Feds Want to Analyze Sewer Samples For Marijuana Use

Citywide pee-tests of sorts are underway in two Washington cities. The University of Puget Sound announced on Monday that researchers have received federal funding to study how the legalization of marijuana has influenced cannabis use by collecting sewer samples in two cities, which will remain unnamed, until the study is complete.

University of Puget Sound chemistry professor Daniel Burgard began sampling sewer waste in December 2013, eight months before legal dispensaries were opened in the state, to establish a baseline. With a $120,000 grant from the National Institutes of Health (NIH), Burgard and his collaborator, Caleb Banta-Green from the University of Washington, will continue to analyze the sewer samples to see if per capita marijuana use has increased with legalization.

“In the state of Washington, it seems like nobody really knows what is going to happen as far as changes in marijuana use,” Burgard said in an interview with Cannabis Now. “We’re a test state like Colorado, so people are pretty interested in getting their hands on as much data as possible.”

The wastewater analysis will provide a more accurate reflection of the shifts in cannabis use after legalization than the traditional method of surveys, which have more room for error, Burgard said. Until December 2016, Burgard and Banta-Green will be sampling and analyzing sewage samples to examine three things: if the data agrees with survey responses, if cannabis consumption increases on certain days of the week and if the legal recreational market has been diminishing black market and medical cannabis sales.

If they don’t see use increasing in the sewage water after recreational marijuana was legalized, Burgard said, then they can infer the legal market was simply replacing one of the other sources.

The National Institute on Drug Abuse, the department within the NIH funding the research, said in an email that they are supporting the study to more fully understand substance use disorders.

“In order to accomplish this mission, it is necessary to understand how substance use is occurring within the population using unbiased techniques, such as the use of sewer-based drug epidemiology,” NIDA’s email statement said.

The study will search for only a metabolized byproduct of cannabis, Burgard said, so the data gathered will not be skewed by any raw or cooked cannabis that finds its way into the sewers. The study will also be measuring the metabolized cannabis numbers against other human-excreted molecules, such as cholesterol, to control for changes in the population size or rain seeping into sewage pipes.

While many people may feel that the study encroaches upon their privacy, the researchers noted that they are only looking for big picture information and will not be able to trace marijuana use back to one person, or even one neighborhood or street.

Allison Holcomb, the main author of Washington’s marijuana law and an ACLU lawyer, called for such tests at a Spokane City Council meeting in 2014.

“Using wastewater data to actually get a baseline of what drug use looks like in various communities over time can help us develop more sound drug policies,” Holcomb said. “It’s too easy for surveys to be skewed.”

Burgard said that he has been asked by officials from Spokane and Colorado’s Department of Public Safety to see if they could conduct a similar study, but that the cities lacked the ability to run studies without fancy equipment to find “low amounts of compounds in a very dirty system.”

Burgard has already successfully conducted a wastewater analysis study for study drug increases during midterms and finals on University of Puget Sound’s campus.

How would you feel if your state did a study like this? Tell us in the comments.