Sunday, January 15, 2017

Prodigious Plants that Depollute

sunflowers

Have you heard of plants capable of extracting minerals from the ground while stopping erosion and decontaminating the soil? That’s what plants called hyperaccumulators do.

A hyperaccumulator is a plant that can grow in places containing very high levels of metals, absorbing them through their roots. They concentrate extremely high levels of metals in their tissues. These plants (some are grasses, trees or cereals) can grow in highly toxic, contaminated land and yet thrive there, where nothing else can. 

Scientists are looking at cultivating these plants to turn their extractive powers back into minerals, but also to counter erosion and absorb the toxic materials generated by mines to attenuate the devastation there. They naturally decontaminate mining and other sites containing heavy metals.

Nickel

Nickel

Nickel is the fifth most abundant element on Earth. It is used extensively in wires, coins and military equipment. Traces of it even appear naturally in most vegetables, fruits, nuts, as well as in chocolate and wine, according to the Nickel Institute. 

But high concentrations of nickel are toxic for most trees and plants. Human exposure to large amounts can cause cancer and other health problems. Workers who refine or weld nickel have higher rates of lung cancer, fibrosis, liver damage and other ailments.

Yet Alyssum murale, a member of the mustard family also called Yellowtuft due to its yellow flowers, thrives on the contaminated land around nickel mines. And other plants absorb other toxic minerals, such as lead, mercury, copper, cadmium, zinc, aluminum, arsenic, palladium, platinum and even rare earth elements, to name just a few. Alyssum_murale

They are hyperaccumulators because they take up metals like nickel and store them in their leaves, flowers and stems. Researchers are interested in using plants like A. murale as a natural means of decontaminating mining and other heavy metal sites with toxic soils. Directly using plants on location as a cleanup technique to remove, degrade or contain contaminants in soils, sludges, sediments, surface water or groundwater even has a name: phytoremediation.

This is definitely good news for the planet. For instance, Helianthus annuus, the common Sunflower, was planted at a contaminated wastewater site in Ashtabula, Ohio. The four-week old plants were reported to have removed more than 95% of the uranium there in 24 hours.

Arabidopsis thaliana

Arabidopsis thaliana