The researchers decline naming certain cities but they revealed one trend: use of methadone and methamphetamine (a prescription opiate withdrawal aid and speed) remained constant over 24 days in these cities, but cocaine consumption routinely spiked on the weekends.
A method of taking a small sample of incoming sewage at a water treatment plant is developed. This method can extract the record of local drug use
Environmental analytical chemist Jennifer Field of Oregon State University and her colleagues, using an automated system to test small samples automatically collected at wastewater treatment plants over a 24-hour period. Solids are centrifuged out and the sewage sample is then chemically separated in various compounds of interest chemically. By measuring the relative mass of the various residual chemicals, the chemists can then identify what specific drugs have been recently used in that community.
The technique might help communities determine where to apply law enforcement or track the success of targeted drug-use prevention efforts.
This article about sampling for local drug use appeared on Scientific American.
I remember an article in a Dutch newspaper mentioning that with a comparable method it has been shown that in Spain the abuse of cocaine is the highest of Europe.