&EPA
U.S. Environmental Protection Agency
       Phytotransformation:
The  Ultimate  Cleaner-upper
National Exposure Research Laboratory
What is phytotransformation?
Research at the NERL Ecosystems Research Division
indicates that plants can transform many organic
contaminants in sediments, soils, and natural waters
to more environmentally acceptable products. A
variety of organic contaminants have been shown to
be degraded by plants and trees. Furthermore, plant
enzyme systems have been shown to be stable in
sediments and soils for long periods of time and still
maintain their activity.  The diagram illustrates the
mechanisms for pollutant uptake by plants.
Benefits
Using the knowledge that some aquatic plants have a high enzymatic activity for breaking down chemical
toxins in soils and surface waters is leading to technology that is both economical and environmentally
friendly to clean up hazardous waste sites, thus eliminating the dangers of further contaminating the
environment with these chemicals.

Research Objective
The objective of our research is to determine which plants contain the most effective enzyme systems for
transforming chemicals to safer products and to develop and incorporate plant/enzyme mediated
transformation algorithms into multimedia models. We seek to quantitatively describe these processes in
air, water, and land systems using molecular descriptors of the organic compounds and physical/chemical
descriptors of the system to model pollutant fate.

Research Approach
   • Identification: develop and separate plant enzymes that may be active in degrading chemicals.
   • Occurrence: determine the occurrence of plant enzymes that have the potential capability of
     degrading a variety of toxic chemicals.
   • Transformation: conduct degradation experiments in selected environmental matrices to
     determine the mechanism and degree of degradation of chemicals to safer products.
   • Effects: determine the efficacy of these plant/enzyme systems  for transforming these chemicals.

Results
   • Several plants (aquatic and terrestrial) have been identified as containing the enzyme that reacts to
     make harmless the trinitrotoluene (TNT) found in abundance at abandoned military sites.
   • Further research has shown that many aquatic and land plants can degrade chlorine compounds and
     restore the contaminated media.
   • Plants have been shown to uptake and degrade organophosphate compounds such as pesticides to
     harmless products.

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                                      Phytotransformation
Benefits
    •  Using the knowledge that some aquatic plants have a high enzymatic activity for breaking down chemical
      toxins in soils and surface waters is leading to technology that is both economical and environmentally
      friendly to clean up hazardous waste sites, thus eliminating the dangers of further contaminating the
      environment with these chemicals.

Purpose
    •  Supports EPA's goal for restoration of contaminated waste sites by providing less expensive and
      environmentally safe methods of cleaning up hazardous waste sites.
    •  Supports EPA's sound science goal by developing algorithms for phytotransformation processes that can
      be incorporated into multimedia models.

Useful publications
    1. Method for Remediating Environmental Contaminants, N. Lee Wolfe, Laura H. Carreira and Mark C. Delgado. Patent Number
       5,711,020, Jan. 20, 1998.
    2. Method and Composition for Remediating Environmental Contaminants., N. Lee Wolfe, Laura H. Carreira and Mark C. Delgado,
       Patent Number 6,100,382, Aug. 8, 2000.
    3. Gao, I, A. W. Garrison, C. Hoehamer, C. S. MazurandN. L. Wolfe. Uptake and Phytotransformation of o,p'-DDT and p,p'-DDT
       by Axenically Cultivated Aquatic Plants. J. Ag. and Food Chem. 48, 6114-6120, 2000.
    4. Gao, J. Al W. A. Garrison, C. Mazur, C. Hoehamer, N. L. Wolfe. Uptake and Phytotransformation of Organophosphorus
       Pesticides by Axenically Cultivated Aquatic Plants. J. Ag.  and Food Chem.  48,6121-6127,2000.
    5. Garrison, W. A., V. A. Nzengung, J. K. Avants, J. J. Ellington, W. J. Jones, D. Rennels andN. L. Wolfe. Phytodegradation of p,p'-
       DTT and the Enantiomers of o,p'-DDT. Environ. Sci. Techno!., 34,1663-1670, 2000.
    6. Susarla, S., S. T. Bacchus, N. L. Wolfe and S. C. McCutcheon. Phytotransformation of Perchlorate and Identification of Metabolic
       Products inMyriophyllum aquaticum. Int. J. Phytoremediation 1(1):97-107, 1999.

Time Line
    •  2004 — Prototype model to quantitatively describe the atmospheric uptake and ensuing enzyme mediated
      transformations of volatile organics by plants.
    •  2006 — Prototype model to quantitatively describe enzyme mediated transformations of organics in
      aquatic systems.
    •  2008 — Prototype model to quantitatively describe enzyme mediated transformation of organics in
      soil/sediment.

Participants
    •  U.S. EPA, Office of Research and Development, National Exposure Research Laboratory, Ecosystems
      Research Division, Athens, GA.
                                     r                             For more information visit the
       For More                     on ac .                  National Exposure Research Laboratory
                                      8^u  °I^                 Ecosystems Research Division Website:
                             lonq.macarthurfflepa.qov                 http://www.epa.gov/athens
     For more information on this and other NERL science projects, visit our Website
                                      http://www.epa.gov/nerl/
 WEB SITE ANNOUNCEMENT                                                              December 2001

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