United States
Environmental Protection
Agency
Office of Solid Waste and
Emergency Response
(5102G)
&EPA A Citizen's Guide
to Phytoremediation
EPA 542-F-01-002
April 2001
www.epa.gov/superfund/sites
www.cluin.org
The
EPA uses many methods to clean up pollution at Superfund and other sites. Some, like phytoremediation, are
considered new or innovative. Such methods can be quicker and cheaper than more common methods. If you
live, work, or go to school near a Superfund site, you may want to learn more about cleanup methods. Perhaps
they are being used or are proposed for use at your site. How do they work? Are they safe? This Citizen's Guide
is one in a series to help answer your questions.
What is phytoremediation?
Phytoremediation uses plants to clean up pollution in the environment. Plants can help clean up
many kinds of pollution including metals, pesticides, explosives, and oil. The plants also help
prevent wind, rain, and groundwater from carrying pollution away from sites to other areas.
How does it work?
Phytoremediation works best at sites with low to medium amounts of pollution. Plants
remove harmful chemicals from the ground when their roots take in water and nutrients from
polluted soil, streams, and groundwater. Plants can clean up chemicals as deep as their roots
can grow. Tree roots grow deeper than smaller plants, so they are used to reach pollution
deeper in the ground.
Once inside the plant, chemicals can be:
• stored in the roots, stems, or leaves
• changed into less harmful chemicals within the plant
• changed into gases that are released into the air as the plant transpires (breathes).
Phytoremediation can occur even if the chemicals are not taken into the plant by the roots.
For example, chemicals can stick or sorb to plant roots. Or they can be changed into less
harmful chemicals by bugs or microbes that live near plant roots. (Please see A Citizen's
Guide to Bioremediation [EPA 542-F-01-001].) The plants are allowed to grow and take
in or sorb chemicals. Afterward, they are harvested and destroyed, or recycled if metals
stored in the plants can be reused. Usually, trees are left to grow and are not harvested.
Plants grown for phytoremediation also can help keep harmful chemicals from moving from a
polluted site to other areas. The plants limit the amount of chemicals that can be carried away
by the wind or by rain that soaks into the soil or flows off the site.
Is phytoremediation safe?
Before phytoremediation begins, EPA studies whether plants grown to clean up pollution can
be harmful to people. EPA tests the plants and air to make sure that the plants do not release
harmful gases into the air.
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For more
information
write the Technology
Innovation Office at:
U.S.EPA(5102G)
1200 Pennsylvania Ave.,
NW
Washington, DC 20460
or call them at
(703) 603-9910.
Further information also
can be obtained at
www.cluin.org or
www.epa.gov/
superfund/sites.
tree roots take
in water and
pollution from
the ground
polluted soil
water table
polluted
groundwater
water enters tree
where pollution is
cleaned up
clean soil
clean
groundwater
Some insects and small animals may eat the plants used for phytoremediation. Scientists are
studying these animals to see whether the plants can harm them. Scientists also are studying
whether these animals pose harm to the larger animals that eat them. In general, as long as plants
are not eaten, they are not harmful to people.
How will it ?
The time it takes to clean up a site using phytoremediation depends
on several factors:
• type and number of plants being used
• type and amounts of harmful chemicals present
• size and depth of the polluted area
• type of soil and conditions present
These factors vary from site to site. Plants may have to be replaced if they are destroyed by
bad weather or animals. This adds time to the cleanup. Often it takes many years to clean up
a site with phytoremediation.
Why use phytoremediation?
EPA uses phytoremediation because it takes advantage of natural plant processes. It requires
less equipment and labor than other methods since plants do most of the work. Trees and plants
can make a site more attractive as well. The site can be cleaned up without removing polluted
soil or pumping polluted groundwater. This allows workers to avoid contact with harmful
chemicals. Phytoremediation has been successfully tested in many locations, and is being used at
several Superfund sites.
NOTE: This fact sheet is intended solely as general guidance and information to the public. It is not intended, nor can it be relied
upon, to create any rights enforceable by any party in litigation with the United States, or to endorse the use of products or services
provided by specific vendors. The Agency also reserves the right to change this fact sheet at any time without public notice.
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