Willow Trees May Suck Up Soil Pollution and Clean Sites

It turns out that willow trees may hold the key for cleaning up soils. Scientists have found that using broad-leaved trees, such as sallow trees in the phytoremediation of contaminated soils may prove to be a cost-effective method for restoring mining areas and landfills.

Chemicals and heavy metals can leach into soils where industrial processes take place. These elements can accumulate over the years, contaminating soils and making them unsuitable for future use once operations have ceased in the area. Yet in this case, the researchers found that plants might be able to help.

"This is a cost-efficient solution for purifying and restoring contaminated soils," said Aki Villa, one of the researchers, in a news release. "There is no need for earth-moving, as harmful materials can be extracted from the soil naturally, with the help of plants. Furthermore, the wood biomass grown in the process can be used for energy production and as raw material for biorefineries."

In fact, the researchers found that willow trees can grow in soil that's high in acidity, and that's contaminated by heavy metals, such as copper, zinc, nickel, chromium or lead. Yet trees aren't the only way to help improve soils.

"The acidity of contaminated soil can be reduced and its growing ability improved with the help of by-products from other processes," said Villa. "For example, wood ash and side products high in nitrogen and calcium can be used to control acidity."

The findings reveal potential methods to help reduce soil contamination in certain regions. This could be huge in terms of restoring an area that's been subject to decades of contamination.

The findings can be found online here.

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