A study by the Desertification Research Center (CIDE, UV-CSIC-GVA) has evaluated, through the analysis of wastewater, drug consumption in the city of Valencia during the period from 2011 to 2020. Cannabis, tobacco, and cocaine were the most consumed, especially during weekends and holiday periods, in agreement with EU estimates. The work, published in the journal Water Research, highlights the efficiency of this epidemiological technique.
The wastewater-based epidemiology (WBE) approach has made it possible to analyze trends in drug consumption in Valencia over a decade; to detect the emergence of new substances of abuse and to identify changes in consumption patterns related to holiday periods or festive events.
For the work, the Food Safety and Environmental Research Group of the University of Valencia (SAMA-UV), at CIDE, analyzed wastewater from three wastewater treatment plants in the city of València and managed to detect a total of 16 psychoactive substances - legal or illegal - eight of which were continuously monitored by chromatographic and mass spectrometric studies.
The results, recently published in the journal Water Research, show that cannabis, tobacco and cocaine were the most consumed drugs, with an average per 1,000 inhabitants of 9.9 g/day for cannabis, 1.7 g/day for cocaine and 1.5 g/day for nicotine (see original data in article). The study also shows an upward consumption trend for all three substances as of 2018. Opiates such as codeine (0.5 g/day), hallucinogens such as bufotenine (0.2 g/day), or stimulants such as ecstasy (MDMA 42 mg/day), amphetamines (36 mg/day) and methamphetamines (20 mg/day) stand out next. Lastly, heroin, ketamine and methadone, among others, were shown to be the least commonly used drugs in Valencia during the study period. Samples for analysis were obtained both in the form of pure substances and their metabolites.
"These data are similar to those found in other Spanish cities and are in agreement with the estimates made for the EU by the European Monitoring Center for Drugs and Drug Addiction," notes engineer Julián Campo, first author of this article and researcher of the SAMA Group at CIDE. The European Drug Report 2021 identified cocaine as the second most widespread and seized stimulant in Europe, and the 2021 Report of the Spanish Observatory on Drugs and Addictions (OEDA), confirmed that cocaine is one of the drugs with the highest prevalence of consumption in the Spanish population aged 15-64 years and in the period 2019-2020, after alcohol and tobacco.
The results of the SAMA-UV group show that, in addition to cocaine, cannabis is among the most frequently detected illicit drugs in wastewater samples. These data are in agreement with different studies conducted for similar periods in 26 EU countries.
Other data provided by the study are the increase in cocaine consumption in the city of Valencia and its surrounding municipalities throughout the decade, coinciding with the general trend observed throughout Europe; the stabilized consumption of methamphetamine, reduced consumption of amphetamine and increased consumption of ecstasy. During weekends and local festivals, mainly Las Fallas, a higher frequency of consumption of psychotropic substances was observed compared to weekdays.
"Similar results have been recorded in different festivals, events or holiday periods in different cities around the world, which confirms the recreational use of some of these substances," says Yolanda Picó, Professor of Nutrition and Bromatology at the University of Valencia and head of the SAMA-UV group.
The results of this work highlight the relevance of wastewater analysis as an excellent complement to classical epidemiological indicators -prevalence data, seizure statistics, etc- when composing an objective, fast, cheap and anonymous overview of drug use patterns in a specific location, as is the case of the city of Valencia", concludes Julián Campo.
Reference:
Julián Campo, Dyana Vitale, Daniele Sadutto, Lucia Vera-Herrera, Yolanda Picó. Estimation of legal and illegal drugs consumption in Valencia City (Spain): 10 years of monitoring. Water Research 240:120082. 2023. DOI: https://doi.org/10.1016/j.watres.2023.120082
CIDE Communication
