Using Plants To Help Keep The Environment Clean

by Art Jones

It has got a big name and an intriguing potential.

It's called phytoremediation and it basically means using green and growing things, such as plants and trees, to help clean up the environment.

Research shows that plants can be used to clean up many kinds of pollution including metals, pesticides, explosives and oil.

Phytoremediation works by using the natural ability trees and plants have to draw water and nutrients out of the soil. When the roots of a plant or tree draw in water or nutrients from polluted soil, streams or ground water they also draw in the pollution. Once inside the plant or tree the pollutant is either stored in the roots, stems or leaves; changed into less harmful chemicals or changed into gases that are released into the atmosphere as the plant breathes.

Phytoremediation can also take place even if the pollutants are not taken in through the roots. For example, pollutants may stick or "sorb" to plant roots. Or they can be changed into less harmful substances by bugs or microbes that live near the roots through a process called bioremediation.

Plants can also be used to help stop wind, rain and groundwater from carrying pollution into other areas.

"This is an intriguing area of scientific research," says Dr. Rory McIntosh of Saskatchewan Environment. "We already know that some plants growing in Saskatchewan, such as red fescue and poplar trees, can remove pollutants from the soil and water. But there are still questions that need to be answered. For example, insects and animals may eat the plants used for phytoremediation. It needs to be determined if they will be harmed or whether they will harm larger animals that may eat them. In general, there is no known threat to humans as long as they don't eat the plants."

Phytoremediation is being tested in several areas in North America and research is being carried out at the University of Saskatchewan in Saskatoon.

"One of things being looked at is the time it takes to clean up a site using phytoremediation," says Environment's McIntosh.

"Because cleanup time is related to the type and number of plants used, the types of pollutants, size and depth of the polluted area and soil conditions, phytoremediation can take years. Plants that have reached maturity are harvested and destroyed or recycled, if the pollutant stored in the plant can be re-used. Usually trees are left to grow and are not harvested."

Environment's McIntosh says the beauty of phytoremediation is that it takes advantage of natural processes, which requires less labour, less equipment and reduces the chances of workers coming in contact with a pollutant. And to top it off, says Environment's McIntosh, the plants and trees look a lot nicer than an area that has been processed using heavy
equipment.

For more information contact:

Rory McIntosh
Forest Entomologist
Saskatchewan Environment
(306) 953-3617
rmcintosh@serm.gov.sk.ca

Or

Art Jones
Communications Consultant
Saskatchewan Environment
(306) 787-5796
(306) 536-8452 (cell)
ajones@serm.gov.sk.ca

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