Clean and grassy

Contaminated soil can be remedied by planting ryegrasses

Last Updated: Saturday 04 July 2015

planting ryegrasses (awned cereal grasses that resemble barley) accelerates the redemption of soil contaminated with polyaromatic hydrocarbons (pahs) and pentachlorophenol (pcp). This was established by a year-long greenhouse study conducted by Phytokinetics Inc, a company based in Logan, Utah, usa. The study was sponsored by the California-based Environment Pro-tection Agency. Both pah s and pcp are carcinogens (Environment Science & Technology , Vol 31, No 10).

Well-mixed samples of contamina-ted soils taken from a site in Portland, Oregon, were used in three different tests. In the first, soil columns amended with nutrients and dolomite were used. The second employed unplanted amended columns, and unplanted, unamended columns were used for the third.The three were periodically examined to determine the extent of removal of contaminants. In the planted columns, the root system provided additional stimulation to the biodegradation rates.

The researchers observed that ryegrass accelerated the removal rates of pcp , among other contaminants. Significantly, no contaminants were found in the plant shoot tissues. By the end of the study, the rise in decontamination rates diminished. The company has already started work on the second phase of the project that involves planting ryegrasses in at the Portland site.

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