The risks associated with the presence of potentially toxic elements in soil, particularly in China, can be controlled thanks to phytoremediation techniques.
Potentially toxic elements (PTEs) can pose health and environmental risks once they enter the soil. But they can also be naturally present in soils, in so called high background areas. And contrary of the assumption that elements from these high background levels are immobile, studies reveal that they can become mobile, posing risks to vegetation and the food chain through weathering, soil acidification, and oxidation-reduction cycles. Geographical factors, such as non-ferrous metal mining, heavy rainfall, and coastal areas, exacerbate the migration potential of PTEs along watersheds.
Helpful plant properties
Phytoremediation techniques to this issue include phytoextraction, intercropping, and phytobarrier methods. Phytoextraction involves using hyperaccumulators plants to absorb elements, like arsenic, in their aerial parts which can then be harvested, effectively reducing soil concentrations. Phyto-exclusion, or phytobarrier, involves planting low-accumulating crop varieties to reduce PTEss uptake in food parts, benefiting yield and crop safety. Intercropping combines hyperaccumulators and low-accumulating crops to reduce PTE concentrations in crops while actively foraging PTEs from the rhizosphere.
These techniques have been tested in several successful case studies, including a project in Hunan province where phytoextraction, phyto-exclusion, and intercropping were employed. Results indicate a significant reduction in PTEs concentrations in crops, improving food safety standards. Mixing these techniques increases their potential to mitigate PTEs contamination in soil and crops, safeguarding human health and the environment.