Elsevier

Science of The Total Environment

Volume 487, 15 July 2014, Pages 673-680
Science of The Total Environment

Analysis of cocaine and nicotine metabolites in wastewater by liquid chromatography–tandem mass spectrometry. Cross abuse index patterns on a major community

https://doi.org/10.1016/j.scitotenv.2013.10.042Get rights and content

Highlights

  • Cross abuse index patterns on licit and illicit drugs by means of sewage assessment

  • Data about cocaine and nicotine consumption from a Portuguese population

  • Co-evaluation of cocaine abuse estimates based on local drug purity levels

Abstract

A method based on sample preparation by solid phase extraction and analysis by liquid chromatography and mass spectrometry was validated and used for simultaneous analysis of cocaine, benzoylecgonine and cotinine in samples collected at the major wastewater treatment plant in the city of Lisbon. The aim was to estimate the consumption of both cocaine and nicotine in this community and establish an index involving both drugs supported by the relevance of nicotine as a significant anthropogenic marker. The study was made on two different weekdays during a month in order to evaluate patterns of consumption outside weekends. Cocaine and nicotine ingestion levels were back-calculated and expressed as mass of pure drugs consumed per day and per 1000 inhabitants (mean: 0.604 g and 5.860 g respectively). Cocaine was also expressed on the basis of local drug purity levels (33.7%) with a corresponding increase on dose assessments, and community drug abuse profiles. The authors sustain that this approach should always be included in drug studies of this kind allowing a better drug abuse assessment. No significant different patterns of consumption were obtained during the working days studied with the exception of one case coincident with a national holiday that showed an increased typical profile found on other non-working day studies, namely weekends. A fairly significant relationship was found between nicotine and cocaine consumption that should be further evaluated in future studies. Pharmacokinetic considerations were made and proposed for cocaine assessment based on the impact on back calculations after common simultaneous consumption of cocaine and ethanol.

Introduction

The analysis of sewage drug biomarkers (SDBs) has recently been established as a complementary approach for monitoring patterns and trends of illicit drug use in communities (Banta-Green et al., 2009, Berset et al., 2010, Castiglioni and Zuccato, 2011, Irvine et al., 2011, Karolak et al., 2010, Metcalfe et al., 2010, Reid et al., 2011, Terzic et al., 2010, Van Nuijs et al., 2009a, Zuccato et al., 2008). In 2012 the first harmonized study involving drug wastewater analysis in 19 European cities has been published (Thomas et al., 2012). Moreover, in 2013, using data from this study, a critical review was made to integrally address the uncertainties associated with the estimations of community drug use through sewage analysis, proposing a set of best practice requirements (Castiglioni et al., 2013).

Cocaine (COC) remains the second most commonly used illicit drug in Europe, although prevalence levels and trends differ considerably between countries (EMCDDA, 2012). In Portugal results from the II National Population Survey on Psychoactive Substances in the Portuguese Population (15–64 years of age), the latest national survey available dated from 2007, indicate that alcohol and tobacco are the licit substances preferably used by the Portuguese population, and cannabis, cocaine and ecstasy, the illicit substances with lifetime prevalence respectively of 11.7%, 1.9% and 1.3% (IDT, 2011). The prevalence of cocaine use in the last 30 days/12 months has increased from 0.1/0.3 (year 2001) to 0.3/0.6 (year 2007), which was a strong incentive for selecting cocaine as the drug of choice for this sewage study in the capital of Portugal, analyzing the influents of the main wastewater treatment plant (WWTP) in the city of Lisbon, Alcântara (Fig. 1).

The aims of this work were (1) to assess the consumption of both cocaine and nicotine through the quantification of cocaine (COC), benzoylecgonine (BE) and cotinine (CT) in the influents of a major urban wastewater treatment plant, by the means of an implemented and validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) analytical method; (2) to establish a relationship index between tobacco and cocaine consumption and (3) to propose a complementary data evaluation for better qualification of epidemiological studies by converting the number of cocaine doses adjusted to the average local purity levels of cocaine. This approach will produce a more realistic view on the extent of drug consumption and trafficking and is proposed as another index to be included on every sewage drug studies.

Section snippets

Reagents and materials

LC–MS grade acetonitrile (ACN) and methanol (MeOH) were obtained from Scharlau® (Scharlau S.L., Sentmenat, Spain). Analytical grade 37% hydrochloric acid (HCl), ammonium hydroxide (NH4OH) and ammonium acetate (CH3COONH4) were purchased from Merck (Darmstadt, Germany) and VWR (Lisbon, Portugal). Ultra-pure water (18.2 MΩ·cm) was obtained from a Millipore-Direct Q3 UV system (Millipore®, Bedford, MA, USA). Individual methanolic or acetonitrile solutions (1 mg/mL) of cocaine (COC), benzoylecgonine

Results and discussion

The sampling process of the influents was made according to the WWTP-Alcântara collection protocol, on a time proportional schedule of 120 min. The uncertainty associated with the different models of sampling has been discussed by several authors (Ort et al., 2010a, Ort et al., 2010b, Castiglioni et al., 2013) regarding optimization of the collection step, being the flow-proportional mode the method that should be adopted for best results, as it minimizes pulse drug flows. In our study, sample

Conclusion

The present project obtained the first sewage forensic estimates (SF/E) in Portugal and confirmed the great potentials of this epidemiological approach in drug abuse assessment. The obtained cocaine and benzoylecgonine concentration results enabled to optimize estimates for the pharmacokinetic parameters to be used on back calculations of cocaine consumption in the population serving the main Lisbon WWTP. Moreover, a possible cross abuse index pattern between cocaine and nicotine consumption

Acknowledgments

This work was funded by REDE/1518/REM/2005 for the LC–MS/MS equipment and by funds from former Projecto Vida and Ordem dos Farmacêuticos (Portuguese Pharmaceutical Society).

We wish to thank José Martins and Paulo Coelho from SIMTEJO-Alcântara Wastewater Treatment Plant (Lisbon) for the supply of wastewater samples and analytical control data; and João Goulão and Óscar Duarte from IDT (Institute on Drugs and Drug Addiction, I.P., Lisbon) for the supply of 2011 Portuguese cocaine purity data and

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