Trashed and excreted cannabinoids may act as pollutants when they enter the water system. Learn more about how the problem of cannabinoid pollutants could be tackled. We discuss the following:
There are an estimated 192 million cannabis users worldwide. As such, they generate a number of different types of waste products, including trash waste and body waste. Additionally, cannabinoids may enter the environment by rain, harvest, and trashed cannabis straw and trashed cannabis products. Obviously, all this waste gets into the environment, more specifically into natural waters primarily by means of raw of treated wastewater.
Cannabinoids easily break down when they enter water systems. Indeed, the urinary metabolite of THC shows up as a pollutant in both untreated and treated wastewaters, source waters, and tap waters. Scientist assume that given the popularity of cannabidiol (CBD) products and the increased legalization of medical marijuana, the amount of cannabis compounds released into the environment will also increase.
The limited amount of research that has now surfaced shows that cannabis products broken down in the environment do act as pollutants and affect the ecosystem. For example, cannabis breakdown products might lead to acute and chronic toxicity and produce complex effects on animal behavior.
Freshwater mollusks and snails exhibit a considerable imbalance in the activity of their antioxidant enzymes when exposed to cannabinoid water pollutants. Moreover, zebrafish that are exposed to THC in amounts as small as 30-50 mg/L show behavioral changes, including slowed down movement (hypolocomotion). However, scientists know little about what lethal the doses of cannabis breakdown compounds are, and what the effects of those doses are that are not lethal.
Traditional wastewater studies have usually excluded cannabis metabolites from their analyses. The reason is because methods to assess cannabinoids in natural waters is still in their infancy and therefore difficult to accomplish. This is important because fresh drinking water is becoming progressively scarce. Therefore, communities increasingly rely on treated wastewaters.
Studies now increasingly look at the presence of cannabinoid metabolites in water. For example, the body breaks down THC into THC-COOH (11-nor-9-carboxy-Δ9-tetrahydrocannabinol), which might show up in treated and untreated wastewaters at a concentration as high as almost 3,000 ng/L. This suggests that existing water treatment plans have the ability to only partly eliminate THC-CCOH.
CBD, on the other hand, does not break down in the blood, and therefore leaves the body unchanged. As a matter of fact, scientists detected CBD in 80% of sewage sludges, in a concentration of 168 ng/g. This is very disconcerting, because the measured CBD pollutant concentration is higher than the measured concentration of THC in the sludge.
One traditional and commonly used way to treat water is by halogenation (adding halogens, such as fluoride, chlorine, bromine, and iodine to the water to get rid of bacteria and other microbes). However, halogenated byproducts, especially the brominated or iodinated kinds, are highly toxic. This is especially true to the halogenated byproducts of cannabinoids.
As a matter of fact, both THC and THC-COOH readily transform into halogenated byproducts in water treatment facilities within seconds. However, when scientists decreased the concentration of chlorine from 10 mg/L to only 1 mg/L, the half-life of THC-COOH decreased to 2 seconds.
Interestingly though, when natural organic matter was present in the wastewater (or in natural waters), cannabinoid chlorination was much slower. Undoubtedly, scientists have shown that when organic matter is present, the halogenation of cannabinoids follows a multistep, complicated and therefore slow process.
In essence, it is important to keep in mind the combination of:
There has been an increased use of cannabinoids resulting from an increase in the popularity of CBD, edible hemp products, medical marijuana, and cannabis medications. Fundamentally, more cannabinoids than before are released as pollutants into the environment, including the water systems.
Most current water treatment systems operate with halogenation. Therefore, researchers and public health professionals and authorities need to keep in mind how these cannabinoids change into potentially poisonous and toxic pollutants. As such, we will know how we can protect the environment from them. As such, current water treatment systems might be outdated to deal with contemporary situations, such as the popularity of cannabis compounds.
Apul OG, Rowles LS 3rd, Khalid A, Karanfil T, Richardson SD, Saleh NB. Transformation potential of cannabinoids during their passage through engineered water treatment systems: A perspective. Environ Int. 2020 Feb 18;137:105586.