Drug users might be less than forthright about their illicit habits—but they all have to pee. With that in mind, scientists are drug-testing entire sewer systems to see what drugs they can trace.
Dan Burgard, an associate chemistry professor, knew students tried to get an edge. But he didn't know about the "study drug."
"I was walking with a student," Burgard said, "and they bemoaned that it wasn't students cheating nowadays to get ahead, but that they were taking Adderall," a potent amphetamine used to treat attention disorders.
Burgard had an idea: Let's test the campus sewage. What he and his students at University of Puget Sound in Tacoma, Washington, found confirmed their suspicions.
Scientists, increasingly able to detect minuscule amounts of compounds, have begun to test sewage to gauge communities' use of illegal drugs. When people take drugs, they are either unchanged or the body turns them into metabolites before they're excreted."The amphetamine levels go through the roof during finals," Burgard said.
"It amazes me it wasn't really until 2005 that anyone had really done this or thought about doing this, now articles are constantly coming out about testing wastewater for drugs," Burgard said. "With the technological advancements, this field is just going nuts."
Though nascent, such research could help tackle the drug problem across America, said Caleb Banta-Green, an assistant professor of public health at the University of Washington.
"If you can look at drug trends through wastewater you can have a conversation with your community and try to make changes. And then, testing the wastewater after such changes, you can see if you're having an impact," Banta-Green said.
Sewage tests, particularly in Europe, are starting to paint a picture of drug trends in various countries and cities:
--In London, cocaine and ecstasy spike at weekends while methadone is used more consistently.
--In Italy, cocaine use has declined while use of marijuana and amphetamines has increased.
--In Sweden and Finland, people use more amphetamines and methamphetamines and less cocaine than other European cities. Also, in Finland, stimulants were more common in large cities.
--In Zagreb, Croatia, marijuana and heroin were the most commonly found illicit drugs, but cocaine and ecstasy showed up more frequently at weekends.
--In Oregon, cocaine and ecstasy are more common in urban than in rural wastewater according to a 2009 study.
--During Superbowl weekend in Miami in 2010, drug levels in sewage did not differ much from a normal weekend.
--In three anonymous Canadian cities, cocaine was the most widely detected drug, while ecstasy levels were much lower than expected, according to a 2011 study.
Burgard estimates that more than 20 such studies have been conducted in Europe over the past decade. In comparison, only a few have been conducted in North America.
Banta-Green said Europe got started with this research earlier but it's starting to gain more traction in the United States. He is writing a paper based on data he collected from 20 US cities.
Wastewater doesn't tell you who's using, how they're using it or why they're using it. Also, by looking at amounts, you don't know if you have "100 heavy users or 1,000 light users," Banta-Green said.
Banta-Green cautions that it's also important to not take one sample in a community – without previous samples or context – and try to draw conclusions about drug use.
But despite such limitations, the technique has advantages over quantifying drug use with surveys, which Burgard called "highly suspect." Given the illegality and stigma of drug use, those surveyed may not always tell the truth, he said.
Testing sewage also covers entire populations, across racial, age, gender and economic statuses, Banta-Green said.
Wastewater doesn't lie.
"Increasingly people have no idea what they're even taking," Banta-Green said. "I was looking at police evidence for the drugs in the Seattle area that were supposed to be ecstasy. The main ecstasy ingredient was only present in 26 of the 81 drugs. Sewage can tell us something about these ingredients."
But some legal and ethical concerns remain.
This type of research has never been litigated, said Leo Beletsky, an assistant professor of law at Northeastern University who specialises in drug policy.
"From a constitutional standpoint, it gets at what your expectation of privacy is. Fourth amendment concerns," Beletsky said.
One parallel legal issue is whether people have an expectation of privacy with their trash. Legal cases have basically decided that the police can go through and not need a warrant. "So when you flush your toilet, you may be waving your privacy rights," he said.
Beletsky said legal issues might arise if the techniques become more sophisticated and researchers could identify if the drugs were coming from certain institutions or even a specific household.
Legal issues aside, there are some ethical concerns, said Jeremy Prichard, a professor of law at the University of Tasmania who wrote an article about the ethics of testing sewage for drugs. Since it's about illegal drugs, the research could attract media attention and stigmatise certain communities, Prichard said. He supports guidelines for researchers to protect people and communities.
"I don't think anyone's saying that this will replace surveys," Burgard said. "But with surveys there's manpower, culling the data, the time to administer the surveys.
"We can run down to the treatment plant and tell you what drugs we find that afternoon."