Current address: Texas AgriLife Research, Department of Ecosystem Science & Management, Texas A&M University, 1619 Garner Field Road, Uvalde, TX 78801.
The Stable Isotope Ratios of Marijuana. II. Strontium Isotopes Relate to Geographic Origin
Article first published online: 5 OCT 2009
© 2009 American Academy of Forensic Sciences
Journal of Forensic Sciences
Volume 54, Issue 6, pages 1261–1269, November 2009
How to Cite
West, J. B., Hurley, J. M., Dudás, F. Ö. and Ehleringer, J. R. (2009), The Stable Isotope Ratios of Marijuana. II. Strontium Isotopes Relate to Geographic Origin. Journal of Forensic Sciences, 54: 1261–1269. doi: 10.1111/j.1556-4029.2009.01171.x
- Issue published online: 23 OCT 2009
- Article first published online: 5 OCT 2009
- Received 28 May 2008; and in revised form 25 Nov. 2008; accepted 29 Nov. 2008.
- forensic science;
- stable isotope ratio;
- heavy isotopes;
- drug intelligence;
- Cannabis sativa;
- thermal ionization mass spectrometry;
Abstract: Effectively addressing marijuana trade is aided by understanding marijuana geographic sources. We analyzed the 87Sr/86Sr of marijuana samples grown in 79 counties across the United States to determine if a primary geologic signal is retained in marijuana, which could therefore be useful for geographic sourcing. The marijuana results were compared with modeled bedrock 87Sr/86Sr values based on 87Rb decay rates and a generalized geologic map of the U.S.A. A significant correlation was observed between marijuana 87Sr/86Sr and modeled bedrock 87Sr/86Sr. Although values clustered near the 1:1 relationship, there was a predominance of positive anomalies, perhaps attributable to carbonate bedrock. A small number of negative anomalies were also observed, which were generally associated with granitic bedrocks. These results suggest that strontium isotopes in marijuana record the geographic origins of marijuana, and that refinement of the base strontium map (or strontium isoscape) and improved understanding of other strontium sources would be productive.