Dec. 16, 2008 – Methamphetamine is the most concentrated illicit drug found in U.S. wastewater, report scientists who've found a way to measure drug use on a citywide basis.
The drugs get into the wastewater because they are excreted in the urine.
Meth was detected in five of seven municipalities in concentrations higher than reported in previous studies -- all done in Europe. The five cities that flushed the most meth were in the Western and Southern regions of the U.S.
It's not the first time scientists have looked for legal and illegal drugs in city water systems. But Oregon State University researcher Jennifer Field, PhD, and colleagues say they've found a better way to do it.
To demonstrate their technique, Field and colleagues looked for a wide variety of drugs in raw sewage collected from seven municipalities in the U.S. They did not name the cities.
Among the study's other findings:
- Cocaine was found in all seven municipalities, although concentrations were much lower than methamphetamine concentrations. Concentrations were similar to those seen in previous studies, all in European cities.
- Ecstasy (MDMA) was detected in five of the seven municipalities.
- MDA (methylenedioxyamphetamine, a psychedelic amphetamine) was detected in three of the seven municipalities.
- Ketamine, used both legally and illegally, was found in two municipalities.
- PCP ("angel dust," phencyclidine) was found in only one municipality.
- No LSD could be detected in any of the seven cities.
- Hydrocodone, oxycodone, and methadone -- frequently prescribed and frequently abused narcotics -- were found in all seven cities.
Field and colleagues note that it's tempting to try to get an estimate of per-person drug use by dividing the concentrations of drugs in wastewater by the population of the city. But they note that this would not be accurate, as commuting and other human behaviors greatly affect population density at various times.
However, they suggest that by measuring creatinine -- a substance that occurs in human urine -- it might be possible to develop a per-person index of drug use.
The findings appear in the Dec. 15 issue of Environmental Science & Technology.