United States Office of Solid Waste and EPA 542-F-01-002

Environmental Protection Emergency Response April 2001

Agency (5102G) www.epa.gov/superfund/sites

www.cluin.org

A Citizen’s Guide

to 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.


 
  


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.

 	


 

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.

  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.
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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.

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.

	  	




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.

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.

tree roots take

in water and

pollution from

the ground

polluted soil

water enters tree

where pollution is

cleaned up

clean soil

clean

groundwater

water table

polluted

groundwater