Pesticides in cannabis: A review of analytical and toxicological considerations

An initial exploration of machine learning for establishing associations between genetic markers and THC levels in Cannabis sativa samples

Cannabis sativa, a globally commercialized plant used for medicinal, food, fiber production, and recreation, necessitates effective identification to distinguish legal and illegal varieties in forensic contexts. This research utilizes multivariate statistical models and Machine Learning approaches to establish correlations between specific genotypes and tetrahydrocannabinol (Δ9-THC) content (%) in C. sativa samples. 132 cannabis leaves samples were obtained from legal growers in Piedmont, Italy, and illegal drug seizures in Turin. Samples were genetically profiled using a 13-loci STR multiplex and their Δ9-THC content was detected through quantitative GC-MS analysis. This study aims to assess the use of supervised classification modelling on genetic data to distinguish cannabis samples into legal and illegal categories, revealing distinct clusters characterized by unique allele profiles and THC content. t-distributed Stochastic Neighbor Embedding (t-SNE), Random Forest (RF) and Partial Least Squares Regression (PLS-R) were executed for the machine learning modelling. All the tested models resulted effective discriminating between legal samples and illegal. Although further validation is necessary, this study presents a novel forensic investigative approach, potentially aiding law enforcement in significant marijuana seizures or tracking illicit drug trafficking routes.

Cannabis use in Parkinson's disease: Patient access to medical cannabis and physician perspective on product safety

The rate of medical cannabis use has increased in parallel with the number of states legalizing its use. Parkinson's disease (PD) patients are of particular concern due to their higher cannabis use rate than in the general US population (25-40 % PD patient cannabis users vs. ∼18 % in the general population), as well as their susceptibility to environmental contaminants in cannabis, including pesticides, toxic elements, solvents, microbes, and mycotoxins. In order to address the complex nature of this industry, we examined the changes in PD-related qualifying conditions in the U.S. from 2019 to 2023. We also conducted an online survey to gain insight into the knowledge, risk perceptions, and opinions regarding medical cannabis and contamination issues from physicians who treated PD patients. The number of states including PD-related qualifying conditions increased over the past 5 years from 28 to 36 states. These conditions included PD (increasing from 14 to 16 states), muscle spasms (14 to 24), anxiety (1 to 5), and pain (17 to 35). State-by-state comparisons revealed high variability in the language used to describe the different qualifying conditions. Online surveys were sent out to 45 neurologists and movement disorder specialists who primarily treated PD patients. The response rate was 44 % from nine states (AZ, CA, FL, MA, MN, WI, PA, IL, and NM). When asked if they were aware of any contaminants in cannabis products, we found that 65 % of the physicians were unaware of any contaminants commonly found in cannabis and only 25 %, 15 %, and 15 % of them were aware of pesticide, toxic element, and solvent contaminants, respectively. In their free-text opinion response on the health impact of cannabis-borne contaminants, "long-term effect" (35 %) and "comorbidities and PD prognosis" (40 %) were identified as the two most common themes. These results point to the need for further regulatory deliberation regarding risks and susceptibility to cannabis contaminants. Additionally, education is needed to inform physicians on cannabis safety issues. Further research will identify the implementation strategies to reduce contaminant exposure and protect patient health.

Direct extraction with acetonitrile of hemp seed oil for the analysis of pesticides by using comprehensive two-dimensional gas chromatography-triple quadrupole mass spectrometry

The method herein described involves a rapid and limited-volume (0.5 mL of acetonitrile) solvent-extraction sample preparation process, for pesticide determination in hemp seed oil. The extraction method was characterized by the absence of both clean-up or pre-concentration steps. The extracts were directly analyzed through cryogenic-modulation comprehensive two-dimensional gas chromatography coupled to triple quadrupole mass spectrometry. The novelty characterizing the present research [compared to a previous one (Arena et al., 2023)] is related to the extension of the number of pesticides (97), and to the investigation of a more challenging matrix, contained in a vegetable oil of increasing interest among consumers. Linearity, limits of detection and quantification, accuracy, precision, recovery, and matrix effect were measured. Particular emphasis was devoted to the matrix effect, with the co-extracted matrix amount defined. Three international regulations (Canada, California, Europe) were considered, and the obtained limits of quantification were found to be too high in five (Canada) and twelve (Europe) cases, for a total number of 15 pesticides. The analysis of ten commercial samples showed the presence of seven pesticide residues in four of them, at concentration levels ranging from 0.02 to 0.98 mg kg-1, with most over the regulation residue limits.

Reasonable access: important characteristics and perceived quality of legal and illegal sources of cannabis for medical purposes in Canada

BACKGROUND

Throughout the past two decades of legal medical cannabis in Canada, individuals have experienced challenges related to accessing legal sources of cannabis for medical purposes. The objective of our study was to examine the sources of cannabis accessed by individuals authorized to use medical cannabis and to identify possible reasons for their use of illegal sources.

METHODS

Individuals who participated in the Cannabis Access Regulations Study (CANARY), a national cross-sectional survey launched in 2014, and indicated they were currently authorized to use cannabis for medical purposes in Canada were included in this study. We assessed differences between participants accessing cannabis from only legal sources versus from illegal sources in relation to sociodemographic characteristics, health-related factors, and characteristics of medical cannabis they considered important. A secondary analysis assessed differences in satisfaction with various dimensions of cannabis products and services provided by legal versus illegal sources.

RESULTS

Half of the 237 study participants accessed cannabis from illegal sources. Individuals accessing cannabis from illegal sources were significantly more likely to value pesticide-free products, access to a variety of strains, ability to select strain and dosage, ability to observe and smell cannabis, availability in a dispensary, and availability in small quantities than did individuals accessing cannabis from only legal sources (all p < 0.05). Additionally, participants gave significantly higher satisfaction scores to illegal sources than to legal sources on service-related dimensions of cannabis access (all p < 0.05).

CONCLUSION

Our findings contribute to an understanding of reasonable access to medical cannabis from a patient perspective and how to assess whether it has been achieved. Characteristics of cannabis products and services valued by patients and appropriate to their needs should be incorporated into legal medical cannabis programs to promote the use of legal medical sources. While pertaining specifically to medical use of cannabis in Canada, the findings of this study may also be instructive for understanding the use of illegal cannabis sources for non-medical purposes in Canada and provide insight for other jurisdictions implementing cannabis regulations for both medical and non-medical purposes.

Controlled environments for cannabis cultivation to support "omics" research studies and production

The cannabis (Cannabis sativa L.) genome is highly heterozygous and, to retain genetic identity, clonal propagation of cultivars is very common. Establishing controlled environments, often involving multiple locations throughout a single grow, is critical for reliably generating materials to be used in research and production. In this article, we break down different periods of the grow cycle, such as cloning, hardening (optional), vegetative growth, flowering growth, and harvest, into individual steps. We are including images and videos for an in-depth coverage of methodological details. We are providing a list of equipment, supplies, reagents, and other resources to help with planning a grow experiment. Finally, we are discussing considerations for different aspects of controlled environments, including lighting, fertilizer regimes, and integrated pest management. With this article, it is our goal to empower researchers to reliably generate disease-free cannabis material suitable for genetic and biochemical studies that require full control of environmental factors.

Comparison of State-Level Regulations for Cannabis Contaminants and Implications for Public Health

BACKGROUND

The presence of contaminants in cannabis presents a potential health hazard to recreational users and susceptible patients with medical conditions. Because of the federally illegal status of cannabis, there are no unified regulatory guidelines mitigating the public health risk of cannabis contaminants.

OBJECTIVE

To inform further research and provide solutions to the public health risk of cannabis contaminants at a national level, we examined the current landscape of state-level contaminant regulations, and cannabis contaminants of concern, as well as patient populations susceptible to contaminants.

METHODS

We examined the regulatory documents for medical and recreational cannabis in all legalized U.S. jurisdictions and compiled a complete list of regulated contaminants, namely, pesticides, inorganics, solvents, microbes, and mycotoxins. We data mined the compliance testing records of 5,654 cured flower and 3,760 extract samples that accounted for ∼6% of California's legal cannabis production in 2020-2021. We also reviewed the publicly available medical cannabis use reports to tabulate the susceptible patient populations.

RESULTS

As of 18 May 2022, 36 states and the District of Columbia listed a total of 679 cannabis contaminants as regulated in medical or recreational cannabis, including 551 pesticides, 74 solvents, 12 inorganics, 21 microbes, 5 mycotoxins, and 16 other contaminants. Different jurisdictions showed significant variations in regulated contaminants and action levels ranging up to four orders of magnitude. A failure rate of 2.3% was identified for flowers and 9.2% for extracts in the California samples. Insecticides and fungicides were the most prevalent categories of detected contaminants, with boscalid and chlorpyrifos being the most common. The contaminant concentrations fell below the regulatory action levels in many legalized jurisdictions, indicating a higher risk of contaminant exposure. Cannabis use reports indicated usage in several patient populations susceptible to contamination toxicity, including cancer (44,318) and seizure (21,195) patients.

DISCUSSION

Although individual jurisdictions can implement their policies and regulations for legalized cannabis, this study demonstrates the urgent need to mitigate the public health risk of cannabis contamination by introducing national-level guidelines based on conventional risk assessment methodologies and knowledge of patients' susceptibility in medical use. https://doi.org/10.1289/EHP11206.

Cannabis smoking and glaucoma in the UK Biobank cohort

BACKGROUND

Cigarette smoking is a well-known risk factor for primary open-angle glaucoma (POAG). Tobacco smoke contains a variety of chemicals, including nicotine, free radicals, and carbon monoxide, all of which can play a role in the development of POAG. Cannabis smoke, like tobacco smoke, contains a comparable variety of carcinogenic and toxic compounds. In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to POAG.

METHODS

Our analysis included all subjects with glaucoma and cannabis smoking information. Data processing was performed on Minerva, a Linux mainframe with Centos 7.6, at the Icahn School of Medicine at Mount Sinai. We used the UK Biobank Data Parser (ukbb parser), a python-based package that allows easy interfacing with the large UK Biobank dataset. Statistical analysis was performed with SPSS 25 and R.

RESULTS

Subjects who used cannabis 100 times or more were significantly younger (10years) when they developed glaucoma than subjects who never used cannabis. The effects of age (P<0.001) and cigarettes (P=0.014) on POAG incidence were significant, but the effect of cannabis use was not (P=0.662). The effect of cannabis use on age at glaucoma diagnosis was significant and unrelated to the effects on intraocular pressure or cigarette pack-years smoked. Analysis of intraocular pressure showed that mean pressures of subjects who used cannabis 11-100 times were significantly lower than those who took no cannabis.

CONCLUSION

Inhaling cannabis smoke is injurious to the eye, but in the case of glaucoma the manifestations are different from those of inhaled tobacco smoke. Cannabis reduces intraocular pressure but accelerates glaucoma development. Cannabis does not increase risk of glaucoma. Cigarette smoking increases risk of glaucoma and significantly accelerates glaucoma development. Apparently, early use of cannabis leads to the earlier development of glaucoma.

Cannabis Cultivation Facilities: A Review of Their Air Quality Impacts from the Occupational to Community Scale

This review addresses knowledge gaps in cannabis cultivation facility (CCF) air emissions by synthesizing the peer-reviewed and gray literature. Focus areas include compounds emitted, air quality indoors and outdoors, odor assessment, and the potential health effects of emitted compounds. Studies suggest that β-myrcene is a tracer candidate for CCF biogenic volatile organic compounds (BVOCs). Furthermore, β-myrcene, d-limonene, terpinolene, and α-pinene are often reported in air samples collected in and around CCF facilities. The BVOC emission strength per dry weight of plant is higher than most conventional agriculture crops. Nevertheless, reported total CCF BVOC emissions are lower compared with VOCs from other industries. Common descriptors of odors coming from CCFs include "skunky", "herbal", and "pungent". However, there are few peer-reviewed studies addressing the odor impacts of CCFs outdoors. Atmospheric modeling has been limited to back trajectory models of tracers and ozone impact assessment. Health effects of CCFs are mostly related to odor annoyance or occupational hazards. We identify 16 opportunities for future studies, including an emissions database by strain and stage of life (growing cycle) and odor-related setback guidelines. Exploration and implementation of key suggestions presented in this work may help regulators and the industry reduce the environmental footprint of CCF facilities.

Marijuana smoking and cataract

BACKGROUND

Cigarette smoking is a well-known risk factor for cataract and other ailments, including heart disease, lung cancer, and chronic obstructive pulmonary disease. Cannabis smoke, like tobacco smoke, contains a comparable variety of carcinogenic and toxic compounds.

PURPOSE

In the present study, we analyzed UK Biobank data to determine whether smoking cannabis, like cigarettes, might be related to cataract.

METHODS

Our analysis included all UK Biobank subjects with cataracts and information on cannabis and cigarette smoking habits. The diagnosis of cataract was ascertained using the 10th Revision of the International Classification of Diseases (ICD10), H25. The age at diagnosis of cataract was obtained from UK Biobank data field 4700. Cannabis information was recorded in UK Biobank category 143, data field 20453, ever taken cannabis.

RESULTS

Subjects who used cannabis 11-100 times or more were significantly younger (4-5 years) when they developed cataract than subjects who never used cannabis. To determine the relationship of current cigarette smoking to cannabis use and age at cataract, the univariate general linear model of SPSS was used, dependent variable age at cataract, fixed factor cannabis use, random factor pack years of cigarettes smoked. Cannabis use was significantly related to age at cataract diagnosis (P<0.001) and independent of the effect of pack-years of cigarettes smoked (P=0.008). Linear regression revealed an insignificant relationship between pack-years of cigarette smoking and age at cataract diagnosis (P=0.073). To further evaluate the relationship of cannabis to cataract, propensity score matching was performed. We identified 28,432 subjects with cataract. Current cigarette smoking and age were covariates; cannabis use (yes/no) was the indicator variable. Current cigarette smoking was significantly associated with a 1.2 odds ratio for cataract. Cannabis use was not significantly associated with the odds ratio for cataract.

CONCLUSION

Like tobacco smoke, cannabis smoke contains thousands of organic and inorganic chemical compounds. Cannabis tar is chemically similar to tar found in tobacco smoke, and over fifty known carcinogens have been identified in cannabis smoke, including nitrosamines, reactive aldehydes, and polycyclic hydrocarbons. Thus, the association of cannabis with cataract that we report here is not entirely surprising. Further studies are warranted.

Development and Validation of a Novel and Fast Detection Method for Cannabis sativa: A 19-Plex Short Tandem Repeat Typing System

In recent years, influenced by the legalization of Cannabis sativa in some countries and regions, the number of people who smoke or abuse C. sativa has continuously grown, cases of transnational C. sativa trafficking have also been increasing. Therefore, fast and accurate identification and source tracking of C. sativa have become urgent social needs. In this study, we developed a new 19-plex short tandem repeats (STRs) typing system for C. sativa, which includes 15 autosomal STRs (D02-CANN1, C11-CANN1, 4910, B01-CANN1, E07-CANN1, 9269, B05-CANN1, H06-CANN2, 5159, nH09, CS1, ANUCS 305, 3735, and ANUCS 302 and 9043), two X-chromosome STRs (ANUCS 501 and 1528), one sex-determining marker (DM016, on Y-chromosome), and a quality control marker (DM029, on autosome). The whole polymerase chain reaction (PCR) process could finish within 1 h, making the system suitable for fast detection. The PCR products were detected and separated with an Applied Biosystems 3500XL Genetic Analyser. Developmental validation studies indicated that the 19-plex typing system was accurate, reliable and sensitive, which could also deconvolute mixed C. sativa samples. Specifically, the sensitivity study showed that a full genotyping profile was obtainable with as low as 125 pg of C. sativa DNA. The species specificity study demonstrated that this multiplex has no cross-reactivity with common non C. sativa DNA. In the population study, a total of 162 alleles at 15 autosomal STRs and 14 alleles at two X-chromosome STRs were detected among 85 samples. The efficiency parameters, including the total discrimination power (TDP) and the combined power of exclusion (CPE) of the system, were calculated to exceed 0.999 999 999 999 988 and 0.998 455 889 684 078, respectively, further proving that the system could meet the needs of individual identification. To the extent of the known studies, this is the first study that included the C. sativa sex-determining marker. In conclusion, the developed new 19-plex STR typing system can successfully achieve the purposes of species identification, gender determination, and individual identification, which could be a powerful tool in tracing trade routes of particular drug syndicates or dealers or in linking certain C. sativa to a crime scene.

In vitro metabolism of tebuconazole, flurtamone, fenhexamid, metalaxyl-M and spirodiclofen in Cannabis sativa L. (hemp) callus cultures

BACKGROUND

Cannabis sativa L. (hemp) is a medicinal plant producing various cannabinoids. Its consumption is legalized for medical use due to the alleged positive health effects of these cannabinoids. To satisfy the demand, C. sativa plants are propagated in contained growth chambers. During indoor propagation, pesticides usually are used to ensure efficient production. However, pesticide registration and safe application in C. sativa has not been investigated in detail.

RESULTS

With this study the metabolic degradation of pesticides in recently established C. sativa callus cultures was examined. Tebuconazole, metalaxyl-M fenhexamid, flurtamone and spirodiclofen were applied at 10 μm for 21 days. Results were compared with metabolism data obtained from Brassica napus L., Glycine max (L.) Merr., Zea mays L. and Tritium aestivum L. callus cultures as well as in metabolism guideline studies. The successfully established C. sativa callus cultures were able to degrade pesticides by oxidation, demethylation, and cleavage of ester bonds in phase I, as well as glycosylation and conjugation with malonic acid in phase II and III. Initial metabolites were detected after Day (D)7 and were traced at D21.

CONCLUSION

The resulting pathways demonstrate the same main degradation strategies as crop plants. Because metabolites could be the main residue, the exposure of consumers to these residues will be of high importance. We present here an in vitro assay for a first estimation of pesticide metabolism in C. sativa. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Analysis of cannabis seizures by non-targeted liquid chromatography-tandem mass spectrometry

Due to the popularity of recreational cannabis use, contamination of this drug with diverse classes of chemicals, including pesticides, mycotoxins, and synthetic cannabinoids, has been identified as major threat for public health. For the detection of these compounds in seized cannabis, a screening workflow involving non-targeted liquid chromatography-tandem mass spectrometry (LCMS/MS) was developed. A Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method was used for the extraction of small bioorganic molecules from ground dried material. Instrumental analysis involved chromatographic separation of compounds and subsequent mass spectrometric detection. Collection of MS and MS/MS information was accomplished by data-dependent acquisition. Compound identification was primarily based on matching acquired MS/MS-spectra to several thousands of reference spectra stored in multiple libraries. Additionally, for selected cannabinoid and pesticide standards, a retention time library was developed. Performance of the workflow was evaluated for 182 pesticides. All tested pesticides were detectable at 5000 μg/kg, 94 % at 500 μg/kg, and 50 % at 50 μg/kg. The workflow was applied to the screening of seized cannabis samples. 41 out of 93 analysed samples (44 %) were tested positive for one or more contaminants impairing quality and/or safety of the material. The detected contaminants included a synthetic cannabinoid (5F-MDMB-PINACA), fifteen pesticide residues (boscalid, carbendazim, chlorantraniliprole, chlorpyrifos, chlorotoluron, cyprodinil, diflubenzuron, ethiofencarb sulfoxide, hexythiazox, iprodione, metalaxyl, pyrimethanil, terbutryn, thiophanate methyl, and trifloxystrobin), and a mycotoxin (sterigmatocystin).

Toxicological aspects of cannabinoid, pesticide and metal levels detected in light Cannabis inflorescences grown in Italy

Recently, the cultivation of light Cannabis, with a total THC content less than 0.6%, has been encouraged due to its industrial and therapeutic potential. This has increased the consumption of hemp for both smoking purposes and food preparation. Even so, Cannabis inflorescences are not subject to EU regulations and standards provided for food and tobacco products. A study was carried out on thirty-one inflorescences samples, collected in different Italian regions, in order to determine cannabinoids, pesticides and metals and to evaluate the exposure of consumers to contaminants and ensure a safe consumption. Contents of THC were always below 0.5%, while CBD ranged between 0.3 and 8.64%. The determination of 154 pesticides showed that 87% of the samples contained fungicides and insecticides in the range 0.01-185 μg/g. The most found are spinosad and cyprodinil. The concentration of metals ranged from 1 to more than 100 μg/g and As, Cd, Co, Cr, Hg, Cu, Mo, Ni and V exceeded the regulatory US limits for inhaled Cannabis products, while Pb exceeded them for both oral and inhaled products. These contaminants are intrinsically toxic and may affect public health. Actions are needed to establish regulatory measures and reduce the adverse effects caused by contaminants in Cannabis.

Harm reduction and cannabis social clubs: Exploring their true potential

AIM

Cannabis Social Clubs (CSCs) seek to offer a community-based drug-policy strategy to efficiently reduce the risks associated with cannabis usage. But the actual mechanisms in place to achieve harm reduction have not yet been studied in depth. The goal of our ongoing research is to better understand what kinds of harm reduction practices exist in CSCs and how widespread they are.

METHOD

For our study we selected 15 CSCs, all members of the Catalonian Federation of Cannabis Associations (CatFac). An on-line survey was designed to collect data on the organizational aspects of each CSC and to focus on the presence or the absence of harm-reduction practices.

RESULTS

The studied sample had some significant gaps in providing information on risk and harm reduction, in offering health support services for general members and also in applying lab-tests on the actual cannabis being used at the CSC.

DISCUSSION

In order to accomplish their role as harm prevention agents, CSCs need to address these specific gaps. Receiving support from innovative drug policies could be a key factor to actualize their harm-reduction potentialities.

CONCLUSION

Further research on the relationship between organizational and structural factors defining the Clubs and their harm reduction practices must be conducted to encourage brand new strategies that support risk reduction within the CSCs.

Analysis of the California list of pesticides, mycotoxins, and cannabinoids in chocolate using liquid chromatography and low-pressure gas chromatography-based platforms

Cannabis legalization has led to the development of a variety of cannabis-infused products with edibles being one of the most popular. The state of California has implemented comprehensive cannabis testing regulations requiring the analysis of cannabinoids (potency) and contaminants, such as pesticides and mycotoxins, in any type of cannabis good. In this work, we propose an analytical workflow for the quantification of the California list of pesticides and mycotoxins, as well as six cannabinoids, in chocolate, using 3 mL of solvent for the extraction. For the analysis of pesticides and mycotoxins, clean-up steps employing a C18 solid-phase extraction cartridge and dispersive solid-phase extraction sorbents were implemented. Gas chromatography amenable pesticides were analyzed using low-pressure gas chromatography coupled to tandem mass spectrometry which allowed for a total method run of 12 min. Both liquid chromatography and gas chromatography instrumental methods had the same analysis time, ensuring satisfactory sample throughput. For the determination of cannabinoids, a dilution of the original organic extract collected for pesticides and mycotoxins analysis (and prior to any clean-up step) was used. Excellent results in terms of analytical figures of merit were obtained for all target analytes.

Phytocannabinoid Pharmacology: Medicinal Properties of Cannabis sativa Constituents Aside from the "Big Two"

Plant-based therapies date back centuries. Cannabis sativa is one such plant that was used medicinally up until the early part of the 20th century. Although rich in diverse and interesting phytochemicals, cannabis was largely ignored by the modern scientific community due to its designation as a schedule 1 narcotic and restrictions on access for research purposes. There was renewed interest in the early 1990s when the endocannabinoid system (ECS) was discovered, a complex network of signaling pathways responsible for physiological homeostasis. Two key components of the ECS, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), were identified as the molecular targets of the phytocannabinoid Δ⁹-tetrahydrocannabinol (Δ⁹-THC). Restrictions on access to cannabis have eased worldwide, leading to a resurgence in interest in the therapeutic potential of cannabis. Much of the focus has been on the two major constituents, Δ⁹-THC and cannabidiol (CBD). Cannabis contains over 140 phytocannabinoids, although only a handful have been tested for pharmacological activity. Many of these minor cannabinoids potently modulate receptors, ionotropic channels, and enzymes associated with the ECS and show therapeutic potential individually or synergistically with other phytocannabinoids. The following review will focus on the pharmacological developments of the next generation of phytocannabinoid therapeutics.