Swedish public broadcaster SVT reports that wastewater collected from city sewers is sent to the Swetox research lab in Stockholm, where cutting-edge technology is used to measure the presence of cocaine, marijuana and amphetamines.
The technology is highly precise — residents of the city of Gävle were found to have snorted 230 doses of cocaine on Christmas Day, and partaken in 7,349 doses of marijuana on a single day in 2015.
Gävle’s municipal drug co-ordinator Johnny Gustafsson told SVT that sewage samples offer a more scientific alternative to traditional self-report surveys.
“We can discover a lot more abuse this way.”
Authorities in some jurisdictions are said to be considering using the method to carry out targeted analyses on specific institutions such as prisons and schools.
Because individual users cannot be identified, the process has so far evaded legal obstacles.