Despite recent approval of pharmaceutical-grade cannabis products for the treatment of childhood epilepsy, some families continue to use artisanal cannabis products as a way to manage seizures in their children. However, such products are typically of unknown composition and quality, and may therefore pose an unpredictable health risk to the child. In the present analysis, 78 samples of cannabis products collected (as part of a previous study) from families of children with epilepsy (average age 8.8 ± 4.6 years) were analyzed for heavy metals (arsenic, cadmium, lead, and mercury), residual solvents (panel of 19 solvents) and pesticides (panel of 57 pesticides).

Due to small sample volumes obtained, only a subset of samples was used in each analysis. Results showed that no cannabis sample exceeded the toxicity limits for heavy metals (n = 51 samples tested). Of the 58 cannabis samples tested for residual solvents, 17 (29%) contained concentrations of ethanol or isopropanol above the generally accepted limit of 5000 parts per million. With the volumes consumed, it was thought unlikely that children were consuming hazardous amounts of residual solvents, although this could not be ruled out in every case. Most samples (n = 31 samples tested) yielded inconclusive results for the pesticides, although one sample contained concentrations of bifenthrin that were 4.9 times higher than the acceptable limit. Overall, these results highlight the need for improved access to quality-assured cannabis products and the education of doctors, patients, and artisanal manufacturers around the contaminant exposure risk in unregulated cannabis products.