Scientists may have come up with a solution to clean up former mining sites that have left the surrounding land contaminated with toxic metals. A grass known as giant Napier grass has been found to be able to decontaminate polluted ground.
Napier grass is a tall perennial plant that is native to the grasslands of Africa. It is a relative to the sugar cane and it is capable of growing in extremely poor soils and is efficient at drawing heavy metals and other pollutants out of the soil.
There have already been some tests conducted with the grass on large sites in Guangdong province. These sites were heavily contaminated by mining activity. It was discovered that the presence of copper, nickel, cadmium as well as zinc and lead were all reduced after the grass was grown in the area.
As a relative to the sugar cane the grass is favoured because it also has the potential for ethanol production.
There are still many variables that must be studied and determined. Factors such as the plants capability to withstand very high concentrations of the pollutants and the efficiency with which the plant can extract it still have to be proven. It also remains to be seen whether it will be possible to grow viable crops on the land after the Napier grass has done its job. Tests would have to be conducted to work out whether the toxins from ground that is thought to be clean ends up in the edible parts of the plant.
The project is a collaboration between the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Hong Kong-based HLM Asia Group and Shaoguan University in China’s Guangdong Province.