Public health officials in Marin County are now tracking illicit drugs in local wastewater — everything from nicotine to methamphetamine and fentanyl. Testing sewer water can illustrate exactly what is “hot” and where, offering a more accurate picture of the drug crisis than simply counting overdoses.
“We know now that our clinical data sources just show us the tip of the iceberg of actual overdoses, because if someone doesn’t call 911, or doesn’t present to the emergency department, we might never hear about it,” said Dr. Haylea Hannah, an epidemiologist for Marin County.
In early February, the Marin public health office began testing weekly samples collected at the Central Marin Sanitation Agency in San Rafael. The move followed the county’s success using sewers for COVID-19 surveillance — communities are increasingly relying on wastewater data to track viral levels, because sewers can show the burden of disease much more accurately than clinical testing data, since people are no longer going to the hospital for PCR tests.
Hannah says the county is testing sewer water for a long list of common drugs like heroin and cocaine. They just added xylazine — also known as “Tranq” — an animal tranquilizer, which is increasingly laced with fentanyl; dealers add fentanyl to extend euphoric effects, but it can cause chronic infections. Since December, five people in San Francisco had low levels of xylazine in their systems when they lethally overdosed.
“New instrumentation can find very small quantities of molecules of interest in the dirty soup that is going down the drain and ultimately into the sewers,” said Rolf Halden, professor and director of the Biodesign Center for Environmental Health Engineering at Arizona State University. “We never know who exactly took a drug, but we can determine the consumption rates of different substances in a community on a per-1,000 people level.”
After someone consumes a drug, their body will metabolize it, and scientists can measure the metabolites that are washed down the drain. That means tests can decipher whether the drug was consumed by a person or flushed down the toilet in a raid.
