1
|
Zhang CY, Li X, Keil Stietz KP, Sethi S, Yang W, Marek RF, Ding X, Lein PJ, Hornbuckle KC, Lehmler HJ. Machine Learning-Assisted Identification and Quantification of Hydroxylated Metabolites of Polychlorinated Biphenyls in Animal Samples. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13169-13178. [PMID: 36047920 PMCID: PMC9573770 DOI: 10.1021/acs.est.2c02027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 06/02/2023]
Abstract
Laboratory studies of the disposition and toxicity of hydroxylated polychlorinated biphenyl (OH-PCB) metabolites are challenging because authentic analytical standards for most unknown OH-PCBs are not available. To assist with the characterization of these OH-PCBs (as methylated derivatives), we developed machine learning-based models with multiple linear regression (MLR) or random forest regression (RFR) to predict the relative retention times (RRT) and MS/MS responses of methoxylated (MeO-)PCBs on a gas chromatograph-tandem mass spectrometry system. The final MLR model estimated the retention times of MeO-PCBs with a mean absolute error of 0.55 min (n = 121). The similarity coefficients cos θ between the predicted (by RFR model) and experimental MS/MS data of MeO-PCBs were >0.95 for 92% of observations (n = 96). The levels of MeO-PCBs quantified with the predicted MS/MS response factors approximated the experimental values within a 2-fold difference for 85% of observations and 3-fold differences for all observations (n = 89). Subsequently, these model predictions were used to assist with the identification of OH-PCB 95 or OH-PCB 28 metabolites in mouse feces or liver by suggesting candidate ranking information for identifying the metabolite isomers. Thus, predicted retention and MS/MS response data can assist in identifying unknown OH-PCBs.
Collapse
Affiliation(s)
- Chun-Yun Zhang
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Xueshu Li
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Kimberly P. Keil Stietz
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, United States
| | - Sunjay Sethi
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, United States
| | - Weizhu Yang
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Rachel F. Marek
- Department
of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Xinxin Ding
- Department
of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, United States
| | - Pamela J. Lein
- Department
of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, United States
| | - Keri C. Hornbuckle
- Department
of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Department
of Occupational and Environmental Health, The University of Iowa, Iowa City, Iowa 52242, United States
| |
Collapse
|
2
|
Martinez A, Awad AM, Jones MP, Hornbuckle KC. Intracity occurrence and distribution of airborne PCB congeners in Chicago. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 812:151505. [PMID: 34762940 PMCID: PMC8810667 DOI: 10.1016/j.scitotenv.2021.151505] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 06/03/2023]
Abstract
To evaluate the magnitude and extent of airborne PCBs in an urban area, we measured and investigated the temporal and spatial behavior of atmospheric concentrations of individual polychlorinated biphenyl (PCB) congeners as well as the sum of all congeners (ΣPCB) in both gas and particle phases at 27 locations across the City of Chicago in a single year (2009). In total, 141 gas-phase air samples were collected, including 22 pairs (44 samples) deployed at the same time but at two different locations, and 46 particle-phase samples. ΣPCB in the gas-phase ranged from 80 to 3000 pg/m3, with a geometric mean (GM) of 530 pg/m3, whereas particle-phase ranged from 8 to 160 pg/m3, with a GM of 28 pg/m3. We found the temporal variability to be about three times larger than the variability over space for all gas-phase congeners and ΣPCB. Around 50% of the sample PCB profiles resembled a mixture of a 1:1 vapor Aroclor mixture of 1016 + 1254, with most of the rest (30%) showing enrichment of PCB 3 (>0.1), which did not match any Aroclor profiles. PCB 11 contributed to ~5% in all samples. The fractions of PCB congeners bound to particles ranged from 0.001 to 0.97. Our analysis shows that airborne PCBs are widely distributed across Chicago and confirms that most locations have a similar PCB distribution, but differ in the concentration levels. Volatilization continues to be the main release process of PCBs into the atmosphere, including both Aroclor and non-Aroclor congeners.
Collapse
Affiliation(s)
- Andres Martinez
- Department of Civil & Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA.
| | - Andrew M Awad
- Department of Civil & Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA
| | - Michael P Jones
- Department of Biostatistics, The University of Iowa, Iowa City, IA 52242, USA
| | - Keri C Hornbuckle
- Department of Civil & Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA
| |
Collapse
|
3
|
Saktrakulkla P, Li X, Martinez A, Lehmler HJ, Hornbuckle KC. Hydroxylated Polychlorinated Biphenyls Are Emerging Legacy Pollutants in Contaminated Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:2269-2278. [PMID: 35107261 PMCID: PMC8851693 DOI: 10.1021/acs.est.1c04780] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 05/04/2023]
Abstract
We measured the concentrations of 837 hydroxylated polychlorinated biphenyls (OH-PCBs, in 275 chromatographic peaks) and 209 polychlorinated biphenyls (PCBs, in 174 chromatographic peaks) in sediments from New Bedford Harbor in Massachusetts, Altavista wastewater lagoon in Virginia, and the Indiana Harbor and Ship Canal in Indiana, USA and in the original commercial PCB mixtures Aroclors 1016, 1242, 1248, and 1254. We used the correlation between homologues and the peak responses to quantify the full suite of OH-PCBs including those without authentic standards available. We found that OH-PCB levels are approximately 0.4% of the PCB levels in sediments and less than 0.0025% in Aroclors. The OH-PCB congener distributions of sediments are different from those of Aroclors and are different according to sites. We also identified a previously unknown compound, 4-OH-PCB52, which together with 4'-OH-PCB18 made up almost 30% of the OH-PCBs in New Bedford Harbor sediments but less than 1.2% in the Aroclors and 3.3% in any other sediments. This indicates site-specific environmental transformations of PCBs to OH-PCBs. We conclude that the majority of OH-PCBs in these sediments are generated in the environment. Our findings suggest that these toxic breakdown products of PCBs are prevalent in PCB-contaminated sediments and present an emerging concern for humans and ecosystems.
Collapse
Affiliation(s)
- Panithi Saktrakulkla
- Interdisciplinary
Graduate Program in Human Toxicology, The
University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Xueshu Li
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Andres Martinez
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Hans-Joachim Lehmler
- Interdisciplinary
Graduate Program in Human Toxicology, The
University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Keri C. Hornbuckle
- Interdisciplinary
Graduate Program in Human Toxicology, The
University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| |
Collapse
|
4
|
Li Y, Bako CM, Saktrakulkla P, Lehmler HJ, Hornbuckle KC, Schnoor JL. Interconversion between methoxylated, hydroxylated and sulfated metabolites of PCB 3 in whole poplar plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 785:147341. [PMID: 33933776 PMCID: PMC8610232 DOI: 10.1016/j.scitotenv.2021.147341] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/20/2021] [Accepted: 04/20/2021] [Indexed: 05/21/2023]
Abstract
Methoxylated polychlorinated biphenyls (MeO-PCBs) are overlooked metabolites of PCBs. In general, they are more toxic to plants than their parent congeners. However, information on the fate of MeO-PCBs and the relationship between methoxylated, hydroxylated and sulfated metabolites of PCBs in plants is scarce. In this work, poplar plants (Populus deltoides × nigra, DN34) were hydroponically and separately exposed to 4'-methoxy-4-monochlorobiphenyl (4'-MeO-PCB 3) and 4'-PCB 3 sulfate for 10 days to investigate the uptake, translocation and metabolism of MeO-PCBs and the relationship between methoxy-PCBs, hydroxyl-PCBs and PCB sulfates within plants. Results showed that 4'-MeO-PCB 3 and 4'-PCB 3 sulfate were taken up by the roots of poplar plants and translocated from roots to shoots and leaves. 4'-OH-PCB 3 and 4'-PCB 3 sulfate were identified as the hydroxylated metabolite and sulfate metabolite of 4'-MeO-PCB 3 in poplar, respectively. In the backward reaction, 4'-OH-PCB 3 and 4'-MeO-PCB 3 were found as metabolites of 4'-PCB 3 sulfate. For exposure groups, the yields of 4'-OH-PCB 3 produced from 4'-MeO-PCB 3 and 4'-PCB 3 sulfate were 1.29% and 0.13% respectively. The yield of 4'-PCB 3 sulfate which originated from 4'-MeO-PCB 3 in wood and root samples of exposure groups was only 0.02%. Only 0.04% of the initial mass of 4'-PCB 3 sulfate was transformed to 4'-MeO-PCB 3 in the exposure groups. The sulfation yield of 4'-OH-PCB 3 was higher than hydrolysis yield of 4'-PCB 3 sulfate, indicating that formation of PCB sulfates was predominant over the reverse reaction, the formation of hydroxy-PCBs. These results provide new perspective on the transport, metabolism, and fate of MeO-PCBs, and also help to better understand sources of OH-PCBs and PCB sulfates in the environment. This study provides the first evidence of interconversion of sulfate metabolites from methoxy-PCBs and methoxy-PCBs from PCB sulfates.
Collapse
Affiliation(s)
- Yanlin Li
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242, United States.
| | - Christian M Bako
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242, United States
| | - Panithi Saktrakulkla
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242, United States
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA 52242, United States
| | - Keri C Hornbuckle
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242, United States
| | - Jerald L Schnoor
- Department of Civil and Environmental Engineering and IIHR Hydroscience and Engineering, The University of Iowa, Iowa City, IA 52242, United States
| |
Collapse
|
5
|
Wang F, Qiu Y, Zhou B. In silico exploration of hydroxylated polychlorinated biphenyls as estrogen receptor β ligands by 3D-QSAR, molecular docking and molecular dynamics simulations. J Biomol Struct Dyn 2021; 40:6798-6809. [PMID: 33645467 DOI: 10.1080/07391102.2021.1890220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Hydroxylated polychlorinated biphenyls (HO-PCBs), as the major metabolites of PCBs, have been reported to act as estrogen receptor β (ERβ) agonists. However, the chemical-biological interactions governing their activities toward ERβ have not been elucidated. Therefore, three dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations, to the best of our knowledge, for the first time were performed to explore the correlation between the structures and activities. The best 3D-QSAR model presented higher predictive ability (R2cv=0.543, R2pred=0.5793/R2cv=0.543, R2pred=0.6795) based on comparative molecular field analysis (CoMFA) and comparative similarity indices analysis (CoMSIA), respectively. At the same time, the derived contour maps indicated the important structural features required for improving the activity. Furthermore, molecular docking studies and MD simulations predicted the binding mode and the interactions between the ligand and the receptor. All the results would lead to a better understanding of the specific mechanism of HO-PCBs on estrogen receptor β (ERβ).Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Fangfang Wang
- School of Life Science, Linyi University, Linyi, China
| | - Yingchao Qiu
- School of Life Science, Linyi University, Linyi, China
| | - Bo Zhou
- State Key Laboratory of Functions and Applications of Medicinal Plants, College of Basic Medical, Guizhou Medical University, Guizhou, China
| |
Collapse
|
6
|
Zehra A, Alshemmari H, Kavil YN, Majid Khan A, Zaffar Hashmi M. Effects of PCB70 and PCB75 on HeLa cell proliferation, membrane integrity and cell signaling pathway. ARAB J CHEM 2021. [DOI: 10.1016/j.arabjc.2020.102985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
7
|
Bako CM, Mattes TE, Marek RF, Hornbuckle KC, Schnoor JL. Biodegradation of PCB congeners by Paraburkholderia xenovorans LB400 in presence and absence of sediment during lab bioreactor experiments. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 271:116364. [PMID: 33412450 PMCID: PMC8183161 DOI: 10.1016/j.envpol.2020.116364] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 12/04/2020] [Accepted: 12/19/2020] [Indexed: 05/21/2023]
Abstract
Experiments were conducted to measure biodegradation of polychlorinated biphenyl (PCB) congeners contained in mixture Aroclor 1248 and congeners present in wastewater lagoon sediment contaminated decades earlier at Altavista, Virginia. A well-characterized strain of aerobic PCB-degrading bacteria, Paraburkholderia xenovorans LB400 was incubated in laboratory bioreactors with PCB-contaminated sediment collected at the site. The experiments evaluated strain LB400's ability to degrade PCBs in absence of sediment and in PCB-contaminated sediment slurry. In absence of sediment, LB400 transformed 76% of Aroclor 1248 within seven days, spanning all homolog groups present in the mixture. In sediment slurry, only mono- and di-chlorinated PCB congeners were transformed. These results show that LB400 is capable of rapidly biodegrading most PCB congeners when they are freely dissolved in liquid but cannot degrade PCB congeners having three or more chlorine substituents in sediment slurry. Finally, using GC/MS-MS triple quadrupole spectrometry, this work distinguishes between physical (sorption to cells) and biological removal mechanisms, illuminates the process by which microorganisms with LB400-type congener specificity can selectively transform lower-chlorinated congeners over time, and makes direct comparisons to other studies where individual congener data is reported.
Collapse
Affiliation(s)
- Christian M Bako
- The Department of Civil & Environmental Engineering, 4105 Seamans Center for the Engineering Arts & Sciences, University of Iowa, Iowa City, IA, USA, 52245
| | - Timothy E Mattes
- The Department of Civil & Environmental Engineering, 4105 Seamans Center for the Engineering Arts & Sciences, University of Iowa, Iowa City, IA, USA, 52245
| | - Rachel F Marek
- The Department of Civil & Environmental Engineering, 4105 Seamans Center for the Engineering Arts & Sciences, University of Iowa, Iowa City, IA, USA, 52245
| | - Keri C Hornbuckle
- The Department of Civil & Environmental Engineering, 4105 Seamans Center for the Engineering Arts & Sciences, University of Iowa, Iowa City, IA, USA, 52245
| | - Jerald L Schnoor
- The Department of Civil & Environmental Engineering, 4105 Seamans Center for the Engineering Arts & Sciences, University of Iowa, Iowa City, IA, USA, 52245.
| |
Collapse
|
8
|
Alikord M, Mohammadi A, Kamankesh M, Shariatifar N. Food safety and quality assessment: comprehensive review and recent trends in the applications of ion mobility spectrometry (IMS). Crit Rev Food Sci Nutr 2021; 62:4833-4866. [PMID: 33554631 DOI: 10.1080/10408398.2021.1879003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ion mobility spectrometry (IMS) is an analytical separation and diagnostic technique that is simple and sensitive and a rapid response and low-priced technique for detecting trace levels of chemical compounds in different matrices. Chemical agents and environmental contaminants are successfully detected by IMS and have been recently considered to employ in food safety. In addition, IMS uses stand-alone or coupled analytical diagnostic tools with chromatographic and spectroscopic methods. Scientific publications show that IMS has been applied 21% in the pharmaceutical industry, 9% in environmental studies and 13% in quality control and food safety. Nevertheless, applications of IMS in food safety and quality analysis have not been adequately explored. This review presents the IMS-related analysis and focuses on the application of IMS in food safety and quality. This review presents the important topics including detection of traces of chemicals, rate of food spoilage and freshness, food adulteration and authenticity as well as natural toxins, pesticides, herbicides, fungicides, veterinary, and growth promoter drug residues. Further, persistent organic pollutants (POPs), acrylamide, polycyclic aromatic hydrocarbon (PAH), biogenic amines, nitrosamine, furfural, phenolic compounds, heavy metals, food packaging materials, melamine, and food additives were also examined for the first time. Therefore, it is logical to predict that the application of the IMS technique in food safety, food quality, and contaminant analysis will be impressively increased in the future. HighlightsCurrent status of IMS for residues and contaminant detection in food safety.To assess all the detected contaminants in food safety, for the first time.Identified IMS-related parameters and chemical compounds in food safety control.
Collapse
Affiliation(s)
- Mahsa Alikord
- Department of Environmental Health, Food Safety Division, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Abdorreza Mohammadi
- Department of Food Science and Technology, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Marzieh Kamankesh
- Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Nabi Shariatifar
- Department of Environmental Health, Food Safety Division, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.,Halal Research Center of the Islamic Republic of Iran, Tehran, Iran
| |
Collapse
|
9
|
White-Rot Fungi for Bioremediation of Polychlorinated Biphenyl Contaminated Soil. Fungal Biol 2021. [DOI: 10.1007/978-3-030-68260-6_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
10
|
McCarthy RA, Gupta AS, Kubicek B, Awad AM, Martinez A, Marek RF, Hornbuckle KC. Signal Processing Methods to Interpret Polychlorinated Biphenyls in Airborne Samples. IEEE ACCESS : PRACTICAL INNOVATIONS, OPEN SOLUTIONS 2020; 8:147738-147755. [PMID: 33335823 PMCID: PMC7742762 DOI: 10.1109/access.2020.3013108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The main contribution of this interdisciplinary work is a robust computational framework to autonomously discover and quantify previously unknown associations between well-known (target) and potentially unknown (non-target) toxic industrial air pollutants. In this work, the variability of polychlorinated biphenyl (PCB) data is evaluated using a combination of statistical, signal processing, and graph-based informatics techniques to interpret the raw instrument signal from gas chromatography-mass spectrometry (GC/MS/MS) data sets. Specifically, minimum mean-squared techniques from the adaptive signal processing literature are extended to detect and separate coeluted (overlapped) peaks in the raw instrument signal. A graph-based visualization is provided which bridges two complementary approaches to quantitative pollution studies: (i) peak-cognizant target analysis (limits data analysis to few well-known compounds) and (ii) chemometric analysis (statistical large-scale data analysis) that is agnostic of specific compounds. Further, peak fitting techniques based on L2 error minimization are employed to autonomously calculate the amount of each PCB present with a normalized mean square error of -18.4851 dB. Graph-based visualization of associations between known and unknown compounds are developed through principal component analysis and both fuzzy c-means (FCM) and k-means clustering techniques are implemented and compared. The efficiency of these methods are compared using 150 air samples analyzed for individual PCBs with GC/MS/MS against traditional target-only techniques that perform analysis across only the known (target) PCBs. Parameter optimization techniques are employed to evaluate the relative contribution of PCB signals against ten potential source signals representing legacy signatures from historical manufacture of Aroclors and modern sources of PCBs produced as by products of pigment and polymer manufacturing. Aroclors 1232, 1254, 1016, and 1221 as well as non-Aroclor 3, 3', dichlorobiphenyl (PCB 11) were found in many of the samples as unique source signals that describe PCB mixtures in air samples collected from Chicago, IL.
Collapse
Affiliation(s)
- Ryan A McCarthy
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242 USA
| | - Ananya Sen Gupta
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242 USA
| | - Bernice Kubicek
- Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242 USA
| | - Andrew M Awad
- Department of Civil and Environmental Engineering and IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242 USA
| | - Andres Martinez
- Department of Civil and Environmental Engineering and IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242 USA
| | - Rachel F Marek
- Department of Civil and Environmental Engineering and IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242 USA
| | - Keri C Hornbuckle
- Department of Civil and Environmental Engineering and IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242 USA
| |
Collapse
|
11
|
Boesen AC, Martinez A, Hornbuckle KC. Air-water PCB fluxes from southwestern Lake Michigan revisited. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:8826-8834. [PMID: 31062242 PMCID: PMC6834886 DOI: 10.1007/s11356-019-05159-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 04/10/2019] [Indexed: 06/03/2023]
Abstract
From simultaneous air and water polychlorinated biphenyl (PCB) measurements collected in September 2010, we re-evaluated the direction and magnitude of net air-water exchange of PCBs in southwest Lake Michigan and compared them with estimations made using similar approaches 15 years prior. Air and water samples were collected during a research expedition on Lake Michigan at 5 km off the coast of Chicago, with prevailing winds from the southwest of our location. Gas-phase ΣPCB concentrations ranged from 190 to 1100 pg m-3 with a median of 770 pg m-3, which is similar to the concentrations measured in the City of Chicago at the same time and similar to concentrations measured in this part of the lake over the last 20 years. Water dissolved-phase ΣPCB concentrations ranged from 150 to 170 pg L-1 with a median of 160 pg L-1, which is one-tenth of that measured in the 1990s. ƩPCB net fluxes showed a slightly absorptive behavior, with a median of (-) 21 ng m-2 day-1 and an interquartile range of (-) 47 to (+) 5 ng m-2 day-1, where (-) and (+) fluxes indicate absorption and volatilization, respectively. Airborne PCB concentrations were higher when the winds were coming from Chicago and drive the deposition. Our fluxes are not significantly different from estimations from 1994 and 1995 and suggest that absorption of PCBs into the waters is slightly more prevalent than 15 years ago. It was confirmed that Chicago remains an important atmospheric source of PCBs to Lake Michigan.
Collapse
Affiliation(s)
- Aaron C Boesen
- Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA
| | - Andres Martinez
- Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA.
| | - Keri C Hornbuckle
- Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, USA
| |
Collapse
|
12
|
Saktrakulkla P, Dhakal RC, Lehmler HJ, Hornbuckle KC. A semi-target analytical method for quantification of OH-PCBs in environmental samples. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020. [PMID: 31359319 DOI: 10.25820/036e-b439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Hydroxylated polychlorinated biphenyls (OH-PCBs) are oxidative metabolites of PCBs and residuals found in original Aroclors. OH-PCBs are known to play a role as genotoxicants, carcinogens, and hormone disruptors, and therefore it is important to quantify their presence in human tissues, organisms, and environmental matrices. Of 837 possible mono-OH-PCBs congeners, there are only ~ 70 methoxylated PCB (MeO-PCB) standards commercially available. Hence, a semi-target analytical method is needed for unknown OH-PCBs. The mass concentrations of these unknowns are sometimes determined by assuming the peak responses of other available compounds. This can bias the results due to the choices and availabilities of standards. To overcome this issue, we investigated the peak responses of all commercially available MeO-PCB standards with gas chromatography (GC) coupling with triple quadrupole (QqQ) mass spectrometry (MS) system, with positive electron impact (EI) ionization at 20-70 eV in selected ion monitoring (SIM) mode. We found correlations between the relative peak responses (RRFs) and the number of chlorine (#Cl) in the molecules of MeO-PCBs. Among the studied models, the quadratic regression of #Cl is the most suitable model in the RRF prediction (RRF = β1 × #Cl^2 + β0) when the peak responses are captured at 30 eV. We evaluated the performance of the model by analyzing 12 synthesized MeO-PCB standards and a PCB-contaminated sediment collected from a wastewater lagoon. We further demonstrate the utility of the model using a different chromatography column and GC-EI-MS system. We found the method and associated model to be sufficiently simple, accurate, and versatile for use in quantifying OH-PCBs in complex environmental samples.
Collapse
Affiliation(s)
- Panithi Saktrakulkla
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA
| | - Ram C Dhakal
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Keri C Hornbuckle
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA.
| |
Collapse
|
13
|
Saktrakulkla P, Dhakal RC, Lehmler HJ, Hornbuckle KC. A semi-target analytical method for quantification of OH-PCBs in environmental samples. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:8859-8871. [PMID: 31359319 PMCID: PMC6986979 DOI: 10.1007/s11356-019-05775-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 06/17/2019] [Indexed: 04/16/2023]
Abstract
Hydroxylated polychlorinated biphenyls (OH-PCBs) are oxidative metabolites of PCBs and residuals found in original Aroclors. OH-PCBs are known to play a role as genotoxicants, carcinogens, and hormone disruptors, and therefore it is important to quantify their presence in human tissues, organisms, and environmental matrices. Of 837 possible mono-OH-PCBs congeners, there are only ~ 70 methoxylated PCB (MeO-PCB) standards commercially available. Hence, a semi-target analytical method is needed for unknown OH-PCBs. The mass concentrations of these unknowns are sometimes determined by assuming the peak responses of other available compounds. This can bias the results due to the choices and availabilities of standards. To overcome this issue, we investigated the peak responses of all commercially available MeO-PCB standards with gas chromatography (GC) coupling with triple quadrupole (QqQ) mass spectrometry (MS) system, with positive electron impact (EI) ionization at 20-70 eV in selected ion monitoring (SIM) mode. We found correlations between the relative peak responses (RRFs) and the number of chlorine (#Cl) in the molecules of MeO-PCBs. Among the studied models, the quadratic regression of #Cl is the most suitable model in the RRF prediction (RRF = β1 × #Cl^2 + β0) when the peak responses are captured at 30 eV. We evaluated the performance of the model by analyzing 12 synthesized MeO-PCB standards and a PCB-contaminated sediment collected from a wastewater lagoon. We further demonstrate the utility of the model using a different chromatography column and GC-EI-MS system. We found the method and associated model to be sufficiently simple, accurate, and versatile for use in quantifying OH-PCBs in complex environmental samples.
Collapse
Affiliation(s)
- Panithi Saktrakulkla
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA
| | - Ram C Dhakal
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Keri C Hornbuckle
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA.
| |
Collapse
|
14
|
Liao Z, Zeng M, Wang L. Atmospheric oxidation mechansim of polychlorinated biphenyls (PCBs) initiated by OH radicals. CHEMOSPHERE 2020; 240:124756. [PMID: 31563106 DOI: 10.1016/j.chemosphere.2019.124756] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 09/03/2019] [Accepted: 09/03/2019] [Indexed: 05/16/2023]
Abstract
Long-range atmospheric transport (LRAT) is the main route for circulating polychlorinated biphenyls (PCBs) from sources to sinks. In the atmosphere, PCBs containing six and less chlorine substitutions exist mainly as vapour, which can be oxidized by OH radical. Here, using quantum chemistry and transition state theory, we calculated the rate coefficients for reactions of OH radical with selected PCBs. The predicted rate coefficients agree with the available experimental values within a factor of 3. Calculations show that all PCBs considered here are persistent with their half-lives longer than 24 h. Reactions of PCBs with OH radical start with OH addition to the phenyl rings, forming PCB-n-OH adducts. Fate of biphenyl-n-OH (BP-n-OH, n = 2, 3, 4) adducts in the atmosphere is investigated. Calculations show that these radical adducts react similarly to benzene-OH adducts, forming hydroxybiphenyl (HO-BP) as main product and bicyclic radicals as minor products in their reaction with O2. Effective rates of reaction with O2 in the atmosphere are relatively slow, ∼1400, ∼45000, and ∼800 s-1 for BP-2-OH, BP-3-OH, and BP-4-OH, respectively. This suggests considerable reactions between BP-n-OH adducts and NO2, forming nitrobiphenyls. The bicyclic radicals from BP-n-OH + O2 would further transform to highly oxidized products as observed in a previous study. PCB-OH adducts react similarly as BP-n-OH radicals. For the three PCB-OH radicals considered here, their reactions with O2 also form HO-PCBs and bicyclic radicals.
Collapse
Affiliation(s)
- Zhihong Liao
- School of Chemistry & Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Min Zeng
- School of Chemistry & Chemical Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Liming Wang
- School of Chemistry & Chemical Engineering, South China University of Technology, Guangzhou, 510640, China; Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou, 510006, China.
| |
Collapse
|
15
|
Cai Y, Rosen Vollmar AK, Johnson CH. Analyzing Metabolomics Data for Environmental Health and Exposome Research. Methods Mol Biol 2020; 2104:447-467. [PMID: 31953830 DOI: 10.1007/978-1-0716-0239-3_22] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The exposome is the cumulative measure of environmental influences and associated biological responses across the life span, with critical relevance for understanding how exposures can impact human health. Metabolomics analysis of biological samples offers unique advantages for examining the exposome. Simultaneous analysis of external exposures, biological responses, and host susceptibility at a systems level can help establish links between external exposures and health outcomes. As metabolomics technologies continue to evolve for the study of the exposome, metabolomics ultimately will help provide valuable insights for exposure risk assessment, and disease prevention and management. Here, we discuss recent advances in metabolomics, and describe data processing protocols that can enable analysis of the exposome. This chapter focuses on using liquid chromatography-mass spectrometry (LC-MS)-based untargeted metabolomics for analysis of the exposome, including (1) preprocessing of untargeted metabolomics data, (2) identification of exposure chemicals and their metabolites, and (3) methods to establish associations between exposures and diseases.
Collapse
Affiliation(s)
- Yuping Cai
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Ana K Rosen Vollmar
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Caroline Helen Johnson
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, USA.
| |
Collapse
|
16
|
Subramanian S, Tehrani R, Van Aken B. Transcriptomic response of Arabidopsis thaliana exposed to hydroxylated polychlorinated biphenyls (OH-PCBs). INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2019; 21:52-59. [PMID: 30648423 PMCID: PMC6548195 DOI: 10.1080/15226514.2018.1523872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hydroxylated polychlorinated biphenyls (OH-PCBs) are toxic contaminants produced by biotic or abiotic transformation of PCBs. In this study, we have tested the toxicity of 2,5-dichlorobiphenyl (2,5-DCB) and three of its OH-derivatives, 2'-OH-, 3'-OH-, and 4'-OH-2,5-DCB toward the model plant, Arabidopsis thaliana. Toxicity tests showed that the parent 2,5-DCB (5 mg L-1) had little effect on the plants, while all three OH-metabolites (5 mg L-1) exhibited a significant toxicity, with 4'-OH-2,5-DCB being the most potent (inhibition concentration 50%-IC50 in germination tests = 9.8 mg L-1 for 2'-OH-2,5-DCB, 9.5 mg L-1 for 3'-OH-2,5-DCB, and 4.8 mg L-1 for 4'-OH-2,5-DCB). Whole-genome expression microarrays (Affymetrix) showed that exposure to the three OH-PCBs resulted in rather similar expression patterns, which were distinct from the one developing in response to 2,5-DCB. Searching an Arabidopsis microarray database (Genevestigator) revealed that, unlike the parent compound, the three OH-derivatives induced expression profiles similar to inhibitors of brassinosteroid synthesis (i.e., brassinazole, propiconazole, and uniconazole), resulting in severe iron deficiency in exposed plants. Our results suggest that the higher phytotoxicity of OH-derivatives as compared to 2,5-DCB is at least partly explained by the inhibition of the brassinosteroid pathway.
Collapse
Affiliation(s)
- Srishty Subramanian
- Department of Civil & Environmental Engineering, Temple University, Philadelphia, PA
| | - Rouzbeh Tehrani
- Department of Civil & Environmental Engineering, Temple University, Philadelphia, PA
| | - Benoit Van Aken
- Department of Chemistry & Biochemistry, George Mason University, Fairfax, VA
| |
Collapse
|
17
|
Zheng X, Dupuis KT, Aly NA, Zhou Y, Smith FB, Tang K, Smith RD, Baker ES. Utilizing ion mobility spectrometry and mass spectrometry for the analysis of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenyl ethers and their metabolites. Anal Chim Acta 2018; 1037:265-273. [PMID: 30292301 DOI: 10.1016/j.aca.2018.02.054] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 02/15/2018] [Accepted: 02/18/2018] [Indexed: 10/17/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent environmental pollutants originating from incomplete combustion of organic materials and synthetic sources. PAHs, PCBs, and PBDEs have all been shown to have a significant effect on human health with correlations to cancer and other diseases. Therefore, measuring the presence of these xenobiotics in the environment and human body is imperative for assessing their health risks. To date, their analyses require both gas chromatography and liquid chromatography separations in conjunction with mass spectrometry measurements for detection of both the parent molecules and their hydroxylated metabolites, making their studies extremely time consuming. In this work, we characterized PAHs, PCBs, PBDEs and their hydroxylated metabolites using ion mobility spectrometry coupled with mass spectrometry (IMS-MS) and in combination with different ionization methods including electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). The collision cross section and m/z trend lines derived from the IMS-MS analyses displayed distinct trends for each molecule type. Additionally, the rapid isomeric and molecular separations possible with IMS-MS showed great promise for quickly distinguishing the parent and metabolized PAH, PCB, and PDBE molecules in complex environmental and biological samples.
Collapse
Affiliation(s)
- Xueyun Zheng
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Kevin T Dupuis
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Noor A Aly
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Yuxuan Zhou
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Francesca B Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Keqi Tang
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Erin S Baker
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99354, United States.
| |
Collapse
|
18
|
Marek RF, Thorne PS, Herkert NJ, Awad AM, Hornbuckle KC. Airborne PCBs and OH-PCBs Inside and Outside Urban and Rural U.S. Schools. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7853-7860. [PMID: 28656752 PMCID: PMC5777175 DOI: 10.1021/acs.est.7b01910] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
PCBs appear in school air because many school buildings were built when PCBs were still intentionally added to building materials and because PCBs are also present through inadvertent production in modern pigment. This is of concern because children are especially vulnerable to the toxic effects of PCBs. Here we report indoor and outdoor air concentrations of PCBs and OH-PCBs from two rural schools and four urban schools, the latter near a PCB-contaminated waterway of Lake Michigan in the United States. Samples (n = 108) were collected as in/out pairs using polyurethane foam passive air samplers (PUF-PAS) from January 2012 to November 2015. Samples were analyzed using GC/MS-MS for all 209 PCBs and 72 OH-PCBs. Concentrations inside schools were 1-2 orders of magnitude higher than outdoors and ranged from 0.5 to 194 ng/m3 (PCBs) and from 4 to 665 pg/m3 (OH-PCBs). Congener profiles were similar within each sampling location across season but different between schools and indicated the sources as Aroclors from building materials and individual PCBs associated with modern pigment. This study is the first cohort-specific analysis to show that some children's PCB inhalation exposure may be equal to or higher than their exposure through diet.
Collapse
Affiliation(s)
- Rachel F. Marek
- IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City IA (USA) 52242
- Corresponding authors’ contact information: Rachel F. Marek: 103 S. Capitol St., 4105 SC, Iowa City, IA 52242, , (319) 335-5585, FAX (319) 335-5660; Keri C. Hornbuckle: 103 S. Capitol St., 4105 SC, Iowa City, IA 52242, ; (319) 384-0789, FAX: (319) 335-5660; Peter S. Thorne: 105 River St., S341A CPHB, Iowa City, IA 52242, , (319) 335-4216, FAX: (319) 384-4138
| | - Peter S. Thorne
- Department of Occupational and Environmental Health, The University of Iowa, Iowa City IA (USA) 52242
- Corresponding authors’ contact information: Rachel F. Marek: 103 S. Capitol St., 4105 SC, Iowa City, IA 52242, , (319) 335-5585, FAX (319) 335-5660; Keri C. Hornbuckle: 103 S. Capitol St., 4105 SC, Iowa City, IA 52242, ; (319) 384-0789, FAX: (319) 335-5660; Peter S. Thorne: 105 River St., S341A CPHB, Iowa City, IA 52242, , (319) 335-4216, FAX: (319) 384-4138
| | - Nicholas J. Herkert
- IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City IA (USA) 52242
- Department of Civil & Environmental Engineering, The University of Iowa, Iowa City IA (USA) 52242
| | - Andrew M. Awad
- IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City IA (USA) 52242
| | - Keri C. Hornbuckle
- IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City IA (USA) 52242
- Department of Civil & Environmental Engineering, The University of Iowa, Iowa City IA (USA) 52242
- Corresponding authors’ contact information: Rachel F. Marek: 103 S. Capitol St., 4105 SC, Iowa City, IA 52242, , (319) 335-5585, FAX (319) 335-5660; Keri C. Hornbuckle: 103 S. Capitol St., 4105 SC, Iowa City, IA 52242, ; (319) 384-0789, FAX: (319) 335-5660; Peter S. Thorne: 105 River St., S341A CPHB, Iowa City, IA 52242, , (319) 335-4216, FAX: (319) 384-4138
| |
Collapse
|
19
|
Subramanian S, Schnoor JL, Van Aken B. Effects of Polychlorinated Biphenyls (PCBs) and Their Hydroxylated Metabolites (OH-PCBs) on Arabidopsis thaliana. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7263-7270. [PMID: 28541669 PMCID: PMC5772893 DOI: 10.1021/acs.est.7b01538] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plants metabolize polychlorinated biphenyls (PCBs) into hydroxylated derivatives (OH-PCBs), which are sometimes more toxic than the parent PCBs. The objective of this research was to compare the toxicity of a suite of PCBs and OH-PCBs toward the model plant, Arabidopsis thaliana. While parent PCBs and higher-chlorinated OH-PCBs exhibited a low or nondetectable toxicity, lower-chlorinated OH-PCBs significantly inhibited the germination rate and plant growth, with inhibition concentration 50% (IC50) ranging from 1.6 to 12.0 mg L-1. The transcriptomic response of A. thaliana to 2,5-dichlorobiphenyl (2,5-DCB), and its OH metabolite, 4'-OH-2,5-DCB, was then examined using whole-genome expression microarrays (Affymetrix). Exposure to 2,5-DCB and 4'-OH-2,5-DCB resulted in different expression patterns, with the former leading to enrichment of genes involved in response to toxic stress and detoxification functions. Exposure to 2,5-DCB induced multiple xenobiotic response genes, such as cytochrome P-450 and glutathione S-transferases, potentially involved in the PCB metabolism. On the contrary, exposure to both compounds resulted in the down-regulation of genes involved in stresses not directly related to toxicity. Unlike its OH derivative, 2,5-DCB was shown to induce a transcriptomic profile similar to plant safeners, which are nontoxic chemicals stimulating detoxification pathways in plants. The differentiated induction of detoxification enzymes by 2,5-DCB may explain its lower phytotoxicity compared to 4'-OH-2,5-DCB.
Collapse
Affiliation(s)
- Srishty Subramanian
- Department of Civil & Environmental Engineering, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Jerald L. Schnoor
- Department of Civil & Environmental Engineering, The University of Iowa, Iowa City, Iowa 52242, United States
| | - Benoit Van Aken
- Department of Civil & Environmental Engineering, Temple University, Philadelphia, Pennsylvania 19122, United States
- Corresponding Author, . Phone: 215-204-7087. Fax: 215-204-4696
| |
Collapse
|
20
|
Bhalla R, Tehrani R, Van Aken B. Toxicity of hydroxylated polychlorinated biphenyls (HO-PCBs) using the bioluminescent assay Microtox(®). ECOTOXICOLOGY (LONDON, ENGLAND) 2016; 25:1438-44. [PMID: 27411941 PMCID: PMC5131519 DOI: 10.1007/s10646-016-1693-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/29/2016] [Indexed: 05/20/2023]
Abstract
Hydroxylated polychlorinated biphenyls (HO-PCBs) are toxic contaminants which are produced in the environment by biological or abiotic oxidation of PCBs. The toxicity of a suite of 23 mono-hydroxylated derivatives of PCBs and 12 parent PCBs was determined using the bacterial bioluminescent assay Microtox(®). All HO-PCBs tested exhibited higher toxicity than the corresponding parent PCB, with effect concentration 50 % (EC50) ranging from 0.07 to 133 mg L(-1). The highest toxicities were recorded with 4-hydroxylated derivatives of di-chlorinated biphenyls (EC50 = 0.07-0.36 mg L(-1)) and 2-hydroxylated derivatives of tri-chlorinated biphenyls carrying a chlorine substituent on the phenolic ring (EC50 = 0.34-0.48 mg L(-1)). The toxicity of HO-PCBs generally decreased when the degree of chlorination increased. Consistently with this observation, a significant positive correlation was measured between toxicity (measured by EC50) and octanol-water partition coefficient (pK ow) for the HO-PCBs under study (Pearson's correlation coefficient, r = 0.74), which may be explained by the lower solubility and bioavailability generally associated with higher hydrophobicity. This study is the first one which assessed the toxicity of a suite of PCBs and HO-PCBs using the bioluminescent assay Microtox(®), showing an inverse correlation between toxicity and hydrophobicity.
Collapse
Affiliation(s)
- Renu Bhalla
- Department of Civil and Environmental Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA, 19122, USA
| | - Rouzbeh Tehrani
- Department of Civil and Environmental Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA, 19122, USA
| | - Benoit Van Aken
- Department of Civil and Environmental Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA, 19122, USA.
| |
Collapse
|
21
|
Detection of methoxylated and hydroxylated polychlorinated biphenyls in sewage sludge in China with evidence for their microbial transformation. Sci Rep 2016; 6:29782. [PMID: 27417462 PMCID: PMC4945941 DOI: 10.1038/srep29782] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/23/2016] [Indexed: 11/10/2022] Open
Abstract
The concentrations of methoxylated polychlorinated biphenyls (MeO-PCBs) and hydroxylated polychlorinated biphenyls (OH-PCBs) were measured in the sewage sludge samples collected from twelve wastewater treatment plants in China. Two MeO-PCB congeners, including 3′-MeO-CB-65 and 4′-MeO-CB-101, were detected in three sludge with mean concentrations of 0.58 and 0.52 ng/g dry weight, respectively. OH-PCBs were detected in eight sludge samples, with an average total concentration of 4.2 ng/g dry weight. Furthermore, laboratory exposure was conducted to determine the possible source of OH-PCBs and MeO-PCBs in the sewage sludge, and their metabolism by the microbes. Both 4′-OH-CB-101 and 4′-MeO-CB-101 were detected as metabolites of CB-101 at a limited conversion rate after 5 days. Importantly, microbial interconversion between OH-PCBs and MeO-PCBs was observed in sewage sludge. Demethylation of MeO-PCBs was favored over methylation of OH-PCBs. The abundant and diverse microbes in sludge play a key role in the transformation processes of the PCB analogues. To our knowledge, this is the first report on MeO-PCBs in environmental matrices and on OH-PCBs in sewage sludge. The findings are important to understand the environmental fate of PCBs.
Collapse
|