Plants absorb nutrients and minerals from the soil as they grow and incorporate them into their leaves and stems. Such plants can be used to remove toxic elements from soil. Cleaning soil in this way is called phytoremediation.
Researchers at the University of Massachusetts Amherst are trying to go beyond phytoremediation and do phytomining, in which hyperaccumulated minerals from the soil can be harvested from plants for use in industrial or manufacturing applications.
One mineral that is critically needed for modern technology is nickel. There are trace amounts of nickel in nearly one million acres of topsoil in the US, making the soil inhospitable for most crops, but the economics and environmental impact of extracting it make doing it impractical.
A common plant, Alyssum murale, is a nickel hyperaccumulator; in fact, up to 3% of the plant’s biomass can be made up of nickel. But the plant is slow-growing and difficult to manage and is also considered an invasive species
Another common plant, Camelina sativa, does not have the downsides associated with Alyssum and is also a rich source of valuable biofuel. The Amherst researchers are working to determine which genes and proteins are responsible for Alyssum’s nickel hyperaccumulation and hope to genetically engineer Camelina sativa to have the same ability.
The researchers believe there is enough nickel in barren soil in the US to supply 50 years of phytomining. It wouldn’t supply all the nickel the economy needs, but it could account for 20 to 30 percent of the projected demand.
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Scientists at UMass Amherst Engineer Plant-based Method of ‘Precious’ Mineral Mining
Photo, posted July 10, 2017, courtesy of Matt Lavin via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio