Final Report: Electrochemical Sensor for Heavy Metals in Groundwater - Phase IV

EPA Grant Number: R825511C022
Subproject: this is subproject number 022 , established and managed by the Center Director under grant R825511
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - Northeast HSRC
Center Director: Sidhu, Sukh S.
Title: Electrochemical Sensor for Heavy Metals in Groundwater - Phase IV
Investigators: Kounaves, Samuel P.
Institution: Tufts University
EPA Project Officer: Hahn, Intaek
Project Period: January 15, 1997 through January 14, 1999
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Hazardous Substance Research Centers , Land and Waste Management

Objective:

The current overall objective of this research project is to develop and demonstrate a practical low-cost field analytical device that can be used to perform rapid on-site in-situ screening and quantitative determination (at part-per-billion levels) of toxic heavy metals in groundwater. A longer term goal is to expand the capability of this instrument to also include on-site analysis for these metals in soil and sediment.

Summary/Accomplishments (Outputs/Outcomes):

Rationale: Approximately 30% of Superfund sites within Federal Regions 1 and 2 have some form of heavy metal groundwater contamination. Analytical data turnaround for state, federal and commercial laboratories using batch analysis methods such as AA or ICP typically exceeds several months, resulting in increased costs and delayed decisions. No other field analytical technology is currently available for in-situ, on-site, determination of EPA priority pollutant heavy metals in groundwater. The ability to obtain such real-time ppb-level data has direct relevance to U.S.EPA and NHSRC research programs focusing on improved and rapid on-site screening, site characterization, remedial actions at waste sites, and in preserving and protecting groundwater resources.

Approach: In order to reach our overall goal in this project, we will: (1) Conduct an on-site demonstration of the previously developed electrochemically-based sensor for the on-site, in-situ determination of Cu(II), Cd(II), Pb(II), and Zn(II). (2) Undertake research with the aim of replacing the current sensors using a Hg-coated iridium ultramicroelectrode array transducer with a non-Hg or polymer-based film to both prevent organic fouling and to increase selectivity.(3) Undertake research and development of sensor transduction chemistries for the electrochemical detection of As(III), Cr(VI), Hg(II), and Se(IV) at the ppb levels.(4) Conduct an on-site, in-situ, demonstration of a probe containing the above developed sensors for all eight metals.

Status: A on-site demonstration of the probe for Cu(II), Cd(II), Pb(II), and Zn(II) has been successfully carried out at the Silresim Superfund site in Lowell, MA. A non-Hg containing sensor for copper has been developed and a patent applied for. Sensors for As(III) and Se(IV) have also been developed and successfully tested. Research for Cr(VI) and Hg(II) sensors has provided several prototypes that are now being evaluated. A full on-site demonstration, with a probe containing sensors for all eight metals, is being planned for the second half of 1999 via funding through the NHSRC Technology Transfer Program.

Technology Transfer and Outreach Plan: Orion Research Inc. has obtained a license for the sensor and has started to develop prototypes of this technology for commercialization in the area of environmental field use. We have also made over 15 presentations at conferences sponsored by The American Chemical Society, The Electrochemical Society, and PITTCON.

An especially unique application has emerged for this EPA/NHSRC sponsored work. We have been selected by NASA to include these sensors on the Mars 2001 Lander. The sensors will be used for electroanalysis of the Martian soil to determine several metal ions, electrochemistry, and the soil redox potential. In conjunction with an array of Ion Selective Electrodes, we will also attempt to (1) identify possible chemical hazards to which humans may someday be exposed and (2) combine the electroanalytical data with other instrumental data to determine if the soil shows any chemical signs of past or present life. More details about this exciting application of our sensors can be found on our WWW site at http://electrochem.tufts.edu/mars.html Exit .

Field projects/demonstrations resulting from the project:

Several sites were used for demonstrating the capabilities of the portable Electrochemical Analysis System (EMA). The wells involved in the field studies encompass various chemical and physical compositions. In this way, the EMA was used in a variety of different, natural matrices. Also, each site contained different amount of heavy metals.

Silresim Chemical Corp site in Lowell, MA. Three wells were measured around the site with a polymer protected IrUMEA and compared to a classical macro electrode with a mercury film. It can be seen that the field data of the ionic forms of Pb and Cu obtained with the polymer protected IrUMEA correlates well with the classical ASV data. ICP-AES data were used to confirm electrochemical data. In general, the field data showed metal contamination has not migrated toward the off-site wells.

Plainville Electroplating site in Plainville, CT. Direct comparisons were made between electrochemical and spectrometry data. In this study, analytical methodologies were used to validate the electrochemical data obtained. Quantification of the metal concentrations was accomplished with the methods of direct calibration and standard addition. The sensitivities for each metal were established for the electrochemical data. Electrochemical samples were acid digested according to EPA method 3005A with HCl and HNO3 with heat. For both techniques, percent recoveries of the check standard were within ±10 % of the curve and precision of the measurements under 5%. Results three wells with both techniques showed the release of metals from strongly bound complexes upon completion of acid digestion for all wells. However for well 3B over 90% of the total metal concentration was due to the labile/ bound fraction of the metal species.

Municipal Landfill in Central Maine for Arsenic In Ground Water. An on site analysis using our field-portable potentiostat and the Au-UMEA was performed on a site containing arsenic in groundwater. The site is a superfund location currently being remediated for dimethlyforamide. Arsenic levels were found to exceed the drinking water limit of 50 µg/L and believed to be naturally occurring with the mechanism being dissolution of natural background arsenic from a saturated zone materials under the landfill. The water had been found to be anoxic with high levels of mostly iron (60 µg/L). Other heavy metals were nondetectable. Our As sensor was used and compared with current EPA validation techniques (GFAAS and ICP-AES). Water samples were taken from an influent pipe at the on-line treatment facility. SWASV values were consistent with 95 % confidence interval determined by the GFAAS data. Minimal interferences were found in obtaining the electrochemical field data. This field demonstration successfully showed the viability of voltammetric field screening for arsenic. This portable equipment in conjunction with the Au-UMEAs provided rapid analysis in groundwater with a measured LOD of 0.1 ppb.

Iron Horse Park site in Billerica, MA. The selenium sensor was used for analysis in groundwater samples. This superfund site, a 553-acre industrial complex, included manufacturing and rail yard maintenance facilities, open storage areas, landfills, and wastewater lagoons. On-site groundwater and surface water are sporadically contaminated with organic and inorganic chemicals, asbestos, and heavy metals including arsenic, cadmium, lead, and selenium. Except for acidification of the water samples with to 0.005M H2SO4, no further treatment of the sample was performed. The Se was found to be below the LOD for our Se sensor. To confirm that the Se sensor was functioning, the groundwater sample was spiked with 100ppb of Se4+ and an appropriate signal was measured. It should be noted that previous ICP data from the EPA showed the amount of Se in the monitoring wells did fluctuate and generally were under the MCL. . Since Se4+ is detected at very positive potentials, many surface-active species can be detrimental to measuring an accurate analytical response. We are currently continuing this investigation by looking at membranes that would offer selectivity for Se4+ and protection of the sensors gold surface. A promising material is sol-gel membrane impregnated with polydiallyldimethyl ammonium chloride. Preliminary experiments on a single sol gel sensor are underway.

Kennecott Copper Mining Company, UT. A second type of selenium sensor was also tested with samples from a mining site plume containing Se which had seeped into the groundwater nearby. It was established that the sample contained mostly selenate (Se6+). A sample of the well water was measured in our lab with the IrUMEA Se sensor after chemical reduction with concentrated HCl. The results were compared with independent HG-ICP-AES and adsorptive SWCSV. The ICP verified the high concentration of Se4+. The Se-sensor showed good precision and yielded a linearly calibration plot. The difference in values could be attributed to the volatile nature of Se under the reducing conditions leading to a lower concentration of Se4+ measured exclusively by the IrUMEA type Se sensor.

From the work described above, analytical methodology for both on site and in-situ groundwater analyses of various heavy metals was developed and verified. The field demonstrations performed illustrate the analytical capabilities and cost-effectiveness of the EMA sensors for rapid screening of metals in groundwater. The practical linear range and LOD are practical for metal concentrations in the environmental samples. The lifetime and reliability of the measurements demonstrate the efficacy of the EMA.


Journal Articles on this Report : 13 Displayed | Download in RIS Format

Other subproject views: All 26 publications 13 publications in selected types All 13 journal articles
Other center views: All 131 publications 39 publications in selected types All 39 journal articles
Type Citation Sub Project Document Sources
Journal Article Feeney R, Herdan J, Nolan M, Tan S, Tarasov V, Kounaves SP. Analytical characterization of microlithographically fabricated Ir-based ultramicroelectrode arrays. Electroanalysis 1998;10(2):89-93. R825511C022 (Final)
not available
Journal Article Feeney R, Kounaves SP. Determination of heterogeneous electron transfer rate constants at microfabricated iridium electrodes. Electrochemistry Communications 1999;1(10):453-458. R825511C022 (Final)
not available
Journal Article Feeney R, Kounaves SP. Microfabricated ultramicroelectrode arrays: Developments, advances, and applications in environmental analysis. Electroanalysis 2000;12(9):677-84. R825511C022 (Final)
not available
Journal Article Feeney R, Kounaves SP. On-site analysis of arsenic in groundwater using a microfabricated gold ultramicroelectrode array. Analytical Chemistry 2000;72(10):2222-2228. R825511C022 (Final)
not available
Journal Article Herdan J, Feeney R, Kounaves SP, Flannery AF, Storment CW, Kovacs GTA, Darling RB. Field evaluation of an electrochemical probe for in Situ screening of heavy metals in groundwater. Environmental Science & Technology 1998;32(1):131-136. R825511C022 (Final)
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  • Journal Article Nolan MA, Tan SH, Kounaves SP. Fabrication and characterizaton of a solid state reference electrode for electroanalysis of natural waters with ultramicroelectrodes. Analytical Chemisty 1997;69(6):1244-47. R825511C022 (Final)
    not available
    Journal Article Nolan MA, Kounaves SP. Kounaves. Effects of mercury electrodeposition on the surface of microlithographically fabricated Ir ultramicroelectrodes. Journal of Electroanalytical Chemistry 1998;453(1-2):39-48. R825511C022 (Final)
    not available
    Journal Article M.A. Nolan and S.P. Kounaves. Failure analysis of microfabricated Ir-ultramicroelectrodes in chloride media. Sensors & Actuators B 1998;50(2):117-124. R825511C022 (Final)
    not available
    Journal Article Nolan MA, Kounaves SP. Effects of chloride ion concentration on mercury(I) chloride formation during ex situ and in situ mercury deposition with selected electrode substrates and electrolytes. Analytical Chemistry 1999;71(6)1176-82. R825511C022 (Final)
    not available
    Journal Article Nolan M, Kounaves SP. Microfabricated array of iridium microdisks as a substrate for direct determination of Cu2+ or Hg2+ using square wave anodic stripping voltammetry. Analytical Chemistry 1999;71(16):3567-3573. R825511C022 (Final)
    not available
    Journal Article Nolan MA, Kounaves SP. The source of the anomalous cathodic peak during ASV with in situ mercury film formation in chloride solutions. Electroanalysis 2000;12(2):96-99. R825511C022 (Final)
    not available
    Journal Article Tan SH, Kounaves SP. Determination of selenium(IV) at a microfabricated gold ultramicroelectrode array using SWASV. Electroanalysis 1998;10(6):364-68. R825511C022 (Final)
    not available
    Journal Article Wang JY, Adeniyi WK, Kounaves SP. Adsorptive stripping analysis of trace nickel at iridium-based ultramicroelectrode arrays. Electroanalysis 2000;12(1):44-47. R825511C022 (Final)
    not available

    Supplemental Keywords:

    Electrochemistry, Sensor, Heavy Metals, Groundwater., RFA, Scientific Discipline, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, POLLUTANTS/TOXICS, Environmental Chemistry, Arsenic, Monitoring/Modeling, Analytical Chemistry, Hazardous Waste, Environmental Monitoring, Water Pollutants, Hazardous, Environmental Engineering, Mercury, field portable monitoring, wastewater, Chromium, in situ sensor, groundwater monitoring, cadmium, industrial effluents, electrochemical sensor, electrochemical treatment, groundwater

    Progress and Final Reports:

    Original Abstract
  • 1997

  • Main Center Abstract and Reports:

    R825511    HSRC (1989) - Northeast HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825511C001 Development of Mechanisms and Kinetic Models on Formation of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans from Aromatic Precursors
    R825511C002 Real-Time Monitoring and Control of Emissions from Stationary Combustors and Incinerators
    R825511C003 Development of Sampling Systems for Continuous Monitoring of Volatile Organic Compounds (VOCs)
    R825511C004 Investigation into the Effectiveness of DNAPL Remediation Strategies in Fractured Media
    R825511C005 Advanced Leak Detection and Location Research: Extending the SERDP-funded Technical Base
    R825511C006 Three-Dimensional Geostatistical Site Characterization with Updating
    R825511C007 Anaerobic Biodegradation of PAHs in Soils and Dredged Sediments: Characterizing, Monitoring and Promoting Remediation
    R825511C008 Substrate Accelerated Death and Extended Lag Phases as Causes of the Recalcitrance of Halogenated Compounds in Anoxic Environments
    R825511C009 Fate and Transport of Nonionic Surfactants
    R825511C010 In Situ Degradation of Petroleum Hydrocarbons and PAHs in Contaminated Salt Marsh Sediments
    R825511C011 Design and Operation of Surfactant-Enhanced Bioslurry Reactors
    R825511C012 Experimental Study of Overland Transport of Cryptosporidium parvum Oocysts
    R825511C013 Development of a Framework for Evaluation of Leaching from Solid Waste
    R825511C014 Use of a New Leaching Test Framework for Evaluating Alternative Treatment Processes for Mercury Contaminated Mixed Waste (Hazardous and Radioactive)
    R825511C015 Field Pilot Test of In Situ Ultrasonic Enhancement Coupled With Soil Fracturing to Detoxify Contaminated Soil
    R825511C016 Development of Sampling Systems for Continuous Monitoring of Volatile Organic Compounds (VOCs)
    R825511C017 Field Demonstration of the Use of Reactive Zero-Valence Iron Powder to Treat Source Zone Sites Impacted by Halogenated Volatile Organic Chemicals
    R825511C018 Technology Transfer of Continuous Non-Methane Organic Carbon (C-NMOC) Analyzer
    R825511C019 Field Sampling and Treatability Study for In-Situ Remediation of PCB's and Leachable Lead with Iron Powder
    R825511C020 Experimental and Modeling Studies of Chlorocarbon Incineration, PIC Formation, and Emissions Control
    R825511C021 Experimental Studies and Numerical Modeling of Turbulent Combustion During Thermal Treatment of Hazardous Wastes: Applied Research for the Generation of Design and Diagnostic Tools
    R825511C022 Electrochemical Sensor for Heavy Metals in Groundwater - Phase IV
    R825511C023 Novel Molecular Tools for Monitoring In-Situ Bioremediation
    R825511C024 Surfactant-Enhanced Bioremediation of Soils in the Presence of an Organic Phase
    R825511C025 Enhanced Microbial Dechlorination of PCBs and Dioxins in Contaminated Dredge Spoils
    R825511C026 Toward A Risk-Based Model for Bioremediation of Multicomponent NAPL Contaminants
    R825511C027 Removal and Recovery of VOCs and Oils from Surfactant-Flushed Recovered Water by Membrane Permeation
    R825511C029 Field Pilot Test of In-Situ Ultrasonic Enhancement Coupled With Soil Fracturing to Detoxify Contaminated Soil in Cooperation with McLaren/Hart Environmental Engineers at the Hillsborough, NJ Site
    R825511C030 In-Situ Field Test of Electroremediation of a Chromate-Contaminated Site in Hudson County, New Jersey
    R825511C031 Electrokinetic Removal of Heavy Metals and Mixed Hazardous Wastes from Partially and Fully Saturated Soils
    R825511C032 Effects of Clay Charge and Confining Stresses on Soil Remediation by Electroosmosis
    R825511C033 Assessment of Surfactant Enhanced Bioremediation for Soils/Aquifers Containing Polycyclic Aromatic Hydrocarbons (PAHs)
    R825511C034 In-Situ Bioremediation of Organic Compounds: Coupling of Mass Transfer and Biodegradation
    R825511C035 Investigation into the Effectiveness of DNAPL Remediation Strategies in Fractured Media
    R825511C036 Field Pilot Scale Demonstration of Trench Bio-Sparge: An In-Situ Groundwater Treatment Technology
    R825511C037 In-Situ Reductive Dehalogenation of Aliphatic Compounds by Fermentative Heterotrophic Bacteria
    R825511C038 The Effect of Carbon-Nitrogen Ratios on Bacterial Transport and Biodegradation Rates In Soils
    R825511C039 Ultrasonic Enhancement of Soil Fracturing Technologies for In-Situ Detoxification of Contaminated Soil
    R825511C040 Full Field Demonstration of Integrated Pneumatic Fracturing and In-Situ Bioremediation
    R825511C041 Determination of Adsorption and Desorption Behavior of Petroleum Products on Soils
    R825511C042 Evaluation of the Potential for Complete Bioremediation of NAPL-Contaminated Soils Containing Polycyclic Aromatic Hydrocarbons (PAHs)
    R825511C043 Characterization of Subsurface NAPL Distributions at Heterogeneous Field Sites
    R825511C044 Development of a Thermal Desorption Gas Chromatograph/Microwave Induced Plasma/Mass Spectrometer (TDGC/MIP/MS) for On-site Analysis of Organic and Metal Contaminants
    R825511C045 Using Trainable Networks for a Three-dimensional Characterization of Subsurface Contamination
    R825511C046 Application of Advanced Waste Characterization to Soil Washing and Treatment
    R825511C047 Electrochemical Sensor for Heavy Metals in Groundwater Phase III
    R825511C048 Improved Luminescence Sensors for Oxygen Measurement
    R825511C049 Preconcentration, Speciation and Determination of Dissolved Heavy Metals in Natural Waters, using Ion Exchange and Graphite Furnace Atomic Absorption Spectrometry
    R825511C050 Experimental and Modeling Studies of Chlorocarbon Incineration and PIC Formation
    R825511C051 PIC Emission Minimization: Fundamentals and Applications
    R825511C052 Project Title: Development of a Two Stage, Pulse Combustion, VOC Destruction Technology
    R825511C053 Development of Sampling Systems for Continuous Monitoring of Volatile Organic Compounds (VOCs)
    R825511C054 FTIR Analysis of Gaseous Products from Hazardous Waste Combustion
    R825511C055 Toxic Metals Volatilization for Waste Separation and Real-time Metals Analyses
    R825511C056 Mixed Metal Removal and Recovery by Hollow Fiber Membrane-Based Extractive Adsorber
    R825511C057 Removal of Volatile Organic Compounds (VOCs) from Contaminated Groundwater and Soils by Pervaporation
    R825511C058 Simultaneous SO2/NO Removal/Recovery by Hollow Fiber Membrane
    R825511C059 Superfund Sites and Mineral Industries Method
    R825511C060 Soil Washing of Mixed Organics/Metal Contamination
    R825511C061 Removal of Cesium, Strontium, Americium, Technetium and Plutonium from Radioactive Wastewater
    R825511C062 Development of a Method for Removal of Nonvolatile Organic Materials from Soil using Flotation
    R825511C063 Recovery of Evaporative Fuel Losses by Vapor Permeation Membranes
    R825511C064 Surfactant Selection Protocol for Ex Situ Soil Washing
    R825511C065 Biofiltration for the Control of Toxic Industrial VOCs Emissions
    R825511C066 Catalytic Oxidation of Volatile Organic Compounds in Water
    R825511C067 Soil Washing for Remediating Metal Contaminated Soils
    R825511C068 Aqueous Absorption and Kinetics of NO by Strong Oxidizing Agents
    R825511C069 Remediation of Dredging Spoils
    R825511C070 Freeze Concentration for Zero-Effluent Processes
    R825511C071 Life Cycle/Pollution Prevention Response to Executive Order 12856
    R825511C072 Faster Better, Cheaper Hazardous Waste Site Characterization and Cleanup: an Adaptive Sampling and Analysis Strategy Employing Dynamic Workplans
    R825511C073 Development of a Comprehensive Computer Model for the Pneumatic Fracturing Process
    R825511C074 Technology Demonstration and Validation of CFAST Field Analytical Instrumentation for Use in Hazardous Waste Site Characterization, Clean-up and Monitoring
    R825511C075 XFLOW: Training Software Simulating Contaminant Site Characterization and Remediation