The rapid growth of inhalable cannabis concentrates raises questions about the safety of acute and chronic exposure to these aerosol mixtures. Due to the nonpolar nature of the aerosol mixture created from cannabis vapor cartridges, traditional aqueous-based capture methods used in e-cigarette or tobacco cigarette studies for analysis of metals are insufficient. Moreover, hydrophobic cannabis concentrates are not miscible with dilute aqueous acids and therefore not ideal for metal spiking unlike electronic nicotine delivery systems. This study describes a method of spiking nonaqueous matrices with aqueous metals standards to investigate aerosolization and recovery of the metals. It also compares various methods for nonpolar aerosol capture and subsequent analysis of 10 metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Sn) in two model cannabis matrices, flower and concentrate. Spiked cannabis concentrates were vaped in commercially available cartridges, and their aerosol mixtures were investigated for recovery of heavy metals via ICP-MS. Spiked flower samples were also combusted to compare collection rates of the 10 metals. Results show that not all metals that are present in the concentrate or flower can be fully recovered in the aerosol capture processes at standard voltage settings or combustion temperatures. These studies also demonstrate the importance of a nonpolar solvent as part of the aerosol collection to increase the recovery of some metals. The high concentration of some metals seen in the concentrate suggests that the devices themselves are potential routes of exposure. The ICP-MS analysis method was further validated by evaluating different parameters including linearity, matrix effect, limit of detection, limit of quantitation, and repeatability.
In recent years, cannabis vaporizer cartridges have increased in popularity and availability, and there are concerns regarding exposure to heavymetal compounds from their use. The physical components of the cartridge devices themselves have been implicated as a potential source of metal exposure, but it is not known if these metals migrate into the inhalable vapor. This study analyzes the components of vaporizer cartridges for 10 different metals and also collects aerosol mixtures from 13 randomly purchased commercially available cannabis cartridges from Washington State to compare their elemental profiles. Results indicate that chromium, copper, nickel, as well as smaller amounts of lead, manganese, and tin migrate into the cannabis oil and inhaled vapor phase, resulting in a possible acute intake of an amount of inhaled metals above the regulatory standard of multiple governmental bodies. Noncartridge heating methods of cannabis flower and concentrate were compared, and results indicate that the heating device itself is a source of metal contamination. As safety and compliance testing regulations evolve, it will be important to include more than the standard As, Cd, Hg, and Pb to the list of regulated metals.
Background
Cannabis species have a propensity to bioaccumulate toxic heavy metals from their growth media. Increased testing for these metals is required to improve the safety of the legal medical and recreational cannabis industries. However, the current methods used for mandated heavy metals tests are not efficient for a large framework. As a result, there is limited testing capacity, high testing costs, and long wait times for results across North America.
Objective
This study aimed to demonstrate that pooling strategies can be used to increase the throughput in cannabis testing labs and reduce some of the strain on the industry.
Methods
This paper presents an algorithm to simulate different pooling strategies. The algorithm was applied to real world data sets collected from Washington and California state testing labs.
Results
Using a single pooling method, a pool size of three samples on average resulted in a 23.8% reduction in tests required for 100 samples for the Washington lab. For the California lab, pooling four samples on average resulted in a 54.1% reduction in tests required for 100 samples.
Conclusion
The algorithms generated from the Washington and California lab data demonstrated that pooled testing strategies can be developed on a case-by-case method to reduce the time, effort, and costs associated with heavy metals tests.
Highlights
The benefits of pooled testing will vary depending on the region and rate of contamination seen in each testing lab. Overall, our results demonstrate pooled testing has the potential to reduce the fiscal costs of testing through increased efficiency, allowing increased testing, leading to greater safety.
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