While debate over the legalization of marijuana continues, states that have legalized the plant for recreational and medical use are facing a challenge that may have been overlooked. Most farmers use federally approved pesticides to help control bugs and mold, but marijuana, while legal in some states, has no oversight by the Federal government. This means that no one is regulating what pesticides can be used to keep bugs away and prevent other damage to the crops. Nonetheless, the crops are valuable, and to protect their investment, many growers have started to use chemicals, which may or may not be safe for the plant or consumers.
Earlier this year, officials in Denver placed a hold on tens of thousands of cannabis plants because of safety concerns for the pesticides used by the farmers. According to recent post on NPR.org, “Colorado doesn't require growers to test the crop for traces of pesticides before being sold, though state agriculture officials did recently release a list of pesticides deemed appropriate for use on cannabis. Washington State, Nevada and Illinois have similar lists.[i]
Experts believe that regulators are simply playing catch-up, and until they do, many people are just turning to whatever works. As far back as 2012, when marijuana became legal in Washington State, growers and distributors were concerned about chemicals in cannabis that could threaten the health of users.
“Many of the chemicals applied to pot plants are intended only for lawns and other non-edibles. Medical cannabis samples collected in Los Angeles have been found to contain pesticide residues at levels 1600 times the legal digestible amount.
“Because the product is generally inhaled rather than eaten, any toxins it carries have an even more direct route into the lungs and blood stream… the situation is all the more concerning for patients smoking medical cannabis, whose health problems could make them more vulnerable to the risks pesticide exposure brings -- especially if they suffer from a liver disease.”[ii]
A research study published in the Journal of Toxicology found that recoveries of residues of pesticides were “as high as 69.5% depending on the device used and the component investigated, suggesting that the potential of pesticide and chemical residue exposures to cannabis users is substantial and may pose a significant toxicological threat in the absence of adequate regulatory frameworks.”[iii]
The study evaluated three different smoking devices and investigated three different pesticides, bifenthrin, diazinon, and permethrin, as well as the plant growth regulator paclobutrazol. “Smoke generated from the smoking devices was condensed in tandem chilled gas traps and analyzed with gas chromatography-mass spectrometry (GC-MS)”
The study found that “chemical residues present on cannabis will directly transfer into the mainstream smoke and ultimately the end user.”[iv]
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[i] http://tpr.org/post/growing-concern-over-unregulated-pesticide-use-among-marijuana-growers
[ii] http://www.huffingtonpost.com/2013/05/24/marijuana-pesticides-contamination_n_3328122.html
[iii] http://www.hindawi.com/journals/jt/2013/378168/
[iv] ibid