Common leafy vegetables like kale, cabbage, and broccoli could soon play a surprising role in the global transition to renewable energy and advanced medical technology.
Researchers from the University of Queensland have discovered that crops in the Brassicaceae family possess a remarkable ability to extract traces of the metal thallium from contaminated soil, a process known as phytomining.
While these plants have long been known to accumulate the heavy metal thallium, they are often monitored primarily as an environmental health risk. However, new research published in the journal Metallomics suggests that this natural trait could be harnessed as a sustainable, non-conventional mining method.
UQ geochemist Dr Amelia Corzo-Remigio, based at the Sustainable Minerals Institute (SMI), led the study using advanced analytical techniques to understand exactly how these plants process thallium.
By employing micro-X-ray fluorescence (μXRF) and X-ray diffraction mapping (XDM) on live kale plants, the team achieved an unprecedented view of the plant’s internal chemistry.
The findings revealed that the plants deposit thallium in a crystallised form, specifically thallium chloride, along the veins inside their leaves.
Dr Corzo-Remigio noted that this crystalline structure makes the metal potentially compatible with existing metallurgical extraction methods.
“Thallium is extremely toxic, but it is also a valuable and industry-critical metal used in medical technologies, optical glass, and semiconductors,” Dr Corzo-Remigio explained.
“So, while posing a significant health risk to humans, many of these same Brassicaceous plants could present a clear opportunity in sustainable mining.”
This research highlights a dual-purpose solution for the future: the ability to remediate and rehabilitate polluted soils while simultaneously securing a sustainable supply of critical elements.
Experts at the SMI’s Centre for Environmental Responsibility in Mining suggest that phytomining will become key to securing certain metals needed to advance medical technologies and transitioning the economy to a renewable energy supply.
Dr Corzo-Remigio said phytomining with Brassicaceous plants also has the potential to help tackle emerging environmental problems arising from mining activities.
“There’s a dual need to remediate and rehabilitate soils while also supplying critical elements in the most sustainable way possible,” Dr Corzo-Remigio said.