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Hughes MF, Clapper HM, Tedla G, Sowers TD, Rogers KR. Simulated gastric leachate of 3D printer metal-fill filaments induces cytotoxic effects in rat and human intestinal models. Toxicol In Vitro 2024; 97:105805. [PMID: 38458500 DOI: 10.1016/j.tiv.2024.105805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/10/2024]
Abstract
Metals are used in 3-dimensional (3D) printer filaments in the manufacture of 3D printed objects. Exposure to the filaments, printed objects and emissions from printing may pose health risks from release of toxic metals. This study investigated the cytotoxicity of extruded 3D printer filament leachates in rat and human intestinal cells. Copper-, bronze-, and steel-fill extruded filaments were incubated in acidic media for 2 h. Leachates were adjusted to pH 7 and cells exposed for 4 or 24 h. Concentration- and time-dependent decreases in rat and human cell viability were observed using a colorimetric assay and confirmed by microscopy. Copper- and bronze-fill leachates were more cytotoxic than steel. Copper-fill leachates had the highest copper concentrations by ICP-MS. Exposure to CuSO4 resulted in concentration-dependent cytotoxicity in rat cells. The copper chelator bathocuproine disulphonate alleviated cytotoxicity of CuSO4 and copper-fill leachate, suggesting that copper ions have a role in the cytotoxicity. Hydrogen peroxide increased and glutathione decreased in rat cells exposed to copper-fill leachate, suggesting the formation of reactive oxygen species. Overall, our data indicate that metals released from the acidic exposure of print objects using metal-fill filaments, especially copper, are toxic to rat and human intestinal cells and additional studies are needed.
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Affiliation(s)
- Michael F Hughes
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States of America.
| | - Haley M Clapper
- Oak Ridge Institute for Science and Education, Research Triangle Park, NC, United States of America
| | - Getachew Tedla
- Oak Ridge Institute for Science and Education, Research Triangle Park, NC, United States of America
| | - Tyler D Sowers
- Center for Environmental Measurement and Modeling, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States of America
| | - Kim R Rogers
- Center for Environmental Measurement and Modeling, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States of America
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2
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Carneiro Barreto MS, Wani RP, Goranov AI, Sowers TD, Fischel M, Douglas TA, Hatcher PG, Sparks DL. Carbon Fate, Iron Dissolution, and Molecular Characterization of Dissolved Organic Matter in Thawed Yedoma Permafrost under Varying Redox Conditions. Environ Sci Technol 2024; 58:4155-4166. [PMID: 38385246 DOI: 10.1021/acs.est.3c08219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Permafrost soils store ∼50% of terrestrial C, with Yedoma permafrost containing ∼25% of the total C. Permafrost is undergoing degradation due to thawing, with potentially hazardous effects on landscape stability and water resources. Complicating ongoing efforts to project the ultimate fate of deep permafrost C is the poorly constrained role of the redox environment, Fe-minerals, and its redox-active phases, which may modulate organic C-abundance, composition, and reactivity through complexation and catalytic processes. We characterized C fate, Fe fractions, and dissolved organic matter (DOM) isolates from permafrost-thaw under varying redox conditions. Under anoxic incubation conditions, 33% of the initial C was lost as gaseous species within 21 days, while under oxic conditions, 58% of C was lost. Under anoxic incubation, 42% of the total initial C was preserved in a dissolved fraction. Lignin-like compounds dominated permafrost-thaw, followed by lipid- and protein-like compounds. However, under anoxic incubation conditions, there was accumulation of lipid-like compounds and reduction in the nominal oxidation state of C over time, regardless of the compound classes. DOM dynamics may be affected by microbial activity and abiotic processes mediated by Fe-minerals related to selective DOM fractionation and/or its oxidation. Chemodiversity DOM signatures could serve as valuable proxies to track redox conditions with permafrost-thaw.
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Affiliation(s)
| | - Rucha P Wani
- Department of Plant & Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
- Department of Earth Sciences, Spatial Sciences Institute, University of Southern California, Los Angeles, California 90089, United States
| | - Aleksandar I Goranov
- Department of Chemistry and Biochemistry, Old Dominion University, 4501 Elkhorn Avenue, Norfolk, Virginia 23529, United States
| | - Tyler D Sowers
- Department of Plant & Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, Durham, North Carolina 27711, United States
| | - Matthew Fischel
- Department of Plant & Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
- USDA-ARS: Sustainable Agriculture Systems Lab, Beltsville, Maryland 20705, United States
| | - Thomas Alexander Douglas
- U.S. Army Cold Regions Research & Engineering Laboratory, Fort Wainwright, Fairbanks, Alaska 99703, United States
| | - Patrick G Hatcher
- Department of Chemistry and Biochemistry, Old Dominion University, 4501 Elkhorn Avenue, Norfolk, Virginia 23529, United States
| | - Donald L Sparks
- Department of Plant & Soil Sciences, University of Delaware, Newark, Delaware 19716, United States
- Hagler Institute Fellow, Texas A&M University, College Station, Texas 77840, United States
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3
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Sowers TD, Blackmon MD, Betts AR, Jerden ML, Scheckel KG, Bradham KD. Potassium jarosite seeding of soils decreases lead and arsenic bioaccessibility: A path toward concomitant remediation. Proc Natl Acad Sci U S A 2023; 120:e2311564120. [PMID: 38048468 PMCID: PMC10723135 DOI: 10.1073/pnas.2311564120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/23/2023] [Indexed: 12/06/2023] Open
Abstract
Soils are common sources of metal(loid) contaminant exposure globally. Lead (Pb) and arsenic (As) are of paramount concern due to detrimental neurological and carcinogenic health effects, respectively. Pb and/or As contaminated soils require remediation, typically leading to excavation, a costly and environmentally damaging practice of removing soil to a central location (e.g., hazardous landfill) that may not be a viable option in low-income countries. Chemical remediation techniques may allow for in situ conversion of soil contaminants to phases that are not easily mobilized upon ingestion; however, effective chemical remediation options are limited. Here, we have successfully tested a soil remediation technology using potted soils that relies on converting soil Pb and As into jarosite-group minerals, such as plumbojarosite (PLJ) and beudantite, possessing exceptionally low bioaccessibility [i.e., solubility at gastric pH conditions (pH 1.5 to 3)]. Across all experiments conducted, all new treatment methods successfully promoted PLJ and/or beudantite conversion, resulting in a proportional decrease in Pb and As bioaccessibility. Increasing temperature resulted in increased conversion to jarosite-group minerals, but addition of potassium (K) jarosite was most critical to Pb and As bioaccessibility decreases. Our methods of K-jarosite treatment yielded <10% Pb and As bioaccessibility compared to unamended soil values of approximately 70% and 60%, respectively. The proposed treatment is a rare dual remediation option that effectively treats soil Pb and As such that potential exposure is considerably reduced. Research presented here lays the foundation for ongoing field application.
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Affiliation(s)
- Tyler D. Sowers
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Durham, NC27711
| | - Matthew D. Blackmon
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Durham, NC27711
| | - Aaron R. Betts
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH45268
| | | | - Kirk G. Scheckel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH45268
| | - Karen D. Bradham
- Center for Environmental Measurement and Modeling, Office of Research and Development, United States Environmental Protection Agency, Durham, NC27711
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4
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Bradham KD, Nelson CM, Sowers TD, Lytle DA, Tully J, Schock MR, Li K, Blackmon MD, Kovalcik K, Cox D, Dewalt G, Friedman W, Pinzer EA, Ashley PJ. A national survey of lead and other metal(loids) in residential drinking water in the United States. J Expo Sci Environ Epidemiol 2023; 33:160-167. [PMID: 35986209 PMCID: PMC10807215 DOI: 10.1038/s41370-022-00461-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/13/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Exposure to lead (Pb), arsenic (As) and copper (Cu) may cause significant health issues including harmful neurological effects, cancer or organ damage. Determination of human exposure-relevant concentrations of these metal(loids) in drinking water, therefore, is critical. OBJECTIVE We sought to characterize exposure-relevant Pb, As, and Cu concentrations in drinking water collected from homes participating in the American Healthy Homes Survey II, a national survey that monitors the prevalence of Pb and related hazards in United States homes. METHODS Drinking water samples were collected from a national survey of 678 U.S. homes where children may live using an exposure-based composite sampling protocol. Relationships between metal(loid) concentration, water source and house age were evaluated. RESULTS 18 of 678 (2.6%) of samples analyzed exceeded 5 µg Pb L-1 (Mean = 1.0 µg L-1). 1.5% of samples exceeded 10 µg As L-1 (Mean = 1.7 µg L-1) and 1,300 µg Cu L-1 (Mean = 125 µg L-1). Private well samples were more likely to exceed metal(loid) concentration thresholds than public water samples. Pb concentrations were correlated with Cu and Zn, indicative of brass as a common Pb source is samples analyzed. SIGNIFICANCE Results represent the largest national-scale effort to date to inform exposure risks to Pb, As, and Cu in drinking water in U.S. homes using an exposure-based composite sampling approach. IMPACT STATEMENT To date, there are no national-level estimates of Pb, As and Cu in US drinking water collected from household taps using an exposure-based sampling protocol. Therefore, assessing public health impacts from metal(loids) in drinking water remains challenging. Results presented in this study represent the largest effort to date to test for exposure-relevant concentrations of Pb, As and Cu in US household drinking water, providing a critical step toward improved understanding of metal(loid) exposure risk.
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Affiliation(s)
- Karen D Bradham
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA.
| | | | - Tyler D Sowers
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - Darren A Lytle
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, OH, 45268, USA
| | - Jennifer Tully
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, OH, 45268, USA
| | - Michael R Schock
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, OH, 45268, USA
| | - Kevin Li
- Independent Researcher, Lansing, MI, 48915, USA
| | - Matthew D Blackmon
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - Kasey Kovalcik
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
| | - David Cox
- QuanTech, 6110 Executive Blvd Suite 206, Rockville, MD, 20852, USA
| | - Gary Dewalt
- QuanTech, 6110 Executive Blvd Suite 206, Rockville, MD, 20852, USA
| | - Warren Friedman
- Office of Lead Hazard Control and Healthy Homes, Department of Housing and Urban Development, Washington, DC, 20410, USA
| | - Eugene A Pinzer
- Office of Lead Hazard Control and Healthy Homes, Department of Housing and Urban Development, Washington, DC, 20410, USA
| | - Peter J Ashley
- Office of Lead Hazard Control and Healthy Homes, Department of Housing and Urban Development, Washington, DC, 20410, USA
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5
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Sowers TD, Blackmon MD, Bone SE, Kirby AM, Jerden ML, Noerpel MR, Scheckel KG, Bradham KD. Successful Conversion of Pb-Contaminated Soils to Low-Bioaccessibility Plumbojarosite Using Potassium-Jarosite at Ambient Temperature. Environ Sci Technol 2022; 56:15718-15727. [PMID: 36239028 PMCID: PMC10398550 DOI: 10.1021/acs.est.2c05606] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Methods promoting lead (Pb) phase transformation in soils are essential for decreasing Pb bioaccessibility/bioavailability and may offer an in situ, cost-efficient process for mitigating contaminant exposure. Recent plumbojarosite (PLJ) conversion methods have shown the greatest potential to reduce soil Pb bioaccessibility, an in vitro bioaccessibility assay measurement of the proportion of Pb solubilized under gastric chemical conditions. Soils tested utilizing the recent PLJ method were found to have a Pb bioaccessibility of <1%, compared to original soils possessing bioaccessibility of >70%. However, this technique requires heat (95-100 °C) to promote mineral transformation. Jarosite-group minerals may incorporate multiple interlayer cations; therefore, we probed the potential for jarosite to remediate Pb via intercalation by reacting presynthesized potassium (K)-jarosite with aqueous Pb and/or Pb-contaminated soil at room temperature. Both K-jarosite and heated PLJ-treated samples were investigated by pairing bioaccessibility analyses with advanced bulk and spatially resolved X-ray absorption spectroscopy analyses. Samples treated with K-jarosite promoted Pb transformation to low-bioaccessibility (<10%) PLJ, with soil being converted to 100% PLJ using both heated and nonheated techniques. μ-X-ray fluorescence (μ-XRF) and μ-X-ray absorption near-edge structure (μ-XANES) showcase significant differences between elemental interactions for heated and nonheated PLJ-treated samples with anglesite impurities being found on the microscale. Although further development is necessary to accommodate for suitable field conditions, results indicate, for the first time, that K-jarosite may successfully convert soil Pb to PLJ without high-temperature conditions. The newfound utility of K-jarosite is expected to be key to future jarosite-based soil Pb remediation method development.
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Affiliation(s)
- Tyler D Sowers
- Center of Environmental Measurement and Modeling, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Matthew D Blackmon
- Center of Environmental Measurement and Modeling, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Alicia M Kirby
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, United States
| | - Marissa L Jerden
- Jacobs Technology, Inc., 109 T.W. Alexander Drive, Research Triangle Park, North Carolina 27711, United States
| | - Matthew R Noerpel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - Kirk G Scheckel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - Karen D Bradham
- Center of Environmental Measurement and Modeling, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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6
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Sowers TD, Nelson CM, Blackmon MD, Jerden ML, Kirby AM, Diamond GL, Bradham KD. Interconnected soil iron and arsenic speciation effects on arsenic bioaccessibility and bioavailability: a scoping review. J Toxicol Environ Health B Crit Rev 2022; 25:1-22. [PMID: 34706629 PMCID: PMC9850428 DOI: 10.1080/10937404.2021.1996499] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Extensive research has examined arsenic (As) bioavailability in contaminated soils and is routinely assessed using in vitro bioaccessibility (IVBA) assays. Analysis of differences in bioaccessibility measurements across IVBA assays and phases is expected to provide valuable insights into geochemical mechanisms controlling soil As bioaccessibility and bioavailability. Soil iron (Fe) content and As speciation are expected to significantly influence IVBA gastric and intestinal phases due to fluctuations in precipitation-dissolution chemistry and sorption reactivity as pH and assay chemical complexity changes. The aim of this review was to examine these relationships by 1) conducting a meta-analysis (n = 47 soils) determining the influence of total Fe on As bioaccessibility measurements and 5 IVBA assays and 2) investigating the effect of As speciation on gastric/intestinal phase IVBA and in vitro-in vivo correlations. Our findings indicate that soil Fe content and As speciation heterogeneity are important in elucidating variability of bioaccessibility measurements across IVBA assays and gastrointestinal phases. Greater focus on coupled As speciation and Fe precipitation chemistry may (1) improve our understanding of soil geochemical factors and assay constituents that influence As in vitro-in vivo correlations and (2) resolve variability in the precision of oral relative bioavailability (RBA) estimated using IVBA assays for soils possessing heterogenous As speciation and Fe composition.
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Affiliation(s)
- Tyler D Sowers
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC, US
| | | | - Matthew D Blackmon
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC, US
| | | | | | | | - Karen D Bradham
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC, US
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Sowers TD, Bone SE, Noerpel MR, Blackmon MD, Karna RR, Scheckel KG, Juhasz AL, Diamond GL, Thomas DJ, Bradham KD. Plumbojarosite Remediation of Soil Affects Lead Speciation and Elemental Interactions in Soil and in Mice Tissues. Environ Sci Technol 2021; 55:15950-15960. [PMID: 34806356 PMCID: PMC9606633 DOI: 10.1021/acs.est.1c06067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Lead (Pb) contamination of soils is of global concern due to the devastating impacts of Pb exposure in children. Because early-life exposure to Pb has long-lasting health effects, reducing exposure in children is a critical public health goal that has intensified research on the conversion of soil Pb to low bioavailability phases. Recently, plumbojarosite (PLJ) conversion of highly available soil Pb was found to decrease Pb relative bioavailability (RBA <10%). However, there is sparse information concerning interactions between Pb and other elements when contaminated soil, pre- and post-remediation, is ingested and moves through the gastrointestinal tract (GIT). Addressing this may inform drivers of effective chemical remediation strategies. Here, we utilize bulk and micro-focused Pb X-ray absorption spectroscopy to probe elemental interactions and Pb speciation in mouse diet, cecum, and feces samples following ingestion of contaminated soils pre- and post-PLJ treatment. RBA of treated soils was less than 1% with PLJ phases transiting the GIT with little absorption. In contrast, Pb associated with organics was predominantly found in the cecum. These results are consistent with transit of insoluble PLJ to feces following ingestion. The expanded understanding of Pb interactions during GIT transit complements our knowledge of elemental interactions with Pb that occur at higher levels of biological organization.
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Affiliation(s)
- Tyler D Sowers
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Sharon E Bone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Matthew R Noerpel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - Matthew D Blackmon
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Ranju R Karna
- Bennett Aerospace, Inc., Engineer Research and Development Center, USACE, Vicksburg, Mississippi 39183, United States
| | - Kirk G Scheckel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - Albert L Juhasz
- Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide, SA 5095, Australia
| | - Gary L Diamond
- SRC, Inc., North Syracuse, New York 13212, United States
| | - David J Thomas
- Center for Computational Toxicology & Exposure, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Karen D Bradham
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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8
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Sowers TD, Nelson CM, Diamond GL, Blackmon MD, Jerden ML, Kirby AM, Noerpel MR, Scheckel KG, Thomas DJ, Bradham KD. High Lead Bioavailability of Indoor Dust Contaminated with Paint Lead Species. Environ Sci Technol 2021; 55:402-411. [PMID: 33307690 PMCID: PMC8204915 DOI: 10.1021/acs.est.0c06908] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
House dust and soils can be major sources of lead (Pb) exposure for children. The American Healthy Homes Survey (AHHS) was developed to estimate Pb exposure from house dust and soil, in addition to other potential household contaminants and allergens. We have combined X-ray absorption spectroscopic (XAS) fingerprinting and in vivo mouse relative bioavailability (RBA) measurements for a subset of house dust and residential soils collected in the AHHS, with the primary objective of gaining a better understanding of determinants of house dust Pb bioavailability. Lead speciation was well related to variations in RBA results and revealed that highly bioavailable Pb (hydroxy)carbonate (indicative of Pb-based paint) was the major Pb species present in house dusts. Measured Pb RBA was up to 100% and is likely driven by paint Pb. To our knowledge, this is the first report of in vivo Pb RBA for U.S. house dust contaminated in situ with paint Pb and corroborates results from a previous study that demonstrated high RBA of paint Pb added to soil. We also report a relatively low RBA (23%) in a residential soil where the major Pb species was found to be plumbojarosite, consistent with a previous report that plumbojarosite lowers Pb RBA in soils.
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Affiliation(s)
- Tyler D. Sowers
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, US
| | - Clay M. Nelson
- SRC, Inc., North Syracuse, New York 13212, United States
| | | | - Matt D. Blackmon
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, US
| | - Marissa L. Jerden
- Jacobs Technology, Inc., 109 T.W. Alexander Drive, RTP, North Carolina 27711, US
| | - Alicia M. Kirby
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, US
| | - Matthew R. Noerpel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, US
| | - Kirk G. Scheckel
- Center for Environmental Solutions & Emergency Response, Office of Research and Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, US
| | - David J. Thomas
- Center for Computational Toxicology & Exposure, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, US
| | - Karen D. Bradham
- Center of Environmental Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, US
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9
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Sowers TD, Wani RP, Coward EK, Fischel MHH, Betts AR, Douglas TA, Duckworth OW, Sparks DL. Spatially Resolved Organomineral Interactions across a Permafrost Chronosequence. Environ Sci Technol 2020; 54:2951-2960. [PMID: 32023050 DOI: 10.1021/acs.est.9b06558] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Permafrost contains a large (1700 Pg C) terrestrial pool of organic matter (OM) that is susceptible to degradation as global temperatures increase. Of particular importance is syngenetic Yedoma permafrost containing high OM content. Reactive iron phases promote stabilizing interactions between OM and soil minerals and this stabilization may be of increasing importance in permafrost as the thawed surface region ("active layer") deepens. However, there is limited understanding of Fe and other soil mineral phase associations with OM carbon (C) moieties in permafrost soils. To elucidate the elemental associations involved in organomineral complexation within permafrost systems, soil cores spanning a Pleistocene permafrost chronosequence (19,000, 27,000, and 36,000 years old) were collected from an underground tunnel near Fairbanks, Alaska. Subsamples were analyzed via scanning transmission X-ray microscopy-near edge X-ray absorption fine structure spectroscopy at the nano- to microscale. Amino acid-rich moieties decreased in abundance across the chronosequence. Strong correlations between C and Fe with discrete Fe(III) or Fe(II) regions selectively associated with specific OM moieties were observed. Additionally, Ca coassociated with C through potential cation bridging mechanisms. Results indicate Fe(III), Fe(II), and mixed valence phases associated with OM throughout diverse permafrost environments, suggesting that organomineral complexation is crucial to predict C stability as permafrost systems warm.
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Affiliation(s)
- Tyler D Sowers
- Delaware Environmental Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716-7310, United States
- Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, Durham, North Carolina 27711, United States
| | - Rucha P Wani
- Delaware Environmental Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716-7310, United States
| | - Elizabeth K Coward
- Delaware Environmental Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716-7310, United States
| | - Matthew H H Fischel
- Delaware Environmental Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716-7310, United States
| | - Aaron R Betts
- Delaware Environmental Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716-7310, United States
| | - Thomas A Douglas
- U.S. Army Cold Regions Research & Engineering Laboratory, 9th Avenue, Building 4070, Fort Wainwright, Fairbanks, 99703 Alaska, United States
| | - Owen W Duckworth
- Department of Crop and Soil Sciences, North Carolina State University, 101 Derieux Street, Campus Box 7620, Raleigh, North Carolina 26795, United States
| | - Donald L Sparks
- Delaware Environmental Institute, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716-7310, United States
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10
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Sowers TD, Holden KL, Coward EK, Sparks DL. Dissolved Organic Matter Sorption and Molecular Fractionation by Naturally Occurring Bacteriogenic Iron (Oxyhydr)oxides. Environ Sci Technol 2019; 53:4295-4304. [PMID: 30843682 DOI: 10.1021/acs.est.9b00540] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Iron (oxyhydr)oxides are highly reactive, environmentally ubiquitous organic matter (OM) sorbents that act as mediators of terrestrial and aqueous OM cycling. However, current understanding of environmental iron (oxyhydr)oxide affinity for OM is limited primarily to abiogenic oxides. Bacteriogenic iron (oxyhydr)oxides (BIOs), common to quiescent waterways and soil redox transitions, possess a high affinity for oxyanions (i.e., arsenate and chromate) and suggests that BIOs may be similarly reactive for OM. Using adsorption and desorption batch reactions, paired with Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry, this work demonstrates that BIOs are capable of sorbing leaf litter-extracted DOM and Suwannee River Humic/Fulvic Acid (SRHA/SRFA) and have sorptive preference for distinct organic carbon compound classes at the biomineral interface. BIOs were found to sorb DOM and SRFA to half the extent of 2-line ferrihydrite per mass of sorbent and was resilient to desorption at high ionic strength and in the presence of a competitive ligand. We observed the preferential sorption of aromatic and carboxylic-containing species and concurrent solution enrichment of aliphatic groups unassociated with carboxylic acids. These findings suggest that DOM cycling may be significantly affected by BIOs, which may impact nutrient and contaminant transport in circumneutral environments.
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Affiliation(s)
- Tyler D Sowers
- Delaware Environmental Institute, Department of Plant and Soil Sciences , University of Delaware , Newark , Delaware 19716-7310 , United States
| | - Kathryn L Holden
- Delaware Environmental Institute, Department of Plant and Soil Sciences , University of Delaware , Newark , Delaware 19716-7310 , United States
| | - Elizabeth K Coward
- Delaware Environmental Institute, Department of Plant and Soil Sciences , University of Delaware , Newark , Delaware 19716-7310 , United States
| | - Donald L Sparks
- Delaware Environmental Institute, Department of Plant and Soil Sciences , University of Delaware , Newark , Delaware 19716-7310 , United States
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Sowers TD, Adhikari D, Wang J, Yang Y, Sparks DL. Spatial Associations and Chemical Composition of Organic Carbon Sequestered in Fe, Ca, and Organic Carbon Ternary Systems. Environ Sci Technol 2018; 52:6936-6944. [PMID: 29770687 DOI: 10.1021/acs.est.8b01158] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Organo-mineral associations of organic carbon (OC) with iron (Fe) oxides play a major role in environmental OC sequestration, a process crucial to mitigating climate change. Calcium has been found to have high coassociation with OC in soils containing high Fe content, increase OC sorption extent to poorly crystalline Fe oxides, and has long been suspected to form bridging complexes with Fe and OC. Due to the growing realization that Ca may be an important component of C cycling, we launched a scanning transmission X-ray microscopy (STXM) investigation, paired with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, in order to spatially resolve Fe, Ca, and OC relationships and probe the effect of Ca on sorbed OC speciation. We performed STXM-NEXAFS analysis on 2-line ferrihydrite reacted with leaf litter-extractable dissolved OC and citric acid in the absence and presence of Ca. Organic carbon was found to highly associate with Ca ( R2 = 0.91). Carboxylic acid moieties were dominantly sequestered; however, Ca facilitated the additional sequestration of aromatic and phenolic moieties. Also, C NEXAFS revealed polyvalent metal ion complexation. Our results provide evidence for the presence of Fe-Ca-OC ternary complexation, which has the potential to significantly impact how organo-mineral associations are modeled.
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Affiliation(s)
- Tyler D Sowers
- Department of Plant and Soil Sciences, Delaware Environmental Institute , University of Delaware , Newark , Delaware 19716 , United States
| | - Dinesh Adhikari
- Department of Civil and Environmental Engineering , University of Nevada , Reno , Nevada 89557 United States
| | - Jian Wang
- Canadian Light Source Inc. , University of Saskatchewan , Saskatoon , Saskatchewan S7N 2 V3 , Canada
| | - Yu Yang
- Department of Civil and Environmental Engineering , University of Nevada , Reno , Nevada 89557 United States
| | - Donald L Sparks
- Department of Plant and Soil Sciences, Delaware Environmental Institute , University of Delaware , Newark , Delaware 19716 , United States
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Sowers TD, Stuckey JW, Sparks DL. The synergistic effect of calcium on organic carbon sequestration to ferrihydrite. Geochem Trans 2018; 19:4. [PMID: 29397451 PMCID: PMC5797485 DOI: 10.1186/s12932-018-0049-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/28/2018] [Indexed: 05/14/2023]
Abstract
Sequestration of organic carbon (OC) in environmental systems is critical to mitigating climate change. Organo-mineral associations, especially those with iron (Fe) oxides, drive the chemistry of OC sequestration and stability in soils. Short-range-ordered Fe oxides, such as ferrihydrite, demonstrate a high affinity for OC in binary systems. Calcium commonly co-associates with OC and Fe oxides in soils, though the bonding mechanism (e.g., cation bridging) and implications of the co-association for OC sequestration remain unresolved. We explored the effect of calcium (Ca2+) on the sorption of dissolved OC to 2-line ferrihydrite. Sorption experiments were conducted between leaf litter-extractable OC and ferrihydrite at pH 4 to 9 with different initial C/Fe molar ratios and Ca2+ concentrations. The extent of OC sorption to ferrihydrite in the presence of Ca2+ increased across all tested pH values, especially at pH ≥ 7. Sorbed OC concentration at pH 9 increased from 8.72 ± 0.16 to 13.3 ± 0.20 mmol OC g-1 ferrihydrite between treatments of no added Ca2+ and 30 mM Ca2+ addition. Batch experiments were paired with spectroscopic studies to probe the speciation of sorbed OC and elucidate the sorption mechanism. ATR-FTIR spectroscopy analysis revealed that carboxylic functional moieties were the primary sorbed OC species that were preferentially bound to ferrihydrite and suggested an increase in Fe-carboxylate ligand exchange in the presence of Ca at pH 9. Results from batch to spectroscopic experiments provide significant evidence for the enhancement of dissolved OC sequestration to 2-line ferrihydrite and suggest the formation of Fe-Ca-OC ternary complexes. Findings of this research will inform modeling of environmental C cycling and have the potential to influence strategies for managing land to minimize OM stabilization.
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Affiliation(s)
- Tyler D. Sowers
- Department of Plant and Soil Sciences and Delaware Environmental Institute, University of Delaware, 221 Academy Street, ISE Lab, Newark, DE 19711 USA
| | - Jason W. Stuckey
- Department of Plant and Soil Sciences and Delaware Environmental Institute, University of Delaware, 221 Academy Street, ISE Lab, Newark, DE 19711 USA
- Biology Department, Multnomah University, 8435 NE Glisan St, Portland, OR 97220 USA
| | - Donald L. Sparks
- Department of Plant and Soil Sciences and Delaware Environmental Institute, University of Delaware, 221 Academy Street, ISE Lab, Newark, DE 19711 USA
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Kang J, Sowers TD, Duckworth OW, Amoozegar A, Heitman JL, McLaughlin RA. Turbidimetric determination of anionic polyacrylamide in low carbon soil extracts. J Environ Qual 2013; 42:1902-1907. [PMID: 25602431 DOI: 10.2134/jeq2013.07.0279] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Concerns over runoff water quality from agricultural lands and construction sites have led to the development of improved erosion control practices, including application of polyacrylamide (PAM). We developed a quick and reliable method for quantifying PAM in soil extracts at low carbon content by using a turbidimetric reagent, Hyamine 1622. Three high-molecular weight anionic PAMs differing in charge density (7, 20, and 50 mol%) and five water matrices, deionized (DI) water and extracts from four different soils, were used to construct PAM calibration curves by reacting PAM solutions with hyamine and measuring turbidity development from the PAM-hyamine complex. The PAM calibration curve with DI water showed a strong linear relationship ( = 0.99), and the sensitivity (slope) of calibration curves increased with increasing PAM charge density with a detection limit of 0.4 to 0.9 mg L. Identical tests with soil extracts showed the sensitivity of the hyamine method was dependent on the properties of the soil extract, primarily organic carbon concentration. Although the method was effective in mineral soils, the highest charge density PAM yielded a more reliable linear relationship ( > 0.97) and lowest detection limit (0.3 to 1.2 mg L), compared with those of the lower charge density PAMs (0.7 to 23 mg L). Our results suggest that the hyamine test could be an efficient method for quantifying PAM in environmental soil water samples as long as the organic carbon in the sample is low, such as in subsurface soil material often exposed at construction sites.
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