If you want the truth, hold your nose. Sewage monitored to track drug use in Adelaide, Australia, has revealed that methamphetamine use doubled in four years.
Reliable data on illegal drug use is difficult to obtain, because users often don’t know what exactly they have taken, or how much. But sewage doesn’t lie, and analysing its chemical components is a cheap way to find out what’s really going on.
Cobus Gerber of the University of South Australia and colleagues studied the chemical components in sewage at four treatment plants in Adelaide between 2011 and 2015. The data gave a detailed picture of the recreational habits of the city’s 1.2 million residents.
They found that MDMA and ecstasy use peaks in December’s summer party season, while cannabis use drops in February – presumably as users await the next harvest. Illegal stimulants are used more at the weekends, while cocaine is most concentrated in the wastewater of affluent areas.
Gerber’s team saw the use of methamphetamine double – confirming evidence from police and hospitals that crystal meth is a growing problem in Australia.
The opioid oxycodone is also on the rise, in line with prescription dispensing data. “The consistent increase in oxycodone is of concern, owing to its high abuse potential,” says Gerber.
Unlike weekend stimulants, there seems to be no clear pattern to explain when people take newer types of psychoactive substances, like mephedrone, which is also known as miaow miaow.
The researchers determined the drug levels by processing raw sewage samples and analysing them with a standard chemistry technique, mass spectrometry. “It’s not as bad as you think, says Gerber.”It’s like doctors with blood – you get used to it.”
“The advantage is that it’s almost instantaneous, so it tells you what is happening across the whole population right now,” says Gerber. “That’s better than asking people what drugs they took a week ago, then collating the data and producing a report a year later.”
The technique, which has previously been used in Europe, could also become valuable for monitoring a population’s health and rates of disease.
Jochen Mueller of the University of Queensland is part of a team that has begun looking for compounds in wastewater that could indicate the prevalence of various diseases, such as diabetes, in real time. He says he is also interested in using sewage to assess how much fruit and vegetables a city’s population is eating.
This kind of research has previously met with some concern from people who are worried about the government monitoring their lifestyles and health. But Mueller says the aim is to improve public health. “Individuals are completely de-identified,” he says. “We’re not trying to catch anybody out.”
Journal reference: Science of the Total Environment, DOI: 10.1016/j.scitotenv.2016.04.183