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Hatch AC, Peloquin D, Kumbar AS, Luxton TP, Clar JG. Transformation of zinc oxide nanoparticles in synthetic lung fluids. J Nanopart Res 2022; 24:153. [PMID: 35873670 PMCID: PMC9288259 DOI: 10.1007/s11051-022-05527-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
UNLABELLED Surface coatings, including paints, stains, and sealants, have recently become a focus of "nano-enabled" consumer product engineering. Specifically, zinc oxide (ZnO) nanoparticles (NPs) have been introduced to surface coatings to increase UV resistance. As more "nano-enabled" products are made available for purchase, questions arise regarding their long-term environmental and human health effects. This study tracked the transformation of NP additives commonly added to consumer paints and stains using ZnO NPs as a model system. During product application and use, there is a risk of inhalation of aerosolized ZnO NPs. To investigate the potential chemical interactions and transformations that would occur after inhalation, ZnO NPs were incubated in two synthetic lung fluids (SLFs). Initial studies utilized ZnO NPs dispersed in Milli-Q water (control), or a commercially available deck stain. Additionally, two commercially available products advertising the inclusion of ZnO NP additives were evaluated. Subsamples were taken throughout incubation and analyzed via atomic absorption spectroscopy to determine both the total (including particulate) zinc concentration and dissolved (non-particulate) zinc concentration. Results indicate that the vast majority of ZnO transformation takes place within the first 24 h of incubation and is primarily driven by SLF pH and composition complexity. Significant dissolution of ZnO NPs was observed when incubated in Gamble's solution (between 25 and 68% depending on the matrix. Additionally, all ZnO solutions saw near immediate dissolution (~ 98-100%) within 3 h of incubation in artificial lysosomal fluid. Results illustrate potential for NPs in consumer products to undergo significant transformation during use and exposure over short time periods. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11051-022-05527-y.
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Affiliation(s)
- Avery C Hatch
- Department of Chemistry, Elon University, Elon, NC 27244 USA
| | - Derek Peloquin
- Oak Ridge Institute for Science and Education (ORISE) Postdoctoral Research Associate, Oak Ridge, USA
| | - Amar S Kumbar
- Analytical and Nanofabrication Laboratory, University of North Carolina, Chapel Hill, NC 27599 USA
| | - Todd P Luxton
- Center for Environmental Solutions and Environmental Response, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224 USA
| | - Justin G Clar
- Department of Chemistry, Elon University, Elon, NC 27244 USA
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2
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Hughes SM, Hendricks MP, Mullaugh KM, Anderson ME, Bentley AK, Clar JG, Daly CA, Ellison MD, Feng ZV, Gonzalez-Pech NI, Hamachi LS, Heinecke CL, Keene JD, Maley AM, Munro AM, Njoki PN, Olshansky JH, Plass KE, Riley KR, Sonntag MD, St. Angelo SK, Thompson LB, Tollefson EJ, Toote LE, Wheeler KE. The Primarily Undergraduate Nanomaterials Cooperative: A New Model for Supporting Collaborative Research at Small Institutions on a National Scale. ACS Nanosci Au 2021; 1:6-14. [PMID: 37102118 PMCID: PMC10114623 DOI: 10.1021/acsnanoscienceau.1c00020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
The Primarily Undergraduate Nanomaterials Cooperative (PUNC) is an organization for research-active faculty studying nanomaterials at Primarily Undergraduate Institutions (PUIs), where undergraduate teaching and research go hand-in-hand. In this perspective, we outline the differences in maintaining an active research group at a PUI compared to an R1 institution. We also discuss the work of PUNC, which focuses on community building, instrument sharing, and facilitating new collaborations. Currently consisting of 37 members from across the United States, PUNC has created an online community consisting of its Web site (nanocooperative.org), a weekly online summer group meeting program for faculty and students, and a Discord server for informal conversations. Additionally, in-person symposia at ACS conferences and PUNC-specific conferences are planned for the future. It is our hope that in the years to come PUNC will be seen as a model organization for community building and research support at primarily undergraduate institutions.
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Affiliation(s)
- Steven M. Hughes
- Department
of Chemistry, Roanoke College, 221 College Lane, Salem, Virginia 24153, United States
| | - Mark P. Hendricks
- Department
of Chemistry, Whitman College, 345 Boyer Avenue, Walla Walla, Washington 99362, United States
| | - Katherine M. Mullaugh
- Department
of Chemistry and Biochemistry, College of
Charleston, 66 George Street, Charleston, South Carolina 29424, United States
| | - Mary E. Anderson
- Department
of Chemistry, Furman University, 3300 Poinsett Highway, Greenville, South Carolina 29613, United States
| | - Anne K. Bentley
- Department
of Chemistry, Lewis & Clark College, 615 S Palatine Hill Rd, Portland, Oregon 97219, United States
| | - Justin G. Clar
- Department
of Chemistry, Elon University, 2625 Campus Box, Elon, North Carolina 27244, United States
| | - Clyde A. Daly
- Department
of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041, United States
| | - Mark D. Ellison
- Department
of Chemistry, Ursinus College, P.O. Box 1000, Collegeville, Pennsylvania 19426, United States
| | - Z. Vivian Feng
- Department
of Chemistry, Augsburg University, 2211 Riverside Avenue, Minneapolis, Minnesota 55454, United States
| | - Natalia I. Gonzalez-Pech
- Department
of Chemistry, Hope College, 35 East 12th Street, Holland, Michigan 49423, United States
| | - Leslie S. Hamachi
- Department
of Chemistry & Biochemistry, California
Polytechnic State University, 1 Grand Avenue, San Luis Obispo, California 93401, United States
| | - Christine L. Heinecke
- Department
of Chemistry & Biochemistry, Loyola
University New Orleans, 6363 St. Charles Avenue, New Orleans, Louisiana 70118, United States
| | - Joseph D. Keene
- Department
of Chemistry, Mercer University, 1501 Mercer University Drive, Macon, Georgia 31207, United States
| | - Adam M. Maley
- Mund-Lagowski
Department of Chemistry and Biochemistry, Bradley University, 1501 W Bradley Avenue, Peoria, Illinois 61625, United
States
| | - Andrea M. Munro
- Department
of Chemistry, Pacific Lutheran University, 12180 Park Avenue, Tacoma, Washington 98447, United States
| | - Peter N. Njoki
- Department
of Chemistry & Biochemistry, Hampton
University, 130 William R. Harvey Way, Hampton, Virginia 23668, United
States
| | - Jacob H. Olshansky
- Department
of Chemistry, Amherst College, 25 East Drive, Amherst, Massachusetts 01002, United States
| | - Katherine E. Plass
- Department
of Chemistry, Franklin & Marshall College, P.O. Box 3003, Lancaster, Pennsylvania 17601, United States
| | - Kathryn R. Riley
- Department
of Chemistry & Biochemistry, Swarthmore
College, 500 College Avenue, Swarthmore, Pennsylvania 19081, United States
| | - Matthew D. Sonntag
- Department
of Chemistry & Biochemistry, Albright
College, P.O. Box 15234, Reading, Pennsylvania 19612, United States
| | - Sarah K. St. Angelo
- Department
of Chemistry, Dickinson College, P.O. Box 1773, Carlisle, Pennsylvania 17013, United States
| | - Lucas B. Thompson
- Department
of Chemistry, Gettysburg College, 300 North Washington Street, Gettysburg, Pennsylvania 17325, United States
| | - Emily J. Tollefson
- Department
of Chemistry, University of Puget Sound, 1500 N Warner Street, Tacoma, Washington 98416, United States
| | - Lauren E. Toote
- Department
of Chemistry & Biochemistry, Elizabethtown
College, 1 Alpha Drive, Elizabethtown, Pennsylvania 17022, United States
| | - Korin E. Wheeler
- Department
of Chemistry & Biochemistry, Santa Clara
University, 500 El Camino Real, Santa Clara, California 95053, United States
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3
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Thornton SB, Luxton TP, Clar JG. Variation in zinc release from surface coatings as a function of methodology. Sci Total Environ 2021; 788:147907. [PMID: 34134384 PMCID: PMC9614699 DOI: 10.1016/j.scitotenv.2021.147907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/23/2021] [Accepted: 05/16/2021] [Indexed: 06/12/2023]
Abstract
Over the last decade the growth of "nano-enabled" products have exploded in both industrial and direct to consumer applications. One area of interest is surface coatings, including paints, stains and sealants. Large scale applications of the products raise questions about both short- and long-term effects to both human and environmental health. Release of nanoparticles (NPs) from surfaces as a function of dermal contact is recognized as a potential human exposure route. Several standardized methods to quantify nanomaterial release have been previously used. In the current study, two standardized method were used to quantify the total mass of NPs released during sampling. ZnO (NPs) were used as a case study as they are commonly added to surface coatings to increase UV resistance. Particles were dispersed in Milli-Q water or a deck stain and applied to sanded plywood surfaces. Total release of Zn due to simulated dermal contact was evaluated using the Consumer Product Safety Commission (CPSC) and National Institute for Occupational Safety and Health (NIOSH) wipe methods. Additionally, three different sampling materials were tested. The total quantity of Zn released between the two methods was dependent upon the material used and how the ZnO was applied to the surface. Critically, less than 3% of the ZnO NPs applied to test surfaces was removed using either method. The results of this study demonstrate how different testing methodologies may result in varying estimates of human and environmental risk from NPs in surface coatings.
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Affiliation(s)
| | - Todd P Luxton
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Research and Emergency Response, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
| | - Justin G Clar
- Elon University, Department of Chemistry, Elon, NC 27244, USA.
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4
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Thornton SB, Boggins SJ, Peloquin DM, Luxton TP, Clar JG. Release and transformation of nanoparticle additives from surface coatings on pristine & weathered pressure treated lumber. Sci Total Environ 2020; 737:139451. [PMID: 32512308 PMCID: PMC8025203 DOI: 10.1016/j.scitotenv.2020.139451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/12/2020] [Accepted: 05/13/2020] [Indexed: 04/14/2023]
Abstract
As the market for "nano-enabled" products (NEPs) continues to expand in commercial and industrial applications, there is a critical need to understand conditions that promote release of nanomaterials and their degradation products from NEPs. Moreover, these studies must aim to quantify both the abundance and form (aggregates, ions, hybrids, etc.) of material released from NEPs to produce reasonable estimates of human and environmental exposure. In this work ZnO nanoparticles (NPs), a common additive in NEP surface coatings, were dispersed in Milli-Q water and a commercially available wood stain before application to pristine and weathered (outdoor 1 year) micronized copper azole pressure treated lumber (MCA). Coated lumber surfaces were sampled consecutively eight times using a method developed by the Consumer Product Safety Commission (CPSC) to track potential human exposure to ZnO NPs and byproducts through simulated dermal contact. Surprisingly, the highest total release of Zn was observed from aged lumber coated with ZnO NPs dispersed in wood stain, releasing 233 ± 26 mg Zn/m2 over the course of all sampling events. Alternatively, separate leaching experiments using a synthetic precipitation solution to simulate environmental release found aged lumber released significantly less Zn than pristine lumber when using the same coating formulation. Zinc speciation analysis also demonstrates that transformation of crystalline ZnO to Zn-organic complexes shortly after application to aged lumber. Regardless of experimental treatment, the majority of applied zinc (>75%) remains on the MCA surface. Finally, this work highlights how the nature of the screening technique (dermal contact vs. leaching) may result in different interpretations of exposure and risk.
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Affiliation(s)
| | - Sarah J Boggins
- Elon University, Department of Chemistry, Elon, NC 27244, USA
| | - Derek M Peloquin
- Oak Ridge Institute for Science and Education (ORISE) Postdoctoral Research Associate, USA
| | - Todd P Luxton
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
| | - Justin G Clar
- Elon University, Department of Chemistry, Elon, NC 27244, USA.
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5
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Clar JG, Platten WE, Baumann E, Remsen A, Harmon S, Rodgers K, Thomas T, Matheson J, Luxton TP. Transformation and release of nanoparticle additives & byproducts from commercially available surface coatings on pressure treated lumber via dermal contact. Sci Total Environ 2019; 694:133669. [PMID: 31382174 PMCID: PMC7440215 DOI: 10.1016/j.scitotenv.2019.133669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/23/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Production and marketing of "nano-enabled" products for consumer purchase has continued to expand. However, many questions remain about the potential release and transformation of these nanoparticle (NP) additives from products throughout their lifecycle. In this work, two surface coating products advertised as containing ZnO NPs as active ingredients, were applied to micronized copper azol (MCA) and aqueous copper azol (ACA) pressure treated lumber. Coated lumber was weathered outdoors for a period of six months and the surface was sampled using a method developed by the Consumer Product Safety Commission (CPSC) to track potential human exposure to ZnO NPs and byproducts through simulated dermal contact. Using this method, the total amount of zinc extracted during a single sampling event was <1 mg/m2 and no evidence of free ZnO NPs was found. Approximately 0.5% of applied zinc was removed via simulated dermal contact over 6-months, with increased weathering periods resulting in increased zinc release. XAFS analysis found that only 27% of the zinc in the as received coating could be described as crystalline ZnO and highlights the transformation of these mineral phases to organically bound zinc complexes during the six-month weathering period. Additionally, SEM images collected after sampling found no evidence of free NP ZnO release during simulated dermal contact. Both simulated dermal contact experiments, and separate leaching studies demonstrate the application of surface coating solutions to either MCA and ACA lumber will reduce the release of copper from the pressure treated lumber. This work provides clear evidence of the transformation of NP additives in consumer products during their use stage.
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Affiliation(s)
- Justin G Clar
- Elon University, Department of Chemistry, Elon, NC 27244, USA
| | | | - Eric Baumann
- Pegasus Technical Services Inc, Cincinnati, OH, USA
| | | | - Steve Harmon
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
| | - Kim Rodgers
- National Health Effects and Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Treye Thomas
- U.S. Consumer Product Safety Commission, Office of Hazard Identification and Reduction, 4330 East West Highway, Bethesda, MD 20814, USA
| | - Joanna Matheson
- U.S. Consumer Product Safety Commission, Office of Hazard Identification and Reduction, 4330 East West Highway, Bethesda, MD 20814, USA
| | - Todd P Luxton
- Elon University, Department of Chemistry, Elon, NC 27244, USA.
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6
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Clar JG, Platten WE, Baumann E, Remsen A, Harmon SM, Rodgers K, Thomas TA, Matheson J, Luxton TP. Release and transformation of ZnO nanoparticles used in outdoor surface coatings for UV protection. Sci Total Environ 2019; 670:78-86. [PMID: 30903905 PMCID: PMC6770995 DOI: 10.1016/j.scitotenv.2019.03.189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 05/31/2023]
Abstract
A major area of growth for "nano-enabled" products has been the addition of nanoparticles (NPs) to surface coatings including paints, stains and sealants. Zinc oxide (ZnO) NPs, long used in sunscreens and sunblocks, have found growing use in surface coating formulations to increase their UV resistance, especially on outdoor products. In this work, ZnO NPs, marketed as an additive to paints and stains, were dispersed in Milli-Q water and a commercial deck stain. Resulting solutions were applied to either Micronized-Copper Azole (MCA) pressure treated lumber or a commercially available composite decking. A portion of coated surfaces were placed outdoors to undergo environmental weathering, while the remaining samples were stored indoors to function as experimental controls. Weathered and control treatments were subsequently sampled periodically for 6 months using a simulated dermal contact method developed by the Consumer Product Safety Commission (CPSC). The release of ZnO NPs, and their associated degradation products, was determined through sequential filtration, atomic spectroscopy, X-Ray Absorption Fine Structure Spectroscopy, and electron microscopy. Across all treatments, the percentage of applied zinc released through simulated dermal contact did not exceed 4%, although transformation and release of zinc was highly dependent on dispersion medium. For MCA samples weathered outdoors, water-based applications released significantly more zinc than stain-based, 180 ± 28, and 65 ± 9 mg/m2 respectively. Moreover, results indicate that the number of contact events drives material release.
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Affiliation(s)
- Justin G Clar
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA; Oak Ridge Institute for Science and Education (ORISE) Postdoctoral Research Associate, USA.
| | | | - Eric Baumann
- Pegasus Technical Services Inc., Cincinnati, OH, USA
| | - Andrew Remsen
- Pegasus Technical Services Inc., Cincinnati, OH, USA
| | - Steve M Harmon
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
| | - Kim Rodgers
- National Health Effects and Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Treye A Thomas
- U.S. Consumer Product Safety Commission, Office of Hazard Identification and Reduction, 4330 EastWest Highway, Bethesda, MD 20814, USA
| | - Joanna Matheson
- U.S. Consumer Product Safety Commission, Office of Hazard Identification and Reduction, 4330 EastWest Highway, Bethesda, MD 20814, USA
| | - Todd P Luxton
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
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7
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Parks AN, Cantwell MG, Katz DR, Cashman MA, Luxton TP, Clar JG, Perron MM, Portis L, Ho KT, Burgess RM. Assessing the release of copper from nanocopper-treated and conventional copper-treated lumber into marine waters II: Forms and bioavailability. Environ Toxicol Chem 2018; 37:1969-1979. [PMID: 29575127 PMCID: PMC6038930 DOI: 10.1002/etc.4140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/06/2018] [Accepted: 03/22/2018] [Indexed: 05/18/2023]
Abstract
One application of nanocopper is as a wood-preserving pesticide in pressure-treated lumber. Recent research has shown that pressure-treated lumber amended with micronized copper azole (MCA), which contains nanosized copper, releases copper under estuarine and marine conditions. The form of copper released (i.e., ionic, nanocopper [1-100 nm in size]) is not fully understood but will affect the bioavailability and toxicity of the metal. In the present study, multiple lines of evidence, including size fractionation, ion-selective electrode electrochemistry, comparative toxicity, and copper speciation were used to determine the form of copper released from lumber blocks and sawdust. The results of all lines of evidence supported the hypothesis that ionic copper was released from MCA lumber and sawdust, with little evidence that nanocopper was released. For example, copper concentrations in size fractionations of lumber block aqueous leachates including unfiltered, 0.1 μm, and 3 kDa were not significantly different, suggesting that the form of copper released was in the size range operationally defined as dissolved. These results correlated with the ion-selective electrode data which detects only ionic copper. In addition, comparative toxicity testing resulted in a narrow range of median lethal concentrations (221-257 μg/L) for MCA lumber blocks and CuSO4 . We conclude that ionic copper was released from the nanocopper pressure-treated lumber under estuarine and marine conditions. Environ Toxicol Chem 2018;37:1969-1979. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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Affiliation(s)
- Ashley N Parks
- National Research Council c/o U.S. EPA, ORD/NHEERL, Atlantic Ecology Division, Narragansett, RI, USA
| | - Mark G Cantwell
- U.S. EPA, ORD/NHEERL, Atlantic Ecology Division, Narragansett, RI, USA
| | - David R Katz
- U.S. EPA, ORD/NHEERL, Atlantic Ecology Division, Narragansett, RI, USA
| | - Michaela A Cashman
- University of Rhode Island, Department of Geosciences, Kingston, RI, USA
| | - Todd P Luxton
- U.S. EPA, ORD/NRMRL, Land and Materials Management Division, Cincinnati, OH, USA
| | - Justin G Clar
- Oak Ridge Institute for Science and Education c/o U.S. EPA, ORD/NRMRL/LMMD, Cincinnati, OH, USA
| | - Monique M Perron
- US EPA, OCSPP, Office of Pesticides Programs, Washington, DC, USA
| | - Lisa Portis
- Lifespan Ambulatory Care Center, East Greenwich, RI USA
| | - Kay T Ho
- U.S. EPA, ORD/NHEERL, Atlantic Ecology Division, Narragansett, RI, USA
| | - Robert M Burgess
- U.S. EPA, ORD/NHEERL, Atlantic Ecology Division, Narragansett, RI, USA
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8
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Clar JG, Platten WE, Baumann EJ, Remsen A, Harmon SM, Bennett-Stamper CL, Thomas TA, Luxton TP. Dermal transfer and environmental release of CeO 2 nanoparticles used as UV inhibitors on outdoor surfaces: Implications for human and environmental health. Sci Total Environ 2018; 613-614:714-723. [PMID: 28938214 PMCID: PMC6738344 DOI: 10.1016/j.scitotenv.2017.09.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 05/30/2023]
Abstract
A major area of growth for "nano-enabled" consumer products have been surface coatings, including paints stains and sealants. Ceria (CeO2) nanoparticles (NPs) are of interest as they have been used as additives in these these products to increase UV resistance. Currently, there is a lack of detailed information on the potential release, and speciation (i.e., ion vs. particle) of CeO2 NPs used in consumer-available surface coatings during intended use scenarios. In this study, both Micronized-Copper Azole pressure-treated lumber (MCA), and a commercially available composite decking were coated with CeO2 NPs dispersed in Milli-Q water or wood stain. Coated surfaces were divided into two groups. The first was placed outdoors to undergo environmental weathering, while the second was placed indoors to act as experimental controls. Both weathered surfaces and controls were sampled over a period of 6months via simulated dermal contact using methods developed by the Consumer Product Safety Commission (CPSC). The size and speciation of material released was determined through sequential filtration, total metals analysis, X-Ray Absorption Fine Structure Spectroscopy, and electron microscopy. The total ceria release from MCA coated surfaces was found to be dependent on dispersion matrix with aqueous applications releasing greater quantities of CeO2 than stain based applications, 66±12mg/m2 and 36±7mg/m2, respectively. Additionally, a substantial quantity of CeO2 was reduced to Ce(III), present as Ce(III)-organic complexes, over the 6-month experimental period in aqueous based applications.
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Affiliation(s)
- Justin G Clar
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA; Oak Ridge Institute for Science and Education (ORISE), Postdoctoral Research Associate, USA
| | | | | | - Andrew Remsen
- Pegasus Technical Services Inc., Cincinnati, OH, USA
| | - Steve M Harmon
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
| | - Christina L Bennett-Stamper
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA
| | - Treye A Thomas
- U.S. Consumer Product Safety Commission, Office of Hazard Identification and Reduction, 4330 East West Highway, Bethesda, MD 20814, USA
| | - Todd P Luxton
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, OH 45224, USA.
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Xu J, Mueller R, Hazelbaker E, Zhao Y, Bonzongo JCJ, Clar JG, Vasenkov S, Ziegler KJ. Strongly Bound Sodium Dodecyl Sulfate Surrounding Single-Wall Carbon Nanotubes. Langmuir 2017; 33:5006-5014. [PMID: 28475342 DOI: 10.1021/acs.langmuir.7b00758] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
NMR techniques have been widely used to infer molecular structure, including surfactant aggregation. A combination of optical spectroscopy, proton NMR spectroscopy, and pulsed field gradient NMR (PFG NMR) is used to study the adsorption number for sodium dodecyl sulfate (SDS) with single-wall carbon nanotubes (SWCNTs). Distinct transitions in the NMR chemical shift of SDS are observed in the presence of SWCNTs. These transitions demonstrate that micelle formation is delayed by SWCNTs due to the adsorption of SDS on the nanotube surface. Once the nanotube surface is saturated, the free SDS concentration increases until micelle formation is observed. Therefore, the adsorption number of SDS on SWCNTs can be determined by the changes to the apparent critical micelle concentration (CMC). PFG NMR found that SDS remains strongly bound onto the nanotube. Quantitative analysis of the diffusivity of SDS allowed calculation of the adsorption number of strongly bound SDS on SWCNTs. The adsorption numbers from these techniques give the same values within experimental error, indicating that a significant fraction of the SDS interacting with nanotubes remains strongly bound for as long as 0.5 s, which is the maximum diffusion time used in the PFG NMR measurements.
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Affiliation(s)
| | | | | | | | | | - Justin G Clar
- Department of Chemistry, Elon University , Elon, North Carolina 27244, United States
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Zhao Y, Clar JG, Li L, Xu J, Yuan T, Bonzongo JCJ, Ziegler KJ. Selective desorption of high-purity (6,5) SWCNTs from hydrogels through surfactant modulation. Chem Commun (Camb) 2016; 52:2928-31. [PMID: 26688107 DOI: 10.1039/c5cc08530f] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Selective desorption of (6,5) single-wall carbon nanotubes from hydrogels only occurs at specific co-surfactant ratios. High-purity fractions are obtained at this ratio even with long elution times and different total co-surfactant concentrations. These results suggest that each (n,m) type forms a thermodynamically-stable surfactant structure in the co-surfactant solution, enabling high-fidelity separations in a single column.
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Affiliation(s)
- Yang Zhao
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA.
| | - Justin G Clar
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, USA
| | - Luping Li
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA.
| | - Jia Xu
- Department of Materials Science & Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Tianyu Yuan
- Department of Materials Science & Engineering, University of Florida, Gainesville, Florida 32611, USA
| | - Jean-Claude J Bonzongo
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, USA
| | - Kirk J Ziegler
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA. and Department of Materials Science & Engineering, University of Florida, Gainesville, Florida 32611, USA
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Clar JG, Li X, Impellitteri CA, Bennett-Stamper C, Luxton TP. Copper Nanoparticle Induced Cytotoxicity to Nitrifying Bacteria in Wastewater Treatment: A Mechanistic Copper Speciation Study by X-ray Absorption Spectroscopy. Environ Sci Technol 2016; 50:9105-9113. [PMID: 27466862 DOI: 10.1021/acs.est.6b01910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
With the inclusion of engineered nanomaterials in industrial processes and consumer products, wastewater treatment plants (WWTPs) could serve as a major sink for these emerging contaminants. Previous research has demonstrated that nanomaterials are potentially toxic to microbial communities utilized in biological wastewater treatment (BWT). Copper-based nanoparticles (CuNPs) are of particular interest based on their increasing use in wood treatment, paints, household products, coatings, and byproducts of semiconductor manufacturing. A critical step in BWT is nutrient removal through nitrification. This study examined the potential toxicity of uncoated and polyvinylpyrrolidone (PVP)-coated CuO, and Cu2O nanoparticles, as well as Cu ions to microbial communities responsible for nitrification in BWT. Inhibition was inferred from changes to the specific oxygen uptake rate (sOUR) in the absence and presence of Cu ions and CuNPs. X-ray absorption fine structure spectroscopy, with linear combination fitting (LCF), was utilized to track changes to Cu speciation throughout exposure. Results indicate that the dissolution of Cu ions from CuNPs drive microbial inhibition. The presence of a PVP coating on CuNPs has little effect on inhibition. LCF analysis of the biomass combined with metal partitioning analysis supports the current hypothesis that Cu-induced cytotoxicity is primarily caused by reactive oxygen species formed from ionic Cu in solution via catalytic reaction intermediated by reduced Cu(I) species.
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Affiliation(s)
- Justin G Clar
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, Ohio 45224, United States
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee 37831, United States
| | - Xuan Li
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, Ohio 45224, United States
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee 37831, United States
| | - Christopher A Impellitteri
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, Ohio 45224, United States
| | - Christina Bennett-Stamper
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, Ohio 45224, United States
| | - Todd P Luxton
- National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 5995 Center Hill Avenue, Cincinnati, Ohio 45224, United States
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Clar JG, Gustitus SA, Youn S, Silvera Batista CA, Ziegler KJ, Bonzongo JCJ. Unique toxicological behavior from single-wall carbon nanotubes separated via selective adsorption on hydrogels. Environ Sci Technol 2015; 49:3913-3921. [PMID: 25710331 DOI: 10.1021/es505925m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Over the past decade, extensive research has been completed on the potential threats of single-wall carbon nanotubes (SWCNTs) to living organisms upon release to aquatic systems. However, these studies have focused primarily on the link between adverse biological effects in exposed test organisms on the length, diameter, and metallic impurity content of SWCNTs. In contrast, few studies have focused on the bioeffects of the different SWCNTs in the as-produced mixture, which contain both metallic (m-SWCNT) and semiconducting (s-SWCNT) species. Using selective adsorption onto hydrogels, high purity m-SWCNT and s-SWCNT fractions were produced and their biological impacts determined in dose-response studies with Pseudokirchneriella subcapitata as test organism. The results show significant differences in the biological responses of P. subcapitata exposed to high purity m- and s-SWCNT fractions. Contrary to the biological response observed using SWCNTs separated by density gradient ultracentrifugation, it is found that the high-pressure CO conversion (HiPco) s-SWCNT fraction separated by selective adsorption causes increased biological impact. These findings suggest that s-SWCNTs are the primary factor driving the adverse biological responses observed from P. subcapitata cells exposed to our as-produced suspensions. Finally, the toxicity of the s-SWCNT fraction is mitigated by increasing the concentration of biocompatible surfactant in the suspensions, likely altering the nature of surfactant coverage along SWCNT sidewalls, thereby reducing potential physical interaction with algal cells. These findings highlight the need to couple sample processing and toxicity response studies.
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Affiliation(s)
- Justin G Clar
- †Engineering School of Sustainable Infrastructure and Environment, Dept. of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
| | - Sarah A Gustitus
- †Engineering School of Sustainable Infrastructure and Environment, Dept. of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
| | - Sejin Youn
- †Engineering School of Sustainable Infrastructure and Environment, Dept. of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
| | - Carlos A Silvera Batista
- ‡Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Kirk J Ziegler
- ‡Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Jean Claude J Bonzongo
- †Engineering School of Sustainable Infrastructure and Environment, Dept. of Environmental Engineering Sciences, University of Florida, Gainesville, Florida 32611, United States
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Clar JG, Silvera Batista CA, Youn S, Bonzongo JCJ, Ziegler KJ. Interactive forces between sodium dodecyl sulfate-suspended single-walled carbon nanotubes and agarose gels. J Am Chem Soc 2013; 135:17758-67. [PMID: 24164680 DOI: 10.1021/ja4052526] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selective adsorption onto agarose gels has become a powerful method to separate single-walled carbon nanotubes (SWCNTs). A better understanding of the nature of the interactive forces and specific sites responsible for adsorption should lead to significant improvements in the selectivity and yield of these separations. A combination of nonequilibrium and equilibrium studies are conducted to explore the potential role that van der Waals, ionic, hydrophobic, π-π, and ion-dipole interactions have on the selective adsorption between agarose and SWCNTs suspended with sodium dodecyl sulfate (SDS). The results demonstrate that any modification to the agarose gel surface and, consequently, the permanent dipole moments of agarose drastically reduces the retention of SWCNTs. Because these permanent dipoles are critical to retention and the fact that SDS-SWCNTs function as macro-ions, it is proposed that ion-dipole forces are the primary interaction responsible for adsorption. The selectivity of adsorption may be attributed to variations in polarizability between nanotube types, which create differences in both the structure and mobility of surfactant. These differences affect the enthalpy and entropy of adsorption, and both play an integral part in the selectivity of adsorption. The overall adsorption process shows a complex behavior that is not well represented by the Langmuir model; therefore, calorimetric data should be used to extract thermodynamic information.
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Affiliation(s)
- Justin G Clar
- Department of Environmental Engineering Sciences and ‡Department of Chemical Engineering, University of Florida , Gainesville, Florida 32611, United States
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