The Elemental Composition of Hemp Flower: Sources of Elemental Impurities and Implications for Consumer Product Safety

ABSTRACT The rapid growth of the cannabis market in the United States has led to increasing focus on the consumer product safety of the myriad of new products entering commerce. The cannabis plant is widely accepted to be an efficient accumulator of potentially toxic elements, and its resinous nature makes it well suited to accumulate surface contaminants. Unfortunately, limited data are currently available on the occurrence of many elements in consumer cannabis, and even fewer studies have examined surface adhered particulate matter. As part of this study, 26 elements (silver, aluminum, arsenic, barium, beryllium, calcium, cadmium, cobalt, chromium, copper, iron, mercury, potassium, magnesium, manganese, molybdenum, sodium, nickel, lead, antimony, selenium, thorium, thallium, uranium, vanadium, and zinc) were quantified in hemp produced for cannabidiol and commercially available hemp marketed for smoking. Additionally, surface adhered particulate matter was examined as a potential contributor of elemental impurities, and various methodologies were compared. Results confirm that hemp entering commerce in the United States contains a variety of elemental impurities and frequently contains adhered particulate matter such as soil minerals, agricultural additives, microplastics/textile fibers, and materials from harvesting/processing equipment. Consumer exposure potential for some elements such as copper was found to be high enough to warrant additional investigation as to the possible health effects and may justify additional oversight from regulators, who should consider expanding testing panels to a larger suite of elements than arsenic, cesium, mercury, and lead.