Waste water analysis using urinary biomarkers allows the reliable detection of actual drug consumption in cities. For the first time, a wide group of scientists have carried out a comparative study regarding the consumption of illegal drugs in 19 European cities, four of which are Spanish, based on waste water analysis. In the case of Spain, cannabis and cocaine consumption is higher than that of other drugs such as methamphetamines and ecstasy, appearing in each of the four cities analysed: Barcelona, Castelló de la Plana, Santiago de Compostela and Valencia.
Research centres and universities from 11 European countries have participated in the study. In the case of Spain, the investigation was carried out by the University Institute of Pesticides and Waters at the Universitat Jaume I in Castelló (researcher responsible, Dr. Félix Hernández), the Department of Preventative Medicine at the Universidad de Valencia (Dr. Yolanda Picó), the Department of Chemical Analysis from the Universidad de Santiago de Compostela (Dr. Benito Quintana) and the Department of Environmental Chemistry, IDAEA-CSIC of the Institute for Environmental Diagnosis and Water Research (IDAEA) of the Scientific Research National Council (CSIC) in Barcelona (Dr. Miren López de Alda). The initiative for the study began in the Norwegian Institute for Water Research (NIVA) and from the Instituto Mario Negri de Investigación Farmacológica, in Milan.
To carry out the investigation, urban waste water was collected from a total of 19 European cities over the course of a week in March 2011. Urinary biomarkers for cocaine, amphetamines, ecstasy, methamphetamines and cannabis were used on the samples. The results were published July 2 6in the specialist journal Science of the Total Environment. The analysis allowed the estimation of drug consumption for each one of the 19 cities and the results were normalised according to the size of the city that was investigated. This means that larger cities, such as London or Barcelona, can be directly compared with smaller cities such as Castelló or Santiago de Compostela.
Amongst the main conclusions of the study, the researchers responsible for the investigation highlight the fact that the highest consumption of cocaine, expressed in milligrams consumed per day per 1000 inhabitants, corresponds to Antwerp, followed by Amsterdam, Valencia, Eindhoven and Barcelona. With regards to Castelló, consumption is similar to that of cities such as Utrecht or London, and slightly higher than Santiago, which is on the same level as Paris, Milan or Brussels. On the other hand, cocaine consumption in Nordic countries can be viewed as low. It is estimated that 365 kilograms is consumed daily, which represents approximately between 10 and 15% of worldwide cocaine consumption, according to estimates from the United Nations Office of Drugs and Organised Crime.
In contrast with cocaine, the consumption of methamphetamines is higher in the north and north-west of Europe, principally in Scandinavia and the Czech Republic. In general, in the group of drugs related to amphetamines, methamphetamines and amphetamines themselves are those which dominate in European waste water. In Castellón, neither of these two drugs was detected in the waters, whereas Barcelona, Valencia and Santiago showed levels which corresponded to mid/low consumption, lower than those levels in the north of Europe.
With regards to MDMA consumption, known as ecstasy, Castelló also appears to be low, as it was not detected in waste water. Ecstasy consumption in Valencia and Santiago is approximately half of that in Barcelona, but, in any case, much lower than consumption in countries such as Holland and Belgium.
Finally, it is important to signal that the highest level of cannabis consumption is in Holland, the highest rating of which is in Amsterdam, followed by France and Spain. Researchers consider that Spain's strategic position in marijuana trafficking has created a market for this substance. Along with Barcelona, smaller cites such as Castelló and Santiago show relatively high consumption levels, slightly higher than the consumption per capita in Valencia.
Drug consumption surveillance programs are extremely useful for the development of efficient police policies and to evaluate the effectiveness of current policies with regards to the fight against drug addiction.
Until recently, the most usual method to measure drug consumption was based on surveys. These studies are carried out in different sectors of society including consumers with different grades of addiction, such as the general population. Addition information is also obtained using police data for drug seizures, along with hospital information for admittence and other medical data. However, there is a noticeable uncertainty with regards to this information due to the lack of reliability of studies based on surveys, especially when dealing with illegal drug use. Furthermore, the results obtained circumscribe long periods of time (annually) and large geographical areas (states, in general).
The approximation employed in this investigation, analysing waste water from water purification plants (EDAR), have allowed the centres to obtain reliable information regarding total consumption of the drugs investigated in real time, according to the investigators responsible for the study.
Kevin Thomas, the NIVA researcher who co-ordinated this co-operative project, believes that the analysis of waste water provides important information relevant to the estimation methods which currently exist. "Via waste water investigation we can can estimate a city's drug consumption. Furthermore, we can quickly measure changes in consumption habits over a short period of time. For example, we can determine if there has been a massive drug disposal via drainage when police raids or drugs seizes take place," the researcher explains.
The methodology used in this project has been applied to a second study carried out in several European cities in 2012. This strategy is applicable in any other country or city. "With the necessary economic support, we have the opportunity to be able to better understand, for the first time, what worldwide drug consumption currently is, trends, or the introduction of new drugs onto the market via the study of biomarkers in waste waters," researchers inform us.
- Kevin V. Thomas, Lubertus Bijlsma, Sara Castiglioni, Adrian Covaci, Erik Emke, Roman Grabic, Félix Hernández, Sara Karolak, Barbara Kasprzyk-Hordern, Richard H. Lindberg, Miren Lopez de Alda, Axel Meierjohann, Christoph Ort, Yolanda Pico, José B. Quintana, Malcolm Reid, Jörg Rieckermann, Senka Terzic, Alexander L.N. van Nuijs, Pim de Voogt. Comparing illicit drug use in 19 European cities through sewage analysis. Science of The Total Environment, 2012; DOI: 10.1016/j.scitotenv.2012.06.069