Illicit stimulant use in the population monitored by wastewater analyses.

Abstract

Illicit stimulant use is a global problem, and accurate and timely information on population stimulant use is essential. However, traditional monitoring methods based on surveys and reporting systems have some limitations, which include the accuracy of the data collected, its relevance to the population as a whole, and the long delays in reporting in a rapidly changing drug scene. These limitations are problematic when using the collected data to develop health and policing policies. Analysis of community wastewater has been suggested to be an objective and quick method to provide supplementary data. However, a detailed knowledge of the pharmacology and chemistry of drugs is required combined with development and validation of techniques before this method is universally applied. The general aims of this thesis were to develop and validate the method of wastewater analysis, and then apply it to monitor illicit stimulant use in the general population. The analytical method used in this study was mainly solid-phase extraction coupled with liquid chromatography- tandem mass spectrometry. Firstly, pre-analysis loss of drugs and metabolites were evaluated. The results from this study showed that negligible loss of the studied drugs occurred after filtration, and all analytes except cocaine and 6 monoacetylmorphine are relatively stable in wastewater. For cocaine use monitoring, its metabolite benzoylecgonine is a more suitable analytical target for stability reasons. To stabilise 6-monoacetylmorphine, the addition of sodium metabisulphite is recommended. Secondly, wastewater analysis was applied to monitor the use of illicit stimulants cocaine, methamphetamine and 3, 4-methylenedioxy-N-methylamphetamine (MDMA) in the State of South Australia, Australia. Data were collected for international comparisons, geographical comparisons and weekly use pattern assessments. Continued monitoring of the wastewater revealed a decline in MDMA use in Adelaide, which provided objective data to support the globally reported MDMA shortage starting from 2009. Since late 2000s, there has been an increase in the use of novel synthetic stimulants. It was suggested that this increase might be associated with the MDMA decline, but it was also possible that these two phenomena were not related. To verify these hypotheses, an analytical method for the analysis of some of the most reported synthetic stimulants was developed, validated and applied. Results showed some sporadic increases in the use of new synthetic stimulants during 2010 and 2011, but these increases were not directly linked with the MDMA decline, suggesting the novel synthetic stimulants have not replaced MDMA. In conclusion, this thesis developed and validated the method of wastewater analysis and gained important information on stimulant use in the population, which cannot be obtained via other monitoring approaches.