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The Stable Isotope Ratios of Marijuana. II. Strontium Isotopes Relate to Geographic Origin
Author(s) -
West Jason B.,
Hurley Janet M.,
Dudás Francis Ö.,
Ehleringer James R.
Publication year - 2009
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2009.01171.x
Subject(s) - bedrock , strontium , isotopes of strontium , geology , isotope , stable isotope ratio , geochemistry , chemistry , geomorphology , physics , organic chemistry , quantum mechanics
Effectively addressing marijuana trade is aided by understanding marijuana geographic sources. We analyzed the 87 Sr/ 86 Sr 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 87 Sr/ 86 Sr values based on 87 Rb decay rates and a generalized geologic map of the U.S.A. A significant correlation was observed between marijuana 87 Sr/ 86 Sr and modeled bedrock 87 Sr/ 86 Sr. 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.