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Processes Controlling the Toxicity and Transport of Nutrients and Contaminants in the Critical Zone Matthew Ginder-Vogel Environmental Soil Chemistry Group.

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Presentation on theme: "Processes Controlling the Toxicity and Transport of Nutrients and Contaminants in the Critical Zone Matthew Ginder-Vogel Environmental Soil Chemistry Group."— Presentation transcript:

1 Processes Controlling the Toxicity and Transport of Nutrients and Contaminants in the Critical Zone Matthew Ginder-Vogel Environmental Soil Chemistry Group and the Center for Critical Zone Research University of Delaware

2 Contributors and Collaborators Funding Sources: NSF, USDA, and DOE-ERSD Light Sources: ALS, APS, NSLS, and SSRL Donald L. Sparks Ryan Tappero Jen Seiter Kristin Staats-Borda University of Delaware Scott Fendorf Stanford University Synchrotron Light Sources Tony Lanzirotti Bill Rao Steve Sutton Matthew Newville Sam Webb Joe Rogers John Bargar Matthew Marcus

3 X-ray Spectroscopy in Environmental Science Dependence on aqueous solid interactions Dependence on aqueous solid interactions Redox transformations play an important role in contaminant mobility Redox transformations play an important role in contaminant mobility Resolving chemical species and bonding environments within solids is challenging Resolving chemical species and bonding environments within solids is challenging Low concentrations and varying scales Low concentrations and varying scales Multiple X-ray techniques are required for thorough characterization Multiple X-ray techniques are required for thorough characterization  -XAS,  -XRD, microtomography, tomography, XAS, XRD  -XAS,  -XRD, microtomography, tomography, XAS, XRD

4 Ni phyotaccumulation by A. murale near an historic Canadian refinery As and PO 4 3- in chicken litter and soils Heavy metals at DOE sites

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6 Uranium(IV) Content After 40 d without Oxygen 0% 61% 0% Outer Injection Well Inner Injection Well Inner Extraction Well Outer Extraction Well Sampling Wells NA 30% 17% NA 51% 54% NA 0% Depth 45 ft 40 ft 35 ft - Average geochemical conditions at time of collection pH 6.5, ~ 5 mM sulfide, 1.5 mM HCO 3 -, ~1 mM TOC, ~3 mM SO 4 -, ~100  M Fe 2+ - Reduced uranium detected throughout stimulation zone (except well #100) - No well contains more than ~ 60% U(IV) Isolation Zone Treatment Zone

7 Bulk Characterization – Well #102 – 40 ft Uranium L-edge XANES * *Multiple scattering not included in table Uranium L-edge EXAFS – 8 months of aging - Ongoing uranium reduction - EXAFS suggests a mixture of uraninite and uranyl-carbonate (Å) (Å 2 )

8 Minerals Identified - Quartz (Q) - Montmorillonite (M) - Muscovite (Mu) - Rutherfordine – UO 2 CO 3 (R) - Uraninite (U) Bulk Characterization – Well #102 – 40 ft

9 Micro-analysis of Uranium and Iron Distribution 100  m Uranium L III Fluorescence Iron K  Fluorescence 10,000 cps 35,000 cps 500 cps 1,000 cps Quartz (Q) Rutherfordine (R) Corrundum (C) - Uranium Hotspots > 90% U(VI) - Diffuse areas ~ 50% U(VI) - Only quartz detected in diffuse areas - No uraninite detected  -XRD

10 Alyssum murale (yellowtuft) Native to Mediterranean serpentine soilsNative to Mediterranean serpentine soils Concentrate trace metals (Ni, Co) in shoot tissue (weight percent) as mechanism to survive metalliferous soil conditionsConcentrate trace metals (Ni, Co) in shoot tissue (weight percent) as mechanism to survive metalliferous soil conditions Accumulators recognized for centuries and used as geobotanical indicators (mineral prospecting)Accumulators recognized for centuries and used as geobotanical indicators (mineral prospecting) Alyssum developed as commercial crop for phytoremediation/phytominingAlyssum developed as commercial crop for phytoremediation/phytomining Meet Alyssum murale (Ni/Co Hyperaccumulator)

11 Metal Localization in Leaves Cobalt preferentially localized at leaf tips/margins Cobalt preferentially localized at leaf tips/margins

12 In situ cobalt localization Co preferentially localized between cells (apoplastic) Co preferentially localized between cells (apoplastic) Differential absorption computed microtomography of hydrated leaf 8 % Co 0.5 % 100  m Grey = Cell structure Color = Cobalt

13 A. murale rhizosheath of Ni/Al-LDH coated quartz sand Ni Ca Root-Mineral-H 2 O Interface : Depletion Gradients in the Rhizosphere Ni Ca ‘ROOT’

14 A G F E D C B Transformations in the Rhizosphere Ni/Al LDH d-spacing ~7.8 Ǻ ABCDEFG

15 Root 100  m Control Bulk material 2 1 Ni Ca Root-Mineral-H 2 O Interface : Phase Transformations in the Rhizosphere

16 Arsenic in Poultry Litter Arsenicals are added to poultry feed for disease prevention and to promote weight gain. Arsenicals are added to poultry feed for disease prevention and to promote weight gain. The source of As is an organic compound, roxarsone. The source of As is an organic compound, roxarsone. Arsenic is introduced to soil and water through land application of poultry litter. Arsenic is introduced to soil and water through land application of poultry litter. Roxarsone degrades into inorganic and organic As compounds through biogeochemical reactions. Roxarsone degrades into inorganic and organic As compounds through biogeochemical reactions. Roxarsone

17 Trace Metal Distribution Trace Metals are Distributed Throughout the Poultry Litter As Cu Mn Zn

18 Trace Metal Associations AsCu AsMn Cu Mn As Arsenic has strong correlations with both Cu and Mn

19 Evolution of Arsenic Speciation Litter samples were collected from a poultry house and stored for 1 year Litter samples were collected from a poultry house and stored for 1 year Arsenic speciation degraded from roxarsone into other inorganic and organic arsenic species. Arsenic speciation degraded from roxarsone into other inorganic and organic arsenic species.

20 Heterogeneous Arsenic Speciation Arsenic speciation varies between particles within a sample. Arsenic speciation varies between particles within a sample. Spot 1 is composed of more reduced species, while spot 4 has roxarsone and oxidized arsenic species. Spot 1 is composed of more reduced species, while spot 4 has roxarsone and oxidized arsenic species

21 Ongoing Research Poultry Manganese oxide surface chemistry Structure of Biogenic Mn-oxides Arsenic and trace metal speciation in fresh excreta and chicken tissues Chemistry and kinetics of As(III) oxidation - bulk- and  -XAS, and  -XRD - rapid-scanning XAS, bulk-XAS, XRD Effect of geochemical conditions on oxide structure - bulk-XAS, XRD Cadmium in Thai rice paddy soils Cd speciation in oscillating redox environments - bulk- and  -XAS, XRD,  -XRD

22 Wish List for NSLS II Bulk X-ray Absorption Spectroscopy Micro X-ray Absorption Spectroscopy Quick Scanning X-ray Absorption Spectroscopy Dedicated work horse line Dedicated work horse line Spot size: 100 nm - 10  m High flux, multi-element, and energy dispersive detectors Proposal System One proposal can receive time on multiple beamlines Variable flux for redox sensitive samples Better detectors mono crystal choice, multi-element detectors, harmonic rejection mirror Software Standardized data collection software


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