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Garvin MC, Schijf J, Kaufman SR, Konow C, Liang D, Nigra AE, Stracker NH, Whelan RJ, Wiles GC. A survey of trace metal burdens in increment cores from eastern cottonwood (Populus deltoides) across a childhood cancer cluster, Sandusky County, OH, USA. Chemosphere 2020; 238:124528. [PMID: 31425869 DOI: 10.1016/j.chemosphere.2019.124528] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 08/04/2019] [Accepted: 08/05/2019] [Indexed: 06/10/2023]
Abstract
A dendrochemical study of cottonwood trees (Populus deltoides) was conducted across a childhood cancer cluster in eastern Sandusky County (Ohio, USA). The justification for this study was that no satisfactory explanation has yet been put forward, despite extensive local surveys of aerosols, groundwater, and soil. Concentrations of eight trace metals were measured by ICP-MS in microwave-digested 5-year sections of increment cores, collected during 2012 and 2013. To determine whether the onset of the first cancer cases could be connected to an emergence of any of these contaminants, cores spanning the period 1970-2009 were taken from 51 trees of similar age, inside the cluster and in a control area to the west. The abundance of metals in cottonwood tree annual rings served as a proxy for their long-term, low-level accumulation from the same sources whereby exposure of the children may have occurred. A spatial analysis of cumulative metal burdens (lifetime accumulation in the tree) was performed to search for significant 'hotspots', employing a scan statistic with a mask of variable radius and center. For Cd, Cr, and Ni, circular hotspots were found that nearly coincide with the cancer cluster and are similar in size. No hotspots were found for Co, Cu, and Pb, while As and V were largely below method detection limits. Whereas our results do not implicate exposure to metals as a causative factor, we conclude that, after 1970, cottonwood trees have accumulated more Cd, Cr, and Ni, inside the childhood cancer cluster than elsewhere in Sandusky County.
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Affiliation(s)
- Mary C Garvin
- Oberlin College, Department of Biology, 119 Woodland St., Oberlin, OH, 44074, USA
| | - Johan Schijf
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, P.O. Box 38, Solomons, MD, 20688, USA.
| | - Sonya R Kaufman
- Oberlin College, Department of Biology, 119 Woodland St., Oberlin, OH, 44074, USA
| | - Courtney Konow
- Oberlin College, Department of Biology, 119 Woodland St., Oberlin, OH, 44074, USA
| | - Dong Liang
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, P.O. Box 38, Solomons, MD, 20688, USA
| | - Anne E Nigra
- Columbia University Mailman School of Public Health, Department of Environmental Health Sciences, 722 West 168th St., New York, NY, 10032, USA
| | - Norberth H Stracker
- Johns Hopkins University School of Medicine, Division of Infectious Diseases, 1830 East Monument St., Room 442, Baltimore, MD, 21287, USA
| | - Rebecca J Whelan
- University of Notre Dame, Department of Chemistry and Biochemistry, 140D McCourtney Hall, Notre Dame, IN, 46556, USA
| | - Gregory C Wiles
- The College of Wooster, Department of Earth Sciences, 944 College Hall, Wooster, OH, 44691, USA
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Schijf J, Ebling AM. Investigation of the ionic strength dependence of Ulva lactuca acid functional group pK(a)s by manual alkalimetric titrations. Environ Sci Technol 2010; 44:1644-1649. [PMID: 20121199 DOI: 10.1021/es9029667] [Citation(s) in RCA: 6] [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: 05/28/2023]
Abstract
We performed a series of manual alkalimetric titrations in NaCl solutions (0.01-5.0 M) at T = 25 degrees C on both fresh and dehydrated samples of the marine chlorophyte Ulva lactuca (sea lettuce), a strong metal accumulator holding considerable promise in biosorbent and biomonitor applications. Functional groups were characterized in terms of their number, site densities, and acid dissociation constants (pK(a)s). FITEQL4.0 modeling shows that, at any ionic strength, titration curves for dehydrated biomass in the pH range 2-10 are adequately described by three functional groups with remarkably uniform site densities of about 5 x 10(-4) mol/g. Lower site densities for fresh U. lactuca are consistent with approximately 87% water content. The pK(a)s display pronounced ionic strength dependent behavior obeying an extended Debye-Huckel relation. Extrapolation to I = 0 yields values of 4.26 +/- 0.04, 6.44 +/- 0.02, and 9.56 +/- 0.04. This information by itself is insufficient to unambiguously identify the groups. Similar site densities suggest that all three are linked to major molecular building blocks of the cell material, pointing to carboxylic acids, phosphate esters, and amines as likely candidates. Highly acidic sulfate esters, not detected in our titrations, may also play a role in trace metal adsorption on U. lactuca.
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Affiliation(s)
- Johan Schijf
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, P.O. Box 38, Solomons, Maryland 20688, USA.
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Short RT, Byrne RH, Hollander D, Schijf J, Toler SK, Vanvleet ES. Oceanography. Mass Spectrom (Tokyo) 2008. [DOI: 10.1002/9780470395813.ch9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Quinn KA, Byrne RH, Schijf J. Sorption of yttrium and rare earth elements by amorphous ferric hydroxide: influence of temperature. Environ Sci Technol 2007; 41:541-6. [PMID: 17310719 DOI: 10.1021/es0618191] [Citation(s) in RCA: 6] [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: 05/14/2023]
Abstract
The sorption of yttrium and the rare earth elements (YREEs) by amorphous ferric hydroxide was investigated between 10 and 40 degrees C over a range of pH (4.7-7.1) in the absence of solution complexation. Distribution coefficients, defined as iKFe = [MSi]T/([M]T[Fe3+]s), where [MSi]T is the concentration of sorbed YREEs, [M]T is the total dissolved YREE concentration, and [Fe3+]s is the concentration of precipitated iron, increased with increasing temperature over the entire investigated pH range. The observed increase in iKFe was largest for the heavy REEs, indicating that relative log iKFe values (i.e., YREE patterns) vary somewhat with temperature. The pH dependence of YREE sorption was described by a surface complexation model of the form iKFe = (sbeta1[H+](-1) + sbeta2[H+](-2))/(sK1[H+] + 1), where sbetan are stability constants for sorption of free YREE ions (M3+) and sK1 is a surface protonation constant for amorphous ferric hydroxide. The influence of temperature on the YREE surface stability constants (sbeta1 and sbeta2) was characterized by calculating molar enthalpies for M3+ sorption (deltaH1(0) and deltaH2(0)) using the van 't Hoff equation. The deltaH1(0) values appropriate to sbeta1 range from 11.8 to 13.4 kcal/mol, whereas the deltaH2(0) values appropriate to sbeta2 range between 7.7 and 12.3 kcal/mol. These values are on the same order of magnitude as enthalpies of the first hydrolysis step for a variety of cations.
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Affiliation(s)
- Kelly A Quinn
- College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, Florida 33701, USA
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Cosden JM, Schijf J, Byrne RH. Fractionation of platinum group elements in aqueous systems: comparative kinetics of palladium and platinum removal from seawater by Ulva lactuca L. Environ Sci Technol 2003; 37:555-560. [PMID: 12630472 DOI: 10.1021/es0259234] [Citation(s) in RCA: 9] [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: 05/24/2023]
Abstract
A marine macroalga, Ulva lactuca L., was used as a substrate to compare the kinetics of palladium (Pd) and platinum (Pt) removal from seawater. This work indicates that, while the equilibrium behaviors of Pd and Pt are in many respects similar, their kinetic behaviors are quite distinct. The removal of both Pt(II) and Pt(IV) from seawater by U. lactuca is slower than the removal of Pd(II) by approximately an order of magnitude. Relative Pd and Pt removal rates are strongly influenced by system hydrodynamics. Under quiescent conditions, lambda(Pd)/lambda(Pt), the ratio of Pd and Pt removal rates, is 7 +/- 2, whereas under turbulent conditions lambda(Pd)/lambda(Pt) can be as large as 27. These observations suggest that the disparate kinetic behaviors of Pd and Pt may produce considerable differences in the environmental dispersion of these elements.
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Affiliation(s)
- Jeanette M Cosden
- College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, Florida 33701, USA
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