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Carbon and nitrogen stable isotopes as indicative of geographical origin of marijuana samples seized in the city of São Paulo (Brazil).

Shibuya EK, Sarkis JE, Negrini-Neto O, Martinelli LA

Laboratório de Caracterização Química e Isotópica, Centro de Química e Meio Ambiente, Instituto de Pesquisas Energéticas e Nucleares, IPEN/CNEN-SP, Av. Lineu Prestes 2242, Cidade Universitária, São Paulo/SP CEP 05508-000, Brazil; Laboratório de Referências Metrológicas, Instituto de Pesquisas Tecnológicas do Estado de São Paulo, IPT-SP, Av. Prof. Almeida Prado, 532, Cidade Universitária, São Paulo/SP CEP 05508-901, Brazil.

The drug trafficking is one of the most serious problems related to the Public Safety in Brazil, especially in the most populous areas of the country, as is the case of the city of São Paulo. In this work, it was developed a methodology that can help tracking the traffic routes of marijuana samples seized in the city of São Paulo, based on stable carbon and nitrogen isotopes, which are related to the climate and plant growth conditions. A model to classify the origin of unknown samples was built using linear discriminant analysis based on about 150 samples apprehended in the main producing regions of the country. Results for 76 samples seized in the city of São Paulo showed that most of them were cultivated in a humid region with the same origin as those from Mato Grosso do Sul. The provenance of 13 outliers samples from Northeast region (an important producing region) also were evaluated and some of them presented same profile of those from Mato Grosso do Sul, pointing to the existence of the traffic routes between the Northeast and Midwest region, probably as a consequence of the intensive field raids by Brazilian Federal Government since 1999.

Published 19 March 2007 in Forensic Sci Int, 167(1): 8-15.
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