Hemp science is now advancing in leaps and bounds compared to the stagnation of the previous few decades. One significant area of research that is currently receiving particular attention is phytoremediation, or decontamination of soil—although the fact that hemp decontaminates soil has been known for some time.
Hemp and the Chernobyl Phytoremediation Project
For almost two decades, industrial hemp growing in the environs of the abandoned Chernobyl nuclear power plant in Pripyat, Ukraine has been helping to reduce soil toxicity.
In 1990, just four years after the initial explosion, the Soviet administration of the time requested that the International Atomic Energy Agency (IAEA) assess the environmental situation. In the 30km exclusion zone surrounding Chernobyl, high concentrations of various toxic metals including lead, cesium-137, strontium-90 and plutonium were found in the soil, as well as in the tissues of plants and animals.
In response, it was decided that a concerted effort to reduce soil contamination through the use of beneficial plants would be undertaken. This process, known as phytoremediation, was implemented almost immediately.
Which Plants are Useful in Phytoremediation?
Various plants have been utilized in Chernobyl for their ability to take up specific contaminants—two brassica varieties to remove chromium, lead, copper and nickel, maize to take up lead (various studies have demonstrated the excellent lead-uptake capability of this important crop), and more recently, sunflower and hemp.
Sunflower plantings began in 1996 subsequent to the development of a variety that promised hitherto unheard-of efficiency of decontamination; hemp plantings soon followed, in 1998. Slavik Dushenkov, a research scientist with Phytotech, one of the organisations behind the hemp plantings, stated that “hemp is proving to be one of the best phyto-remediative plants we have been able to find”.
As well as in Ukraine, rural areas in neighbouring Belarus were affected by the Chernobyl incident., Authorities there have also considered the use of hemp as a decontaminant. However, it is not clear if any programs involving hemp were ever implemented.
Where Else is Hemp Used in Phytoremediation?
In Puglia, Italy, industrial hemp is being used on a wide scale to assist in the decontamination of some of Europe’s most polluted soils. The Ilva steel plant, the largest of its kind in Europe, has poisoned local soil, plants, animals, and human residents for decades with its toxic emissions. Within a 20km radius of the plant, grazing livestock is prohibited.
Since 2012, when the extent of the crisis became apparent, farmers have planted millions of cannabis plants in an effort to decontaminate the soil. In that time, the local area of hemp cultivation has increased from 3 to 300 hectares. Around 100 farmers are growing hemp, and the movement has even proved to be an economic stimulus. A new hemp processing plant has opened to convert the harvest into fibre for clothing and construction.
Since the devastating Fukushima Dai-ichi nuclear power plant accident in 2011, there have been calls for Japan to implement hemp phytoremediation. However, due to the Cannabis Control Law forced into Japanese law by the occupying U.S. powers in 1948, hemp may only be grown under license – and these are highly restricted and difficult to obtain.
A few months after the incident, Fukushima residents began to plant millions of sunflowers, as well as field mustard and amaranth, in an attempt to soak up cesium and other toxins from the soil. The Japan Aerospace Exploration Agency also began an experimental project involving sunflowers in 2011, and various projects since have investigated algae, buckwheat and spinach for their uptake abilities. But it seems that hemp has not been utilized to date.
Research Into Hemp as a Soil Decontaminant
There is extensive research into the ability of hemp to act as a phytoremediator. An Italian study published in Plant and Soil in 2003 showed that hemp had the ability to absorb cadmium, chromium and nickel from soil, and that high concentrations of the heavy metals had little effect on plant morphology.
In fact, “an increase in phytochelatin and DNA content was observed during development” of the hemp plants, suggesting “ability to avoid cell damage by activating different molecular mechanisms”.
In 2005, a German study published in Biologia Plantarum concluded that hemp was unaffected by root concentrations of cadmium as high as 800 mg/kg, but that leaf and stem concentrations of 50 – 100 mg/kg “had a strong effect on plant viability and vitality”. This study also noted that soil pH affected the rate of cadmium uptake.
In 2010, a Chinese study investigated eight crops, including hemp, for their ability to uptake zinc. Zinc is a heavy metal that is beneficial in trace amounts but potentially phytotoxic at higher concentrations.
According to this study, “all crops, except sunflower, could grow quite well under 400–800 mg kg?1 Zn stress”. Hemp showed “small inhibitions in plant growth”, indicating “a strong tolerance to high Zn concentrations”.
Transgenic Hemp Varieties for Phytoremediation
More recently, a Pakistani study published in 2015 identified several genes in hemp associated with tolerance of heavy metals including nickel, cadmium and copper. These results may assist in the development of transgenic hemp varieties with improved ability to uptake metals.
The use of genetically-modified hemp in phytoremediation projects may not be without precedent. In 2017, the University of Virginia announced a collaboration with a biotechnology company known as 22nd Century, which “has developed proprietary hemp plants that are particularly well-suited for use in phytoremediation”.
Phytotech, the biotechnology company involved with the Chernobyl company, used “specially selected and engineered plants”, although there appears to be little information available regarding the development of the hemp varieties used.
It is not clear whether these varieties were developed through marker-assisted breeding or are truly transgenic (involving the transfer of genes from one organism to another), or – in the latter case – what the potential implications of this would be.
How Can Hemp From Contaminated Soil Sites Be Safely Used?
In 2012, a Romanian study investigated the nutritional safety of hemp seed produced from plants grown in soils containing cadmium, magnesium, iron and various other metals. The study found that five distinct Romanian hemp strains developed different nutritional profiles according to uptake of the various metals in the soil.
Ominously, all varieties also tested above the safe legal limit for cadmium—despite the soil testing within the safe limit. Levels were particularly high in the Armanca and Silvana strains. Cadmium is a toxic heavy metal that can cause various serious health complications. Excessive dietary intake can lead to joint and bone deformities, respiratory illness, anaemia, and kidney failure.
However, in 2009 another Chinese study showed that cadmium concentration was 25-29.5 times higher in the roots of hemp compared to the shoots, “suggesting the plant can be classified as a Cd excluder”.
Thus, even if hemp used to remove cadmium from contaminated soil is unsafe for consumption, its fibre can still be useful for textile and construction applications. As well as this, hemp biomass can be used in a number of other industrial applications, such as for biofuel.
Hemp could benefit hundreds of thousands of contaminated sites
As a proven, valuable tool in the fight to repair human-inflicted damage to our soils and ecosystems, hemp could potentially benefit hundreds of thousands of sites across the globe. It is estimated that in the USA alone there are 30,000 sites requiring remediation.
For many years, US restrictions on hemp cultivation precluded any large-scale operations from being implemented. However, now that restrictions on hemp cultivation are lifting in many US states, this situation is changing.
The biotech company 22nd Century has stated: “Because there are more than 30,000 sites that require soil remediation in the United States alone, phytoremediation is expected to become a significant area of business for 22nd Century”.
We will continue to follow this topic and will issue more updates as soon as new information becomes available.
- Disclaimer:Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.
31 thoughts on “Hemp and the Decontamination of Radioactive Soil”
So is radioactive superweed impossible?
Too funny that hemp adobe building material used in extremely green homes uses magnesium as a “glue” or binder for its strength. I say grow the strain that takes up the most magnesium to kickstart what is added later? Ive been a hobby cannabis breeder for about 45 yrs now. Maybe the hemp protein I eat now is pulling out mercury from my 35 yrs of eating albacore tuna? hope so….
What happens to the hemp plants that are used to help decontaminate the soil around Chernobyl? I would tend to think that any radioactive elements will remain that way according to half life values whether in the soil, a plant, or in the air if the plant is burned as some sort of fuel, converted or not. Maybe the plant can be processed to put some of the scary genie back into a bottle to be stored on a shelf for a few thousand years. Still the problem of what do you do with the leftover plant products? Does anyone test for radioactivity in cannabis/hemp products for human use or consumption? And if so, what would be safe levels? There are places on earth where levels can be naturally higher than others, along with the messes mankind can be attributed to. Just another concern to add to heavy metals and other toxins.
Do anybody know which plants absorbs more iron from soil ?
Could you extract the radiation after the hemp has absorbed it and some how reuse the heavy metals and radioactive materials be repurposed some how? And would the plant material be at a safe level to compost?
The waste now is radioactive and the only current method research has come up with so far is spread it out evenly? Has science overlooked a natural means to contain and destroy this particular absorbent safely ? Can we send waste down VERY DEEP HOLES in the Earths crust? The technology to do so is available and there are some holes that already exist that go several miles down.
Enjoying all this great information
Hey, could you please cite your references and sources for this report?
Thank you for your comment. I’ve just checked through this article and all the links (in green) to sources are working, apart from the first one and the last one. I will contact Seshata, the author, and ask if she has additional sources that can be linked to instead. I hope this helps 🙂
With best wishes,
Yes this is something we are just starting to put together. I feel that one bio remediated product such as hemp could be remediated by mycoremediation. Exciting times! Unfortunately there is a lot of toxic soil out there. Most organic soil could be first remediated by hemp.
I also had such idea after the lecture of the article. Then fruiting bodies of fungi used could be safely send to disposal (much smaller volumes)
I’m working with my KS state rep to pass a hemp bill this session legalizing the plant.
How are plants used for phytoremediation disposed of? I assume they are not useable in any manner.
Thanks for the research. Very interesting artcle.
Excellent information. Why the big nations are not taking any initiative to reclaim the soil.? People are more worried about their personal gains than this. Soil contamination is a serious problem that too with radioactive materials.
I would lije to know whrre can i get seeds
i live plants any kind and love to grow them
I have serious doubt that any plant could effectively decontaminate a area highly radiactive.
Explanation: I do agree that plants have different absorption rate of different elements.
What must be understand is some Radiactive elements decay rapidly and loose their radioactivity in weeks , months and years dependant of their activity and molecular weight as example Radioactive Iodine decays fast in days and week but Plutonium takes 100 thousands of years to decay from dangerous level to more natural one. When a plant absorb a radioactive substance it maybe a low level one or a high level but in both case absorption does not change the rate of decay. An advantage is that plant could fixe into their cells the elements therefore in large quantity of plants the radioactive dust is not spreading elsewhere/everywhere.
Thats great news, it seems to be a versatile plant that can do good.
two questions come up for me, and I’m more just throwing them out there instead of looking for answers.
1. Could repeated remediations spread and diffuse heavy metal levels until they are balanced and under toxicity threshold levels? for example, planting in a toxic area, using the biomass produced for compost fodder or wormery feed, then re-planting until the metals are dispersed over a less concentrated area?
2. There was some mention about toxic ash from burning, but would you have the same results from pyrolysis (gasification)? Would heavy metals transfer to syngas, or would they stay with the bio char, and thus once again be used as an additive to diffuse the metals in small amounts into non-toxic soils?
3. I also saw mention of stamets and mycoremediation. Perhaps use hemp to isolate metals from the soil into biomass, then mushrooms to further process them until either more stable or uniformly distributed?
My interests would specifically be in bio-remediation of fly ash in desert conditions. It would be helpful for presenting to the local college’s agroforestry branch as a project.
Where do the radioactive plants go once they’ve absorbed the radio nucleotides? Another
potential problem? In a debate: hemp deactivates radiation. I say hogwash.
I have also wondered about the accumulation of heavy metals during the bio-remediation process. Have there been any experiments attempted? Conceptually, much could be learned using spectrum analysis processes. There is also the possibility of re-processing as a bio-fuel. Would the metals break down further under combustion or would they remain as airborne contaminants? Much science to be accomplished here.
Excellent article, BTW.
I don’t understand why this information isn’t more available.
I have researched some things online about hemp and cancer killing properties and it got me to thinking about the rise in the legalization of Marijuana in some states and the growing of hemp threw the farm bill soon after the fukushima incident call me crazy but I really think there may be a connection here
Working partly in the field of functional medicine it is sometimes demonstrated through Hair Tissue Mineral Analysis that people who are keen on hemp in all its forms jave high levels of heavy metals such as Cadmium, Uranium, Arsenic and Lead and possibly other metsls as well. This may imply that those manufacturers involved in hemp produce have poor control of the soil conditions where the hemp used for human consumption and clothing is being cultivated. Does anyone know of certification labels setting the standards for hemp produce low in heavy mrtals? We have to remember that some soils may naturally be high in heavy metals, or various natural soil improvement rock products. So simply avoiding industrially polluted soils will not guarantee that hemp (very often) labelled as organic or environmental friendly, will have acceptable levels of heavy metals.
Hey, this is interesting, thank you for bringing it to my attention. I will have to look into the existing guidelines, I haven’t come across anything regarding levels of heavy metals in soil yet but there could be some non-specific guidelines that still apply. These results of the Hair Tissue analysis – are they available to source online in any form, or could you make them available?
This is great information and it suprises me that legislation is preventing the clean up in Japan as that is an environmental disaster according to some intelligent physicists. Has anyone done any research on what happens when you burn the hemp in bio diesel? Wouldn’t the chemicals the plants absorb in the ground cause these metals to be released into the air? I am not a scientist and hope I don’t sound ignorant on the subject. The reason for my questions is that I am interested in cleaning up a large piece of ground I have from high levels of arsenic from farming. Thanks in advance for responding:)
Hi Joey, apologies for the delay in responding. Disposal of accumulator plants is a tricky issue, and if levels of heavy metals are beyond a certain threshold they are considered toxic waste and must be disposed of accordingly. How this applies to hemp has not been ascertained, as far as I’m aware, although I will update if I find anything specific to it. This article (http://www.energyjustice.net/biomass/phyto) has some interesting links to further reading.
I am founder of Kentucky Hemp Industries and am looking for scientific data/studies on hemp utilized for phytoremediation. Any assistance will be gratefully received.
Hello Moseley, thank you for your comment.
It is possible that articles on the Hemp Industries Association website might be useful for you (www.thehia.org) and the Hemp Cleans initiative was also doing research into phytoremediation last year (hempcleans.com). If we find any studies dedicated to this, I will get in touch again. Good luck with Kentucky Hemp Industries, more power to your elbow! With best wishes, Scarlet
Mr Putney the local team is working on StLouis nuclear decontamination of the old Manhattan Project Nuclear waste burried in a landfill (Westlake and Bridgeton) as well as along the Cold Water Creek areas. see: blog.mohempenergy.org for pot testing info and future plans.
Does that mean radioactive superweed is impossible?
I have some information if you didn’t already find it.
Excellent article Seshata! Paired with Paul Stamets use of fungi as a bio-remediation tool, this looks to be an excellent way to teach stewardship of our land and resolve the mistakes we have made as a species so far. Thanks for the research!