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 consumpution, 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.