It is estimated that approximately 137,000 km²* of agricultural land in Europe is contaminated to varying degrees by heavy metals. This means that the land can only be used for non-food production. UCLouvain researchers are exploring the promising use of cannabis to meet the problem’s challenges!
Cannabis, or hemp, has been widely used by humans for more than 10,000 years, but it has received bad press in recent decades and its cultivation has been banned in many countries. The reason? The addictive and harmful effects on the brains of young people who use it regularly as a recreational psychotropic drug.
And yet this plant, of which there are many varieties with no psychotropic effects, has undeniable positive qualities and could provide valuable benefits to our societies. This is the focus of the work of Marie Luyckx, a PhD student in the Plant Physiology Research Group led by Prof. Stanley Lutts at the Earth and Life Institute. Among hemp’s particularly interesting aspects are:
- its ability to extract heavy metals from soil;
- its stalks, which are sources of fibre used in the textile and construction industries;
- its flowers, which contain substances called cannabinoids that are of wide-ranging pharmaceutical interest.
Focusing on environmental issues, including the use of plants for the management of soil contaminated by heavy metals (phytoremediation), UCLouvain researchers began by investigating the first two aspects. It was an original approach, starting with the question: Can hemp be used to clean up soil contaminated by heavy metals, while producing quality fibres. If the research proves the answer is yes, this will have three advantages:
- cleaning up agricultural soils contaminated with heavy metals (cadmium, zinc, lead, etc.) released directly into the soil or into the atmosphere by industrial sites or excessive use of fertilisers;
- maintaining the productivity of soils unsuitable for food crops; and
- ensuring vegetation cover on these bare lands and thus avoiding both soil erosion by water or wind and pollution of waterways and adjacent lands.
To carry out her investigations, Ms Luyckx developed projects and experiments with two partners, ISA Lille and the University of Luxembourg. The first stage of her PhD research concluded that hemp is indeed a plant capable of tolerating heavy metal contamination and that it implements resistance strategies when faced with a polluted environment. The second stage checked hemp’s capacity to accumulate heavy metals. ‘We found that hemp accumulates heavy metals in its aerial parts at significant levels,’ Ms Luyckx explains. The fibres of these ‘contaminated’ plants were analysed and the results show that their mechanical properties are not altered by the presence of heavy metals. ‘These fibres could therefore continue to be used in the construction and textile industries, depending on Oeko-tex standards and/or the associated treatment for preventing the heavy metals from being released afterwards.’
UCLouvain researchers will also soon start researching hemp plant flowers. These contain the cannabinoids that are becoming increasingly popular in the pharmaceutical sector. Will the flowers of plants, which will have grown on polluted soils and accumulated heavy metals in their aerial parts, be healthy and suitable for having their cannabinoids extracted for therapeutic use? Researchers have good reason to believe so, but the research needs to confirm it. More in the next episode...
*Tóth, G., Hermann, T., Da Silva, M. R., & Montanarella, L. (2016). Heavy metals in agricultural soils of the European Union with implications for food safety. Environment international, 88, 299‑309.
Sanisol: for a healthy vegetable garden!
Still on the subject of heavy metal soil pollution, but this time regarding vegetable gardens, UCLouvain researchers have developed a tool that analyses and cleans soil before planting vegetables. Because what is the point of putting all the energy into growing your own vegetables if they are ultimately less healthy than those from the supermarket?
Marie Luyckx bio
PhD student in the Plant Physiology Research Group at the Earth and Life Institute