Phytoremediation
Phytoremediation is an innovative and sustainable approach to environmental clean-up that uses plants to remove, degrade, or immobilise pollutants from soil, water, or air. This natural process harnesses the power of plant roots, leaves, and stems to absorb and break down harmful substances such as heavy metals, pesticides, solvents, and even radioactive compounds.
This green technology provides a cost-effective and environmentally friendly alternative to traditional remediation methods, such as excavation or chemical treatments. By using vegetation as natural filters, it not only helps to detoxify contaminated areas but also improves soil quality, supports biodiversity, and reduces reliance on harmful chemical interventions.
Commonly used species in this technique include sunflowers, mustard greens, and various types of hemp: all of which can absorb and transform pollutants in the environment. This page will explore how the process works, the types of contaminants it can address, and the promising role it plays in sustainable environmental management.
The Phytoremediation Process
During the process of absorbing water from the soil, plants can also absorb various contaminents as deep as their roots.
The Plant can then:
store these contaminents within its roots, stems and leaves
Convert them into less harmful chemicals
Have the contaminents in the roots broken down by microbes and converted into less harmful chemicals
The process can take several years to occur, however it utilises the plants natural process saving energy, equiptment and labor
Phytorememdiation also has additional envirionmental benefits as whilst it removes contaminents from the soil it also can control soil errosion and improve air quality.
There are Six main strategies of phytoremediation:
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The roots absorb contaminents within the soil and allows them to accumilate above ground. This can then be periodically havested to remove them from the soil
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Phytostabilization aims to reduce the mobility of heavy metals by establishing a plant cover on the surface of the contaminated sites
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Plant roots enhance biodegradation by stimulate microbes within the soil to degrade organic contaminants.
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Plants absorb contaminents through their roots and release them via their leaves into the atmosphere
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Contaminents are absorbed in through the roots and metabolised either in the root, stem or leaves
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The use of deep rooted trees to degrate contaminents in ground water
Hemp in Phytoremediation
Fast Growth and Deep Roots
Hemp is known for its rapidly growing, and deep root system allowing it to cover a larger area and remove contaminants from the soil.
Bioaccumilation
Hemp has the ability to absorb toxins, heavy metals, and other contaminants from the soil through its roots, storing them in its tissues. This makes it highly effective for use in environmental clean-up efforts.
Biomass Production
Hemp generates large volumes of biomass, which can be harvested and processed after remediation to further reduce residual pollutants.
Adaptability
This versatile crop thrives in a wide range of environmental conditions, making it well-suited for clean-up projects across diverse regions.
These qualities ensure the efficient extraction of heavy metals from contaminated soil. Additionally, hemp’s high biomass presents numerous commercial opportunities post-harvest.
Growing Hemp In Contaminated Soil
Industrial hemp plants, can effectively grow in polymetallic contaminated soils whilst still producing biomass and seeds making it effective in phytomanagement. Some growth characteristics of the hemp cultivars in the more contaminated soil were stunted, however, the absence of toxic metals in the above ground organs shows the feasibility of cultivating industrial hemp on more contaminated sites
Contaminated biomass as an energy resource.
It has been recommended to integrate phytoremediation technologies with biomass energy valorisation to transform unproductive contaminated soils into revitalised and productive areas.
Evidence has suggested that anaerobic Digestion and/or incineration of contaminated biomass has proved to be the most energy efficient and environmentally sustainable systems
Accelerating Phytoremediation
The remediation potential of hemp can be enhanced when combined with the algae Spirulina, which has been shown to accelerate the uptake of heavy metals.
Research indicates that irrigating hemp with Spirulina-enriched water improves selective compartmentalisation, increasing metal absorption by the plant. At higher concentrations, Spirulina also acts as a growth promoter, boosting final biomass yields.
Further studies have found that introducing arbuscular mycorrhizal fungi (AMF) into hemp roots can significantly enhance metal uptake. This is due to AMF's ability to stimulate plant growth and improve the efficiency of metal absorption from the soil.