Collecting wastewater direct from the source can help researchers identify the latest new psychoactive substances.
If you like a good night out on the latest synthetic drug du jour, you could soon start looking at public toilets in a different way.
A new publication by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) provides a rundown on how to scan through sewage to keep tabs of drug use trends in cities—and it contains a section explaining why public loos could be the next big thing when it comes to spotting newly-popular psychoactive substances.
Toxicologists and researchers attempting to put together a picture of which drugs are being used in a certain area have been analysing wastewater for about a decade. This involves collecting samples from wastewater treatment plants and scouring them for traces of substances: the higher the percentage of a substance, the more widespread its assumed consumption in the monitored community.
The procedure works well for drug epidemiologists on the lookout for the usual suspects: cocaine, heroin, amphetamine and so on. It is far less efficient, though, at gauging use patterns of new lab-made drugs such as so-called "legal highs"—chemicals with effects similar to illicit drugs, but not always explicitly forbidden.
"Not even users know what substance is in what they're taking"
"There are too many new psychoactive substances arising on the market—only in 2014, we got at least 100 new drugs," Liesbeth Vandam, one of the toxicologists who worked on the project, told me in a phone call. "We can assume that the user base for each of them is low, which means they are difficult to find in wastewater [because of weaker concentration]."
To make things more difficult, such substances are constantly tweaked—sometimes to elude bans—so toxicologists do not really know what chemicals they should be looking for in their samples. Self-reporting is ruled out, Vandam said, because "not even users know what substance is in what they're taking."
But over the last two or three years some scientists have taken their analysis closer to the source. The report references recent studies that detail how sourcing wastewater directly from public toilets where drug use is expected to be of interest, rather than waiting for it to reach water plants, could help find suspicious chemicals more effectively. One team of toxicologists from London's King's College and Guy's and St Thomas' Hospital has tested this technique in London and other British cities.
The team, led by Dr John Archer, placed portable urinals (which collected pee in a 400-litre tank) in city centres and near places where novel drug consumption was considered more likely, such as nightclubs. Since the urine was not diluted by other sewage or rainwater, it could be broken down to its chemical elements, which were then compared against a vast database of substances with known psychoactive effects. In all cases, researchers detected significant quantities of novel psychoactive substances (such as mephedrone, cathine, and hordenine) in pooled urine.
EMCDDA's report hails the technique as a way to carry out a more geographically detailed analysis, and even as a method to spot drugs whose use is still unknown: by placing the urinals near notorious druggy hangouts, you'd have a useful pee-based update of what's hot on the city's drug scene.
There are other potential applications. One can easily imagine how such a technique could lead to police expeditions to clubs or neighborhoods where snitch-pissoirs have revealed drugs are being used. But so far, law enforcement doesn't seem too keen on sifting through your pee (and the technique is not able to identify individuals).
"The technique is still not quite sensitive enough to be used on its own to advise law enforcement," Archer told me in a phone call. "It could be a component of a larger array of resources—it could be combined with crime surveys, hospital reports, etc. But right now I am not aware of law enforcement thinking about using this."
A 2014 UK Home Office report on new psychoactive substances in England mentioned the studies as a complementary way to spot new substances (all of which will soon become illegal in the UK under a newly-approved law).
The method could also be useful in judging the impact of policing efforts.
"Urine sampling could be done just before some new law enforcement or social campaign starts, and then again after it has been carried out," Vandam told me. "Comparing the substance levels before and after could be a tool for analysing whether the policy worked."