phytoremediation resource guide - clu-in · epa 542-b-99-003 june 1999 phytoremediation resource...

United StatesEnvironmental ProtectionAgency

Solid Waste andEmergency Response(5102G)

EPA 542-B-99-003June 1999www.epa.gov/tioclu-in.org

Phytoremediation ResourceGuide

EPA 542-B-99-003June 1999

Phytoremediation Resource Guide

U.S. Environmental Protection AgencyOffice of Solid Waste and Emergency Response

Technology Innovation OfficeWashington, DC 20460

Notice

This resource guide was prepared by: Environmental Management Support, Inc., 8601 GeorgiaAvenue, Suite 500, Silver Spring, MD 20910 under contract 68-W6-0014, work assignments 73 and94, with the U.S. Environmental Protection Agency. Mention of trade names or commercial productsdoes not constitute endorsement or recommendation for use. For more information about this projectcontact: Dawn Carroll, U.S. Environmental Protection Agency (5102G), Technology Innovation Office,401 M Street, SW, Washington, DC 20460, 703-603-1234, e-mail: [email protected].

i

FOREWORD

Identifying and accessing pertinent information resources that will help site cleanup managers evaluateinnovative technologies is key to the broader use of these technologies. This Guide is intended toincrease awareness about technical information and specialized resources related to phytoremediationtechnologies.

Specifically, this document identifies a cross section of information intended to aid users in remedialdecision-making, including abstracts of field demonstrations, research documents, and information toassist in the ordering of publications. In addition, the look-up format of this document allows the userto quickly scan available resources and access more detailed abstracts.

Please let us know about additional information that could make this Guide (and others in the series)more useful to you. This and the other reports listed below are available to the public from theTechnology Innovation Office Home Page: http://www.epa.gov/tio.

Bioremediation Resource GuideGroundwater Treatment Technology Resource Guide

Physical/Chemical Treatment Technology Resource GuideSoil Vapor Extraction (SVE) Enhancement Technology Resource Guide

Soil Vapor Extraction Treatment Technology Resource Guide

ii

TABLE OF CONTENTS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

HOW TO USE THIS GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

HOW TO ORDER DOCUMENTS LISTED IN THIS GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

TECHNOLOGY SUMMARY AND MATRIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

ABSTRACTS OF PHYTOREMEDIATION RESOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Publications Containing Multiple Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Organic Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Overviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Field Studies and Demonstrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Publications Containing Multiple Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Inorganic Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Overviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Field Studies and Demonstrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Publications Containing Multiple Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Internet Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

iii

INTRODUCTION

EPA is committed to identifying the most effective and efficient means of addressing the thousands ofhazardous waste sites in the United States. Therefore, the Office of Solid Waste and EmergencyResponse’s (OSWER’s) Technology Innovation Office (TIO) is working in conjunction with the EPARegions and research centers and with industry to identify and encourage the further development andimplementation of innovative treatment technologies.

One way to encourage the use of these technologies is to ensure that decision-makers are aware of themost current information on technologies, policies, and other sources of assistance. This Guide wasprepared to help identify documents that can directly assist Federal and State site managers,contractors, and others responsible for the evaluation of technologies. Specifically, this Guide isdesigned to help those responsible for the remediation of RCRA, UST, and CERCLA sites that mayemploy phytoremediation technologies.

This Guide provides abstracts of over 100 phytoremediation overviews, field studies anddemonstrations, research articles, and Internet resources. It also provides a brief summary ofphytoremediation. Finally, a matrix is also provided to allow easy screening of the abstractedreferences.

To develop this Guide, a literature search using relevant terms was conducted on a variety ofcommercial and Federal databases including:& National Technical Information Service (NTIS)& Energy Science and Technology& Enviroline& Water Resources Abstracts& Pollution Abstracts.

In addition, Internet resources yielded numerous citations. These Internet resources include: & U.S. Environmental Protection Agency

http://www.epa.gov& U.S. Army Corps of Engineers Phytoremediation Research

http://www.wes.army.mil/EL/phyto& U.S. Army Environmental Center

http://aec-www.apgea.army.mil:8080& Air Force Center for Environmental Excellence

http://www.afcee.brooks.af.mil& U.S. Department of Energy

http://www.doe.gov& U.S. Department of Agriculture

http://www.usda.gov& The Hazardous Waste Clean-Up Information Home Page

http://clu-in.org& The Ground Water Remediation Technologies Analysis Center

http://www.gwrtac.org

iv

& The Remediation Technologies Development Forumhttp://www.rtdf.org

& The Great Plains/Rocky Mountain Hazardous Substance Research Centerhttp://www.engg.ksu.edu/HSRC

& The Phytoremediation Electronic Newsgroup Networkhttp://www.dsa.unipr.it/phytonet

& The Interstate Technology and Regulatory Cooperation Working Grouphttp://www.sso.org/ecos/itrc

& Battellehttp://www.battelle.org

The selected references are not an exhaustive list of all available literature, but rather a representativesample of available print and Internet resources. For a more extensive list of phytoremediationresources, visit the Remediation Technologies Development Forum, Phytoremediation of OrganicsAction Team’s Home Page at http://www.rtdf.org/public/phyto. The Remediation TechnologiesDevelopment Forum is a public-private partnership operated by the U.S. Environmental ProtectionAgency. The Phytoremediation of Organics Action Team includes representatives from industry andgovernment who share an interest in further developing and evaluating the use of plants and trees toremediate contaminated soil and water. The Action Team has compiled a bibliography containing over1,400 citations of peer-reviewed journal articles, presentations and posters from conferences, bookchapters, and articles from newspapers and magazines. The bibliography may be viewed or searchedonline.

Due to the inherent lag time between document publication and subsequent listing in electronicdatabases, there may be more recent references available than those included in the Guide. Most of thereferences in the Guide are of documents published between 1994 and 1998. The documents selectedare available from suppliers such as EPA’s National Service Center for Environmental Publications, theNational Technical Information Service, document delivery services, and a variety of libraries.Descriptions of specific technologies and methodologies in this Guide does not represent anendorsement by EPA.

v

HOW TO USE THIS GUIDE

When using this Guide to identify resource information on phytoremediation technologies, you maywish to take the following steps:

1. Turn to the Phytoremediation Resource Matrix located on pages ix through xxii of this Guide.This matrix lists all abstracted resources alphabetically by document type, identifies the type ofinformation provided by each document, and provides a document ordering number whenavailable. Documents in the matrix are divided into the following topical categories: generalinformation, organic contaminants, inorganic contaminants, and Internet resources.

2. Select the documents that appear to fit your needs based on the information in the matrix.

3. Check the page number provided in the matrix. This refers to the page number of the documentabstract in the Guide.

4. Review the abstract that corresponds to the document in which you are interested to confirm thatthe document will fit your needs.

5. If the document appears to be appropriate, note the document number highlighted under theabstract. For example:

EPA Document Number: EPA 542-R-97-004

[Note: Some documents do not have ordering numbers. These documents can be obtained throughlocal, technical, or university libraries.]

6. Turn to the section entitled “How to Order Documents Listed in this Guide” on page vi of thisGuide and order your document using the directions provided.

vi

HOW TO ORDER DOCUMENTS LISTED IN THIS GUIDE

Documents listed in this Guide are available through a variety of sources. When ordering documentslisted in the Abstracts section of this Guide, use the number listed in the bar below the document title,or refer to the source indicated as part of the citation. If using the Phytoremediation ResourceMatrix, use the page number listed with the document title to refer to the complete citation andabstract. EPA 542 documents may be obtained through the National Service Center for EnvironmentalPublications (NSCEP), and EPA 530 documents may be obtained from the RCRA Information Center(RIC). These document repositories provide in-stock documents free of charge, but document suppliesmay be limited. Documents obtained through the National Technical Information Service (NTIS) areavailable for a fee; therefore, prior to purchasing a document through NTIS, you may wish to review acopy at a technical or university library, or a public library that houses government documents.

Document TypePublication numbers with the following prefixes:

ADDEPB

NTIS provides documents for a fee.

Document SourceNational Technical Information Service (NTIS)5285 Port Royal RoadSpringfield, VA 22161Tel: 1-800-553-NTISFax: (703) 605-6900Internet: http://www.ntis.gov/

Publications numbers beginning with:

EPA 542

National Service Center for EnvironmentalPublications (NSCEP)P.O. Box 42419Cincinnati, OH 45242-2419Tel: 1-800-490-9198Fax: (513) 489-8695Internet: http://www.epa.gov/ncepihom/

A document title or number is needed to place an order with NSCEP.Some out-of-stock documents may be purchased from NTIS.

Publications numbers beginning with:

EPA 530

RCRA Information Center (RIC)401 M St., SW Mailcode: 5305Washington, DC 20460Tel: (703) 603-9230Fax: (703) 603-9234Internet: http://www.epa.gov/epaoswer/general/

ricorder.htm

vii

TECHNOLOGY SUMMARY

Phytoremediation is the direct use of living plants for in situ remediation of contaminated soil, sludges,sediments, and ground water through contaminant removal, degradation, or containment. Growing and,in some cases, harvesting plants on a contaminated site as a remediation method is an aestheticallypleasing, solar-energy driven, passive technique that can be used to clean up sites with shallow, low tomoderate levels of contamination. This technique can be used along with or, in some cases, in place ofmechanical cleanup methods. Phytoremediation can be used to clean up metals, pesticides, solvents,explosives, crude oil, polycyclic aromatic hydrocarbons, and landfill leachates.

Phytoremediation has been studied extensively in research and small-scale demonstrations, but full-scale applications are currently limited in number. Further development and research of themechanisms described below likely will lead to wider acceptance and use of phytoremediation.

Phytoremediation is a general term for several ways in which plants are used to remediate sites byremoving pollutants from soil and water. Plants can degrade organic pollutants or contain and stabilizemetal contaminants by acting as filters or traps. Some of the methods that are being tested are describedbelow.

Phytoextraction Phytoextraction, also called phytoaccumulation, refers to the uptake andtranslocation of metal contaminants in the soil by plant roots into theaboveground portions of the plants. Certain plants called hyperaccumulatorsabsorb unusually large amounts of metals in comparison to other plants. One ora combination of these plants is selected and planted at a site based on the typeof metals present and other site conditions. After the plants have been allowedto grow for several weeks or months, they are harvested and either incineratedor composted to recycle the metals. This procedure may be repeated asnecessary to bring soil contaminant levels down to allowable limits. If plantsare incinerated, the ash must be disposed of in a hazardous waste landfill, butthe volume of ash will be less than 10% of the volume that would be created ifthe contaminated soil itself were dug up for treatment.

Rhizofiltration Rhizofiltration is the adsorption or precipitation onto plant roots or absorptioninto the roots of contaminants that are in solution surrounding the root zone.The plants to be used for cleanup are raised in greenhouses with their roots inwater rather than in soil. To acclimate the plants once a large root system hasbeen developed, contaminated water is collected from a waste site and broughtto the plants where it is substituted for their water source. The plants are thenplanted in the contaminated area where the roots take up the water and thecontaminants along with it. As the roots become saturated with contaminants,they are harvested and either incinerated or composted to recycle thecontaminants.

Phytostabilization Phytostabilization is the use of certain plant species to immobilize contaminantsin the soil and ground water through absorption and accumulation by roots,

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adsorption onto roots, or precipitation within the root zone. This processreduces the mobility of the contaminant and prevents migration to the groundwater or air, and it reduces bioavailability for entry into the food chain. Thistechnique can be used to reestablish a vegetative cover at sites where naturalvegetation is lacking due to high metal concentrations in surface soils orphysical disturbances to surficial materials. Metal-tolerant species can be usedto restore vegetation to the sites, thereby decreasing the potential migration ofcontamination through wind erosion, transport of exposed surface soils, andleaching of soil contamination to ground water.

Phytodegradation Phytodegradation, also called phytotransformation, is the breakdown ofcontaminants taken up by plants through metabolic processes within the plant,or the breakdown of contaminants external to the plant through the effect ofcompounds (such as enzymes) produced by the plants. Pollutants are degraded,incorporated into the plant tissues, and used as nutrients.

Rhizodegradation Rhizodegradation, also called enhanced rhizosphere biodegradation,phytostimulation, or plant-assisted bioremediation/degradation, is thebreakdown of contaminants in the soil through microbial activity that isenhanced by the presence of the rhizosphere and is a much slower process thanphytodegradation. Microorganisms (yeast, fungi, or bacteria) consume anddigest organic substances for nutrition and energy. Certain microorganisms candigest organic substances such as fuels or solvents that are hazardous tohumans and break them down into harmless products through biodegradation.Natural substances released by the plant roots—sugars, alcohols, andacids—contain organic carbon that provides food for soil microorganisms, andthe additional nutrients enhance their activity. Biodegradation is also aided bythe way plants loosen the soil and transport water to the area.

Phytovolatilization Phytovolatilization is the uptake and transpiration of a contaminant by a plant,with release of the contaminant or a modified form of the contaminant to theatmosphere from the plant. Phytovolatilization occurs as growing trees andother plants take up water and the organic contaminants. Some of thesecontaminants can pass through the plants to the leaves and volatilize into theatmosphere at comparatively low concentrations.

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PHYTOREMEDIATION RESOURCE MATRIX

The Phytoremediation Resource Matrix displays summary information on references listed in the Abstracts section of the Guide with theexception of publications containing multiple papers. Both the Matrix and Abstracts sections are organized using the same contaminant-basedcategories. Internet Resources are listed in a separate matrix following printed references. The first column of the Matrix displays thedocument title, ordering number (when applicable), and page number of the full abstract in the Abstracts section. The second column(Technology Type) lists the technologies that the article addresses. Definitions for these technologies can be found in the Technology Summaryon page vii. Column three denotes the media treated, and column four denotes the contaminants treated.

Document TitleDocument Ordering Number[Abstract Page Number in Guide]

TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

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s

Pest

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Her

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GENERAL INFORMATION

The 1998 United States Market for Phytoremediation [1] Unspecified q q q q

The Advancement of Phytoremediation as an InnovativeEnvironmental Technology for Stabilization, Remediation, orRestoration of Contaminated Sites in Canada: A Discussion Paper[2]

Unspecified

q q q q

Bioremediation and Phytoremediation Glossary [2] Unspecified q q q q

A Citizen’s Guide to Phytoremediation [2]EPA 542-F-98-011

Unspecifiedq q q q q q

Compost-Enhanced Phytoremediation of Contaminated Soil [2]EPA 530-R-98-008

Unspecifiedq q q

Introduction to Phytoremediation [2] Unspecified q q q q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

anic

s

Pest

icid

es/

Her

bici

des

Met

als

Rad

ionu

clid

es

Exp

losi

ves

x

Legal and Social Concerns to the Development of BioremediationTechnologies [3]DE96015254

Unspecifiedq q q q

Phytoremediation [3]EPA 625-K-96-001

Unspecifiedq q q q

Phytoremediation [3] Unspecified q q q q

Phytoremediation: A Clean Transition from Laboratory toMarketplace? [3]

Phytoremediation: A New Technology Gets Ready to Bloom [3] Unspecified q q q q

Phytoremediation Bibliography [4] Unspecified q q q q

Phytoremediation Field Demonstrations in the U.S. EPA SITEProgram [4]

Phytoextractionq q q q

Phytoremediation: It Grows on You [4] Unspecified q q q q

Phytoremediation on the Brink of Commercialization [4] Unspecified q q q q

Phytoremediation: Technology Overview Report [5] Unspecified q q q q

Phytoremediation: Using Green Plants to Clean Up ContaminatedSoil, Groundwater, and Wastewater [5]

Phytostabilizationq q q q

Remediation Technologies Screening Matrix and Reference Guide[5]

Unspecifiedq q q q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

anic

s

Pest

icid

es/

Her

bici

des

Met

als

Rad

ionu

clid

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Exp

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ves

xi

Stemming the Toxic Tide [5] Phytoextraction q q q q

Technology Evaluation Report: Phytoremediation [6] Unspecified q q q q

Using Phytoremediation to Clean Up Contamination at MilitaryInstallations [6]DE97007971

Unspecifiedq q q q q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

anic

s

Pest

icid

es/

Her

bici

des

Met

als

Rad

ionu

clid

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Exp

losi

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ORGANIC CONTAMINANTS

Overviews

Mechanisms of Phytoremediation: Biochemical and EcologicalInteractions Between Plants and Bacteria [7]

Rhizodegradationq q

Phytoremediation of TCE in Groundwater Using Populus [8] PhytodegradationPhytovolatilization q q

Field Studies and Demonstrations

Demonstration Plan for Phytoremediation of Explosive-Contamina-ted Groundwater in Constructed Wetlands at Milan ArmyAmmunition Plant, Milan, Tennessee. Volumes 1 and 2. FinalReport [8]ADA311121/8/XAB, ADA311122/6/XAB

Phytodegradation

q q

Evaluation of Various Organic Fertilizer Substrates and HydraulicRetention Times for Enhancing Anaerobic Degradation ofExplosives-Contaminated Groundwater While Using ConstructedWetlands at the Milan Army Ammunition Plant, Milan, Tennessee[8]ADA349293

Phytodegradation

q q

Field Scale Evaluation of Grass-Enhanced Bioremediation of PAHContaminated Soils [8]

Rhizodegradationq q

Friendly Forests [9] PhytostabilizationPhytodegradationRhizodegradation

q q q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

anic

s

Pest

icid

es/

Her

bici

des

Met

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Rad

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Groundwater Phytoremediation Test Facility, University ofWashington [9]

Rhizofiltrationq q

Phreatophyte Influence on Reductive Dechlorination in a ShallowAquifer Containing TCE [9]

Rhizodegradationq q

Phytoremediation of Dissolved-Phase Trichloroethylene UsingMature Vegetation [10]

Phytovolatilizationq q

Phytoremediation of Groundwater at Avesta Sheffield Pipe [10] Unspecified q q q

Phytoremediation of Organic and Nutrient Contaminants [10] Phytodegradation q q q q

Pilot-Scale Use of Trees to Address VOC Contamination [10] Phytodegradation q q

Screening of Aquatic and Wetland Plant Species for Phytoremedia-tion of Explosives-Contaminated Groundwater from the Iowa ArmyAmmunition Plant. Final Report [10]ADA322455/7/XAB

Phytodegradation

q q

Screening Submersed Plant Species for Phytoremediation ofExplosives-Contaminated Groundwater from the Milan ArmyAmmunition Plant, Milan, Tennessee. Final Report [11]

Phytodegradationq q

Research

Adsorption of Naphthalene onto Plant Roots [11] Phytostabilization q q

Aromatic Nitroreduction of Acifluorfen in Soils Rhizospheres andPure Cultures of Rhizobacteria [11]

Rhizodegradationq q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

anic

s

Pest

icid

es/

Her

bici

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Met

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Rad

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Bacterial Inoculants of Forage Grasses that Enhance Degradation of2-Chlorobenzoic Acid in Soil [11]

Rhizodegradationq q

Bioremediation Bacteria to Protect Plants in Pentachlorophenol-Contaminated Soil [12]

Rhizodegradationq q

Decreased Transpiration in Popular Trees Exposed to 2,4,6-Trinitrotoluene [12]

Phytovolatilizationq q

Degradation of Polychlorinated Biphenyls by Hairy Root Culture ofSolanum nigrum [12]

Phytodegradationq q

Detoxification of Phenol by the Aquatic Angiosperm, Lemna gibba[12]

Phytodegradationq q

Effect of Hybrid Poplar Trees on Microbial Populations Importantto Hazardous Waste Bioremediation [13]

Rhizodegradationq q q

Effects of Ryegrass on Biodegradation of Hydrocarbons in Soil [13] Rhizodegradation q q

A Field Facility for Phytoremediation Research [13] Phytodegradation q q q

Greenhouse Evaluation of Agronomic and Crude Oil-Phytoremediation Potential Among Alfalfa Genotypes [13]

Phytodegradationq q

The Influence of Planting and Soil Characteristics onMineralization of 2,4,5-T in Rhizosphere Soil [14]

Rhizodegradationq q

Mineralization of 2,4-Dichlorophenol by Ectomycorrhizal Fungi inAxenic Culture and in Symbiosis with Pine [14]

Rhizodegradationq q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

anic

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Pest

icid

es/

Her

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Met

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Rad

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Phytoremediation Experimentation with the Herbicide Bentazon[14]

Phytodegradationq q

Phytoremediation: Modeling Removal of TNT and Its BreakdownProducts [14]

Phytodegradationq q

Phytoremediation of 1,4-dioxane by Hybrid Poplars [14] PhytovolatilizationRhizodegradation q q

Phytoremediation of Hazardous Wastes [15] Phytodegradation q q q

Phytoremediation of Organic Contaminants: A Review ofPhytoremediation Research at the University of Washington [15]

Phytodegradationq q q

Phytoremediation of Pesticide-Contaminated Soils [15] Rhizodegradation q q

Phytoremediation of Trichloroethylene with Hybrid Poplars [16] Rhizofiltration q q

Phytoremediation, Plant Uptake of Atrazine and Role of RootExudates [16]

Rhizodegradationq q

Phytotreatment of TNT-Contaminated Groundwater [16] Phytodegradation q q

Plant Cell Biodegradation of a Xenobiotic Nitrate Ester,Nitroglycerin I [16]

Phytodegradationq q

Plant-Enhanced Remediation of Petroleum Contaminated Soil [17] PhytodegradationRhizodegradation q q

Plant-Enhanced Subsurface Bioremediation of NonvolatileHydrocarbons [17]

Rhizodegradationq q


TechnologyType

Media Contaminants

Soil

Gro

und

Wat

er

Org

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Pest

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Potential of Phytoremediation as a Means for Habitat Restorationand Cleanup of Petroleum Contaminated Wetlands [17]

Phytodegradationq q

Rhizosphere Microbial Populations in Contaminated Soils [17] Rhizodegradation q q

Transformation of TNT by Aquatic Plants and Plant TissueCultures [18]

Phytodegradationq q

Uptake and Fate of Organohalogens from ContaminatedGroundwater in Wood Plants [18]

PhytodegradationPhytovolatilization q q


TechnologyType

Media Contaminants

Soil

Gro

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Wat

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Org

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INORGANIC CONTAMINANTS

Overviews

Emerging Technologies for the Remediation of Metals in Soils:Phytoremediation [18]

Unspecifiedq q

Literature Review: Phytoaccumulation of Chromium, Uranium,Plutonium in Plant Systems [19]

Phytoextractionq q q

Remediation of Metal-Contaminated Sites Using Plants [19] Phytoextraction q q

Restoration of Mined Lands—Using Natural Processes [19] Unspecified q q

Status of In Situ Phytoremediation Technology [19]EPA 542-R-97-004

PhytoextractionPhytostabilizationRhizofiltration

q q


Phytoaccumulation of Trace Elements by Wetlands Plants: I.Duckweed [20]

Phytoextractionq q

Relationship Between Sulfur Speciation in Soils and PlantAvailability [20]

Phytoextractionq q

Removal of Uranium from Water Using Terrestrial Plants [20] Rhizofiltration q q

Research

Differences in Root Uptake of Radiocesium by 30 Plant Taxa [20] Phytoextraction q q


TechnologyType

Media Contaminants

Soil

Gro

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Wat

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Org

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Enhanced Accumulation of Pb in Indian Mustard by Soil-AppliedChelating Agents [21]

Phytoextractionq q

Evaluation of Tamarisk and Eucalyptus Transpiration for theApplication of Phytoremediation [21]

Phytoextractionq q

Feasibility of Using Plants to Assist in the Remediation of HeavyMetal Contamination at J-Field, Aberdeen Proving Ground,Maryland. Final Report [21]

Phytoextractionq q

Lead-Contaminated Sediments Prove Susceptible toPhytoremediation [21]

Phytoextractionq q

Lead Uptake and Effects on Seed Germination and Plant Growth ina Pb Hyperaccumulator Brassica pekinensis Rupr. [22]

Phytoextractionq q

Metal Accumulation by Aquacultured Seedlings of Indian Mustard[22]

Phytoextractionq q

Phytoextraction of Cadmium and Zinc from a Contaminated Soil[22]

Phytoextractionq q

Phytoextraction of Zinc by Oat (Avena sativa), Barley (Hordeumvulgare), and Indian Mustard (Brassica juncea) [23]

Phytoextractionq q

Phytoextraction: the Use of Plants to Remove Heavy Metals fromSoils [23]

Phytoextractionq q

Phytofiltration of Hazardous Cadmium, Chromium, Lead and ZincIons by Biomass of Medicago sativa (Alfalfa) [23]

Rhizofiltrationq q


TechnologyType

Media Contaminants

Soil

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Phytoremediation of a Radiocesium-Contaminated Soil: Evaluationof Cesium137 Bioaccumulation in the Shoots of Three Plant Species[23]

Phytoextractionq q

Phytoremediation of Lead-Contaminated Soils: Role of SyntheticChelates in Lead Phytoextraction [24]

Phytoextractionq q

Phytoremediation of Selenium Laden Soils: A New Technology[24]

Phytoextractionq q

Phytoremediation of Uranium-Contaminated Soils: Role of OrganicAcids in Triggering Uranium Hyperaccumulation in Plants [24]

Phytoextractionq q

Potential for Phytoextraction of 137Cs from a Contaminated Soil [25] Phytoextraction q q

Potential Remediation of 137Cs and 90Sr Contaminated Soil byAccumulation in Alamo Switchgrass [25]

Phytoextractionq q

Rhizofiltration: the Use of Plants to Remove Heavy Metals fromAqueous Streams [25]

Rhizofiltrationq q

The Role of EDTA in Pb Transport and Accumulation by IndianMustard [25]

Phytoextractionq q

A Search for Lead Hyperaccumulating Plants in the Laboratory [26] RhizofiltrationPhytoextraction q q

Selenium Accumulation by Brassica Napus Grown in Se-laden Soilfrom Different Depths of Kersterson Reservoir [26]

Phytoextractionq q


TechnologyType

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Test Plan for the Phytoremediation Studies of Lead-ContaminatedSoil from the Sunflower Army Ammunition Plant, Desoto, Kansas.Vol. 1 and Vol. 2 [26]ADA342667, ADA342668

Phytoextraction

q q

Toxicity of Zinc and Copper to Brassica Species: Implications forPhytoremediation [26]

PhytoextractionPhytostabilization q q

Toxic Mercury Reduction and Remediation Using TransgenicPlants with a Modified Bacterial Gene [27]

PhytoextractionPhytostabilization q

Zinc and Cadmium Accumulation in the Hyperaccumulator ThlaspiCaerulescens in Response to Limestone and Compost Applicationsto a Heavy Metal Contaminated Site in Palmerton, Pennsylvania[27]

Phytoextraction

q q

xxi

Web Site TitleURL[Abstract Page Number in Guide]

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INTERNET RESOURCES

Advanced Applied Technology Demonstration Facility (AATDF)http://www.ruf.rice.edu/~aatdf [27] q q

Air Force Center for Environmental Excellence (AFCEE)http://www.afcee.brooks.af.mil [27] q q

Alternative Treatment Technology Information Center (ATTIC)http://www.epa.gov/attic [28] q q q q

CLU-IN: Hazardous Waste Clean-Up Informationhttp://clu-in.org [28] q q q q

Environmental Security Technology Certification Program (ESTCP)http://www.estcp.org [28] q q q q

Federal Remediation Technologies Roundtablehttp://www.frtr.gov [28] q q q q

GNET: The Global Network of Environment and Technologyhttp://www.gnet.org [28]

Great Plains/Rocky Mountain Hazardous Substance Research Centerhttp://www.ecc.ksu.edu/HSRC [28] q q q

Ground Water Remediation Technologies Analysis Center (GWRTAC)http://www.gwrtac.org [29] q q q q

Web Site TitleURL[Abstract Page Number in Guide]

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xxii

Innovative Treatment Remediation Demonstration (ITRD) http://www.em.doe.gov/itrd [29] q q q

Interstate Technology and Regulatory Cooperation Working Group (ITRC)http://www.sso.org/ecos/itrc [29] q q

PHYTONET - Phytoremediation Electronic Newsgroup Networkhttp://www.dsa.unipr.it/phytonet [29] q q q q

Remediation Technologies Development Forum (RTDF) Phytoremediation of Organics Action Teamhttp://www.rtdf.org/public/phyto [29]

q q q

Strategic Environmental Research and Development Program (SERDP)http://www.serdp.gov [30] q q

U.S. Army Corps of Engineers Phytoremediation Researchhttp://www.wes.army.mil/EL/phyto [30] q q

U.S. Army Environmental Center (USAEC)http://aec-www.apgea.army.mil:8080 [30] q q q q

U.S. Department of Agriculture (USDA)http://www.usda.gov [29] q q q q

1

ABSTRACTS OF PHYTOREMEDIATION RESOURCES

The resources below describe the contents of pertinent phytoremediation documents and Internet resources. Thereferences and resources are organized alphabetically within each of the following categories:

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Publications Containing Multiple Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Organic Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Overviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Field Studies and Demonstrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Publications Containing Multiple Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Inorganic Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Overviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Field Studies and Demonstrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Publications Containing Multiple Papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Internet Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

To quickly identify documents and resources pertinent to your interest area, see the Phytoremediation ResourceMatrix on pages ix-xxii of this Guide. The documents and resources in the matrix are organized alphabeticallywithin the categories identified above. Listings in the matrix can be cross-referenced with the abstracts by referringto the page number provided in the matrix. In an effort to limit the number of resources listed here, documentspublished prior to 1990 are not included. These abstracts were obtained from several databases, including theNational Technical Information Service, Energy Science and Technology, Enviroline, Water Resources Abstracts,and Pollution Abstracts as well as several Internet resources.

General Information

The 1998 United States Market forPhytoremediationGlass, D.J.D. Glass Associates, Inc., Needham, MA 140 pp April1998

Phytoremediation, the use of plants, trees, and othervegetation to remove, sequester, or degradeenvironmental contaminants, has attracted a great dealof interest in recent years. Drawing on the abilities ofplants to accumulate metals and other substances ortake up and transpire large amounts of water,phytoremediation is an effective, low-cost treatmenttechnology that is beginning to gain the attention of

private and industrial site owners, regulators, and theenvironmental engineering community. This reportincludes a technology summary, commercial companyprofiles, research group profiles, an industry analysisand market forecast, summaries of several completedand ongoing phytoremediation projects, a review of theadvantages and disadvantages of the technology, and aglossary.

2

The Advancement of Phytoremediation as anInnovative Environmental Technology forStabilization, Remediation, or Restoration ofContaminated Sites in Canada: A Discussion Paper McIntyre, T. and Lewis, G.M.Journal of Soil Contamination v 6:3 p 227(15) May1997

Environment Canada's Environmental TechnologiesAdvancement Division is exploring the potential ofphytoremediation as a major, long-term technologyapproach. The benefits and limitations ofphytoremediation and its potential for bioremediationof soil and ground water in Canada are discussed.Research issues that will need to be addressed to furtherphytoremediation technology are examined. Otherregulatory, legal, commercial, and social issues areconsidered briefly.

Bioremediation and Phytoremediation Glossary Bentjen, S.Available athttp://members.tripod.com/~bioremediation

This glossary lists terms related to bioremediation(microbial degradation) and phytoremediation(remediation using green plants) of environmentalpollutants. Links to other environmental glossariesappear at the bottom of the page.

A Citizen’s Guide to PhytoremediationU.S. EPA, Office of Solid Waste and EmergencyResponse 6 pp August 1998Available at http://clu-in.org

EPA Document Number: EPA 542-F-98-011

EPA’s Technology Innovation Office has published aTechnology Fact Sheet that describes whatphytoremediation is, how it works, what its limitationsare, and where to find additional information.

Compost-Enhanced Phytoremediation ofContaminated SoilU.S. EPA, Office of Solid Waste and EmergencyResponsePublished in Analysis of Composting as anEnvironmental Remediation Technology p 87(12) April 1998


Phytoremediation is a developing technology in whichhigher plants and microorganisms associated with plantroots are the active agents for uptake and/ordegradation of toxic inorganic and organic compoundsin soil and water. Plants can also provide containmentby reducing the erosional transport of contaminatedsoil. Numerous reports indicate that plants can take upand degrade toxic organic compounds in soil, whileother work indicates microorganisms in the rhizosphereare very competent degraders of soil-borne organics.This process might be suitable for soil remediationand/or inexpensive confinement of shallowcontaminated water. Phytoremediation ofmetal-contaminated soil relies on the ability of plants toaccumulate metals at concentrations substantially abovethose found in the soil in which they grow.Phytoremediation has very large economic advantagesover mechanically intensive technologies.

Introduction to PhytoremediationU.S. EPA, National Risk Management ResearchLaboratoryTo be issued in 1999To be available at http://www.rtdf.org

This handbook is the work of the EPAPhytoremediation Handbook Team in conjunction withthe Remediation Technologies Development Forum(RTDF) Phytoremediation Action Team. It wasdeveloped to provide a tool for site regulators, owners,neighbors, and managers to evaluate the applicability ofphytoremediation to a site. Phytoremediation projectshave been proposed or applied to ecosystem restorationand soil, surface water, ground water, and sedimentremediation. This document identifies, defines, andprovides a framework to evaluate thesephytoremediation applications, although it is not adesign guide. It also presents case studies illustratingfield applications of phytoremediation.

Abstracts of Phytoremediation Resources General Information

3

Legal and Social Concerns to the Development ofBioremediation Technologies Bilyard, G.R.; et al.150 pp Sep 1996

NTIS Document Number: DE96015254

The social and legal framework within whichbioremediation technologies must be researched,developed, and deployed in the U.S. are discussed inthis report. Discussions focus on policies, laws andregulations, intellectual property, technology transfer,and stakeholder concerns. These discussions areintended to help program managers, scientists andengineers understand the social and legal frameworkwithin which they work, and be cognizant of relevantissues that must be navigated during bioremediationtechnology research, development, and deploymentactivities. While this report focuses on the legal andsocial environment within which the DOE operates, thelaws, regulations and social processes could apply toother sites nationwide. This report identifies specificissues related to bioremediation technologies, includingthose involving the use of plants; native, naturallyoccurring microbes; non-native, naturally occurringmicrobes; genetically engineered organisms; andmicrobial products (e.g., enzymes, surfactants,chelating compounds).

Phytoremediation Rock, S. and Pope, D.Published in Seminars: Bioremediation of HazardousWaste Sites: Practical Approaches to Implementation p8.1(9) 1996

EPA Document Number: EPA 625-K-96-001

Chapter eight of the seminar publication contains adescription of the different aspects of phytoremediation,applications and examples, a bibliography, andillustrations from the poster session.

Phytoremediation Salt, D.E.; Smith, R.D.; and Raskin, I.Annual Review of Plant Physiology and PlantMolecular Biology v 49 p 643(26) 1998

Phytoremediation, a cost-effective plant-based approachto remediation, takes advantage of the ability of plantsto concentrate elements and compounds from theenvironment and to metabolize various molecules intheir tissues. Several field trials have confirmed thefeasibility of using plants for environmental cleanup.This review concentrates on the most developed subsetsof phytoremediation technology and on the biologicalmechanisms that make phytoremediation work.

Phytoremediation: A Clean Transition fromLaboratory to Marketplace? Boyajian, G.E. and Carreira, L.H.Natural Biotechnology v 15:2 p 127(2) 1997

In recent years, the potential of plants forenvironmental cleanup—phytoremediation—has beenrecognized, and U.S. government agencies and privatecorporations have responded by increasingly supportingresearch in this area. The report in this issue by Goel etal. both advances our basic knowledge of plantbiochemistry and demonstrates that plants are indeedcapable of tackling such exotic xenobiotic contaminantsas nitroglycerin.

Phytoremediation: A New Technology Gets Ready toBloom Bishop, J.Environmental Solutions v 10:4 p 29(6) May-June 1997

Phytoremediation is the use of selected crop plants ortrees to extract or promote degradation of toxicsubstances in soils, ground water, surface water,wastewater and sediments. It may be possible in somecases to harvest such contaminants as heavy metals thathave been taken up by plants and recover them forrecycling. In other variations, plants stimulate thegrowth of naturally occurring microbial populations,which then degrade organic contaminants, such aspetroleum hydrocarbons, in soils. At appropriate sites, the cost of applying phytoremediation techniques mayrange from half to less than 20% of the cost of usingphysical, chemical, or thermal techniques.


4

Phytoremediation Bibliography Available at http://www.rtdf.org

This searchable bibliography of over 1,400 citations isthe work of the EPA Phytoremediation Handbook Teamin conjunction with the Remediation TechnologiesDevelopment Forum (RTDF) Phytoremediation ActionTeam. The bibliography is updated frequently.

Phytoremediation Field Demonstrations in the U.S.EPA SITE Program Rock, S. and Beckman, S. In Situ and On-Site Bioremediation: Volume 3Battelle Press, Columbus, OH p 323 [abstract only]1998

U.S. EPA National Risk Management ResearchLaboratory’s SITE program is evaluatingphytoremediation’s efficacy and cost at field scaledemonstrations on sites in Oregon, Utah, Texas, andOhio. The Superfund Innovative TechnologyEvaluation (SITE) Program is a part of EPA’s researchinto alternative cleanup methods for hazardous wastesites. The EPA teamed with USAF, USGS, Ohio EPA,Chevron USA, Phytotech, Inc., and Phytokinetics, Inc.to accomplish these demonstrations. At a wood treaterin Portland, Oregon, shallow soil contaminated withPCP and PAHs is being treated with a perennialryegrass. In Ogden, Utah, a combination of poplartrees, juniper trees, alfalfa, and fescue has been plantedto remediate a petroleum spill which has polluted boththe soil and the ground water. On an Air Force facilitynear Fort Worth, Texas, cottonwood trees are beingused to intercept a part of a large TCE ground waterplume. In Ohio, the shallow soil of a former metalplating facility is the site for a demonstration ofphytoextraction of lead, cadmium, and hexavalentchromium using Indian mustard. Each demonstrationincludes monitoring the soil, ground water, and plantmaterial. The sites were planted in 1996, and will bemonitored until at least 1999. [Abstract only.Additional information is available at http://clu-in.orgunder the SITE Demonstration Program page.]

Phytoremediation: It Grows on You Boyajian, G. E. and Devedjian, D.L.Soil & Groundwater Cleanup p 22(5) February-March1997

Phytoremediation is a small but growing subset of insitu remediation technologies for contaminated soil.Plants can be effective remediators by reachingcontaminants through their root systems, their ability toaccumulate metals and degrade organic compounds,and their reduced cost compared with other approaches.However, only those plants having the appropriatebiochemical pathways are effective for soil cleanup.Identification of appropriate plants for remediation oforganic compounds and heavy metals is discussed.

Phytoremediation on the Brink ofCommercialization Watanabe, M.E.Environmental Science & Technology v 31:4 p 182A(4)1997

Academic, government, and corporate researchers havea body of data on the ability of certain plants to eitherremove pollutants from the environment or render themharmless, and they are looking for ways to improvethese traits through plant breeding and moleculartechniques. In the past three years, at least three newcompanies have formed to use plants to clean sitescontaminated with heavy metals or organics.Phytoremediation is a natural process carried out byplants, especially those that are able to survive incontaminated soil and water. Hyperaccumulators areplants that can absorb high levels of contaminants withtheir roots and concentrate them either there or inshoots and leaves. Researchers have foundhyperaccumulator species by collecting plants in areaswhere soil contains greater than usual amounts ofmetals or other potentially toxic compounds because ofgeological factors or pollution. Among the plants thathave been collected and used in field trials are speciesfrom the genus Thlaspi, or Alpine pennycress, whichaccumulate zinc, cadmium, or lead, and Alyssumspecies, which accumulate nickel. Both genera belongto the mustard family Brassicaceae. Plants from otherfamilies also have been shown to remove cobalt,copper, chromium, manganese, or selenium fromcontaminated soils.


5

Phytoremediation: Technology Overview ReportMiller, R.Groundwater Remediation Technologies AnalysisCenter, Pittsburgh, PA 26 pp 1996Available at http://www.gwrtac.org

Phytoremediation uses plants to cleanup contaminatedsoil and ground water, taking advantage of plants'natural abilities to take up, accumulate, and/or degradeconstituents of their soil and water environments.Research results report it to be applicable to a broadrange of contaminants including numerous metals,radionuclides, and various organic compounds (such aschlorinated solvents, BTEX, PCBs, PAHs,pesticides/insecticides, explosives, nutrients, andsurfactants). According to information reviewed,general site conditions best suited for use ofphytoremediation include large areas of low tomoderate surface soil (0 to 3 feet) contamination orlarge volumes of water with low-level contaminationsubject to low (stringent) treatment standards. Majoradvantages reported for phytoremediation as comparedto traditional remediation technologies include thepossibility of generating less secondary wastes, minimalassociated environmental disturbance, and the ability toleave soils in place and in a usable condition followingtreatment. Cited disadvantages include the long lengthsof time required (usually several growing seasons),depth limitations (3 feet for soil and 10 feet for groundwater), and the possibility of contaminant entrance intothe food chain through animal consumption of plantmaterial.

Phytoremediation: Using Green Plants to Clean UpContaminated Soil, Groundwater, and WastewaterNegri, M. C. and Hinchman, R.R.9 pp 1996

Phytoremediation, an emerging cleanup technology forcontaminated soils, ground water, and wastewater thatis both low-tech and low-cost, is defined as theengineered use of green plants to remove, contain, orrender harmless such environmental contaminants asheavy metals, trace elements, organic compounds, andradioactive compounds in soil or water. Currentresearch at Argonne National Laboratory includes a

successful field demonstration of a plant bioreactor forprocessing the salty wastewater from petroleum wellsand a greenhouse experiment on zinc uptake in hybridpoplar (Populus sp.). Because the roots sequester mostof the contaminant taken up in most plants, a majorobjective of this program is to determine the feasibilityof root harvesting as a method to maximize the removalof contaminants from soils. Available techniques andequipment for harvesting plant roots, including youngtree roots, are being evaluated and modified asnecessary for use.

Remediation Technologies Screening Matrix andReference GuideFederal Remediation Technologies RoundtableAvailable at http://www.frtr.gov

This reference guide provides a "yellow pages" ofremediation technologies. It is intended to be used toscreen and evaluate candidate cleanup technologies forcontaminated installations and waste sites in order toassist remedial project managers (RPMs) in selecting aremedial alternative. It incorporates cost andperformance data to the maximum extent available andfocuses primarily on demonstrated technologies. Alllevels of remediation technologies are included in thisguide. These technologies are applicable at all types ofsite cleanups: Superfund, DoD, DOE, RCRA, state,private, etc.

Stemming the Toxic Tide Dutton, G.Compressed Air v 101:4 p 38(5) June 1996

Phytoremediation, the use of plants to clean up toxicsubstances in soil and water, has been proposed as aneffective treatment for contaminated soil and sludge atindustrial locations, including Superfund sites. Theapproach represents a cost-effective alternative toconventional remediation methods. Elements beingconsidered as targets of phytoextraction include nickel,zinc, copper, selenium, cadmium, chromium, lead,cobalt, manganese, and several radionuclides. Specificplants and processes being used to clean soil and waterare identified. Problems with the approach includedisposal issues and time and depth limitations.


6

Technology Evaluation Report: Phytoremediation Schnoor, J.L.Ground-Water Remediation Technologies AnalysisCenter 43 pp October 1997Available at http://www.gwrtac.org

Phytoremediation is best applied at sites with shallowcontamination by organic, nutrient, or metal pollutants.Phytoremediation is well-suited for use at very largefield sites where other methods of remediation are notcost-effective or practicable; at sites with lowconcentrations of contaminants where only "polishingtreatment" is required over long periods of time; and inconjunction with other technologies where vegetation isused as a final cap and closure of the site. There arelimitations to the technology that need to be consideredcarefully before it is selected for site remediation. Theseinclude: limited regulatory acceptance, long duration oftime sometimes required for clean-up to below actionlevels, potential contamination of the vegetation andfood chain, and difficulty establishing and maintainingvegetation at some toxic waste sites. This detailedreport discusses the current status of phytoremediationto treat soils and ground water. Several fielddemonstration summaries are presented, with suchinformation as: participants, compounds treated, sitecharacteristics, results, and contacts.

Using Phytoremediation to Clean Up Contaminationat Military Installations Zellmer, S.D.; Hinchman, R.R.; Negri, M.C.;Schneider, J.F.; and Gatliff, E.G. 19 pp July 1997

NTIS Document Number: DE97007971

An emerging technology for cleaning contaminatedsoils and shallow ground water is phytoremediation, anenvironmentally friendly, low-cost, and low-techprocess. Phytoremediation encompasses allplant-influenced biological, chemical, and physicalprocesses that aid in the uptake, degradation, andmetabolism of contaminants by either plants orfree-living organisms in the plant's rhizosphere. A

phytoremediation system can be viewed as a biological,solar-driven, pump-and-treat system with an extensive,self-extending uptake network (the root system) thatenhances the soil and below-ground ecosystem forsubsequent productive use. Argonne NationalLaboratory has been conducting basic and appliedresearch in phytoremediation since 1990.

Publications Containing Multiple Papers

Phytoremediation of Soil and Water Contaminants Kruger, E.L.; Anderson, T.A.; and Coats, J.R. (eds.)Developed from a symposium sponsored by theDivision of Agrochemicals and the Division ofEnvironmental Chemistry at the 212th NationalMeeting of the American Chemical Society, August25-29, 1996, Orlando, Florida.American Chemical Society, Washington, DC 318 pp1997

Emerging Technologies in Hazardous WasteManagement VII: The 7th ACS Special Symposium,17-20 September 1995, Atlanta, GeorgiaTedder, D.W. (ed.)American Chemical Society, Washington, DC 1352 pp1995

Bioremediation Through Rhizosphere TechnologyAnderson, T.A. and Coats, J.R. (eds.) American Chemical Society, Washington, DC 249 pp1994

Bioremediation of Surface and SubsurfaceContamination (Annals of the New York Academyof Sciences, Vol. 829) Bajpai, R. and Zappi, M. (eds.) 1997

In Situ and On-Site Bioremediation, Vol. 3Alleman, B.C. and Leeson, A. (eds.)Battelle Press, Columbus, OH 570 pp 1997

Abstracts of Phytoremediation Resources Organic Contaminants

7

Proceedings of the Annual Conference on HazardousWaste ResearchGreat Plains/Rocky Mountain Hazardous SubstanceResearch Center, Kansas State University, Manhattan,KSTables of contents, abstracts, and selected papers fromthe 1994 Ninth Annual Conference onward areavailable at http://www.engg.ksu.edu/HSRC

Proceedings of the International Seminar on Use ofPlants for Environmental Remediation (ISUPER) Council for Promotion of Utilization of OrganicMaterials (CPOUM), Kosaikan, Tokyo, Japan 1997

Annual International Conference onPhytoremediationInternational Business Communications,Southborough, MA (1st:1996, 2nd:1997, 3rd:1998)

Proceedings of the 12th Annual Conference onContaminated Soils: Analysis, Site Assessment, Fate,Environmental and Human Risk Assessment,Remediation and Regulation, 20-23 October 1997,Amherst, MA Kostecki, P. T. and Calabrese, E.J. (eds.)Environmental Health Sciences Program, School ofPublic Health, University of Massachusetts, Amherst,MA, 1997

Journal of Soil Contaminationv 7:4 July 1998

Soil & Groundwater Cleanup February-March 1999

Soil & Groundwater Cleanup February-March 1998

International Journal of PhytoremediationFirst Issue (v 1:1) to be published by CRC Press inMarch 1999.

PhytoremediationTerry, N. and Bañuelos, G.S. (eds.)Ann Arbor Press, (In press. Release expected Summer1999).

Superfund Innovative Technology EvaluationProgram: Technology Profiles, 9th Edition


Organic Contaminants

Overviews

Mechanisms of Phytoremediation: Biochemical andEcological Interactions Between Plants and BacteriaSiciliano, S.D. and Germida, J.J.Environmental Reviews v 6:1 p 65(15) 1998

This review concentrates on plant-bacteria interactionsthat increase the degradation of hazardous organiccompounds in soil. Plants and bacteria can formspecific associations in which the plant provides thebacteria with a specific carbon source that induces thebacteria to reduce the toxicity of the contaminated soil.Alternatively, plants and bacteria can form nonspecificassociations in which normal plant processes stimulatethe microbial community, which in the course ofnormal metabolic activity degrades contaminants insoil. Plants can provide carbon substrates and nutrients,as well as increase contaminant solubility. Thesebiochemical mechanisms increase the degradativeactivity of bacteria associated with plant roots. Inreturn, bacteria can augment the degradative capacityof plants or reduce the toxicity of the contaminated soil.


8

Phytoremediation of TCE in Groundwater usingPopulusChappell, J.Status Report Prepared for the U.S. EPA TechnologyInnovation Office, 1997Available at http://clu-in.org

This report is intended to provide a basic orientation tophytoremediation and a review of its use for shallowground water remediation. It contains informationgathered from a range of currently available sources,including project documents, reports, periodicals,Internet searches, and personal communication withinvolved parties. No attempts were made toindependently confirm the resources used.


Demonstration Plan for Phytoremediation ofExplosive-contaminated Groundwater inConstructed Wetlands at Milan Army AmmunitionPlant, Milan, Tennessee. Volumes 1 and 2. FinalReportBehrends, L.; Sikora, F.; Kelly, D.; Coonrod, S.; andRogers, B.209 pp (Vol. 1), 496 pp (Vol. 2) Jan 1996

NTIS Document Number: ADA311121/8/XAB (Vol. 1)ADA311122/6/XAB (Vol. 2)

This plan demonstrates the technical and economicfeasibility of using phytoremediation in an artificial,constructed wetlands for treatment ofexplosives-contaminated ground water at Milan ArmyAmmunition Plant. Validated data on cost andeffectiveness of this demonstration will be used totransfer this technology to the user community.

Evaluation of Various Organic Fertilizer Substratesand Hydraulic Retention Times for EnhancingAnaerobic Degradation of Explosives-ContaminatedGroundwater While Using Constructed Wetlands atthe Milan Army Ammunition Plant, Milan,Tennessee Behrends, L.L.; Almond, R.A.; Kelly, D.A.; Phillips,W.D.; and Rogers, W.J.383 pp May 1998

NTIS Document Number: ADA349293

This document describes studies conducted at the MilanArmy Ammunition Plant (MAAP) to improve thedesign, operation, and cost of gravel-based anaerobiccells when phytoremediating explosives-contaminatedground water. A typical gravel-based wetland consistsof an anaerobic cell for removing the bulk of theexplosive-contaminates, and an aerobic cell forremoving CBOD-5, nutrients, total suspended solids,and small quantities of explosive by- products. Thecells are connected in series with the anaerobic cellbeing the first cell. Small-scale anaerobic test cells wereused to determine: (1) If the hydraulic retention time ofa large demonstration-scale anaerobic cell at MAAPcould be reduced, and (2) if other carbon sources couldbe used as an anaerobic feedstock. The study resultsindicate that: (1) The existing anaerobic cell's 7.5-dayretention time should not be reduced since residualexplosive by-products were present in the effluent oftreatments with a 3.5-day retention time. (2) Dailyapplication of a relatively soluble substrate, such asmolasses syrup, will provide better explosives removalthan periodic application of less soluble substrates suchas milk replacement starter and sewage sludge.

Field Scale Evaluation of Grass-EnhancedBioremediation of PAH Contaminated Soils Sorensen, D.L.; Sims, R.C.; and Qiu, X.EPA Risk Reduction Engineering Laboratory’s 20thAnnual Research Symposium, 15-17 March 1994,Cincinnati, OH p 92(3)

A field pilot-scale study was launched to assess thepotential of prairie grasses to enhance bioremediationof PAH-contaminated soils. The ongoing research isdesigned to test the hypothesis that the deep, fibrousroot system of the grasses improves aeration in soil anddegradative capability in the rhizosphere. Averagephenanthrene levels declined dramatically in bothvegetated and unvegetated plots. Acenaphthylene alsodeclined in both sites with time and was detected inhigher concentrations in unvegetated shallow soilrelative to vegetated shallow soil. Preliminary dataindicate slow degradation in test plots and providesome evidence that Buffalo grass sod plantingenhanced degradation in the near surface.


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Friendly ForestsMiller, J. A.Third International Conference on Health, Safety,Environment in Oil and Gas Exploration andProduction, 9 June-12 Sep 1996, New Orleans,LouisianaSociety of Petroleum Engineers (SPE), Inc.,Richardson, TX p 717(6) 1996

Trees can be used to extract ground water from aquifersand serve as a natural pumping system forcontaminated ground water plume control.Simultaneously, the trees create a rhizospherebiodegradation zone and extract hydrocarbons throughuptake in the transpiration stream. Phytoremediationhas been proposed for cleanup of historical petroleum hydrocarbon andchlorinated hydrocarbon contamination as an in situtreatment method of reasonable cost that requires littlemaintenance. The initiative of one major oilfieldservice company at a Louisiana site is described. Thedemonstration began in June 1995 with the planting of92 hybrid poplar trees for the purposes of (1)controlling ground water movement; (2) taking upconstituents from soil and ground water; and (3)enhancing bioremediation of soil and ground water inthe rhizosphere. Results to date are reported.

Groundwater Phytoremediation Test Facility,University of WashingtonContact: Stuart E. Strand, Research Associate ProfessorBox 352100, College of Forest Resources, University ofWashington, Seattle, WA 98195Tel/Fax: 206-543-5350 E-mail:[email protected]

The Ground water Phytoremediation Test Facility(GWPTF) was constructed in 1994 in Fife,Washington. The facility covers about one-quarter acreand is equipped with 12 double-lined test beds, each 12ft x 18 ft x 4.5 ft deep. The site has equipment forhandling, mixing, and delivering syntheticallycontaminated water and for decontaminating theeffluent water using carbon adsorption units. The testfacility has been used to provide the first near-full-scaletesting of phytoremediation of chlorinatedhydrocarbons in ground water. Results indicate nearlycomplete uptake of TCE and carbon tetrachloride by

poplar trees with no detectable TCE or CT emissions.The GWPTF test beds allow easy monitoring ofinfluent and effluent mass fluxes of chlorinatedsolvents. A permit is required to conductdemonstrations. Technology developers and the sitemanager work together to file the permit. It takes aboutsix months to obtain a permit. State and localregulations apply. Permission to add injectants forremediation may be granted on a case-by-case basis.

Phreatophyte Influence on Reductive Dechlorinationin a Shallow Aquifer Containing TCELee, R.W.; Jones, S.A.; Kuniansky, E.L.; Harvey, G.J.;and Eberts, S.M.Bioremediation and Phytoremediation: Chlorinatedand Recalcitrant CompoundsBattelle Press, Columbus, OH p 263(6) 1998

At Carswell Field, Fort Worth Naval Air Station JointReserve Base in Texas, a phytoremediationdemonstration project is being conducted to determineif eastern cottonwood trees are effective in remediatingshallow trichloroethylene-contaminated ground water.Two tree plots were prepared and planted in April1996, and baseline sampling began shortly thereafter.A stand of whips (cuttings) and a stand of 1- to2-year-old trees are included in the study. After 18months, the root systems were not sufficientlyestablished to alter the chemistry and microbiology ofthe ground water. However, a nearby maturecottonwood tree was found to have changed groundwater chemistry, causing oxygen consumption, ironreduction, methane production, and reductivedechlorination of TCE in the vicinity of the rootsystem. Ground water levels and TCE concentrations inthe aquifer will be monitored to establish baselineconditions and to map changes within the aquiferthroughout the life of the demonstration. Costsassociated with the planting and cultivation of each treestand will be compared to help assess the practicabilityof phytoremediation as a cleanup technology.Demonstration sampling will continue until the year2000.


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Phytoremediation of Dissolved-PhaseTrichloroethylene Using Mature Vegetation Doucette, W.J.; Bugbee, B.; Hayhurst, S.; Plaehn,W.A.; Downey, D.C.; Taffinder, S.A.; and Edwards, R.Bioremediation and Phytoremediation: Chlorinatedand Recalcitrant CompoundsBattelle Press, Columbus, OH p 251(6) 1998

At a study site at Cape Canaveral Air Station, FL,transpiration gas and tissues of live oak, castor bean,and saw palmetto growing above a trichloroethylene(TCE)-contaminated ground water plume werecollected and analyzed for TCE and its metabolites.Results showed that measurable levels of TCE weredetected in seven of 15 transpiration-gas samples.Trichloroethylene, 2,2,2-trichloroethanol,2,2,2-trichloroacetic acid, and 2,2-dichloroacetic acidwere detected in all plant tissue types from all threespecies. Generally, metabolite concentrations werehigher than TCE concentrations. Highest TCEconcentrations were found in the roots, while highestmetabolite concentrations were detected in leaf andstem samples.

Phytoremediation of Groundwater at AvestaSheffield Pipe Glanders, G.A. and Lundquist, J.B.Iron and Steel Engineer v 75:5 p 39(3) May 1998

Ground water contaminated with volatile organiccompounds and nitrate from spent pickle liquor isbeing remediated by a phytoremediation process usinglimpograss. Limpograss is a high protein,nitrate-loving grass that also serves as a valuable sourceof animal feed.

Phytoremediation of Organic and NutrientContaminants Schnoor, J.L.; Licht, L.A.; McCutcheon, S.C.; Wolfe,N.L.; and Carreira, L.H.Environmental Science & Technology v 29:7 p 318A(6)1995

Phytoremediation, the use of vegetation for the in situtreatment of contaminated soils and sediments, is anemerging technology that promises effective and

inexpensive cleanup of certain hazardous waste sites.Remediation using plants is best suited to sites withshallow contamination (<15 ft depth); moderatelyhydrophobic pollutants (BTEX compounds, chlorinatedsolvents, nitrotoluene ammunition wastes), or excessnutrients (nitrate, ammonium, and phosphate). Thetechnology has been used effectively in a number offull-scale and pilot studies that are mentioned in thearticle.

Pilot-Scale Use of Trees to Address VOCContamination Compton, H.R.; Haroski, D.M.; Hirsh, S.R.; andWrobel, J.G.Bioremediation and Phytoremediation: Chlorinatedand Recalcitrant Compounds

Battelle Press, Columbus, OH p 245(6) 1998At the Aberdeen Proving Ground, MD, significantlevels of VOCs have been detected in the ground water,primarily in the surficial aquifer, at depths toapproximately 12 m. A study was conducted to assessphytoremediation as a viable alternative forremediating the shallow ground water contamination.Over a 4000-m2 plot, 183 hybrid poplar trees wereplanted, and seasonal transpiration gas and watersamples were analyzed. The data revealed that the treeswere removing or degrading VOCs at the site asindicated by the presence of VOCs and theirdegradation products in transpiration gas, condensate,and leaf tissue. A gradient of ground water flow hasformed toward the phytoremediation test plot, with aground water depression of approximately 0.1 m.Analysis of nematode samples suggested that the soilhabitat is improving due to the presence of the trees.

Screening of Aquatic and Wetland Plant Species forPhytoremediation of Explosives-ContaminatedGroundwater from the Iowa Army AmmunitionPlant. Final Report Best, E.P.; Zappi, M.E.; Fredrickson, H.L.; Sprecher,S.L.; and Larson, S.L.74 pp January 1997

NTIS Document Number: ADA322455/7/XAB


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Munitions material such as 2,4,6-trinitrotoluene (TNT)and hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX) andtheir combustion and decomposition products can enterthe environment from production activities, field usage,and disposal. The capabilities of plants to absorb,accumulate, and metabolize, directly or indirectly,various organic substances suggest their use in thephytoremediation of contaminated environments.

Screening Submersed Plant Species forPhytoremediation of Explosives-ContaminatedGroundwater from the Milan Army AmmunitionPlant, Milan, Tennessee. Final ReportBest, E.P.; Sprecher, S.L.; Fredrickson, H.L.; Zappi,M.E.; and Larson, S.L.89 pp November 1997

Phytoremediation systems are being considered as analternative to other ground water extraction and surfacetreatment techniques due to their ability to enhanceremoval of potentially toxic or mutagenic munitionsmaterial such as 2,4,6-trinitrotoluene (TNT),hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX), andtheir degradation products. This study evaluated therelative ability of ten species to decrease levels of TNTand RDX explosives and related contaminants inground water at the Milan Army Ammunition Plant,Milan, Tennessee.

Research

Adsorption of Naphthalene onto Plant Roots Schwab, A. P.; Al-Assi, A. A.; and Banks, M. K.Journal of Environmental Quality v 27:1 p 220(5)January-February 1998

During phytoremediation, PAHs that are resistant todegradation may adsorb to the surfaces of plant roots,making the roots an important sink for specific PAHs.Tall fescue and alfalfa were grown in a greenhouseunder controlled conditions, and roots were harvestedat three growth stages: vegetative, flowering, andmature. Naphthalene adsorption to the various plantroots was then evaluated. Results show that the mass ofnaphthalene volatilized was the largest component ofthe mass balance (32-45%). The mass in solution wasusually greater than that adsorbed to the roots. Theaffinity of naphthalene for alfalfa roots was greater than

that for tall fescue roots, but fescue roots were presentin much greater quantities in the soil compared withalfalfa. Naphthalene adsorption on the roots of bothplant species increased with plant age.

Aromatic Nitroreduction of Acifluorfen in SoilsRhizospheres and Pure Cultures of RhizobacteriaZablotowicz, R.M.; Locke, M.A.; and Hoagland, R.E.Agricultural Research Service September 1996

Reduction of the nitro group in acifluorfen (anitrodiphenyl ether herbicide) to aminoacifluorfen is amajor catabolic transformation of this herbicide insoils, rhizospheres, and pure cultures of certainbacteria. Aromatic nitroreduction occurs more rapidlyin rhizosphere soils compared to root-free soil, with arapid incorporation into unextractable humic soilcomponents. Factors affecting acifluorfen-nitroreductase activity in cell suspensions and cell-freeextracts of these bacteria were studied. Microbialaromatic nitroreductase activity in soils andrhizospheres can be an important biotransformation inthe degradation of acifluorfen and other nitroaromaticherbicides.

Bacterial Inoculants of Forage Grasses ThatEnhance Degradation of 2-Chlorobenzoic Acid inSoil Siciliano, S.D. and Germida, J.J.Environmental Toxicology and Chemistry v16:6 p1098(7) June 1997

A study was conducted to examine the potential ofrhizosphere inoculants to enhance the degradation ofcontaminants in soil. 2-Chlorobenzoic acid was used asthe model contaminant, along with 11 bacterial strainsand 16 forage grass species. Results showed that threeof the forage species—Bromus biebersteinii, Elymusdauricus, and Agropyron riparum—grew well in the2-chlorobenzoic acid-contaminated soil and alsoenhanced the disappearance of the compound. The bestbacterial inoculants proved to be Pseudomonasaeruginosa strain R75 and P. savastoanoi strain CB35.The inoculation of the forage grasses with eitherbacterial strain increased significantly the


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disappearance of 2-chlorobenzoic acid over that ofunplanted controls.

Bioremediation Bacteria to Protect Plants inPentachlorophenol-Contaminated Soil Pfender, W.F.Journal of Environmental Quality v 25:6 p 1256(5)November-December 1996

Pseudomonas strain SR3, a known pentachlorophenol-degrader, was added to a pentachlorophenol-contaminated soil, and the ability of the bacteria toprotect Proso millet sown in the soil was assessed. Plants were removed from the soil 28 days after planting with roots, shoots, and soil analyzed forpentachlorophenol. Seedling emergence was found tobe 50 and 62% for bacteria-treated and control seeds,respectively, in pentachlorophenol-contaminated soil.In uncontaminated soil, emergence rates were 100 and87%, respectively. Bacterial treatment greatly increasedfinal plant biomass in contaminated soil, bringing rootand total plant weights to nearly the same as thoseobserved for plants grown in uncontaminated soil. Incontaminated soil planted with bacteria-treated seeds,the final pentachlorophenol level was only 3 mg/kg, ascompared to 5 and 157 mg/kg for the millet-only andnonplanted contaminated soils, respectively.

Decreased Transpiration in Poplar Trees Exposed to2,4,6-TrinitrotolueneThompson, P.L.; Ramer, L.A.; Guffey, A.P.; andSchnoor, J.L.Environmental Toxicology & Chemistry v 17:5 p902(5) May 1998

Poplar trees were exposed to 2,4,6-trinitrotoluene(TNT), and the effects on transpiration were examined.The TNT concentrations used were 0, 1, 3, 5, 10, and15 mg/l. Levels of TNT uptake reached the detectionlimit of 4 ppm after only 1 hour of exposure, with TNTremoved at a relatively rapid rate. TNT concentrationsof greater than 5 mg/l were toxic to the trees, with thedecrease in biomass attributed to the inhibition of leafgrowth. This level decreased transpiration significantlyafter 11 days of exposure. Overall, the hybrid poplar

exhibited a tolerance for TNT that was higher than thatof duckweed and similar to that of yellow nutsedge.

Degradation of Polychlorinated Biphenyls by HairyRoot Culture of Solanum nigrum Mackova, M.; Macek, T.; Kucerova, P.; Burkhard, J.;Pazlarova, J.; and Demnerova, K.Biotechnology Letters v 19:8 p 787(4) August 1997

Hairy root cultures of Solanum nigrum proved capableof transforming PCBs under controlled conditions. Theimpact of several different plant growth regulators oncell growth and transformation of PCBs are analyzed.Plant cells proved capable of transforming PCBs evenafter growth had stopped. A 20% reduction in PCBconversion efficiency was observed in young inoculum(16 days), as compared against older inocula (37 and68 days). The PCB transformation rate was stimulatedwith increasing size of inoculum.

Detoxification of Phenol by the Aquatic Angiosperm,Lemna gibba Barber, J.T.; Sharma, H.A.; Ensley, H.E.; Polito, M.A.;and Thomas, D.A.Chemosphere v 31:6 p 3567(8) September 1995

In many cases, plants have the ability to metabolizeorganic pollutants by transformation and conjugationreactions followed by compartmentalizing products intheir tissues. The toxicity and fate of phenol in theangiosperm Lemna gibba were investigated. Over a 16day growth period, almost 90% of the applied phenoldisappeared from solution. While the disappearance ofphenol was attributed to plant uptake, the appearance ofadditional compounds in the media indicated thatmetabolism occurred, with the release of themetabolites back to the media. The primary metabolitewas identified as phenyl-(gr)b-D-glucoside, which wasfound to be approximately half as toxic as the parentcompound.


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Effect of Hybrid Poplar Trees on MicrobialPopulations Important to Hazardous WasteBioremediationJordahl, J.L.; Foster, L.; Schnoor, J.L.; and Alvarez,P.J.J.Environmental Toxicology and Chemistry v 16:6 p1318(4) June 1997

Microbial populations from the rhizosphere ofseven-year-old hybrid poplar trees were characterizedin terms of five specific phenotypes: total heterotrophs;denitrifiers; pseudomonads; degraders of benzene,toluene, and xylenes (BTX); and atrazine degraders.The concentrations of these phenotypes were measuredin three rhizosphere samples and in three control soilsamples taken from an adjacent corn field. All types ofmicrobial populations were higher in the poplarrhizosphere than in the surrounding soil. Highestconcentrations were found for total heterotrophs,followed by denitrifiers, pseudomonads, BTXdegraders, and atrazine degraders. These findings arediscussed in relation to bioremediation potential.

Effects of Ryegrass on Biodegradation ofHydrocarbons in Soil Gunther, T.; Friedrich-Schiller-Universitat J.;Dornberger, U.; and Fritsche, W.Chemosphere v 33:2 p 203(13) July 1996

The influence of ryegrass on the biodegradation ofapplied aliphatics and PAHs was investigated using aseries of laboratory soil-column experiments. A definedmixture of saturated, unsaturated, and branched-chainaliphatics and PAHs was added to the soil columns.Results show that the artificially applied aliphatichydrocarbons disappeared faster and to a greater extentin ryegrass-planted columns than in the non-rootsystems. The enhanced disappearance of the pollutantsin the rhizosphere was accompanied by higher valuesfor microbial plate counts and soil respiration rates forthe vegetated systems, which indicated the primary roleof microbial degradation. In contrast to the aliphatics,the amount of PAHs decreased rapidly in both systems,and the differences between planted and unplanted soilwere insignificant.

A Field Facility for Phytoremediation Research Rhykerd, R.L.; Hallmark, M.T.; and Munster, C.L.The 1998 ASAE Annual International Meeting, 11-16July 1998, Orlando, Florida American Society of Agricultural Engineers, St.Joseph, MI 1998

A recently developed phytoremediation computermodel may be extremely useful in predicting the fate ofrecalcitrant hydrocarbons in soil. A field facility forphytoremediation research has been constructed toprovide empirical data to validate and calibrate themodel. Trinitrotoluene (TNT);2,2',5,5'-tetrabromobiphenyl (PBB); and chrysene havebeen tested. Due to the hazardous nature of thesehydrocarbons, the soil-contaminant mixture wasisolated from the field environment using two lysimeterdesigns. Soil in both the box and column lysimeterswere contaminated with 10 mg of each contaminant perkg of soil. Vegetation treatments consisted of fallow,warm season grass (Johnsongrass), cool season grass(Canadian wild-rye grass), and a warm/cool seasongrass rotation (Johnsongrass/Canadian wild-rye grass).Both the box and column lysimeters functioned well incollecting parameters necessary to validate andcalibrate the computer model.

Greenhouse Evaluation of Agronomic and CrudeOil-Phytoremediation Potential Among AlfalfaGenotypesWiltse, C. C.; Rooney, W. L.; Chen, Z.; Schwab, A. P.;and Banks, M. K.Journal of Environmental Quality v 27:1 p 169(5)January-February 1998

Twenty alfalfa plants were evaluated in terms of theiragronomic performance and phytoremediation potentialfor crude oil-contaminated soil. Among the genotypes,differences were observed in total forage yield,maturity, plant height, and leaf-burn rating. Totalpetroleum hydrocarbon concentrations in soil after 12months ranged 3799-5754 mg/kg for soils with thealfalfa plants and averaged 4610 mg/kg in theunvegetated control. When each genotype wasconsidered separately, two genotypes had totalpetroleum hydrocarbon concentrations that weresignificantly lower than that of the unvegetated control.Plants growing in contaminated soil, however,


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exhibited later maturation and shorter heights thanthose growing in uncontaminated soil.

The Influence of Planting and Soil Characteristicson Mineralization of 2,4,5-T in Rhizosphere Soil Boyle, J.J. and Shann, J.R.Journal of Environmental Quality v 27:3 p 704(6)May-June 1998

Soils from an abandoned pasture, a forest, and afloodplain near Cincinnati, OH, were used as substratefor timothy grass, red clover, and sunflower, andevaluated in terms of their mineralization of2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Microbialactivity, biomass, and mineralization of 2,4,5-T inrhizosphere soil were determined before and afterplanting. Results showed that microbial activity andbiomass were dependent upon soil type in the unplantedplots. In soils with lower values, planting significantlyincreased biomass and/or activity, independent of plantspecies. Overall, soil type was the most significant determinant of microbial biomass, activity, andxenobiotic degradation.

Mineralization of 2,4-Dichlorophenol byEctomycorrhizal Fungi in Axenic Culture and inSymbiosis with Pine Meharg, A.A.; Cairney, J.W.G.; and Maguire, N.Chemosphere v 34:12 p 2495(10) June 1997

The fungal mycelium associated with mycorrhizalplants provides a means of enhancing the volume ofrhizospheric soil compared to bulk soil, which canenhance soil remediation. Two ectomycorrhizal fungalspecies—Suillus variegatus and Paxillusinvolutus—were evaluated in terms of their ability todegrade 2,4-dichlorophenol in batch culture and inassociation with Pinus sylvestris. Results indicate that2,4-dichlorophenol was readily degraded by bothspecies, but P. involutus proved to be much moreefficient than S. variegatus. In the presence of pineseedlings, mycorrhizal symbiosis increasedmineralization by both species, but the increase wasmuch more dramatic for S. variegatus, which underthese conditions became the more efficient degrader of2,4-dichlorophenol.

Phytoremediation Experimentation with theHerbicide Bentazon Conger, R.M. and Portier, R.J.Remediation v 7:2 p 19(19) 1997

An experiment was performed on six species of trees todetermine the feasibility of remediating ground watercontaminated with an agricultural herbicide, bentazon,at a site in southern Louisiana. Fate studies onbentazon support that it is translocated to the plantleaves where it is degraded to lower-order derivativecompounds within short periods of time. Bothtranspiration observations and dosing tests suggest thatboth the most favorable phreatophyte and speciestolerant of bentazone exposure was the black willow(Salix nigra).

Phytoremediation: Modeling Removal of TNT andIts Breakdown ProductsMedina, V.F. and McCutcheon, S.C.Remediation v 7:1 p 31(15) Winter 1996

The success of phytoremediation techniques for thetreatment of TNT-contaminated ground water andwastewater is evaluated. Two differentphytoremediation techniques are examined: controlledreactors and constructed wetlands. The benefits offeredby controlled reactors include: greater control overoperating parameters, reduced chances of contaminantmigration, and reduced chances that animals will feedon the plants. Constructed wetlands are generally lessexpensive and often provide aesthetic and ecologicalbenefits. A first-order, nonreversible reaction,plug-flow, finite-difference model was used to predictthe disappearance of TNT from a constructed wetland.

Phytoremediation of 1,4-dioxane by Hybrid Poplars Aitchison, E.W.; Schnoor, J.L.; Kelley, S.L.; andAlvarez, P.J.J.Proceedings of the 12th Annual Conference onHazardous Waste Research, 20-22 May 1997, KansasCity, Missouri

The suspected carcinogen 1,4-dioxane has a half-life insoils and ground water of several years, while itshalf-life in the atmosphere in the presence of NO and


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hydroxyl radicals is several hours. The researchers examine 1,4-dioxane volatilization into the atmospherevia plant transpiration, evaluating the capacity ofrooted cuttings of hybrid poplar trees to take up andtranslocate 1,4-dioxane. Study results indicate thatpoplar uptake of 1,4-dioxane far exceeds itsdegradation by indigenous root-zone microorganisms.The majority of 1,4-dioxane taken up into the plant wasvolatilized, with the remaining mass concentratedprimarily in the stem. Rapid uptake of 1,4-dioxane byhybrid poplar trees makes phytoremediation anattractive treatment alternative atdioxane-contaminated sites, and research into thistreatment methodology will continue.

Phytoremediation of Hazardous WastesMcCutcheon, S.C.; Wolfe, N.L.; Carreria, L.H.; andOu, T.Y.Innovative Technologies for Site Remediation andHazardous Waste Management: Proceedings of theNational Conference, 23-26 July 1995, Pittsburgh,PennsylvaniaAmerican Society of Civil Engineers, New York, NY p597(8) 1995

Analyzing the effectiveness of phytoremediationinvolves rigorous pathway analyses, mass balancedeterminations, and identification of specific enzymesthat break down trinitrotoluene (TNT), other explosives(RDX and HMX), nitrobenzene, and chlorinatedsolvents (such as TCE and PCE). For example, TNT iscompletely and rapidly degraded by nitroreductase andlaccase enzymes. As part of the natural lignificationprocess, the aromatic ring is broken and the carbon inthe ring fragments is incorporated into new plant fiber.The use of created wetlands and otherphytoremediation applications guided by rigorous fieldbiochemistry and ecology promises to be a vital part ofa newly evolving field, ecological engineering.

Phytoremediation of Organic Contaminants: AReview of Phytoremediation Research at theUniversity of Washington Newman, L.A.; Doty, S.L.; Gery, K.L.; Heilman, P.E.;et al.Journal of Soil Contamination, v 7:4, p 531(12), 1998

Studies to determine the potential for phytoremediationof fully chlorinated compounds, brominatedcompounds, and nonhalogenated compounds areunderway. When using phytoremediation, it isimportant to select not only a plant that is capable ofdegrading the pollutant in question, but also one thatwill grow well in that specific environment. One way tosupplement the arsenal of plants available for remedialactions is to utilize genetic engineering tools to insertinto plants those genes that will enable the plant tometabolize a particular pollutant. Hybrid technologies,such as using plants in pumping and irrigation systems,also enable plants to be used as a remedial methodwhen the source of the pollutant is beyond the reach ofplant roots, or when planting space directly over thepollutant is unavailable or restricted. Thus, thepotential uses of phytoremediation are expanding as thetechnology continues to offer new, low-cost remediationoptions.

Phytoremediation of Pesticide-Contaminated Soils Kruger, E.L.; Anderson, T.A.; and Coats, J.R.Air & Waste Management Association’s 89th AnnualMeeting, 1996, Nashville, TennesseeAvailable at http://www.awma.org

Screening tests of rhizosphere soils from 15 plantspecies were conducted to determine their ability tomineralize two common herbicide contaminants:atrazine and metolachlor. Mineralization of14C-atrazine or 14C-metolachlor, applied at 50 ppmeach, was monitored. Kochia rhizosphere soil exhibitedthe greatest mineralization of 14C-atrazine. Otherrhizosphere soils that exhibited the ability to mineralizehigh concentrations of atrazine included musk thistle,catnip, foxtail barley, witchgrass, and lambsquarters.None of the rhizosphere soils tested exhibited a positiveresponse for 14C-metolachlor mineralization.Mineralization of atrazine was considerable after 36days, while mineralization of metolachlor was minimal.The percentage of extractable atrazine for kochiavegetated soils was significantly less than fromnonvegetated soil. Combustion of plants revealed that11% of the applied 14C was taken up by kochia. Thisresearch indicates that the use of plants in remediatingsoils looks promising.


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Phytoremediation of Trichloroethylene with HybridPoplars Gordon, M.; Choe, N.; Duffy, J.; Ekuan, G.; Heilman,P.; Muiznieks, I.; Newman, L.; Ruszaj, M.; Shurtleff,B.B.; Strand, S.; and Wilmoth, J.Phytoremediation of Soil and Water ContaminantsAmerican Chemical Society, Washington, DC p 177(9)1997

The ability of hybrid plants to absorb trichloroethylene(TCE) from ground water was examined. Initial studiesused axenic tumor cultures of H11-11 grown in thepresence of 14C-TCE. These cells metabolized the TCEto produce trichloroethanol, di- and trichloroaceticacid. Some of the TCE was incorporated into insoluble,non-extractable cell residue, and small amounts weremineralized to 14C-CO2. Rooted poplar cuttings grownin PVC pipes produced the same metabolites whenexposed to TCE. Mass balance studies indicate that thepoplars also transpire TCE. In addition one of the firstcontrolled field trials for this technology is beingconducted. Trees were planted in cells lined with highdensity polyethylene and exposed to TCE via anunderground water stream during the growing season.Cells containing trees had significantly reduced TCElevels in the effluent water stream compared to controlcells containing only soil. These results show thatsignificant TCE uptake and degradation occur inpoplars.

Phytoremediation, Plant Uptake of Atrazine andRole of Root ExudatesBurken, J.G. and Schnoor, J.L.Journal of Environmental Engineering v 122:11 p958(6) 1996

The potential of phytoremediation in the cleanup ofcontaminated sites and prevention of non-point-sourcepollution was examined with the pesticide atrazine intwo experimental systems. Uptake was determined inbatch experiments with 14C ring-labeled atrazine andhybrid poplar trees grown in two soil types.Mineralization was studied utilizing soil microcosmswith the addition of root exudates. Results indicate thatpoplar cuttings were able to uptake the majority ofapplied atrazine that was not tightly sorbed to theorganic fraction of the soil, with no detectable adverseeffects to the trees. The addition of root exudate to

microcosms showed slight stimulation and the additionof ground-up root biomass revealed large stimulation ofmineralization to 14CO2. This research indicates thatvegetative uptake and degradation in the rhizospherecan play a major role in remediation at hazardous wastesites.

Phytotreatment of TNT-Contaminated GroundwaterRivera, R.; Medina, V.F.; Larson, S.L.; andMcCutcheon, S.C.Journal of Soil Contamination, v 7:4, p 511(20), 1998

Phytoremediation is a viable technique for treatingmunitions-contaminated ground water and wastewater.Continuous flow reactor studies were conducted at threedifferent influent concentrations of 2,4,6-trinitrotoluene(TNT): 1, 5, and 10 ppm. Retention times varied from12 to 76 days. Batch experiments were conducted toconfirm the phytodegradation of amino-derivatives ofTNT. Plant tissue was analyzed for TNT andbreakdown products. Preliminary batch studies werealso conducted on the degradation of RDX. Initially,the control removed TNT as efficiently as the plantreactors. However, as time continued, the efficiency ofthe control dipped below that of the plant reactors,suggesting that adsorption was initially the mechanismof removal. Up to 100% of the TNT was removed.Batch studies found that ADNT anddiaminonitrotoluene (DANT) were phytodegraded. Thebatch studies indicated that the degradation of RDXwas slower than that for TNT. Different plants weremore efficient at removing RDX than those forremoving TNT, suggesting that there are differences inthe removal mechanisms.

Plant Cell Biodegradation of a Xenobiotic NitrateEster, NitroglycerinGoel, A.; Kumar, G.; Payne, G.F.; and Dube, S.K.Natural Biotechnology v 15:2 p 174(4) 1997

The ability of plants to metabolize glycerol trinitrate(GTN, nitroglycerin), was examined using cultured plant cells and plant cell extracts. Intact cells rapidlydegrade GTN with the initial formation of glyceroldinitrate (GDN) and the later formation of glycerolmononitrate (GMN). Cell extracts were shown to be


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capable of degrading GTN with the simultaneousformation of GDN in stoichiometric amounts. Thedegradative activities of plant cells are only ten timesless than those reported for bacterial GTN degradation.These results suggest that plants may serve a directdegradative function for the phytoremediation of sitescontaminated by organic nitrate esters.

Plant-Enhanced Remediation of PetroleumContaminated Soil Novak, J.T. and Al-Ghazzawi, Z.Proceedings of the 1997 29th Mid-Atlantic Industrialand Hazardous Waste ConferenceTechnomic Publishing Co., Lancaster, PA p 605(9)1997

Phytoremediation is an easy and inexpensive methodfor treating petroleum-contaminated soils. Thephytoremediation mechanism is related to directcontaminant uptake or indirect plant mechanismswhich catalyze pollutant-microbe interaction in therhizosphere. These mechanisms and their importanceare studied.

Plant-Enhanced Subsurface Bioremediation ofNonvolatile HydrocarbonsChang, Y.Y. and Corapcioglu, M.Y.Journal of Environmental Engineering v 124:2 p162(8) February 1998

Phytoremediation has become a promising new area ofresearch for in situ cleanup of large volumes of slightlycontaminated soils. A model that can be used as apredictive tool in phytoremediation operations wasdeveloped to simulate the transport and fate of aresidual hydrocarbon contaminant interacting withplant roots in a partially saturated soil. Time-specificdistribution of root quantity through soil, as well as rootuptake of soil water and hydrocarbon, was incorporatedinto the model. In addition, the microbial activity in thesoil rhizosphere was modeled with a biofilm theory.The simulation results showed enhancedbiodegradation of a hydrocarbon contaminant mostlybecause of increased biofilm metabolism of organiccontaminants in a growing root system of cotton.Simulations also show that a high mean daily

root-water uptake rate increases the contaminantretardation factors because of the resulting low watercontent. The ability to simulate the fate of ahydrocarbon contaminant is essential in designingtechnically efficient and cost-effective, plant-aidedremedial strategies and in evaluating the effectivenessof a proposed phytoremediation scheme.

Potential of Phytoremediation as a Means forHabitat Restoration and Cleanup of PetroleumContaminated Wetlands Lin, Q. and Mendelssohn, A.Phytoremediation of Soil and Water Contaminants American Chemical Society, Washington, DC 1997

Oil spills in coastal wetlands often kill vegetation andcontaminate wetland sediment for many years. Thepotential of phytoremediation for habitat restorationand cleanup of contaminated marshes was studied withmarsh mesocosms. Soil sods of Spartina alternifloraand Spartina patens (common coastal marsh grasses)were dosed with crude oil. Two years after applicationof the oil to the soil sods, these two Spartina specieswere transplanted into oiled and unoiled sods todetermine the potential for habitat restoration and oilphytoremediation. The regrowth biomass was notsignificantly affected by oil for combined biomass ofthe two species and significantly higher with oil forSpartina alterniflora, suggesting the potential forhabitat restoration by transplanting after oil spills. Oildegradation was enhanced by phytoremediation incombination with fertilization. The oil degradation ratewas negligible in the absence of vegetation, but it wassignificantly higher in the presence of transplantedvegetation and fertilizer. Whether increaseddegradation of residual oil was due to the enhancementof soil microbial activity by the fertilizer or byphytoremediation is presently being investigated.

Rhizosphere Microbial Populations in ContaminatedSoils Nichols, T.D.; Wolf, D.C.; Rogers, H.B.; Beyrouty,C.A.; and Reynolds, C.M.Water, Air, and Soil Pollution v 95:1-4 p 165(14) 1997

Abstracts of Phytoremediation Resources Inorganic Contaminants

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Rhizosphere microbial populations may enhancebioremediation of soil contaminated with organicchemicals. A growth chamber study was conducted toevaluate rhizosphere microbial populations incontaminated and non-contaminated soil. Alfalfa(Medicago sativa L.) and alpine bluegrass (Poa alpinaL.) were grown in soil containing a mixture of organicchemicals for 14 weeks. The equal mixture ofhexadecane, (2,2-dimethylpropyl)benzene,cis-decahydronaphthalene (decalin), benzoic acid,phenanthrene, and pyrene was added at levels of 0 and2000 mg/kg. At nine weeks, the organic chemicaldegrader (OCD) populations were significantly higherin rhizosphere and contaminated soils than in bulk andnon-contaminated soils. Selective enrichment of OCDpopulations was observed in contaminated rhizospheresoil. Higher numbers of OCD in contaminatedrhizospheres suggest potential stimulation ofbioremediation around plant roots.

Transformation of TNT by Aquatic Plants and PlantTissue CulturesHughes, J. B.; Shanks, J.; Vanderford, M.; Lauritzen,J.; and Bhadra, R.Environmental Science & Technology v 31:1 p 266(6)1997

The ability of plants to uptake and transform2,4,6-trinitrotoluene (TNT) was investigated using theaquatic plants Myriophyllum spicatum, axenicMyriophyllum aquaticum, and Catharanthus roseushairy root cultures. Studies demonstrate that bothMyriophyllum and C. roseus transform TNT. Primaryproducts of transformation were not identified, andmineralization was not observed. Mass balancesdemonstrate that a large percentage of the unknownTNT transformation products were associated with theplant. This fraction could be at least partially recoveredfrom the plant tissue with methanol extraction. Asoluble fraction was also present in the medium. Theformation of soluble, uncharacterized transformationproducts is a concern for potential phytoremediationapplications.

Uptake and Fate of Organohalogens fromContaminated Groundwater in Woody Plants Sytsma, L.; Mulder, J.; Schneider, J.; et al.Proceedings of the 213th National Meeting of theAmerican Chemical Society, 13-17 April 1997, SanFrancisco, CaliforniaAmerican Chemical Society, Washington, DC p 891997

Phytoremediation uses green plants for low-cost,low-tech remediation processes in which selected plantsand natural or engineered microorganisms worktogether to metabolize, convert, absorb, accumulate,sequester, or otherwise render harmless multipleenvironmental contaminants. There is evidence thatplants can degrade a portion of many organiccontaminants and form less volatile compounds whichare sequestered in the plant tissue. The remainder ofthe contaminant is passed out of the leaf tissue with thetranspiration stream. Hybrid poplar plants fed by TCE-and PCE-spiked nutrient solutions in a greenhouseshowed elevated degradation product levels in theleaves within a week, as well as evidence forevapotranspiration of the TCE and PCE.


Bioremediation and Phytoremediation: Chlorinatedand Recalcitrant Compounds: the FirstInternational Conference on Remediation ofChlorinated and Recalcitrant Compounds,Monterey, California, May 18-21, 1998 Wickramanayake, G.B. and Hinchee, R.E. (eds.)Battelle Press, Columbus, OH 301 pp 1998

Inorganic Contaminants

Overviews

Emerging Technologies for the Remediation ofMetals in Soils: PhytoremediationInterstate Technology and Regulatory CooperationWork Group (ITRC), Metals in Soils Work Team 15 pp1998Available at http://www.sso.org/ecos/itrc

Phytoremediation is a means of removing organic orinorganic contaminants from soils, sediments, andground water using plants. This document focuses on


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issues related to the remediation of metals in soils. Thetechnology, its applicability to sites and contaminants, and associated costs are outlined. Several approaches tophytoremediation are explored. The document alsopresents regulatory and stakeholder concerns anddiscusses research needs.

Literature Review: Phytoaccumulation ofChromium, Uranium, and Plutonium in PlantSystems Hossner, L.R.; Loeppert, R.H.; Newton, R.J.; andSzaniszlo, P.J.Amarillo National Resource Center for Plutonium, TX53 pp May 1998

Phytoremediation is an integrated approach to thecleanup of contaminated soils that combines thedisciplines of plant physiology, soil chemistry, and soilmicrobiology. Removal of metals from contaminatedsoils using accumulator plants is the goal ofphytoremediation. The emphasis of this review hasbeen placed on chromium (Cr), plutonium (Pu), anduranium (U). With the exception of Cr, these metalsand their decay products exhibit two problems:radiation dose hazards and their chemical toxicity.Radiation dose hazards introduce the need for specialprecautions in reclamation beyond that associated withnon-radioactive metals. The uptake of metals by plantsoccurs predominantly by way of channels, pores, andtransporters in the root plasma membrane. Mostvascular plants absorb toxic and heavy metals throughtheir roots to varying degrees.

Remediation of Metal-Contaminated Sites UsingPlants Azadpour, A. and Matthews, J.E.Remediation v 6:3 p 1(18) 1996

The current technologies employed for removal ofheavy metals from soils often involve expensive ex situprocesses requiring sophisticated equipment forremoval, transportation, and purification of the soil. Insitu bioremediation is receiving increasing attentionbecause of its relative effectiveness and low cost.Phytoremediation, a new type of bioremediation, usesmetal-tolerant hyperaccumulator plants to take up

metal ions from soils and store them in the plant itself.To select the appropriate phytoremediation technology,the technical feasibility, cost effectiveness, andavailability of the suitable plant species must beexamined. Before phytoremediation can be exploited ona contaminated site, greenhouse-scale confirmatorytesting is necessary to measure plant uptake andcorrelate shoot metal concentrations to available soilmetals. These tests also validate that the harvesting andsubsequent disposal of metal-containing plant tissuesare environmentally safe and manageable.

Restoration of Mined Lands—Using NaturalProcessesBradshaw, A.Ecological Engineering v 8:4 p 255(15) August 1997

In many countries legislation now requires that surfacesoils disturbed by mining activities be conserved andreplaced, but there is a vast heritage of contaminatedland left by past mining. The processes of naturalsuccession demonstrate that unaided restoration can beachieved along with the development of fullyfunctioning soils. Plants can readily provide organicmatter, lower soil bulk density, bring mineral nutrientsto the surface, and accumulate them in an availableform. Most importantly, some species can fix andaccumulate nitrogen rapidly in quantities more thanadequate for normal ecosystem functioning. Certainextreme soil conditions may occur that prevent plantgrowth, particularly physical conditions, gross lack ofcertain nutrients, and toxicity. However, ecosystemrestoration can be achieved at low cost, and the productbe self-sustaining in the long term.

Status of In Situ Phytoremediation TechnologyU. S. EPA, Office of Solid Waste and EmergencyResponsePublished in Recent Developments for In SituTreatment of Metal Contaminated Soils p 31(12)


This chapter offers an overview of differentphytoremediation approaches: phytoextraction,


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phytostabilization, and rhizofiltration, as well as aperformance and cost summary, applications and future development analyses, and a list of metalhyperaccumulating plants.


Phytoaccumulation of Trace Elements by WetlandPlants: I. DuckweedZayed, A.; Gowthaman, S.; and Terry, N.Journal of Environmental Quality v 27:3 p 715(7)May-June 1998

The removal of trace elements by wetland vegetation isenhanced by the use of appropriate plant species.Results are presented from the first in a series ofwetland-plant evaluations in terms of the removal oftrace elements from contaminated water. Duckweedwas considered for its phytoaccumulation of cadmium(Cd), chromium (Cr), copper (Cu), lead (Pb), nickel(Ni), and selenium (Se). The data show that Cd wasaccumulated to the greatest levels, followed by Se, Cu,and Cr, and then Pb and Ni.

Relationship Between Sulfur Speciation in Soils andPlant AvailabilityShan, X.-Q.; Chen, B.; Zhang, T.-H.; Li, F.-L.; Wen,B.; and Qian, J.Science of the Total Environment v 199:3 p 237(10)1997

Both bench-scale experiments and field surveys wereconducted to investigate the relationship between sulfurspeciation in soils and sulfur concentration in plants.Soil sulfur was fractionated into water-soluble sulfate(S1), adsorbed sulfate (S2), carbonate-occluded sulfate(S3), ester sulfate (S4) and carbon-bonded sulfur (S5).Water-soluble sulfate was the most easily availableform of soil sulfur, followed by adsorbed sulfate, estersulfate, carbon-bonded sulfur and carbonate-occludedsulfate. Changes in concentrations of the differentforms of soil sulfur after bench-scale experiments gavedirect evidence to the order of availability. S1 and S2

decreased significantly, S4 also decreased, whereas S5

and S3 remained almost unchanged. These resultssuggest that water-soluble and adsorbed sulfate aredirectly available to plants, while the mineralization of

sulfate from organic sulfur, especially from estersulfate, also contributes to plant uptake of sulfur.

Removal of Uranium from Water Using TerrestrialPlantsDushenkov, S.; Vasudev, D.; Kapulnik, Y.; Gleba, D.;Fleisher, D.; Ting, K.C.; and Ensley, B.Environmental Science & Technology v 31:12 p3468(6) December 1997

Uranium (U) contamination of ground water poses aserious environmental problem in uranium miningareas and in the vicinity of nuclear processing facilities.Preliminary laboratory experiments and treatabilitystudies indicate that the roots of terrestrial plants can beefficiently used to remove U from aqueous streams(rhizofiltration). Almost all of the U removed from thewater in the laboratory using sunflower plants wasconcentrated in the roots. Rhizofiltration technologyhas been tested in the field with U-contaminated waterat concentrations of 21—874 )g/L at a former Uprocessing facility in Ashtabula, OH. The pilot-scalerhizofiltration system provided final treatment to thesite source water and reduced U concentration to <20)g/L before discharge to the environment. Systemperformance was subsequently evaluated underdifferent flow rates permitting the development ofeffectiveness estimates for the approach.

Research

Differences in Root Uptake of Radiocesium by 30Plant TaxaBroadley, M.R. and Willey, N.J.Environmental Pollution v 97:1-2 p 11(5) 1997

The concentration of Cesium (Cs) was measured in theshoots of 30 plant taxa after exposing the roots to 0.1)g/g radiolabelled Cs soil for 6 hours. The maximumaccumulation differences were between Chenopodiumquinoa and Koeleria macrantha (20-fold in Csconcentration and 100-fold in total Cs accumulated).The lowest Cs concentrations occurred in slow growingGramineae and the highest in fast growingChenopodiaceae. If radiocesium uptake by theChenopodiaceae during chronic exposures showssimilar patterns to those reported here after acute


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exposure, then the food contamination implications andthe potential for phytoremediation of radiocesium contaminated soils using plants in this family may beworth investigating.

Enhanced Accumulation of Pb in Indian Mustard bySoil-Applied Chelating AgentsBlaylock, M.J.; Salt, D.E.; Dushenkov, S.; Zakharova,O.; Gussman, C.; Kapulnik, Y.; Ensley, B.D.; andRaskin, I.Environmental Science & Technology v 31 p 860(6)1998

Phytoremediation is emerging as a potential cost-effective solution for the remediation of contaminatedsoils. Because contaminants such as lead (Pb) havelimited bioavailability in the soil, a means ofsolubilizing Pb in the soil and facilitating its transportto plant shoots is vital to the success ofphytoremediation. Indian mustard (Brassica juncea)was used to demonstrate the capability of plants toaccumulate high tissue concentrations of Pb whengrown in Pb-contaminated soil. A concentration of1.5% Pb in the shoots of B. juncea was obtained fromsoils containing Pb (600 mg/kg) amended withsynthetic chelates such as EDTA. The accumulation ofPb in the tissue corresponded to the concentration of Pb in the soil andthe concentration of EDTA added to the soil. Theaccumulation of Cadmium, Copper, Nickel, and Zincfrom contaminated soil amended with EDTA and othersynthetic chelators was also demonstrated. The researchindicates that the accumulation of metals in the shootsof B. juncea can be enhanced through the application ofsynthetic chelates to the soil, facilitating high biomassaccumulation as well as metal uptake.

Evaluation of Tamarisk and EucalyptusTranspiration for the Application ofPhytoremediationTossell, R.W.; Binard, K.; Sangines-Uriarte, L.;Rafferty, M.T.; and Morris, N.P.Bioremediation and Phytoremediation: Chlorinatedand Recalcitrant CompoundsBattelle Press, Columbus, OH p 257(6) 1998

A greenhouse study was conducted to evaluatephytoremediation using tamarisk and eucalyptus at asite in East Palo Alto, CA, where the ground water wascontaminated with arsenic. The initial study assessedwhether the trees could tolerate arsenic and sodiumfound in the ground water and soil. Over the course ofthe study, tamarisk used significantly more water thaneucalyptus, but eucalyptus water use was substantiallyhigher than tamarisk when normalized to shoot mass.Water use by both species was substantially lower fortrees exposed to high sodium treatments, but tamariskwas less affected than eucalyptus.

Feasibility of Using Plants to Assist in theRemediation of Heavy Metal Contamination atJ-Field, Aberdeen Proving Ground, Maryland. FinalReportJastrow, J.D.29 pp November 1995

Interest in the development of in situ bioremediationtechnologies has grown substantially over the lastdecade. The purpose of this project was to investigatethe potential for using plants to remediate soilscontaminated with heavy metals. Phragmites australis,one of the dominant species in the Toxic Burning Pits(TBP) area and other contaminated sites within J-Field,appears to be both tolerant of heavy metal contaminatedsoil conditions and capable of producing large amountsof biomass. Consequently, this project has concentratedon characterizing heavy metal accumulation byPhragmites australis growing in the TBP area relativeto soil concentrations and availabilities. This type ofinformation is necessary to determine the feasibility ofusing this species to assist in the remediation of metalcontaminated soils at J-Field.

Lead-Contaminated Sediments Prove Susceptible toPhytoremediationGoldsmith, W.Soil and Groundwater Cleanup p 15(3)February/March 1998[Also available at http://www.bioengineering.comunder the title Phytoremediation Potential for Lead-Contaminated River Sediments]


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Most conventional technologies for removal or cappingof lead-contaminated river sediments are neithertechnically nor economically practicable. Engineered wetlands for removal of lead from riverine sedimentsappear to offer a sound approach to cleanup viaphytoextraction followed by harvesting. Plants havebeen identified that grow in this type of environmentand possess a documented ability to take up lead intoleaves, roots, and stems. Recent research suggests thatphytoremediation conducted over a period of years canoffer significant benefits in sediment cleanup.

Lead Uptake and Effects on Seed Germination andPlant Growth in a Pb Hyperaccumulator Brassicapekinensis Rupr.Xiong, Z.-T.Bulletin of Environmental Contamination Toxicology v60:2 p 285(7) February 1998

The ability of Brassica pekinensis Rupr. tohyperaccumulate lead could make it effective for thephytoremediation of contaminated soils. The effect ofvarious concentrations of lead on the germination ofseeds and growth of plants was investigated. Generallygermination and growth of roots and shootsdemonstrated dose-related inhibition. Bioaccumulationof lead in root, stem, and leaf was related to leadconcentration in the growth medium. Rootsbioconcentrated lead to between 27 and 34 times theconcentration in growth medium. Stem and leafbioconcentration ranged from four to seven times andtwo to three times, respectively. The shoot to root ratioof lead was 0.9 for this plant species, which compareswell with other hyperaccumulators. High ratios allowlead concentrated in shoots to be easily removed byharvesting.

Metal Accumulation by Aquacultured Seedlings ofIndian MustardSalt, D.E.; Pickering, I.J.; Prince, R.C.; Gleba, D.;Dushenkov, S.; Smith, R.D.; and Raskin, I. Environmental Science & Technology v 31 p 1636(9)1997

Indian mustard (Brassica juncea (L.) Czern) seedlingsgrown in aerated water were able to accumulate various

metals from contaminated water over a range ofenvironmentally relevant metal concentrations.Seedlings concentrated the divalent cations Lead(II),Strontium(II), Cadmium(II), and Nickel(II) 500-2000times and concentrated monovalent Cesium(I) andhexavalent Chromium(IV) 100-250 times fromcontaminated water containing the competing ions Ca,Mg, K, SO4, and NO3. At the lowest Cadmium (Cd)concentration studied, Cd levels were reduced to below10 ppb ()g/L). In the absence of competing ions, Cdaccumulation in seedlings increased 47-fold. Thissuggests that a better understanding of the biologicalprocesses governing uptake and accumulation of Cd byseedlings should allow the application of moderngenetic engineering techniques to improve theirselectivity and capacity for Cd removal from waterscontaining high levels of competing ions. As a first stepin this process, we have started to define the tissue andcellular localization of Cd, its accumulation rates andpossible uptake mechanisms, and the role ofintracellular chelates in Cd detoxification. IntracellularCd accumulation in seedlings was mediated bysaturable transport system(s) and inhibitedcompetitively in shoots and non-competitively in rootsby Ca2+, Zn2+, and Mn2+. Phytochelatins, the Cd-bindingpeptides known to be involved in Cd resistance inmature plants, also accumulated in B. juncea seedlingsexposed to Cd. Our results suggest that the use ofaquacultured seedlings of B. juncea could provide anovel approach to the treatment of various metal-contaminated waste streams.

Phytoextraction of Cadmium and Zinc from aContaminated SoilEbbs, S.D.; Lasat, M.M.; Brady, D.J.; Cornish, J.;Gordon, R.; and Kochian, L.V.Journal of Environmental Quality v 26:5 p 1424(7)September-October 97

The phytoextraction ability of Brassica juncea, B.napus, and B. rapa toward cadmium (Cd) and zinc(Zn) in a contaminated soil was determined andcompared to that exhibited by Thlaspi caerulescens,Agrostis capillaris, and Festuca rubra. Results showedthat T. caerulescens achieved shoot Cd concentrationsapproximately ten times as great as those of the threeBrassica species, while shoot Zn concentrations in T.caerulescens were approximately 2.5 times as great.


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However, due to the significantly greater biomassproduced by the Brassica species, this species was more effective in removing Zn and equally effective inremoving Cd as T. caerulescens.

Phytoextraction of Zinc by Oat (Avena sativa),Barley (Hordeum vulgare), and Indian Mustard(Brassica juncea)Ebbs, S.D.; and Kochian, L.V.Environmental Science & Technology v 32:6 802(5)1998

The success of phytoremediation depends on theselection of plant species and soil amendments thatmaximize contaminant removal. Indian mustard(Brassica juncea) has been shown to be effective inphytoextracting Zn, particularly after the syntheticchelate EDTA has been applied to the soil. However,the effectiveness of grass species for phytoremediationhas not been addressed in great detail. A hydroponicscreening of 22 grass species indicated that oat (Avenasativa) and barley (Hordeum vulgare) tolerated thehigh copper, cadmium, and zinc concentrations presentin the solution and also accumulated elevatedconcentrations of these metals in the plant shoots. Ahydroponic experiment comparing these two grasses toIndian mustard indicated that, although shoot Znconcentrations were greater for Indian mustard, thegrasses were considerably more tolerant. The results ofthis experiment suggest that barley has aphytoremediation potential equal to, if not greater than,that for B. juncea.

Phytoextraction: the Use of Plants to Remove HeavyMetals from SoilsKumar, P. B. A. N.; Dushenkov, V.; Motto, H.; andRaskin, I.Environmental Science & Technology v 29:5 p 1232(7)May 1995

The process of phytoextraction, the use of plants toremove heavy metals from soils, generally requires thetranslocation of heavy metals to the easily harvestableshoots. Several cultivars of Indian mustard (Brassicajuncea) were investigated for their ability to efficientlyaccumulate lead and other heavy metals. The Brassica

species included B. nigra, B. oleracea, B. campestris,B. carinata, B. juncea, and B. napus. Results indicatethat B. juncea and B. nigra had the highestmetal-accumulating ability among the species tested.Shoot growth was only slightly affected by exposure tolead over the concentration range tested. For the othermetals examined, chromium had the highestphytoextraction coefficient, followed by cadmium,nickel, zinc, and copper.

Phytofiltration of Hazardous Cadmium, Chromium,Lead and Zinc Ions by Biomass of Medicago sativa(Alfalfa) Gardea-Torresdey, J.L.; Gonzalez, J.H.; Tiemann, K.J.;Rodriguez, O.; and Gamez, G. Journal of Hazardous Materials v 57:1-3 p 29(11)1998

Previous laboratory batch experiments of Medicagosativa (Alfalfa) indicated that the African shootspopulation had an appreciable ability to bind copper(II)and nickel(II) ions from aqueous solution. Batchlaboratory pH profile, time dependency, and capacityexperiments were performed to determine the bindingability of the African shoots for cadmium(II),chromium(III), chromium(VI), lead(II), and zinc(II).Batch pH profile experiments indicate that the optimumpH for metal binding is approximately 5.0. Timedependency experiments demonstrate that metalbinding to the African alfalfa shoots occurred within 5minutes. Binding capacity experiments revealed thefollowing amounts of metal ions bound per gram ofbiomass: 7.1 mg Cd(II), 7.7 mg Cr(III), 43 mg Pb(II),4.9 mg Zn(II), and 0 mg Cr(VI). The results from thesestudies will be useful in the use of phytofiltration toremove and recover heavy metal ions from aqueoussolution.

Phytoremediation of a Radiocesium-ContaminatedSoil: Evaluation of Cesium137 Bioaccumulation in theShoots of Three Plant SpeciesLasat, M.M.; Fuhrmann, M.; Ebbs, S.D.; Cornish, J.E.;and Kochian, L.V.Journal of Environmental Quality v 27:1 p 165(5)January-February 1998


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At Brookhaven National Laboratory's Hazardous WasteManagement Facilities, the potential for cesium-137(137Cs) extraction from contaminated soil by three plantspecies was studied. In addition, the effect of applying ammonium nitrate to contaminated soil on 137Csextraction was evaluated. The plants used were Indianmustard, red root pigweed, and tepary bean. Resultsshow that red root pigweed concentrated the highestlevel of 137Cs in shoots, followed by Indian mustard andtepary bean. Red root pigweed also producedsignificantly more shoot biomass than the other twospecies. Ultimately, red root pigweed removed 30- to60-fold more 137Cs from the soil than either of the othertwo species. For red root pigweed and tepary bean, theaddition of ammonium nitrate produced only a slightincrease in the level of 137Cs in shoots.

Phytoremediation of Lead-Contaminated Soils: Roleof Synthetic Chelates in Lead PhytoextractionHuang, J.W.; Chen, J.; Berti, W.R.; and Cunningham,S.D.Environmental Science & Technology v 31:3 p 800(6)March 1997

Studies have shown that lead (Pb) is accumulated in theroots of plants if Pb is bioavailable in the growthmedia. However, Pb bioavailability is limited. Therelative efficiencies of selected synthetic chelates inenhancing Pb phytoextraction were compared. Corn,pea, goldenrod, sunflower, and ragweed were used, incombination with the chelates, EDTA, HEDTA, DTPA,EGTA, and EDDHA. Results show that Pb in soilsolution increased linearly with increasing levels ofHEDTA added to a Pb-contaminated soil. In all plantspecies tested, there was a surge in shoot Pbconcentrations in response to the application ofHEDTA, with the highest shoot Pb concentrationsfound in pea, followed by corn and sunflower. Whenexperiments were continued with pea and corn plants,Pb accumulation was highest in the presence of EDTA,followed in decreasing order by HEDTA, DTPA,EGTA, and EDDHA. The rank in the efficiency inenhancing total Pb accumulation in shoots was thesame as that found in enhancing soil Pb desorption.

Phytoremediation of Selenium Laden Soils: A NewTechnologyBanuelos, G.S.; Ajwa, H.A.; Terry, N.; and Zayed, A.Journal of Soil and Water Conservation v 52:6 p426(5) November-December 1997

Selenium (Se) is naturally present in many soils aroundthe U.S. High concentrations of Se may exert toxicimpacts on plants and animals. The performance ofseveral plant species (including canola, Indian mustard,birdsfoot trefoil, tall fescue, and kenaf) inphytoremediation projects aimed at reducing soil Selevels to below toxic concentrations are reviewed. Thebest plants for these types of projects include Brassicaand Astragalus species.

Phytoremediation of Uranium-Contaminated Soils:Role of Organic Acids in Triggering UraniumHyperaccumulation in PlantsHuang, J.W.; Blaylock, M.J.; Kapulnik, Y.; and Ensley,B.D.Environmental Science & Technology v 32:7 p 2004(5)1998

Uranium (U) phytoextraction, the use of plants toextract U from contaminated soils, is an emergingtechnology. In this research, the effects of various soilamendments on U desorption from soil to soil solutionwere investigated, physiological characteristics of Uuptake and accumulation in plants were studied, andtechniques to trigger U hyperaccumulation in plantswere developed. Of the organic acids (acetic acid, citricacid, and malic acid) tested, citric acid was the mosteffective in enhancing U desorption and subsequentaccumulation in plants. Shoot U concentrations ofBrassica juncea and Brassica chinensis grown in a U-contaminated soil (total soil U, 750 mg/kg) increased from less than 5 mg/kg to more than 5000 mg/kg incitric acid-treated soils. These results suggest that Uphytoextraction may provide an environmentallyfriendly alternative for the cleanup of U-contaminatedsoils.


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Potential for Phytoextraction of 137CS from aContaminated SoilLasat, M.M.; Norvell, W.A.; and Kochian, L.V.Agricultural Research Service, Beltsville, MD February1998

Cesium-137 (137Cs) is a long-lived by-product ofnuclear fission. Phytoremediation ofradiocesium-contaminated sites is impeded by the marked capacity of soils to tightly adsorb 137Cs andlimit its availability for plant uptake. Bioavailabilitytesting of a number of soil extractants from an agedcontaminated soil obtained from Brookhaven NationalLaboratory demonstrated that ammonium salts releaseda large portion of the radiocesium trapped in the soil.This same amendment greatly stimulated thebioaccumulation of 137Cs in plant shoots. Use of the bestperforming plant species from a species selection trial(cabbage), in conjunction with amending the soil withammonium nitrate, resulted in dramatic improvementsin the accumulation of 137Cs in plant shoots comparedwith the results of many previous published studies (10to 300-fold improvement). These findings indicate thatthe phytoremediation of 137Cs contaminated soils is avery promising cleanup technology.

Potential Remediation of 137Cs and 90SrContaminated Soil by Accumulation in AlamoSwitchgrassEntry, J.A. and Watrud, L.S.Water, Air, and Soil Pollution v 104:3-4 p 339(14) June1998

Alamo switchgrass was evaluated on its ability toremove cesium-137 and strontium-90 fromcontaminated soil. Results show that the above-groundbiomass of the plants accumulated 36% of thecesium-137 and 44% of the strontium-90 in the growthmedium. However, the accumulated concentrations inthe plants declined after two harvests. For bothradionuclides, the duration of exposure correlatedcurvilinearly with accumulation by the plants. As theconcentration of both radionuclides increased in thegrowth medium, total seedling accumulation andconcentration of radioisotopes in plant tissue alsoincreased curvilinearly. The overall findings revealedthat Alamo switchgrass may be a good candidate

species for remediating radionuclide-contaminatedsoils.

Rhizofiltration: the Use of Plants to Remove HeavyMetals from Aqueous StreamsDushenkov, V.; Kumar, P. B. A. N.; Motto, H.; andRaskin, I.Environmental Science & Technology v 29:5 p 1239(7)May 1995

Rhizofiltration is the use of plants to remove heavymetals from aqueous streams. Hydroponically grownroots of Indian mustard (Brassica juncea) wereinvestigated for their ability to remove lead, cadmium,copper, chromium, nickel, and zinc from solution. Therate of lead removal depended on the initialconcentration in solution and showed a monotonicdecline with time. Since the magnitude of lead removalwas proportional to the root weight, much fasterremoval rates were achieved when a larger root masswas used. Significant removal rates were also seen forthe other metals. Only live roots were able to removemetals from solution.

The Role of EDTA in Pb Transport andAccumulation by Indian MustardVassil, A.D.; Kapulnik, Y.; Raskin, I.; and Salt, D. Plant Physiology v 117 p 447(7) 1998

Indian mustard (Brassica Juncea) plants exposed tolead (Pb) and EDTA in hydroponic solution were ableto accumulate up to 55 mmol/kg Pb in dry shoot tissue(1.1%[w/w]). This represents a 75-fold concentration ofPb in shoot tissue over that in solution. A thresholdconcentration of EDTA (0.25 mmol) was found to berequired to stimulate this dramatic accumulation ofboth Pb and EDTA in shoots. The majority of Pb inthese plants is transported in coordination with EDTA.Exposure of Indian mustard to high concentrations ofPb and EDTA caused reductions in both thetranspiration rate and the shoot water content. Theonset of these symptoms was correlated with thepresence of free protonated EDTA (H-EDTA) in thehydroponic solution, suggesting that free H-EDTA ismore phytotoxic than Pb-EDTA. These studies clearlydemonstrate that coordination of Pb transport by EDTA


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enhances the mobility within plants of this otherwiseinsoluble metal ion, allowing plants to accumulate highconcentrations of Pb in shoots. The finding that both H-EDTA and Pb-EDTA are mobile within plants also has important implications for the use of metal chelates inplant nutritional research.

A Search for Lead Hyperaccumulating Plants in theLaboratoryGhosh, S.; and Rhyne, C.Agriculture and Plant Science Meeting, MississippiState University, 1997

The research objective is to identify plant speciescapable of sustained healthy growth in elevated leadconcentrations and to evaluate their effectiveness inaccumulating high levels of lead in various parts of theplants. A modified hydroponic growing system wasused to suspend plants in aqueous solutions of eitherHoagland's nutrient medium or varying concentrationsof Pb(NO3)2 in the laboratory. Thirty-three differentplant species were tested and grouped into fivecategories based on their growth potential and leaduptake. Two plant species, Ipomoea lacunosa andSesbania exaltata, appear to have significant potentialas lead hyperaccumulators. After the desired exposureperiod, plants were harvested and separated into leaves,stems and roots to analyze and locate the accumulationof lead in different plant parts. Morphologicalcharacteristics (height and dry weight) of the plantswere also observed.

Selenium Accumulation by Brassica Napus Grown inSe-laden Soil from Different Depths of KestersonReservoirBanuelos, G.S.; Ajwa, H.A.; Wu, L.; and Zambrzuski,S.M.Agricultural Research Service, Beltsville, MD August1997

Elevated levels of selenium (Se) have been measured insediment at Kesterson Reservoir and contributed to thedeath and deformities observed in waterfowlfrequenting this site. As part of a remediation strategyto lower levels of soil Se, canola was planted inSe-contaminated sediment collected from the Reservoir,

as well as on-site. Canola lowered Se concentrationsmore effectively under greenhouse conditions than inthe field. The study clearly shows that extrapolatingresults from greenhouse to field conditions should bedone with caution. Using canola to lower Se levels atKesterson Reservoir will be a long-term managementstrategy under field conditions.

Test Plan for the Phytoremediation Studies ofLead-Contaminated Soil from the Sunflower ArmyAmmunition Plant, Desoto, Kansas. Vol. 1 and Vol. 2Behel, D.; Kelly, D.; Pier, P.; Rogers, B.; and Sikora,F.233 pp (v 1), 291 pp (v 2) October 1996

NTIS Document Number: ADA342667 (vol. 1) ADA342668 (vol. 2)

This document provides a test plan for studying andimproving techniques for remediating lead-contaminated soils using phytoremediation. It alsodiscusses a study to examine the uptake of lead byplants in contaminated soil.

Toxicity of Zinc and Copper to Brassica Species:Implications for PhytoremediationEbbs, S.D. and Kochian, L.V.Journal of Environmental Quality v 26:3 p 776(6) 1997

The toxicity of Zn and Cu in three species from thegenus Brassica was examined to determine if theseplants showed sufficient tolerance and metalaccumulation to phytoremediate a site contaminatedwith these two heavy metals. Hydroponically grown 12day-old plants of Brassica juncea, B. rapa, and B.napus were grown for an additional 14 days in thepresence of either elevated Zn (6.5 mg/L), Cu (0.32mg/L), or Zn plus Cu to quantify the toxic effects ofthese metals on several different growth parameters.With few exceptions, both root and shoot dry weight forall three species decreased significantly in the presenceof heavy metals. In terms of heavy metal removal, theBrassica species were more effective at removing Znfrom the nutrient solution than Cu. The extent of Znand Cu removal was reduced when both metals werepresent as compared to the single heavy metal

Abstracts of Phytoremediation Resources Internet Resources

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treatments. The implications of these results forphytoremediation are discussed.

Toxic Mercury Reduction and Remediation UsingTransgenic Plants with a Modified Bacterial GeneRugh, C.L.; Gragson, G.M.; Meagher, R.B.; andMerkle, S.A. University of Georgia, Athens, GAHortScience v 33:4 p 618(4) July 1998

The objective of this paper is to give a brief overview ofthe concepts and progress of microbial- and plant-assisted pollution remediation research. A summary ofefforts to genetically engineer plants for mercuryreduction and detoxification, as well as considerationsfor future research toward this goal, will be presented.

Zinc and Cadmium Accumulation in theHyperaccumulator Thlaspi Caerulescens in Responseto Limestone and Compost Applications to a HeavyMetal Contaminated Site in Palmerton,PennsylvaniaLi, Y.M.; Chaney, R.L.; Kershner, B.A.; Chen, K.Y.;Angle, J.S.; and Baker, A.J.Agricultural Research Service, Beltsville, MDSeptember 1997

Research is being conducted to develop a newtechnology using plants to remove Zn and Cd fromcontaminated soils which require remediation. Thlaspicaerulescens is a perennial herb which accumulates Zn(>3%) from soils to much higher foliar levels thaneconomic crops. At the Palmerton, PA site, soil metalconcentrations are very high and the soils arenon-calcareous. It is likely that Thlaspi may suffer Znphytotoxicity. Studies were conducted to characterizethe long term effect of limestone and compostapplications on plant biomass and Zn and Cdaccumulation. In addition, the uptake of metals byhyperaccumulator T. caerulescens was compared touptake by a local metal-tolerant species, Merlin redfescue. In this paper, we report that compost treatmentreduced metal phytotoxicity. We have also determinedthat higher soil pH and organic matter were theimportant factors attributing to the large shoot biomassaccumulation for Thlaspi.


Metal-Contaminated Soils: In Situ Inactivation andPhytorestoration Vangronsveld, J. and Cunningham, S. (eds.) R.G. Landes, Austin, TX

Bioremediation of Inorganics, Vol. 3Hinchee, R.E.; Means, J.L.; and Burris, D.R. (eds.)Battelle Press, Columbus, OH 184 pp 1995

Plants That Hyperaccumulate Metals: Their Role inPhytoremediation, Microbiology, Archaeology,Mineral Exploration, and Phytomining Brooks, R. R. (ed.)CAB International, New York

Internet Resources

Advanced Applied Technology DemonstrationFacility (AATDF)http://www.ruf.rice.edu/~aatdf

AATDF is a research facility funded by the Departmentof Defense, Army Corps of Engineers, WaterwaysExperiment Station (WES) through the Energy andEnvironmental Systems Institute at Rice University.One of its long-term projects involves evaluating andrecommending innovative treatment technologies insupport of faster and cheaper remediation.

Air Force Center for Environmental Excellence(AFCEE)http://www.afcee.brooks.af.mil

The Air Force Center for Environmental Excellenceprovides a complete range of environmental,architectural, and landscape design, planning andconstruction management services and products.Environmental restoration is one of its several businesslines, and its services include: studies andinvestigations, project design, cleanup, long-termoperation/monitoring, program support, and newrestoration technology research. It was formed in 1991.


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Alternative Treatment Technology InformationCenter (ATTIC)http://www.epa.gov/attic

The EPA Office of Research and Development (ORD)Alternative Treatment Technology Information Center(ATTIC) is a comprehensive computer database systemproviding up-to-date information on innovativetreatment technologies. ATTIC provides access toseveral independent databases as well as a mechanismfor retrieving full-text documents of key literature. Thesystem provides information to make effective decisionson hazardous waste clean-up alternatives.

CLU-IN: Hazardous Waste Clean-Up Informationhttp://clu-in.org

The Hazardous Waste Clean-Up Information (CLU-IN)Web Site provides information about innovativetreatment technologies to the hazardous wasteremediation community. It describes programs,organizations, publications, and other tools for federaland state personnel, consulting engineers, technologydevelopers and vendors, remediation contractors,researchers, community groups, and individual citizens.The site was developed by the U.S. EPA but is intendedas a forum for all waste remediation stakeholders.

Environmental Security Technology CertificationProgram (ESTCP)http://www.estcp.org

ESTCP's goal is to demonstrate and validate promising,innovative technologies that et the Department ofDefense's (DoD's) most urgent environmental needs.These technologies provide a return on investmentthrough cost savings and improved efficiency. Thecurrent cost of environmental remediation andregulatory compliance in the Department is significant.Innovative technology offers the opportunity to reducecosts and environmental risks. ESTCP's strategy is toselect lab-proven technologies with broad DoD andmarket application. These projects are aggressivelymoved to the field for rigorous trials that documenttheir cost, performance, and market potential.Successful demonstration leads to acceptance of

innovative technologies by DoD end-users and theregulatory community.

Federal Remediation Technologies Roundtablehttp://www.frtr.gov The mission of the Roundtable is to exchangeinformation and provide a forum for joint activityregarding the development and demonstration of innovative technologies for hazardous waste siteremediation. The exchange synthesizes the technicalknowledge that Federal Agencies have compiled andprovides a more comprehensive record of performanceand cost. Members include major developers and usersof these technologies: Department of Defense (U.S.Army, U.S. Army Corps of Engineers, U.S. Navy, U.S.Air Force), U.S. Department of Energy, U.S.Department of the Interior, and the U.S. EnvironmentalProtection Agency.

GNET: The Global Network of Environment andTechnologyhttp://www.gnet.org

GNET® is an on-line global information center forenvironmental technology. The site contains aninteractive environmental technology database(TechKnow) that houses information onphytoremediation and over 1,500 other technologies.

Great Plains/Rocky Mountain Hazardous SubstanceResearch Centerhttp://www.engg.ksu.edu/HSRC

Kansas State University leads a fourteen-institutionconsortium for the Great Plains/ Rocky MountainHazardous Substance Research Center. The othermember institutions are Lincoln, Haskell IndianNations, Colorado State, Montana State, South DakotaState, and Utah State Universities, along with theuniversities of Iowa, Northern Iowa, Missouri,Montana, Nebraska, Utah, and Wyoming. The centerwas established in 1989 to conduct research pertainingto hazardous substances produced through agriculture,forestry, mining, mineral processing, and other


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activities of local interest. It serves Federal Regions 7and 8. Specific research projects focus on soil and watercontaminated by heavy metals from mining wastes andother industrial activities, soil and ground watercontaminated by organic chemicals, wood preservativesthat contaminate ground water, pesticides identified ashazardous substances, improved technologies andmethods for characterizing and analyzing contaminatedsoil, and waste-minimization and pollution-preventionmethods and technologies. The tables of contents,abstracts, and selected papers of the Proceedings of theAnnual Conference on Hazardous Waste Researchbeginning with the Ninth Annual Conference (1994)onward may also be viewed at the Web site.

Ground Water Remediation Technologies AnalysisCenter (GWRTAC)http://www.gwrtac.org

The Ground Water Remediation Technologies AnalysisCenter (GWRTAC) is a focal point for the collectionand analysis of information on ground waterremediation. The members of GWRTAC compile,analyze, and disseminate information on innovativeground water remediation technologies. Technicalteams are selectively chosen from ConcurrentTechnologies Corporation (CTC), the University ofPittsburgh, and other supporting institutions.

Innovative Treatment Remediation Demonstration(ITRD) http://www.em.doe.gov/itrd

The Innovative Treatment Remediation Demonstration(ITRD) Program is funded by the DOE Office ofEnvironmental Restoration (EM-40) to help acceleratethe adoption and implementation of new and innovativeremediation technologies. Developed as aPublic-Private Partnership program with Clean Sites,Inc., and the Environmental Protection Agency's (EPA)Technology Innovation Office (TIO) and coordinated by Sandia National Laboratories, the ITRD Programattempts to reduce many of the classic barriers to theuse of new technologies by involving government,industry, and regulatory agencies in the assessment,

implementation, and validation of innovativetechnologies.

Interstate Technology and Regulatory CooperationWorking Group (ITRC)http://www.sso.org/ecos/itrc

The Interstate Technology and Regulatory CooperationWorking Group (ITRC) was established in December,1994 by the Develop On-Site Innovative TechnologyCommittee, referred to as the DOIT CoordinatingGroup of the Western Governors Association. TheMission of the ITRC is to facilitate cooperation amongstates in the common effort to test, demonstrate,evaluate, verify and deploy innovative environmentaltechnology, particularly technology related to wastemanagement, site characterization and site cleanup.Regulators from 24 states are collaborating withrepresentatives from federal agencies, industry, andstakeholder groups to raise the comfort level ofenvironmental decision makers about using newtechnologies. By pooling their experience andknowledge in permitting innovative technologies andby publishing and distributing their work products,ITRC is making it easier for state regulatory agencies toapprove new technologies.

PHYTONET - Phytoremediation ElectronicNewsgroup Networkhttp://www.dsa.unipr.it/phytonet

The Phytonet Newsgroup was developed to allow easyworldwide communications between scientists whowork on problems related with Phytoremediation andApplication of Plant Systems to EnvironmentalControl. The Phytoremediation Electronic Network,moderated by Nelson Marmiroli, is operated by theDepartment of Environmental Sciences, University ofParma, Italy.

Remediation Technologies Development Forum(RTDF) Phytoremediation of Organics Action Teamhttp://www.rtdf.org/public/phyto


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The Phytoremediation of Organics Action Team wasestablished in 1997, as one of seven Action Teamsunder the Remediation Technologies DevelopmentForum (RTDF). The Phytoremediation of OrganicsAction Team includes representatives from industryand government who share an interest in furtherdeveloping and evaluating the of use of plants and treesto remediate contaminated soil and water.

Strategic Environmental Research and DevelopmentProgram (SERDP)http://www.serdp.gov

The Strategic Environmental Research andDevelopment Program is the Department of Defense’s(DoD) corporate environmental R&D program, plannedand executed in full partnership with the Department ofEnergy (DOE) and the Environmental ProtectionAgency (EPA), with participation by numerous otherfederal and non-federal organizations. Within its broadareas of interest, the Program focuses on Cleanup,Compliance, Conservation, and Pollution Preventiontechnologies.

U.S. Army Corps of Engineers PhytoremediationResearchhttp://www.wes.army.mil/EL/phyto

The U.S. Army Corps of Engineers InnovativeTechnology Program mission is to inform, encourage,promote, and support the development and use ofinnovative technology for environmental investigationand remediation. Its Phytoremediation Research site ispart of the Waterways Experiment StationEnvironmental Laboratory Web site.

U.S. Army Environmental Center (USAEC)http://aec-www.apgea.army.mil:8080

The USAEC Technology link provides access todescriptions of innovative restoration technologydemonstrations conducted at numerous Armyinstallations.

U.S. Department of Agriculture (USDA)http://www.usda.gov

In addition to supporting research to improveagricultural production, the USDA also supportsresearch concerning remediation of soil and groundwater contaminated with pesticides, herbicides, andfertilizers. The Current Research Information System(CRIS) database is a documentation and reportingsystem for ongoing and recently completed researchprojects. The Technology Transfer Automated RetrievalSystem (TEKTRAN) provides abstracts of researchresults from the UDSA’s Agricultural Research Servicethat will be published as articles or documents.

CRIS: http://cristel.nal.usda.gov:8080TEKTRAN: http://www.nal.usda.gov/ttic/tektran