Using hemp to clean polluted land
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A project shows that hemp plants effectively and economically remove complex manufactured chemicals from contaminated soil
Spotted: In Limestone, a small town on the edge of the Maine-Canada border, the American indigenous tribe The Aroostook Band of Micmacs are using hemp to clean up 600 acres of polluted land.
The land, which was formerly Loring Air Force Base, was given back to the tribe by the US government in 2009. However, it was so polluted that it was deemed a federal Superfund site – a category given to polluted locations requiring long-term treatments to clean up hazardous contamination. The soil was found to be full of perfluoroalkyl and polyfluoroalkyl substances (PFAS). PFAS, also known as ‘forever chemicals’, are difficult to break down and research has suggested they could possibly be a human carcinogen.
In 2019, the Micmac Nation, Upland Grassroots, and their research partners joined forces to test whether the Micmacs’ hemp plants were removing PFAS from the contaminated soil. After two years collecting data on three different plots, they found the hemp effectively lowered PFAS levels. The technique is referred to as ‘phytoremediation’, and is a highly attractive option for cleansing land from certain contaminants as it is both affordable and does not disturb the soil much.
Prior to the legalisation of industrial hemp in 2018, “huge companies could excavate or do these very intrusive processes. But there was nothing the layperson could really do to clean land,” Chelli Stanley, a founder of the environmental organisation Upland Grassroots explains.
Moving forward, further research is needed to find best practices on how to later dispose of the PFAS-laden plants. Meanwhile, a new water tank has been installed in Loring and the investigation has gained a chemical engineer from the University of Virginia interested in using enzymes to break down PFAS.
Other innovations spotted by Springwise that tackle soil pollution include a new technique for removing heavy metals from soil, and a subsurface real estate project that aims to regenerate contaminated areas.