Every year Europe grows 900,000 hectares of rapeseed to produce biodiesel, the region’s leading biofuel. But what if this crop could provide a second ecological payoff? Scientists at Ireland’s Institute of Technology, Carlow, are trying to use it for environmental cleanup, too.

Mining and industry processes contaminate soil with heavy metals—including arsenic, copper and nickel—rendering it unusable for agriculture. Although some noncommercial plants can grow in such soils and even take up and remove the metals, potentially useful crops—rapeseed, for one—fare poorly in these conditions. Carlow postdoctoral student Olivia Odhiambo wondered whether bacteria, which assist plants in modifying metals and converting nitrogen into energy, could also help rapeseed thrive in polluted earth.

Odhiambo isolated three strains of bacteria, including a mutant form of Pseudomonas fluorescens, that facilitate the growth of trees in contaminated conditions. After confirming that the bacteria help rapeseed grow faster in healthy soil, too, she tested them in metal-rich soil. Preliminary results suggest that the bacteria helped the oilseed flourish, perhaps because the microbes convert the metals into harmless by-products.

Whether rapeseed can accumulate enough metal to “clean” soil significantly remains an open question, according to Leon Kochian, a plant biologist at Cornell University. But if it can, scientists could use the plants, which grow in a range of climates, as decontaminants around the world—and then use the seeds for biofuel.

Note: This article was originally printed with the title, "Crops Could Cleanse Soil".

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