According to a federally funded study, marijuana use went up in Washington state after beginning legal marijuana sales in 2014.
One major city, Tacoma, saw consumption double over three years.
“It’s stinky,” remarked lead author Dan Burgard, a chemist at the University of Puget Sound. He added,”But we’ve worked with urine, we’ve worked with wastewater, and we’ve worked with port-a-potties. It’s not as bad a port-a-potties.”
Two sewage treatment plants that serve the 200,000 people of Tacoma were involved in the study. The scientists would pick up a cooler full of frozen wastewater samples, thaw them and analyze them using liquid chromatography and mass spectrometry, looking for THC-COOH.
THC-COOH is a substance that is produced when the body metabolizes THC, found in marijuana.
The researchers found that the consumption of THC doubled from December 2013 to December 2016.