In the past decade, cannabis – the popular smoke-able drug also known as pot, green, and of course, weed – has been legalized in many US states. At present, thirty-eight of the fifty states have legalized this drug for medical use, and twenty-four have legalized it for recreational use, including California, Washington, and New York. This means that in these places, users can legally purchase cannabis from stores and use it to responsibly relax and enjoy themselves in a similar way to alcohol.
Unlike alcohol, whose side effects include lowered inhibitions, a flushed face, and feeling sociable, cannabis can have much less pronounced side effects, including forgetfulness, laughter, and pain relief throughout the body. However, recent reports have found that some users of weed in the United States are experiencing side effects not associated with the cannabis plant itself. These worrisome effects have been linked to the pesticides used to grow the marijuana plants sold legally in the United States.[1]
Understanding what these chemicals are and how they can affect your body is crucial to knowing what is normal when using cannabis products so that you can stay safe and healthy.
Understanding Cannabis as a Weed
As a slang term, weed is very well suited to describe cannabis: unlike other popular recreational drugs such as cocaine and MDMA, cannabis is not a human-made substance, but rather is a plant that naturally grows around the globe. As an invasive, broad-leafed green species, it can take over otherwise cultivated and less robust plants when it has access to proper sunlight, well-drained and nitrogen-rich soils, warmth, and plenty of moisture in the surrounding air. In other words, in some places around the world, it acts like a common garden weed.
Research shows that this weed is commonly found in parts of Southern Europe as well as broadly across Southeast Asia and in some parts of the Middle East. However, since humans have cultivated cannabis for nearly as long as our existence on the planet, the plant has been transported and introduced in many environments to which it is not native and where it grows less efficiently.[2] In these environments, promoting its growth has become concerning, particularly in recent decades, since its popularity as a smoke-able or ingestable recreational drug has skyrocketed across the United States. Consequently, it has become a cash crop and, like other plants that we grow to make money, is therefore often treated with chemicals to help it grow as efficiently as possible.
Modern Pesticide Use: Health Impacts
Chemicals that are used specifically to grow cash crops are known as pesticides, and they have harmful environmental impacts and health effects. The many different varieties of pesticides available for different growing purposes are ubiquitous across our modern agricultural practices. A study from 1995 showed that a shocking 100% of adults living in the United States had some amount of pesticide residue in their urine.[3] This is why we are advised to wash our fruits and vegetables carefully before we eat.
Not all pesticides are harmful, but many can have adverse effects and even be extremely dangerous to humans who consume them. While many of these more dangerous pesticides are strictly regulated around the world, the United States has been reported to lag far behind other nations in banning harmful chemicals in agriculture – 72 pesticides which have been made illegal in the EU are still in common use in the United States. Even Brazil and China have banned a handful of extremely dangerous pesticides that the United States continues to use to encourage crop growth and manage environments.[4]
Pesticides present a severe danger to users of cannabis in states where it is illegal, as farms where the plant is grown are unregulated and therefore much more likely to use dangerous chemicals in a bid to grow plants quickly, often in cramped environments where the plant would not naturally thrive. However, even where cannabis is legal to use and where growing operations are regulated, the use of dangerous pesticides can have an adverse effect on users. It is not as easy to wash a bag of legally-acquired dried cannabis as it is a tomato from the shop.
Recently, a report in California showed that over half of the legal cannabis products purchased in the state showed dangerously high concentrations of pesticides and that the cannabis products which presented the highest risk to users were vapes. The side effects of these harmful chemicals can include:
- Dizziness
- Nausea
- Memory loss
- Diarrhea
- Headaches
- Rashes
- Liver failure
- Increased risk of cancer
Understanding the risks of ingesting even legal cannabis products can help you stay safe and healthy. One of the key factors is the amount consumed: like the pesticides from our foods, a small amount is not likely to cause much harm, but consuming too many pesticides can be dangerous. While cannabis use is not inherently bad, being aware of the risks of consuming too much or using it in the wrong circumstances is key to staying healthy and well.
[1] Reinl, J. (2024) That dizzy feeling isn’t the weed – Chinese pesticides used on pot farms linked to nausea, memory loss and even cancer. Daily Mail. https://www.dailymail.co.uk/health/article-13543437/weed-Chinese-pesticides-grow-pot-nausea-memory-California-cancer.html
[2] Rull, V. (2022) Origin, early expansion, domestication and anthropogenic diffusion of Cannabis, with emphasis on Europe and the Iberian Peninsula. Perspectives in Plant Ecology, Evolution, and Systematics. V 55. June 2022. https://doi.org/10.1016/j.ppees.2022.125670.
[3] Hill, R.H. et al. (1995) Pesticide Residues in Urine of Adults Living in the United States: Reference Range Concentrations. Environmental Research, 71:2. https://doi.org/10.1006/enrs.1995.1071
[3] Donley, N. The USA lags behind other agricultural nations in banning harmful pesticides. Environ Health 18, 44 (2019). https://doi.org/10.1186/s12940-019-0488-0
