Grantee Research Project Results

Speciation of chromium in environmental media using capillary electrophoresis with multiple wavlength UV/visible detection

EPA Grant Number: R828771C005
Subproject: this is subproject number 005 , established and managed by the Center Director under grant R828771
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for the Study of Childhood Asthma in the Urban Environment
Center Director: Hansel, Nadia
Title: Speciation of chromium in environmental media using capillary electrophoresis with multiple wavlength UV/visible detection
Investigators: Stone, Alan T. , OMelia, Charles R.
Institution: The Johns Hopkins University
EPA Project Officer: Aja, Hayley
Project Period: October 1, 2001 through September 30, 2002
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (2001) Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

The speciation of chromium controls it's tendency to become adsorbed or precipitated, it's ability to be transported by water or wind borne particles, it's tendency to react with oxidants (e.g. O2, MnO2), reductants (e.g. FeII, natural organic matter), and ligands (e.g. carbonate, phosphate, natural organic matter) and it's toxicity towards humans and other organisms. The diphenylcarbazide (DPC) test for distinguishing CrVI from CrIII is currently the most commonly applied chromium speciation technique.

In order to resolve interference problems inherent in the DPC test and to gain new information about CrIII speciation, we propose using: (i) capillary electrophoresis (CE) with multiple wavelength UV-visible detection for identifying and quantifying CrVI and CrIII dissolved species in surface waters, soil and sediment interstitial waters, and in ground waters. Small chromium-containing colloids are also found in many samples. If time allows, methods of characterizing these small colloids by CE will also be investigated. We are presently the only U.S. group investigating the use of CE for characterizing metal speciation. Wayne Garrison (EPA, Athens, GA) is employing CE to characterize natural and synthetic organic compounds.

Approach:

CE-based methods for accurately characterizing dissolved chromium in water and interstitial samples relevant to hazardous waste sites will be developed. CE efficiently resolves analytes based upon differences in molecular charge and hydrodynamic radii. We will investigate how (i) properties of the capillary wall and CE electrolyte medium; (ii) possible metal ion and ligand exchange reactions within the capillary; and (iii) non-chromium sample constituents affect the resolution and detection limit of CE. Authentic standards for CrIII complexes with low MW ligands likely to be encountered at hazardous waste sites will be synthesized; surface and subsurface water samples from pristine and chromium-contaminated field sites will be collected. Characterization of field samples of different pH, redox status, total chromium concentrations, and major constituent concentrations (total and dissolved iron, NOM, ionic strength) is an important part of this work. In the case of small colloids, the presence of FeIII and natural organic matter may affect colloidal charge and aggregation properties.

Expected Results:

A CE instrument equipped with diode-array UV-visible detector currently can be purchased for $50,000 and mastered in a few weeks by individuals lacking specialized training. Hence, CE-UV/VIS could become as common as GC-FID/ECD, HPLC-UV/VIS, and AAS in providing accurate information for risk assessment and risk management activities. We plan to demonstrate to environmental practitioners how new and accurate speciation information can be used to improve our understanding of the environmental behavior, health effects, and ecotoxicological effects of chromium.

Publications and Presentations:

Publications have been submitted on this subproject: View all 5 publications for this subproject | View all 108 publications for this center

Journal Articles:

Journal Articles have been submitted on this subproject: View all 1 journal articles for this subproject | View all 20 journal articles for this center

Supplemental Keywords:

toxics, inorganics, trace analysis, oxidation state, complexation., RFA, Scientific Discipline, Health, PHYSICAL ASPECTS, Water, Waste, Chemical Engineering, Hydrology, Environmental Chemistry, Geochemistry, Health Risk Assessment, Analytical Chemistry, Risk Assessments, Hazardous Waste, Physical Processes, Chemistry and Materials Science, Ecological Risk Assessment, Ecology and Ecosystems, Engineering, Chemistry, & Physics, Environmental Engineering, Hazardous, electrochemical technology, fate and transport, hazardous waste treatment, aquatic ecosystem, chemical exposure, contaminant transport, contaminant dynamics, fate and transport , analytical measurement methods, environmental risks, exposure, chemical composition, chemical detection techniques, ecotoxicological effects, adsorption, chemical kinetics, human exposure, chromium speciation, groundwater contamination, chemical releases, capillary elecrophoresis, capillary electrophoresis, hydrodynamics, groundwater, hazardous substance contamination

Progress and Final Reports:

Final

Main Center Abstract and Reports:

R828771    Center for the Study of Childhood Asthma in the Urban Environment

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R828771C001 Co-Contaminant Effects on Risk Assessment and Remediation Activities Involving Urban Sediments and Soils: Phase II
R828771C002 The Fate and Potential Bioavailability of Airborne Urban Contaminants
R828771C003 Geochemistry, Biochemistry, and Surface/Groundwater Interactions for As, Cr, Ni, Zn, and Cd with Applications to Contaminated Waterfronts
R828771C004 Large Eddy Simulation of Dispersion in Urban Areas
R828771C005 Speciation of chromium in environmental media using capillary electrophoresis with multiple wavlength UV/visible detection
R828771C006 Zero-Valent Metal Treatment of Halogenated Vapor-Phase Contaminants in SVE Offgas
R828771C007 The Center for Hazardous Substances in Urban Environments (CHSUE) Outreach Program
R828771C008 New Jersey Institute of Technology Outreach Program for EPA Region II
R828771C009 Urban Environmental Issues: Hartford Technology Transfer and Outreach
R828771C010 University of Maryland Outreach Component
R828771C011 Environmental Assessment and GIS System Development of Brownfield Sites in Baltimore
R828771C012 Solubilization of Particulate-Bound Ni(II) and Zn(II)
R828771C013 Seasonal Controls of Arsenic Transport Across the Groundwater-Surface Water Interface at a Closed Landfill Site
R828771C014 Research Needs in the EPA Regions Covered by the Center for Hazardous Substances in Urban Environments
R828771C015 Transport of Hazardous Substances Between Brownfields and the Surrounding Urban Atmosphere