Busted! Sewage is indicator of cocaine use

Look out, Lubbock, you've been busted.

A Texas Tech researcher has used sewage water to track cocaine use in the city, concluding that it's used up to a third more on weekends than on weekdays.

Researchers find a lot of amazing things in sewage. And apparently levels indicating use of illegal drugs is a way to get some indication of prevalence. (Yes, you could just ask people, but most of them would lie.)

Juliet Kinyua was a master's student at Texas Tech's Institute for Forensic Science when she decided to test sewage water headed for the local treatment plant. She has since moved on and is a doctoral student at The Institute of Environmental and Human Health, but her findings were recently  reported in the peer-reviewed Journal of Forensic Science.

Using a process called "sewage epidemiology," Kinyua tested the water coming into the facility, then analyzed samples with gas chromatography-mass spectrometry to test for a chemical created when humans metabolize cocaine.

 According to the Texas Tech press office, this kind of testing is more commonly used in Europe to pinpoint neighborhoods where residents use high amounts of illegal drugs as well as what kinds of drugs are being abused.

Kinyua said she didn't know what to expect. She collected samples on Mondays, which would be representative of what happened over the weekend, and on Fridays, which would reflect cocaine use during the week.

According to the press release, when a human ingests cocaine, 45 percent of the amount is turned into a metabolite called benzoylecgonine, or BE, Kinyua said. The chemical is only produced when humans take the drug.

"We know that 45 percent of cocaine gets metabolized into BE. It's stable, and you can detect it within 96 hours of intake," Kinyua said. That's why we chose to go with that. When we screened wastewater, we were able to calculate backwards and estimate how much cocaine was being used."

Todd Anderson, a professor of environmental toxicology at TIEHH who was one of Kinyua's supervisors, said that the study may be one of the first peer-reviewed research projects of its kind to publish illegal drug usage evidence found by screening water collected from a sewage treatment facility in the United States. 

"We were surprised by the findings," Anderson said in the Texas Tech press release. "When you convert it back to cocaine equivalents and look at doses and divide that by number of people the waste treatment plant serves, 269,000 people, it winds up being a higher number than I thought."

 "People tend not to be honest on drug surveys," Anderson said. "You get some feel for what actual cocaine use is. If we could sample the wastewater treatment system at different points within a city, you could isolate drug use or determine drug use in certain parts of a city. If resources are limited, you could have intervention programs focused on specific parts of a city instead of broadly applied."