Sewer Sludge Can Reveal Which Drugs a Community Is On, and When

Sergio Moraes/Reuters

Sewage epidemiology, or the study of chemicals present in human waste, is a burgeoning field in the world of illegal drug monitoring. Testing for drugs in public water supplies has revealed many interesting population trends, including a recent study that found that amphetamine levels in the wastewater at a Washington college campus “go through the roof” during final exam time.  

Most studies to date have analyzed drugs carried in urine, which have been dissolved in water as the compounds enter the sewer system. But a new study suggests that method of analysis may have lead researchers to significantly underestimate the amount of drugs flowing through the system.

The study, led by Bikram Subedi and Kurunthachalam Kannan of the New York State Department of Health, sampled both wastewater and solid waste from two small communities just outside of Albany, New York. They searched for both the drugs themselves, as well as some of their metabolites—the compounds that result from the drug’s transformation in the body. They found morphine, a metabolite of heroin, in 100 percent of the untreated wastewater samples, cocaine metabolites in 93 percent of it, as well as high levels of MDMA excretions. Over the course of one week, they monitored changes in metabolite levels in the waste. In effect, they were measuring drug use during that week in real time.

The results from sampling both the wastewater and solid waste were significant: The per capita consumption of cocaine in the Albany area was estimated at four times higher than that found in a previous U.S. study, and the level of amphetamine abuse was about six times higher. The results are most dramatic when compared to sewage studies in Europe: The amphetamine levels in Albany were three-to-27-times higher. As the BBC points out, this might indicate that sewage epidemiology “would benefit from getting to grips with the solids.”

Plus, it turns out the wastewater treatment plants don’t do a great job of removing drug ingredients from the water. While about 99 percent of cocaine was removed, the study found that just around 4 percent norcocaine, a “pharmacologically active metabolite of cocaine,” was removed. In the case of methadone and methamphetamine, the treatment plant achieved the unfortunate feat of “negative removal”: It converted their related compounds back into the original drugs.