Cannabis (marijuana) contamination of United States and foreign paper currency

It is well known that United States paper currency in general circulation is contaminated with trace amounts of illicit substances such as cocaine, heroin and marijuana. As is the case with cocaine, differentiating "background levels" of the various cannabinoid constituents of Cannabis sativa L., namely, Delta(9)-tetrahydrocannabinol (THC), cannabinol (CBN), and cannabidiol (CBD) contaminating currency found in the general circulation from currency associated with illegal drug activity is imperative if a legal nexus is to be established with the latter. We analyzed 165 randomly collected paper currency notes from 12 U.S. cities (N = 125) and 4 foreign countries (N = 40) for THC, CBD, CBN, 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol, and 11-hydroxy-Delta(9)-tetrahydrocannabinol. Uncirculated US 1 dollar notes were added as negative controls. Drug residues were washed from individual bills, extracted using a liquid-liquid extraction protocol, derivatized, and quantitated by gas chromatography-mass spectrometry by selected ion monitoring. For the US 1 dollar currency, THC was present in 1.6% (2 notes), CBN 10.31% (13 notes), CBD 1.6% (2 notes). The following concentrations were determined: 0.085 microg/bill and 0.146 microg/bill for THC; 0.014-0.774 microg/bill (mean 0.166 microg/bill) for CBN; and 0.032 microg/bill and 0.086 microg/bill for CBD. For the foreign currency (Colombia, Qatar, India, and New Zealand), THC and CBN were present in 22.5% (9 notes). The following concentration ranges were determined: THC 0.026-0.065 microg/bill (mean 0.049 microg/bill), CBN 0.061-0.197 microg/bill (mean 0.115 microg/bill). All of the positive THC and CBN were found in the New Zealand polypropylene notes. This study demonstrated that marijuana (cannabinoids) may contaminate both paper and plastic currency.