Why Consumers Should Learn About Hemp Phytoremediation

large hemp farm

The plant, cannabis sativa, is one of the most useful and versatile plants known to man. When grown in ideal conditions, provided plenty of nutrients, and nurtured by humans, cannabis sativa produces tons of chemical compounds. We typically refer to this version of the plant as cannabis, marijuana, ganja, or any of the other hundreds of slang names used for the herb throughout history.

On the other hand, when grown as a field crop, planted and harvested by farming equipment, the plant is commonly referred to as hemp. Although the hemp variety of cannabis sativa produces lesser quantities of the medicinal compounds found in the plant, the plant itself is a renewable resource which provides raw materials for a plethora of everyday products like fabrics, food (hemp seeds and hemp hearts), plastics, and basically anything that is petroleum-based, including fuels.

However, although hemp has the ability to create all of these physical products after harvesting, hemp also performs a vital service to the environment while it’s growing. Phytoremediation is a biological process performed by many different botanical species. Some researchers are looking to hemp phytoremediation with high expectations for the future of our environment.

Unfortunately, this natural process, while beneficial for the environment, may not be as helpful for the production of dietary supplements or any products intended for human consumption. To understand the good, and the bad, of hemp phytoremediation, let's start with a science lesson.

Hemp Phytoremediation 101

small hemp plant in soil, ready to perform hemp phytoremediation

Phytoremediation is a process in which plants absorb toxins and heavy metals from the soil, air, and water around them. Simply stated, plants are like a sponge to Mother Nature, and she uses them to clean up natural toxins, as well as, the messes humans leave behind. There are several ways this happens:

  • Phytoaccumulation: As plant roots absorb the water and nutrients they need to survive, they also absorb contaminants, storing them in their shoots and leaves. If you've ever put a white carnation in colored water and watched the flower change colors, this is a rudimentary visualization of phytoaccumulation. Hemp and other botanicals readily absorb toxic metals such as lead, cadmium, nickel, zinc and even arsenic and accumulated within the plant.
  • Phytovolatilization: In this process, the plants absorb organic contaminants, but rather than storing them like metals, the pollutants actually get released through the plant's leaves.
  • Phytodegradation: Some contaminants meet their doom once absorbed by a plant. Through phytodegradation, the plant not only consumes the pollutants, but the plant metabolizes and destroys the chemical within its tissue, eliminating it altogether.

How Phytoremediation is Used

hemp plants

While phytoremediation is a naturally occurring process in nature, environmentalists are taking advantage of the plant's ability to clean a wide variety of substances from the soil, water, and air including:

  • Metals
  • Radioactive Elements
  • Pesticides
  • Explosives
  • Fuels
  • Volatile and Semi-Volatile Organic Compounds

For example, last year, farmers in Italy made international headlines for using hemp to remove toxic levels of dioxin from a sheep farm. Contaminants from a nearby steel plant polluted the farm so severely; the rancher had to put down the entire herd. With serious doubts about any future livestock, the farmer decided to plant industrial hemp as a means to decontaminate the soil.

Likewise, hemp is also well-known for being used at the 1986 Chernobyl nuclear disaster site in an effort to remove strontium and cesium, two radioactive elements, from the ground. An article from the New Scientist in 1999 states that after researchers harvested the plants, they found the plant remains were rich in cesium.

Why Hemp is Perfect

lots of hemp growing outside

Cannabis sativa species of plants are a hyperaccumulator for chemicals such as lead, cadmium, magnesium, copper, chromium, and cobalt which are commonly released into the environment through smelting, sewage sludge, and vehicle emissions. The fibers within the plant are not negatively impacted by the accumulation of chemicals, and industrial hemp also doesn't need the same resources or nutrients, making it a less expensive cleanup option. Additionally, the typical cannabis sativa plant grows to maturity within 8-12 weeks, much less time than other bio-accumulators.

Depending on the type of contaminant absorbed by the plant, after harvest, the plant material can be incinerated in a closed system, or if deemed safe, it could still be used for fiber or fuel production.

Soil Contamination in the US

holding contaminated soil

Before things like pesticides, herbicides, fungicides, and other toxic products became commonplace, the Earth's soils were organic and unadulterated. While some contaminants are naturally occurring, these products have caused toxins to exceed the safe levels in many areas of the country. As such, humans are exceedingly exposed to soil contaminants in various ways:

  • Ingestion – while some women commonly report craving dirt during pregnancy, most of us are not deliberating eating dirt. However, children frequently play in the dirt and mud and likely consume more than you realize. Additionally, not properly washing fruits and vegetables before eating them can happen without your knowledge, especially if you eat out frequently.
  • Inhalation – if you've ever experienced a dust storm, you likely inhaled dirt particles into your nose and lungs. In addition to inhaling the dust, you're also inhaling the contaminants. Likewise, if you're burning and inhaling contaminated plant material, you're inhaling the pollutants within it.
  • Absorption – just as we absorb cannabinoids through the skin using various topicals and lotions, we can also absorb other chemical agents through the skin as well.
  • Phytoremediation – cannabis sativa is not the only plant that absorbs toxins from the soil, many vegetables and herbs also perform this miraculous process. Unfortunately, eating vegetables grown in toxic soil can put you at risk.

While minimal exposure to these toxins isn't harmful, repeated and prolonged exposure can cause serious health issues. Unfortunately, the prevalence of soil contamination in the United States is astronomical. Industrial and manufacturing sites, landfills and toxic dump sites, and the overuse of pesticides and herbicides in farming practices, all contribute to the increasing number of pollutants exposed to humans on a daily basis.

Not Safe for Consumption

cultivating hemp

Clearly, hemp phytoremediation could prove to be a significant benefit for the environment, but it may also prove to be extremely detrimental for humans. Consuming plants grown in toxic soil and water means consumers also consume the potentially harmful contaminants absorbed by the plant as well. In fact, many theorize the process of phytoremediation may be the reason the FDA still has concerns about hemp-derived cannabidiol products and dietary supplements.

Tobacco Industry Lessons

growing tobacco plants outside with a pretty sunset

As Americans, thanks to mandated tobacco education programs, we know and understand that tobacco contains thousands of harmful substances, including at least 70 known carcinogens, but how do you think most of the contaminants got there? Poor farming practices, including overuse of pesticides and herbicides, are a likely culprit.

Now, consider all the southern states, such as Kentucky, who are looking to hemp to save the economy the tobacco industry is losing. Farming hemp where once toxic tobacco operations took place may not be in the best interest of the consumer. Although using the raw plant material to make building materials, plastics and biofuels may still be viable; many hemp producers are growing hemp to produce CBD products for human and pet consumption.

Likewise, should other farmers in agricultural-heavy states in the Midwest decide to jump into the market to get their own little piece of the green rush, hemp-derived extracts could be deadly. Knowing what we know about hemp phytoremediation, plants cultivated and harvested from the same, contaminated soils where tobacco and other agriculture crops were once grown, are not as safe as a dietary supplement.

In fact, agricultural contamination is turning up in some very troubling places and could be foreshadowing potential problems within the hemp sector.

I'll Have the Cheerios, Hold the Glyphosate, Please

bowl of cheerios

As one of the first solid foods most American children are introduced to during infancy, Cheerios have been a pantry staple in the majority of households for decades. Yet, new studies reveal this beloved, and presumably healthy, oat-based cereal contains significant levels of glyphosate, a deadly carcinogen found in Round-Up, a common agricultural and household herbicide. Come to find out, not only is the chemical used during the cultivation process but just before harvest, oats are resprayed with the liquid as a drying agent to make harvest easier and less expensive.

Although the amount of glyphosate found in most food products is below what the EPA declares "safe" – the question becomes, is it safe if you consume the products daily? Almost every diaper bag in America includes a little plastic container of Cheerios. Is glyphosate a substance which we want to feed to our babies in any quantity?

Similarly, hemp and cannabis harvests from fields where farmers historically used Round-Up or other similar chemicals will produce contaminated products. As many people turn to the herb, especially oils, tinctures, and concentrates, consuming a contaminated product could do the consumer more harm than good.

Cannabis Concentrate Conundrum

cannabis shatter in a pile

Cannabis extracts are also commonly called concentrates because it concentrates the cannabinoids from the plant material into a much smaller footprint. In a study in the Journal of Toxicological Sciences, researchers tested 57 samples from California's medical marijuana market and found approximately 80 percent of the cannabis concentrates also contained concentrated contaminants as well. While some of the chemical pollutants were residual solvents from the extraction process, other chemicals found in the extracts include pesticides and chemicals used during cultivation.

In an oversimplification, if you have an ounce of cannabis which contains 100 molecules of cannabinoids and 50 particles of a contaminant, the oil extracted from that cannabis will have a similar ratio of components, but condensed into about 4 grams of consumable product.

Regulations to the Rescue

hemp seeds and a hemp flower

Understanding how phytoremediation allows hemp to pull toxins from the soil and store them in its leaves gives us better insight as to why cultivation regulations are so relevant. Additionally, it highlights why the federal authorities may have a valid reason for creating new rules for the newly legal industrial hemp industry. And, while many tobacco, corn, or soybean farmers may want to snag their piece of the market, doing so ethically and responsibly requires a more in-depth look into the toxicity level of the soil.

Just as many growers in the legal cannabis industry go out of their way to grow clean cannabis, hemp producers may need to move their crop inside if they intend to produce consumable products such as nutraceuticals or dietary supplements. Maintaining organic soils and pest management processes is critical for protecting the quality and safety of cannabis or hemp-derived supplements. Going one step further, most well-respected cannabis grow operations even filter their water using reverse osmosis to eliminate any contamination from the original water source.

Education for All

While no one enjoys excessive rules and regulations, we can certainly understand the necessity for them when they protect certain fundamentals like preserving human life or preventing death and disease. Living in an era where data and information are as close as our fingertips, it's essential for cannabis producers and consumers alike to understand the importance of the science behind hemp phytoremediation.

By understanding the science of hemp phytoremediation, producers can take the necessary steps to ensure their crops stay contaminant-free and safe for human consumption. Likewise, by understanding how phytoremediation has the potential to make cannabis and hemp products harmful, consumers learn the importance in the transparency of batch testing results and knowing how and where their cannabis is grown. Finally, by staying educated about all aspects of the plant, we begin to understand the importance of clean, legal cannabis cultivation and processing operations to help the industry gain legitimacy and acceptance.

Above all, we must question, why do we need regulations from the FDA to put product safety above net profits? In an industry built on the benefits of cannabis sativa, producers shouldn't lose focus on what matters most... helping consumers, not harming them.


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Kristina Etter
Through an educated and responsible approach to cannabis, Kristina Etter and her husband restored their health, saved their marriage, and changed their lives. Now, as a cannabis writer, she strives to end stigmas and increase awareness of using the herb for health and wellness.