor to tissue distribution of TBOEP and TNBP. However, the contribution of blood perfusion and active transport to tissue-specific OPE accumulation needs to be further investigated. Lower accumulation of metabolites than parent chemicals was observed, with metabolite parent concentration factors (MPCFs) <1. Di-alkyl phosphate (DAP), bis(2‑butoxyethyl) phosphate (BBOEP) and di(n-butyl) phosphate (DNBP) were the most abundantly formed metabolites of TBOEP and TNBP in various tissues, followed by the monohydroxylated OPEs (OH-OPEs). However, bis(2‑butoxyethyl) hydroxyethyl phosphate (BBOEHEP), was detected at much lower levels in the tissues. All the investigated metabolites showed high production rates (kprod,metabolites) in the fish liver, followed by the GI tract and the kidney, indicating the importance of the hepatobiliary and urinary systems in eliminating the metabolites. Our study suggested that metabolism plays an important role in eliminating these two alkyl-OPEs in rare minnow and results in different tissue distribution mechanisms for metabolites and their compounds.
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Affiliation(s)
- Rui Hou
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Shengwu Yuan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Chenglian Feng
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Yiping Xu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Kaifeng Rao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zijian Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Xu F, Eulaers I, Alves A, Papadopoulou E, Padilla-Sanchez JA, Lai FY, Haug LS, Voorspoels S, Neels H, Covaci A. Human exposure pathways to organophosphate flame retardants: Associations between human biomonitoring and external exposure. ENVIRONMENT INTERNATIONAL 2019; 127:462-472. [PMID: 30978481 DOI: 10.1016/j.envint.2019.03.053] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 06/09/2023]
Abstract
Organophosphate flame retardants (PFRs) have largely replaced the market of polybrominated diphenyl ethers (PBDEs). Concerns about PFR contamination and its impact on human health have consequently increased. A comprehensive investigation on the human exposure pathways to PFRs is to be endeavoured. This study investigated the occurrence of PFR metabolites in human urine, serum and hair, correlating them with external exposure data that was presented in our previous studies. Participants from Oslo (n = 61) provided a set of samples, including dust, air, handwipes, food, urine, serum and hair. Associations between PFR metabolites analyzed in the biological samples and the PFRs in environmental samples were explored. Different sampling strategies for dosimeters (e.g. floor/surface dust, personal/stationary air) were also compared to understand which is better for predicting human exposure to PFRs. Seven out of the eleven target PFR metabolites, including diphenyl phosphate (DPHP) and bis(1-chloro-2-propyl)-1-hydroxy-2-propyl phosphate (BCIPHIPP), were frequently detected (DF > 30%) in urine. DPHP was the most frequently detected metabolite in both serum and hair. Several PFR metabolites had higher levels in morning urine than in afternoon urine. Floor dust appeared to be a better proxy for estimating PFR internal exposure than surface dust, air, and handwipes. Some PFRs in handwipes and air were also correlated with their metabolites in urine and hair. Age, beverage consumption and food consumption were negatively associated with DPHP levels in urine. Discrepancies observed between the external and internal exposure for some PFRs call for further investigation on PFR bioaccessibility and clearance.
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Affiliation(s)
- Fuchao Xu
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
| | - Igor Eulaers
- Department of Bioscience, Aarhus University, Frederiksborgvej 399, PO Box 358, 4000 Roskilde, Denmark
| | - Andreia Alves
- Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium
| | - Eleni Papadopoulou
- Department of Environmental Exposure and Epidemiology, Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, PO box 222, Skøyen, 0213 Oslo, Norway
| | - Juan Antonio Padilla-Sanchez
- Department of Environmental Exposure and Epidemiology, Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, PO box 222, Skøyen, 0213 Oslo, Norway
| | - Foon Yin Lai
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Line Småstuen Haug
- Department of Environmental Exposure and Epidemiology, Division of Infection Control and Environmental Health, Norwegian Institute of Public Health, PO box 222, Skøyen, 0213 Oslo, Norway
| | - Stefan Voorspoels
- Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium
| | - Hugo Neels
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
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60
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Li J, Zhao L, Letcher RJ, Zhang Y, Jian K, Zhang J, Su G. A review on organophosphate Ester (OPE) flame retardants and plasticizers in foodstuffs: Levels, distribution, human dietary exposure, and future directions. ENVIRONMENT INTERNATIONAL 2019; 127:35-51. [PMID: 30901640 DOI: 10.1016/j.envint.2019.03.009] [Citation(s) in RCA: 197] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 05/24/2023]
Abstract
Given the ongoing studies on the adverse effects of organophosphate ester (OPE) flame retardants and plasticizers on human health, there is an increasing scientific interest in the risk of exposure to OPEs via dietary intake. Using peer-reviewed literature published up to 2018, this review surveyed and compiled the available and reported data on the concentrations and distributions of 30 OPEs based on their occurrence in various food samples from around the world. Regardless of sampling locations or food categories, 22 OPEs were detectable in at least one of analyzed sample, and there were clear variations in OPE levels among samples from different locations or food categories. For instance, cereals and fats/oils were the most contaminated by OPEs in China and Belgium, whereas fats/oils and desserts were the main polluted products in Sweden. In contrast, vegetables, fruits, fluid dairy products, and cereals were reported as the primary categories of food polluted by OPEs in Australia. Animal-based food categories such as eggs, fish and meat were the least contaminated, whereas the highest median OPE concentrations were found in meat and fish from the United State. The levels and distribution patterns of OPEs in foodstuffs demonstrated a tremendous difference even when collected from the same country and the same food item. Rice from China had the highest tris(2‑chloroethyl) phosphate (TCEP, mean: 29.8 ng/g dw) levels, whereas 2‑ethylhexyl‑diphenyl phosphate (EHDPP, mean: 4.17 ng/g ww), triphenyl phosphate (TPHP, mean: 26.14 ng/g ww), tris(2-chloroisopropyl) phosphate (TCIPP, mean: 0.87 ng/g ww) and tributyl phosphate (TNBP, median: 0.55 ng/g ww) concentrations were the highest in the same food category from Sweden, Belgium, Australia, and the United States, respectively. These discrepancies may be due to a variety of reasons such as differences in OPE physico-chemical properties, extent of usage, uptake, metabolic pathways, industrial food manufacturing processes, OPE level differences as a function of habitat, and accumulation and degradability of OPEs in different species. It is worth noting that, due to its worldwide usage in food packaging materials, EHDPP was more prominently found in processed food compared to non-processed food. Based on reported OPE levels in various foods, this review conducted a preliminary assessment of human exposure to OPEs through dietary intake, which suggested that the OPE estimated daily intake (EDI) for humans was around 880 ng/kg bw/day (95th percentile). This value was well below the corresponding OPE health reference dose given by the U.S. EPA (≥15,000 ng/kg bw/day). Even so, dietary exposure to OPEs via food intake may be not negligible based on some important factors such as dilution effects, cooking processes, and the contribution of as yet unknown means of OPE exposure. Overall, this review highlights several gaps in our understanding of OPEs in foodstuffs: 1) the investigation of contamination levels of OPEs in foodstuffs should be extended to other regions, especially North America and European countries, where OPEs are widely used and frequently detected in environmental samples, and 2) newly identified OPE derivatives/by-products, e.g., OP diesters and hydroxylated metabolites, which have been reported as end-products of OPE enzymatic metabolism or degradation through aqueous hydrolysis, and which may co-exist with parent OPEs, could also be screened with precursor OPEs in foodstuffs in future studies.
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Affiliation(s)
- Jianhua Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - Luming Zhao
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario K1A 0H3, Canada
| | - Yayun Zhang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - Kang Jian
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - Jinhua Zhang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - Guanyong Su
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
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Hao Z, Zhang Z, Lu D, Ding B, Shu L, Zhang Q, Wang C. Organophosphorus Flame Retardants Impair Intracellular Lipid Metabolic Function in Human Hepatocellular Cells. Chem Res Toxicol 2019; 32:1250-1258. [PMID: 30966736 DOI: 10.1021/acs.chemrestox.9b00058] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Organophosphorus flame retardants (OPFRs), a replacement for brominated flame retardants, have gradually been accepted as endocrine disrupting chemicals (EDCs). Recently, evidence has shown that these EDCs could cause chronic health problems, such as obesity, and referred to as metabolic disruptors. However, the disturbance to lipid metabolism caused by OPFRs remains poorly understood, especially at biological molecular levels. Herein, we used the human hepatocellular cells (HepG2) to study the lipid metabolism disruption caused by nine OPFRs (halogenated-, aryl-, and alkyl-containing). All the tested OPFRs, excluding the long carbon chain alkyl-OPFRs, could cause intracellular triglyceride (TG) and/or total cholesterol (TC) accumulation. In detail, aryl-OPFRs (TPhP and TCP) induced both TC and TG deposition. Halogenated-OPFRs (TCEP, TBPP, TDCPP, and TCPP) induced intracellular TG accumulation, and only TDCPP also induced TC accumulation. Furthermore, TPhP induced lipid accumulation through regulation genes encoding proteins involved in fatty acid β-oxidation, lipid, and fatty acid synthesis. All the halogenated-OPFRs cause TG accumulation only, enacted through β-oxidation rather than lipid synthesis. TPhP and TDCPP induced TC accumulation through both PPARγ and srebp2 signaling. Mitochondrial dysfunction including decreased oxygen consumption rate and ATP content may also contribute to lipid metabolic disruption by the tested OPFRs. Our data indicated that halogenated- and aryl-OPFRs may not be safe candidates, and further information should be made available as potential for, as well as the mechanism of, metabolic disruption. And long carbon chain alkyl-OPFRs may be safer than the other two groups.
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Affiliation(s)
- Zhengliang Hao
- College of Life Science , Zhejiang Chinese Medical University , Hangzhou 310053 , Zhejiang People's Republic of China
| | - Zhijie Zhang
- College of Life Science , Zhejiang Chinese Medical University , Hangzhou 310053 , Zhejiang People's Republic of China
| | - Dezhao Lu
- College of Life Science , Zhejiang Chinese Medical University , Hangzhou 310053 , Zhejiang People's Republic of China
| | - Bin Ding
- College of Life Science , Zhejiang Chinese Medical University , Hangzhou 310053 , Zhejiang People's Republic of China
| | - Lin Shu
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang University of Technology , Hangzhou 310032 , Zhejiang People's Republic of China
| | - Quan Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang University of Technology , Hangzhou 310032 , Zhejiang People's Republic of China
| | - Cui Wang
- College of Life Science , Zhejiang Chinese Medical University , Hangzhou 310053 , Zhejiang People's Republic of China
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Mitchell CA, Reddam A, Dasgupta S, Zhang S, Stapleton HM, Volz DC. Diphenyl Phosphate-Induced Toxicity During Embryonic Development. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:3908-3916. [PMID: 30864794 PMCID: PMC6445678 DOI: 10.1021/acs.est.8b07238] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Diphenyl phosphate (DPHP) is an aryl phosphate ester (APE) used as an industrial catalyst and chemical additive and is the primary metabolite of flame retardant APEs, including triphenyl phosphate (TPHP). Minimal DPHP-specific toxicity studies have been published despite ubiquitous exposure within human populations following metabolism of TPHP and other APEs. Therefore, the objective of this study was to determine the potential for DPHP-induced toxicity during embryonic development. Using zebrafish as a model, we found that DPHP significantly increased the distance between the sinus venosus and bulbus arteriosis (SV-BA) at 72 h postfertilization (hpf) following initiation of exposure before and after cardiac looping. Interestingly, pretreatment with d-mannitol mitigated DPHP-induced effects on SV-BA length despite the absence of DPHP effects on pericardial area, suggesting that DPHP-induced cardiac defects are independent of pericardial edema formation. Using mRNA-sequencing, we found that DPHP disrupts pathways related to mitochondrial function and heme biosynthesis; indeed, DPHP significantly decreased hemoglobin levels in situ at 72 hpf following exposure from 24 to 72 hpf. Overall, our findings suggest that, similar to TPHP, DPHP impacts cardiac development, albeit the potency of DPHP is significantly less than TPHP within developing zebrafish.
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Affiliation(s)
- Constance A. Mitchell
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Aalekhya Reddam
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Subham Dasgupta
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Sharon Zhang
- Division of Environmental Sciences and Policy, Duke University, Durham, North Carolina 27708, United States
| | - Heather M. Stapleton
- Division of Environmental Sciences and Policy, Duke University, Durham, North Carolina 27708, United States
| | - David C. Volz
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
- Corresponding Author Phone: (951) 827-4450. Fax: (951) 827-4652.,
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Wei K, Yin H, Peng H, Lu G, Dang Z. Bioremediation of triphenyl phosphate in river water microcosms: Proteome alteration of Brevibacillus brevis and cytotoxicity assessments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 649:563-570. [PMID: 30176467 DOI: 10.1016/j.scitotenv.2018.08.342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/24/2018] [Accepted: 08/24/2018] [Indexed: 06/08/2023]
Abstract
Triphenyl phosphate (TPHP), an organophosphate flame retardant, was detected in river water samples collected from an electronic waste recycling area in Guiyu, Southern China. The concentrations of TPHP ranged from not detected to 347.2 ng/L, with an average of 138.8 ng/L. The bioaugmentation potential of Brevibacillus brevis on TPHP biodegradation by aerobic microcosms contained in river water from Guiyu was assessed. The results showed that TPHP degradation efficiency was significantly improved to 97.9% by bioaugmentation with B. brevis after 96 h incubation. A total of 182 significantly changed proteins in B. brevis were identified and quantified by isobaric tags for relative and absolute quantification (iTRAQ) in response to TPHP stress. The differentially expressed proteins were mainly associated with energy metabolism, lipid metabolism, cell wall biosynthesis, amino acid transport, and metabolism. The identification that proteins of B. brevis respond to TPHP existence provides novel insights into biodegradation mechanisms of bacteria under environmental stress. Additionally, cytotoxicity assays indicated that the degrading intermediates of TPHP, namely diphenyl phosphate and phenyl phosphate, were less cytotoxic to human HepG2 cells compared with TPHP. Collectively, these findings suggest that aerobic bioaugmentation with degrading microorganisms is a potential strategy for in situ treatment of TPHP-contaminated sites.
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Affiliation(s)
- Kun Wei
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem, Restoration in Industry Clusters, Guangdong Provincial Engineering and Technology, Research Center for Environxmental Risk Prevention and Emergency Disposal, School of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, PR China
| | - Hua Yin
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem, Restoration in Industry Clusters, Guangdong Provincial Engineering and Technology, Research Center for Environxmental Risk Prevention and Emergency Disposal, School of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, PR China.
| | - Hui Peng
- Department of Chemistry, Jinan University, Guangzhou 510632, Guangdong, PR China
| | - Guining Lu
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem, Restoration in Industry Clusters, Guangdong Provincial Engineering and Technology, Research Center for Environxmental Risk Prevention and Emergency Disposal, School of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, PR China
| | - Zhi Dang
- Key Laboratory of Ministry of Education on Pollution Control and Ecosystem, Restoration in Industry Clusters, Guangdong Provincial Engineering and Technology, Research Center for Environxmental Risk Prevention and Emergency Disposal, School of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, PR China
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64
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Fu Z, Chen J, Wang Y, Hong H, Xie H. Quantum chemical simulations revealed the toxicokinetic mechanisms of organic phosphorus flame retardants catalyzed by P450 enzymes. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2018; 36:272-291. [PMID: 30457030 DOI: 10.1080/10590501.2018.1537564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The metabolic fate and toxicokinetics of organic phosphorus flame retardants catalyzed by cytochrome P450 enzymes (CYPs) are here investigated by in silico simulations, leveraging an active center model to mimic the CYPs, triphenyl phosphate (TPHP), tris(2-butoxyethyl) phosphate and tris(1,3-dichloro-2-propyl) phosphate as substrates. Our calculations elucidated key main pathways and predicted products, which were corroborated by current in vitro data. Results showed that alkyl OPFRs are eliminated faster than aryl and halogenated alkyl-substituted OPFRs. In addition, we discovered a proton shuttle pathway for aryl hydroxylation of TPHP and P = O bond-assisted H-transfer mechanisms (rather than nonenzymatic hydrolysis) that lead to O-dealkylation/dearylation of phosphotriesters.
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Affiliation(s)
- Zhiqiang Fu
- a Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology , Dalian University of Technology , Dalian , China
| | - Jingwen Chen
- a Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology , Dalian University of Technology , Dalian , China
| | - Yong Wang
- b State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics (LICP) , Chinese Academy of Sciences , Lanzhou , China
| | - Huixiao Hong
- c National Center for Toxicological Research , U.S. Food and Drug Administration , Jefferson , Arkansas , USA
| | - Hongbin Xie
- a Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology , Dalian University of Technology , Dalian , China
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Kollitz EM, Kassotis CD, Hoffman K, Ferguson PL, Sosa JA, Stapleton HM. Chemical Mixtures Isolated from House Dust Disrupt Thyroid Receptor β Signaling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:11857-11864. [PMID: 30212187 PMCID: PMC6433547 DOI: 10.1021/acs.est.8b03283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
House dust is a source of exposure to chemicals that can impact hormone regulation. This study was designed to evaluate the potential of house dust mixtures ( n = 137) to disrupt thyroid hormone nuclear receptor signaling in a cell-based reporter assay and to examine associations with thyroid hormones (TH) measured in residents of the homes. Approximately 41% of the extracts (ranging from 10.5 to 4.097 μg of dust/mL) significantly antagonized thyroid receptor β (TRβ) signaling by 20-67% relative to the hormone control. The concentrations of 12 flame retardants (FRs) quantified in the mixtures were significantly correlated with TRβ antagonism; however, they were inactive when tested individually. We hypothesize that the observed antagonism is due to mixture effects or unidentified compounds that co-occur with FRs. Dust extract potency was significantly associated with free thyroxine (FT4, rs = -0.64, p < 0.001), suggesting that more potent dust samples are associated with higher FT4 levels in residents. Overall, these results suggest that house dust is a significant source of exposure to TH-disrupting chemicals, and TRβ may have a role in mediating effects of exposure on TH levels. Additional studies are needed to identify the chemical(s) driving the observed effects on TRβ and to determine if these changes lead to any adverse outcomes.
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Affiliation(s)
- Erin M. Kollitz
- Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 27708, United States
| | - Christopher D. Kassotis
- Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 27708, United States
| | - Kate Hoffman
- Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 27708, United States
| | - P. Lee Ferguson
- Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 27708, United States
| | - Julie Ann Sosa
- Department of Surgery, University of California at San Francisco, 513 Parnassus Avenue, San Francisco, California 94117, United States
| | - Heather M. Stapleton
- Nicholas School of the Environment, Duke University, Box 90328, Durham, North Carolina 27708, United States
- Corresponding Author Information: Phone: (919) 613-8717,
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66
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Ingle ME, Mínguez-Alarcón L, Carignan CC, Butt CM, Stapleton HM, Williams PL, Ford JB, Hauser R, Meeker JD. The association between urinary concentrations of phosphorous-containing flame retardant metabolites and semen parameters among men from a fertility clinic. Int J Hyg Environ Health 2018; 221:809-815. [PMID: 29739653 PMCID: PMC5997557 DOI: 10.1016/j.ijheh.2018.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/01/2018] [Accepted: 05/01/2018] [Indexed: 12/01/2022]
Abstract
BACKGROUND The use of PFRs has steadily increased as brominated compounds have been or are being phased out. Human exposure is widespread and animal studies have shown adverse impacts on male reproduction, but human data are lacking. OBJECTIVE To study the associations between urinary concentrations of phosphorous-containing flame retardant (PFR) metabolites and semen parameters. METHODS A subset of 220 men from an existing longitudinal cohort of couples were recruited from Massachusetts General Hospital fertility clinic between 2005 and 2015. Semen parameters included sperm count, concentration, motility, and morphology; some men had samples measured from multiple clinic visits (up to five visits; n = 269 semen samples). Metabolites [bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPHP), isopropylphenyl phenyl phosphate (ip-PPP), tert-butylphenyl phenyl phosphate (tb-PPP) and bis(1-chloro-2-propyl) phosphate (BCIPP)] were measured in urine samples (between one and five urine samples per participant; n = 355 urine samples). Semen parameters were evaluated continuously and dichotomized for models. Metabolites were assessed for associations with semen parameters as continuous and categorized into quartiles using multivariable generalized mixed models, adjusted for specific gravity, age, BMI, smoking, and abstinence period. RESULTS Metabolites BDCIPP, DPHP, and ip-PPP were detected in a high proportion of urine samples (85%, 86%, and 65% respectively). Concentrations varied by season of collection, particularly for BDCIPP where samples collected in the summer were approximately 2-fold higher than concentrations of other seasons (p < 0.0001). The odds of having a sperm count less than 39 mil/ejaculate decreased by 20% for increasing BDCIPP concentrations (p = 0.04). When regressing semen parameters on PFR metabolite quartiles, some negative associations were observed for individual quartiles among sample volume and morphology, but overall associations were weak and inconsistent. CONCLUSION Detection rates were high for BDCIPP, DPHP, and ip-PPP. We did not observe consistent associations between PFR metabolites and semen parameters. Due to the high prevalence of exposure, further investigation of other potential health effects should be conducted.
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Affiliation(s)
- Mary E Ingle
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Lidia Mínguez-Alarcón
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Courtney C Carignan
- Department of Food Science and Nutrition, Michigan State University, East Lansing, MI, USA; Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| | - Craig M Butt
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | | | - Paige L Williams
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Jennifer B Ford
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Russ Hauser
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Obstetrics and Gynecology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA.
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67
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Hou R, Huang C, Rao K, Xu Y, Wang Z. Characterized in Vitro Metabolism Kinetics of Alkyl Organophosphate Esters in Fish Liver and Intestinal Microsomes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3202-3210. [PMID: 29439571 DOI: 10.1021/acs.est.7b05825] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tris(2-butoxyethyl) phosphate (TBOEP) and tris( n-butyl) phosphate (TNBP) are the most commonly used alkyl organophosphate esters (alkyl-OPEs), and they increasingly accumulate in organisms and create potential health hazards. This study examined the metabolism of TNBP and TBOEP in Carassius carassius liver and intestinal microsomes and the production of their corresponding monohydroxylated and dealkylated metabolites. After 140 min of incubation with fish liver microsomes, the rapid depletion of TNBP and TBOEP were both best fitted to the Michaelis-Menten model (at administrated concentrations ranging from 0.5 to 200 μM), with a CLint (intrinsic clearance) of 3.1 and 3.9 μL·min-1·mg-1 protein, respectively. But no significant ( P > 0.05) biotransformation was observed for these compounds in intestinal microsomes at any administrated concentrations. In fish liver microsomes assay, bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) and bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate (3-OH-TBOEP) were the most abundant metabolites of TBOEP, and dibutyl-3-hydroxybutyl phosphate (3-OH-TNBP) was the predominant metabolite of TNBP. Similarly, the apparent Vmax values (maximum metabolic rate) of BBOEHEP and 3-OH-TNBP were also respectively highest among those of other metabolites. Further inhibition studies were conducted to identify the specific cytochrome P450 (CYP450) isozymes involved in the metabolism of TNBP and TBOEP in liver microsomes. It was confirmed that CYP3A4 and CYP1A were the significant CYP450 isoforms catalyzing the metabolism of TNBP and TBOEP in fish liver microsomes. Overall, this study emphasized the importance of hydroxylated metabolites as biomarkers for alkyl-OPEs exposure, and further research is needed to validate the in vivo formation and toxicological implications of these metabolites.
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Affiliation(s)
- Rui Hou
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Chao Huang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Kaifeng Rao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Yiping Xu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Zijian Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
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68
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Zeng X, Wu Y, Liu Z, Gao S, Yu Z. Occurrence and distribution of organophosphate ester flame retardants in indoor dust and their potential health exposure risk. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2018; 37:345-352. [PMID: 28986991 DOI: 10.1002/etc.3996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 08/29/2017] [Accepted: 10/02/2017] [Indexed: 06/07/2023]
Abstract
The occurrence and distribution of 10 organophosphate ester (OP) flame retardants/plasticizers were studied in indoor dust collected in 2 districts of Wuhan City. Total concentrations of the 10 OPs (ΣOPs) varied from 86.5 to 6389 ng/g in 26 dust samples in Caidian District and from 300 to 10 186 ng/g in 27 samples in Jiang'an District. In most dust samples tris(2-chloroethyl) phosphate was dominant over the other OPs, with concentrations of 9.14 to 2722 ng/g (mean 388 ng/g) in Caidian District and 57.3 to 3718 ng/g (mean 616 ng/g) in Jiang'an District. The calculated hazard indices, based on estimated exposure dose via dust ingestion to the reference dose, were much lower than 1. The results suggested that the inhabitants in the 2 regions were at low risk of exposure through dust ingestion. Environ Toxicol Chem 2018;37:345-352. © 2017 SETAC.
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Affiliation(s)
- Xiangying Zeng
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - Yang Wu
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhiyang Liu
- Institute of Atmospheric Environment, Guangdong Provincial Academy of Environmental Science, Guangzhou, China
| | - Shutao Gao
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry, Guangdong Key Laboratory of Environment and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
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Wan W, Huang H, Lv J, Han R, Zhang S. Uptake, Translocation, and Biotransformation of Organophosphorus Esters in Wheat (Triticum aestivum L.). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:13649-13658. [PMID: 29125288 DOI: 10.1021/acs.est.7b01758] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The uptake, translocation and biotransformation of organophosphate esters (OPEs) by wheat (Triticum aestivum L.) were investigated by a hydroponic experiment. The results demonstrated that OPEs with higher hydrophobicity were more easily taken up by roots, and OPEs with lower hydrophobicity were more liable to be translocated acropetally. A total of 43 metabolites including dealkylated, oxidatively dechlorinated, hydroxylated, methoxylated, and glutathione-, and glucuronide- conjugated products were detected derived from eight OPEs, with diesters formed by direct dealkylation from the parent triesters as the major products, followed with hydroxylated triesters. Molecular interactions of OPEs with plant biomacromolecules were further characterized by homology modeling combined with molecular docking. OPEs with higher hydrophobicity were more liable to bind with TaLTP1.1, the most important wheat nonspecific lipid transfer protein, consistent with the experimental observation that OPEs with higher hydrophobicity were more easily taken up by wheat roots. Characterization of molecular interactions between OPEs and wheat enzymes suggested that OPEs were selectively bound to TaGST4-4 and CYP71C6v1 with different binding affinities, which determined their abilities to be metabolized and form metabolite products in wheat. This study provides both experimental and theoretical evidence for the uptake, accumulation and biotransformation of OPEs in plants.
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Affiliation(s)
- Weining Wan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , P.O. Box 2871, Beijing 100085, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Honglin Huang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , P.O. Box 2871, Beijing 100085, China
| | - Jitao Lv
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , P.O. Box 2871, Beijing 100085, China
| | - Ruixia Han
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , P.O. Box 2871, Beijing 100085, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Shuzhen Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , P.O. Box 2871, Beijing 100085, China
- University of Chinese Academy of Sciences , Beijing 100049, China
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70
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Zhou L, Hiltscher M, Püttmann W. Occurrence and human exposure assessment of organophosphate flame retardants in indoor dust from various microenvironments of the Rhine/Main region, Germany. INDOOR AIR 2017; 27:1113-1127. [PMID: 28556503 DOI: 10.1111/ina.12397] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/23/2017] [Indexed: 06/07/2023]
Abstract
We analyzed organophosphate flame retardants (OPFRs) in 74 indoor dust samples collected from seven microenvironments (building material markets, private cars, daycare centers, private homes, floor/carpet stores, offices, and schools) in the Rhine/Main region of Germany. Ten of 11 target OPFRs were ubiquitously detected, some with more than 97% detection frequency, including tris(1,3-dichloroisopropyl)phosphate (TCIPP), tris(2-butoxyethyl)phosphate (TBOEP), triphenyl phosphate (TPHP), and tris(isobutyl) phosphate (TIBP). Total concentrations (∑OPFRs) ranged from 5.9 to 4800 μg/g, with TBOEP and TCIPP being the most abundant congeners. The ∑OPFRs in schools, private cars, offices, and daycare centers were significantly (P<.05) higher than in private homes. The ∑OPFRs for building material markets (19 μg/g) and floor/carpet stores (20 μg/g) showed no significant difference to the other microenvironments, likely because of forced ventilation. The profiles of OPFRs in dust samples from offices and private homes were highly similar, while profiles from the other five microenvironments were substantially different. Comparison of our results with previous studies indicates a significant global variation in OPFR concentrations and their profiles, reflecting distinct fire safety regulations in different countries and/or different sampling strategies. Dust ingestion constitutes the major exposure pathway to OPFRs for toddlers, while air inhalation is the major pathway for adults.
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Affiliation(s)
- L Zhou
- Department of Environmental Analytical Chemistry, Institute of Atmospheric and Environmental Sciences, J. W. Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - M Hiltscher
- Department of Environmental Analytical Chemistry, Institute of Atmospheric and Environmental Sciences, J. W. Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - W Püttmann
- Department of Environmental Analytical Chemistry, Institute of Atmospheric and Environmental Sciences, J. W. Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
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Ren G, Hu J, Shang Y, Zhong Y, Yu Z, An J. Tributylphosphate (TBP) and tris (2-butoxyethyl) phosphate (TBEP) induced apoptosis and cell cycle arrest in HepG2 cells. Toxicol Res (Camb) 2017; 6:902-911. [PMID: 30090552 DOI: 10.1039/c7tx00180k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 08/29/2017] [Indexed: 11/21/2022] Open
Abstract
The purpose of this study was to investigate the cytotoxic effects of tributylphosphate (TBP) and tris (2-butoxyethyl) phosphate (TBEP) and to explore the underlying molecular mechanism focusing on oxidative stress, apoptosis, and cell cycle arrest. The results showed that TBP and TBEP could inhibit cell proliferation, induce cellular reactive oxidative stress, and suppress the mitochondrial membrane potential in HepG2 cells. TBP and TBEP could induce both mitochondrial and p53 mediated apoptosis through different mitogen-activated protein kinase (MAPK) signal pathways. TBP activated the c-Jun N-terminal kinase (JNK) and extracellular regulated protein kinase (ERK1/2) pathways, while TBEP activated the JNK pathway. Furthermore, TBP and TBEP caused a concentration-dependent decrease of cyclin D1 expression and an increase of cyclin-dependent kinase (CDK) inhibitor proteins such as p21 and p27, resulting in significant cell cycle arrest in the G0/G1 phase. Taken together, the toxicity of TBP and TBEP on the HepG2 cells was associated with apoptosis and cell cycle arrest induced by oxidative stress.
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Affiliation(s)
- Guofa Ren
- Institute of Environmental Pollution and Health , School of Environmental and Chemical Engineering , Shanghai University , Shanghai 200444 , P. R. China . ; ; Tel: +86-021-66137736
| | - Jingwen Hu
- Institute of Environmental Pollution and Health , School of Environmental and Chemical Engineering , Shanghai University , Shanghai 200444 , P. R. China . ; ; Tel: +86-021-66137736
| | - Yu Shang
- Institute of Environmental Pollution and Health , School of Environmental and Chemical Engineering , Shanghai University , Shanghai 200444 , P. R. China . ; ; Tel: +86-021-66137736
| | - Yufang Zhong
- Institute of Environmental Pollution and Health , School of Environmental and Chemical Engineering , Shanghai University , Shanghai 200444 , P. R. China . ; ; Tel: +86-021-66137736
| | - Zhiqiang Yu
- State Key Laboratory of Organic Geochemistry , Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 510640 , P. R. China
| | - Jing An
- Institute of Environmental Pollution and Health , School of Environmental and Chemical Engineering , Shanghai University , Shanghai 200444 , P. R. China . ; ; Tel: +86-021-66137736
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72
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Zhang Q, Wang J, Zhu J, Liu J, Zhao M. Potential Glucocorticoid and Mineralocorticoid Effects of Nine Organophosphate Flame Retardants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:5803-5810. [PMID: 28430429 DOI: 10.1021/acs.est.7b01237] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Organophosphate flame retardants (OPFRs), as alternatives of polybrominated diphenyl ethers (PBDEs), have been frequently detected in the environment and biota, and could pose adverse effects on organisms. However, information on the potential endocrine disruption of OPFRs, especially their effects on steroid hormone receptors, such as glucocorticoid and mineralocorticoid receptors (GR/MR), is limited. In this study, the dual-luciferase reporter gene assay via GR/MR and a H295R steroidogenesis assay were employed to evaluate the endocrine disruption of nine OPFRs. We found TMPP, TPHP, and TDBPP exhibited both GR and MR antagonistic activities, while TNBP and TDCIPP only showed MR antagonistic property within a concentration range of 10-8 to 10-5 mol/L(M). In the H295R steroidogenesis assay, the fold changes of eight steroidogenic genes in response to OPFRs were further studied. We found CYP17,CYP21, and CYP11B1 expression were significantly down-regulated following TMPP, TPHP, or TDBPP exposure at a concentration of 2 × 10-6 M. Meanwhile TMPP decreased the production of cortisol and TDBPP down-regulated the secretion of aldosterone. Our results indicate that some OPFRs can interact with GR and MR, and have the potential to disturb steroidogenesis. Data provided here will be helpful to comprehensively understand the potential endocrine disruption of OPFRs.
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Affiliation(s)
- Quan Zhang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology , Hangzhou, Zhejiang 310032, China
- Department of Environmental Health, Harvard T.H. Chan School of Public Health , Landmark Center West, Boston, Massachusetts 02215, United States
| | - Jinghua Wang
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology , Hangzhou, Zhejiang 310032, China
| | - Jianqiang Zhu
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology , Hangzhou, Zhejiang 310032, China
| | - Jing Liu
- College of Environmental and Resource Sciences, Zhejiang University , Hangzhou 310058, China
| | - Meirong Zhao
- Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology , Hangzhou, Zhejiang 310032, China
- Department of Environmental Health, Harvard T.H. Chan School of Public Health , Landmark Center West, Boston, Massachusetts 02215, United States
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73
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Van den Eede N, Ballesteros-Gómez A, Neels H, Covaci A. Does Biotransformation of Aryl Phosphate Flame Retardants in Blood Cast a New Perspective on Their Debated Biomarkers? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:12439-12445. [PMID: 27766855 DOI: 10.1021/acs.est.6b03214] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Aryl phosphate flame retardants (aryl-PFRs), such as triphenyl phosphate (TPHP) and 2-ethylhexyl diphenyl phosphate (EHDPHP), are emerging contaminants that can exhibit toxic properties, including severe aquatic toxicity and endocrine disruptive effects. Monitoring exposure to aryl-PFRs through specific biomarkers is necessary to assess the health risk associated with chronic exposure. Hydrolytic serum enzymes could play an important role in the formation of the hydrolysis product diphenyl phosphate (DPHP), the seemingly most abundant in vivo biomarker of TPHP in urine. Here, we assess whether serum enzymes have an impact on the toxicokinetics of TPHP and EHDPHP and on the contribution of both aryl-PFRs to in vivo DPHP levels. TPHP and EHDPHP were incubated separately with pooled human serum to measure the formation of hydrolysis products DPHP and 2-ethylhexyl phenyl phosphate (EHPHP) by liquid chromatography-tandem mass spectrometry. Clearance of TPHP and EHDPHP was 70 and 8.6 mL/min/L serum (as measured by formation of DPHP and EHPHP, respectively). No discernible amount of DPHP was produced from EHDPHP by serum hydrolases. Our results suggest that serum hydrolases can significantly contribute to the in vivo levels of DPHP formed from TPHP and can play an important role in the toxicokinetics, toxicity, and selection of biomarkers for aryl-PFRs.
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Affiliation(s)
- Nele Van den Eede
- University of Antwerp, Toxicological Center , Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Ana Ballesteros-Gómez
- University of Antwerp, Toxicological Center , Universiteitsplein 1, 2610 Wilrijk, Belgium
- VU University Amsterdam, Institute for Environmental Studies , De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands
| | - Hugo Neels
- University of Antwerp, Toxicological Center , Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Adrian Covaci
- University of Antwerp, Toxicological Center , Universiteitsplein 1, 2610 Wilrijk, Belgium
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74
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Butt CM, Hoffman K, Chen A, Lorenzo A, Congleton J, Stapleton HM. Regional comparison of organophosphate flame retardant (PFR) urinary metabolites and tetrabromobenzoic acid (TBBA) in mother-toddler pairs from California and New Jersey. ENVIRONMENT INTERNATIONAL 2016; 94:627-634. [PMID: 27397928 PMCID: PMC4980246 DOI: 10.1016/j.envint.2016.06.029] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 06/17/2016] [Accepted: 06/23/2016] [Indexed: 05/19/2023]
Abstract
The use of alternative chemical flame retardants in consumer products is increasing as the result of the phase-out of polybrominated diphenyl ethers. Today, the most commonly detected alternatives in residential furniture include the organophosphate flame retardants (PFRs) and the Firemaster (R) 550 mixture (FM550). Urinary levels of dialkyl and diaryl phosphate esters, and 2-ethylhexyl tetrabromobenzoate (EH-TBB) have been used as biomarkers of human exposure to PFRs and FM550, respectively. In a previous study, we demonstrated that toddlers had significantly higher levels of PFRs relative to their mothers in a cohort from New Jersey; however, it is unclear if there are regional differences in exposure. It is possible that exposure to PFRs may be higher in California relative to other US States due to the California flammability standard, as was seen previously observed for PBDEs. In the current study, we examined urinary levels of PFR metabolites and TBBA in 28 mother-child pairs from California, USA, collected in 2015, and compared them with levels measured in our previous study from New Jersey. Urine samples were extracted using solid-phase extraction and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Diphenyl phosphate (DPHP), isopropyl-phenyl phenyl phosphate (ip-PPP), bis(1,3-dichloro-2propyl) phosphate (BDCIPP) and BCIPHIPP conjugates were detected in 100% of mother and child urine samples, while bis(1-chloro-2-propyl) phosphate (BCIPP), tert-butyl-phenyl phenyl phosphate (tb-PPP) and TBBA were detected in < 50% of samples. Interestingly, BCIPHIPP conjugates were detected in 100% of the urine samples, suggesting ubiquitous exposure to the parent compound, tris(1-chloro-2-propyl) phosphate (TCIPP). The current study found significantly higher BDCIPP levels in California toddlers and higher and ip-PPP levels in mothers as compared to the New Jersey cohort, which may be reflective of California's furniture flammability standard. For example, BDCIPP levels in California children were 2.4 times higher than those in New Jersey children. Consistent with our previous work, the current study showed higher PFR and EH-TBB exposure in children, likely due to increased hand-mouth behavior. Children's DPHP and BDCIPP levels, on average, were 5.9 times and 15 times those of their mothers. Positive correlations between paired mothers and their children were shown for DPHP and BCIPHIPP conjugates but not BDCIPP or ip-PPP. In the children, several predictors of hand-mouth behavior were associated with BDCIPP, DPHP and ip-PPP urine levels, but no associations were observed with BCIPHIPP conjugates.
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Affiliation(s)
- Craig M Butt
- Nicholas School of the Environment, Duke University, Durham, NC 27708, United States
| | - Kate Hoffman
- Nicholas School of the Environment, Duke University, Durham, NC 27708, United States
| | - Albert Chen
- Nicholas School of the Environment, Duke University, Durham, NC 27708, United States
| | - Amelia Lorenzo
- Nicholas School of the Environment, Duke University, Durham, NC 27708, United States
| | | | - Heather M Stapleton
- Nicholas School of the Environment, Duke University, Durham, NC 27708, United States.
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75
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Gramec Skledar D, Tomašič T, Carino A, Distrutti E, Fiorucci S, Peterlin Mašič L. New brominated flame retardants and their metabolites as activators of the pregnane X receptor. Toxicol Lett 2016; 259:116-123. [DOI: 10.1016/j.toxlet.2016.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/01/2016] [Accepted: 08/05/2016] [Indexed: 01/30/2023]
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76
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Su G, Letcher RJ, Yu H. Organophosphate Flame Retardants and Plasticizers in Aqueous Solution: pH-Dependent Hydrolysis, Kinetics, and Pathways. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8103-11. [PMID: 27347783 DOI: 10.1021/acs.est.6b02187] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Despite the growing ubiquity of organophosphate (OP) triesters as environmental contaminants, parameters affecting their aquatic chemical stabilities are currently unknown. The present study examined the pH-dependent (7, 9, 11, or 13) hydrolysis of 16 OP triesters in mixtures of 80 ng/mL for each OP triester over a period of 35 days at 20 °C. For the pH = 7, 9, and 11 solutions, 10 of the 16 OP triesters were stable and with no significant (p > 0.05) degradation. For the remaining 6 OP triesters, significant degradation occurred progressing from the pH = 7 to 11 solutions. At pH = 13, except for tributyl phosphate and tris(2-ethylhexyl) phosphate, 14 OP triesters were degraded with half-lives ranging from 0.0053 days (triphenyl phosphate) to 47 days (tripropyl phosphate). With increasingly basic pH the order of OP triester stability was group A (with alkyl moieties) > group B (chlorinated alkyl) > group C (aryl). Numerous OP diesters were identified depending on the pH level of the solution, whereas OP monoesters were not detectable. This is consistent with no significant (p > 0.05) depletion observed for 5 OP diesters in the same 4 solutions and over same 35 day period, suggesting OP diesters are end products of base-catalyzed hydrolysis of OP triesters. Our results demonstrated that pH-dependent hydrolysis of OP triesters does occur, and such instability would likely affect the fate of OP triesters in aqueous environments where the pH can be variable and basic.
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Affiliation(s)
- Guanyong Su
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Hongxia Yu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210023, China
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77
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Su G, Greaves AK, Teclechiel D, Letcher RJ. In Vitro Metabolism of Photolytic Breakdown Products of Tetradecabromo-1,4-diphenoxybenzene Flame Retardant in Herring Gull and Rat Liver Microsomal Assays. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:8335-8343. [PMID: 27351066 DOI: 10.1021/acs.est.6b02172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Tetradecabromo-1,4-diphenoxybenzene (TeDB-DiPhOBz) is used as a flame retardant chemical and has been hypothesized to be the precursor of methoxylated polybrominated diphenoxybenzene (MeO-PB-DiPhOBz) contaminants reported in herring gulls from sites across the Laurentian Great Lakes. Here, by irradiating the parent TeDB-DiPhOBz (solution 1) with natural sunlight or UV, we prepared three solutions where solution 2 was dominated by the Br8-11-PB-DiPhOBzs, along with Br5-8-PB-DiPhOBzs (solution 3) and Br4-6-PB-DiPhOBzs (solution 4). The in vitro metabolism of TeDB-DiPhOBz and PB-DiPhOBzs was investigated using harvested wild herring gull (Larus argentatus) and adult male Wister-Han rat liver microsomal assays. After a 90 min incubation period of solution 1 in gull or rat microsomal assays, there was no significant (p > 0.05) depletion of TeDB-DiPhOBz. OH-PB-DiPhOBz metabolites were detectable after gull and rat microsomal assay incubation with solutions 3 or 4, and showed clear species-specific differences. Also detected were two polybrominated hydroxylated metabolites having polybenzofuran structures. Overall, this study suggested that TeDB-DiPhOBz is slowly metabolized in vitro, and also indicated that if wild herring gulls are exposed (e.g., via the diet) to photolytic products of TeDB-DiPhOBz, OH-PB-DiPhOBz and other metabolites could be formed. OH-PH-DiPhOBz are likely precursors to MeO-PB-DiPhOBz contaminants that we reported previously in eggs of wild Great Lakes herring gulls.
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Affiliation(s)
- Guanyong Su
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Alana K Greaves
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
| | - Daniel Teclechiel
- AccuStandard , 125 Market Street, New Haven, Connecticut 06513, United States
| | - Robert J Letcher
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University , Ottawa, Ontario K1A 0H3, Canada
- Department of Chemistry, Carleton University , Ottawa, Ontario K1S 5B6, Canada
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78
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Krivoshiev BV, Dardenne F, Covaci A, Blust R, Husson SJ. Assessing in-vitro estrogenic effects of currently-used flame retardants. Toxicol In Vitro 2016; 33:153-62. [DOI: 10.1016/j.tiv.2016.03.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 03/07/2016] [Accepted: 03/11/2016] [Indexed: 01/16/2023]
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