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Professor proposes testing for illicit drugs in municipal wastewater

Pilot study gives “a good approximation” of how many people are consuming the drugs.


A forensics professor at Université du Quebec à Trois-Rivières has proposed using chemical analysis of municipal effluent to determine the rate of illicit drug use in a community.

Any person who consumes a drug – whether it be illicit or a legal pharmaceutical – excretes traces of the drug in their urine and feces, which are then flushed into the municipal sewage system. However, water treatment facilities remove only a tiny proportion of these trace chemicals from the wastewater, explains the professor, André Lajeunesse.

“So, in the municipal effluent – that is, the water coming out of the water treatment plant – there remain traces of this illicit drug use tied to human activity. By measuring these traces, it should be possible for us to provide some pertinent information for our investigation,” explains Dr. Lajeunesse in an article on the UQTR news site, EnTête.

To test his idea, Dr. Lajeunesse took samples from the outflow of an unnamed wastewater treatment facility and analyzed them in the lab with the help of his research assistant Nicolas Gilbert, an undergraduate student in chemistry. They focussed on three drugs: cocaine, ecstasy and fentanyl.

Their analysis found trace amounts of the drugs and their metabolites in the water samples. They then made various calculations to estimate the rate of consumption in the population, taking into account such factors as the usual dose of the drug, the percentage normally excreted by the body, and the outflow rate and number of people served by the treatment plant. “These calculations gave us a good approximation of the number of people who consume the drugs we studied,” says Dr. Lajeunesse. Cocaine was the top drug of choice, followed by ecstasy and fentanyl. The researchers have not yet published their findings in a peer-reviewed journal.

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