Wastewater analyses from DTU Environment are being incorporated into a major European project to estimate the extent of drug abuse in the EU.
In Oslo, methamphetamines are a big hit on weekends, while cocaine is the preferred party drug in London, Amsterdam and Copenhagen. These findings were revealed by calculations based on analyses of wastewater collected in 44 cities in 18 European countries in 2015. The drugs end up in the sewers when citizens excrete them via their urine.
Methods for estimating drug abuse in a society through wastewater analysis constitute a blooming academic area entitled ‘Wastewater-based Epidemiology’, which is still in its infancy and continues to struggle with a high degree of uncertainty. And it is precisely this aspect that the international research project Sewprof—where DTU Environment is one of the partners—is seeking to improve.
The Copenhagen wastewater samples were collected under the direction of Pedram Ramin, a PhD student at DTU Environment who will be defending his thesis in December 2016.
Pedram Ramin’s research has focused in particular on developing the mathematical models used for the calculations that may provide information about drug abuse within a given geographical area. However, this has also required knowledge of what happens to the drugs in the wastewater itself.
“The drugs are constantly broken down chemically in the sewers; this means that instead of searching for ecstasy or cocaine in the wastewater, we look for the drugs produced when they degrade,” explains Associate Professor Benedek Plósz of DTU Environment, who is Pedram Ramin’s supervisor.
The wastewater data are being included in the work of the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) to track the spread of narcotics in Europe.
Sewer in the lab
Identification of narcotic substances in sewers is complicated even further by the fact that numerous factors influence how a substance degrades: the time it has been in the sewer, the temperature and pH value of the wastewater, biofilm in the sewer, and the speed at which the water flows through the sewer itself.
Researchers at DTU Environment were therefore obliged to run experiments in the laboratory to simulate conditions in the Copenhagen sewers as closely as possible. In order to ensure the right composition of biofilm and substances in the ‘test sewer’, researchers collected generous volumes of wastewater, and to identify the correct and stable products of the drugs’ degrading, a number of illegal drugs including heroin and cocaine were acquired and added to the sewer setup in the laboratory.
Although models for calculating drug abuse have become more accurate, estimates will always be subject to a degree of uncertainty. Benedek Plósz explains:
“It is far from certain that substances are ingested and excreted in the same geographical location.”
Nevertheless, the wastewater analyses Pedram Ramin conducted during the 2014 Distortion Festival in Copenhagen revealed that cocaine consumption in the Danish capital increased 20-fold during the festival in relation to a normal weekday.
Benedek Plósz relates that researchers are close to being able to present a newly developed tool with the capacity to assist authorities in tracing the spread of drugs, identifying especially problematic geographic areas, and then using this knowledge to plan more efficient social and preventative input.