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Phytoremediation: What Is It? And How Hemp Helps The Environment


Phytoremediation helps the environment. Hemp can help to remediate soil, so CBD and hemp products are environmentally friendly.

Phytoremediation: The Highlights

  • Soil and groundwater all around the world have been contaminated by pollution, pesticides, wars, factories, and cars.
  • Toxic heavy metals and other contaminants are absorbed by grains, fruit, and vegetables and pose health risks.
  • There are six phytoremediation strategies that allow contaminants to absorbed, rendered harmless, or trapped within the soil by certain plant species.
  • Hemp has been shown to absorb and accumulate heavy metals and certain radioactive compounds.
  • Because of this, hemp needs to be cultivated organically and tested for contaminants to ensure that CBD and hemp products are safe to use.

What Is Phytoremediation?

After many wars, farming with pesticides, mining, and pollution, and the use of fossil fuels, the soil in which much of our fresh produce grows, including hemp, is full of toxic heavy metal ions such as arsenic, lead, zinc, copper, and cadmium, which are inorganic contaminants.

Organic pollutants or organic contaminants are also present in the soil and consist of non-chlorinated and chlorinated solvents such as DDT, ethane, and benzene as well as petroleum hydrocarbon.

These environmental contaminants also result in contaminated groundwater which is just as bad.

Our bodies need some of these trace elements such as zinc, copper, and manganese. They boost our metabolism, keep our immune system strong, and keep our skin healthy.

The issue is that the levels of these elements in the soil are very high and vegetables, herbs, spices, grains and the animals we eat tend to absorb them in unhealthy concentrations that are toxic.

There are many health risks associated with contaminated soils. Some elements like lead have no place in our bodies. These substances accumulate in our tissues, including in the brain.

They have linked to cancer and neurodegenerative diseases like Alzheimer’s disease as discussed in a 2015 review published in the Frontiers of Cellular Neuroscience.

Many people know about the contaminated soils in parts of Europe and China. Fresh produce and grains grown in China were tested in 2017, and some had far higher levels of heavy metals than is considered safe. But the U.S and many other parts of the world are affected too.

Phytoremediation is a form of bioremediation or environmental remediation and is one of the more cost-effective ways to fix this problem. Plants that absorb and render the contaminants harmless or allow them to be trapped and allow them to be removed from the environment are planted in order to clean the contaminated soils.

Phytoremediation Strategies

Different species of plants have different ways of purifying contaminated soil. There are six different phytoremediation strategies and some plants use more than one although this isn’t the case for them all. The strategy or strategies used will also depend on the type of contaminant as each of them has different properties.


Phytodegradation is also known as phytotransformation. The plant absorbs toxins which are present in trace amounts in the soil and groundwater, and then degrades or mineralizes them by metabolizing them.

Depending on how the plant works, this can be done in the leaves, stem, or roots. Plant enzymes are responsible for this action. Specific enzymes target specific contaminants, kind of like how certain enzymes in laundry detergent get rid of certain types of stains.

Some common plants species that do this are poplar trees (other plants in the Populus species too) and watermilfoils.


Phytostabilization, also known as phytoimmobilization or phytosequestration, takes care of both inorganic contaminants such as arsenic, lead, and cyanide, and organic contaminants. There are a number of ways that plants can do this.

Root exudates are biochemicals released by the plant roots into the soil to defend themselves from bacteria and other substances that would harm the plants. These exudates change toxic metals and trap them. Plant species that release chelating agents are great for this.

The contaminants can also be absorbed by the roots, or adsorbed which is to keep the contaminants immobilized in a film so that they can be kept from spreading. Lovegrasses (Eragrostis) and gladioli work in this way.


Phytovolatilization is when a plant absorbs contaminants and releases them into the atmosphere. This phytoremediation process works on organic and inorganic contaminants.

This sounds bad but certain elements such as cadmium and selenium are transformed into a non-toxic form by plant enzymes before being released.

Transgenic plants (plants cultivated with genes from different plant species), specifically those with genes from thale cress and tulip trees often work in this way. Other plants such as silver-leafed milkvetch also do this.


Phytoextraction is also called phytoaccumulation, phytoabsorption, or phytosequestration. Similar to phytostabilization in that the contaminants are absorbed and stored in the plant roots, phytoextraction stores pollutants in the leaves and stems.

This is particularly useful for removing heavy metals, so much so that the metals can be recovered to be reused by burning the plants. This is why plant species that have a high biomass production (biomass is organic matter produced by the plants to create energy, fuel, etc) and are resilient are chosen for this purpose.

Plant species with a high bioconcentration factor and translocation factor (basically how well a plant can absorb contaminants and move them from the roots to other parts of the plant) such as a pennycress and Chinese brake work in the way.

This remediation process can also be used for other inorganic environmental contaminants and organic contaminants too.


Phytofiltration or rhizofiltration involves the absorption of contaminants around the root zone into the roots of the plants. This works especially well for radioactive materials and heavy metals. Plants with a high absorption surface (high root biomass) are preferred for this phytoremediation strategy.

This strategy is commonly used in hydroponics which is when plants are grown in water. The brown mustard plant (Brassica juncea), phragmites, and sunflowers are good for phytofiltration.


Also known as phytostimulation, rhizodegradation makes use of the exudates of the roots to degrade organic compounds. These exudates also provide soil microorganisms which also break down certain contaminants with the nutrients such as organic acids and sugars that they need to survive. This also improves the health and viability of the soil, in general, resulting in better plant growth.

Hemp – A Blessing And A Curse For Phytoremediation

Hemp is a phytoaccumulator which is able to absorb and store heavy metals as seen in a 2003 study, and some radioactive compounds as seen in a 2011 study. This is great news for the environment and people since there will be less of these harmful compounds present in the food we eat.

However, the fact that hemp so readily absorbs contaminants also means that products created from hemp could be contaminated. As an example, one of the heavy metals that hemp absorbs is cadmium which is very harmful to inhale. Considering that many CBD products are smoked or vaped, this poses quite a risk.

Many heavy metals can accumulate in our bodies in harmful levels if we ingest them regularly and they can be absorbed by our skin too. Many CBD products are eaten and used topically.

When the CBD market took off and with the 2018 Farm Bill allowing industrial hemp to be grown, there are many farmers cashing in on it. Not all of them are farming organically and not all manufacturers test their products.

Responsible Hemp Cultivation

Hemp that’s used to manufacture CBD and hemp products that will be consumed in any way or absorbed into the skin needs to be ethically grown. Soil and water need to be tested for contaminants. The best way to prevent future soil contamination, as well as contaminated water and hemp plants, is to farm hemp organically.

Only buy reputable brands of CBD and hemp oil and only from licensed dispensaries. You can go onto companies’ websites to see whether they have tested their products or not. Testing should preferably be done by a third-party lab. You should be able to receive the lab reports when contacting them.

Phytoremediation – Final Thoughts

Phytoremediation is still a fairly new practice, but compared to other types of environmental remediation, it’s a more affordable solution to a big problem. Hemp has long been used for many purposes such as making cloth and building material in addition to having numerous health benefits. The fact that hemp can help to purify the soil is just one more reason that it’s amazing.

But the accumulation of harmful compounds in the tissues of the plant does mean that hemp products can contain high concentrations of pollutants and cause more health problems instead of helping to relieve them.

When you are looking to purchase hemp or CBD products, always make sure that the brand you decide to buy has been tested for contaminants as well as for the actual CBD content. Buying organic hemp CBD products is the safest and most environmentally friendly way to go.

But make sure that it’s a product that has been certified organic. That way you’ll be making sure you have a good quality product that truly benefits your health and helps you to treat ailments such as chronic pain and insomnia.