ARI SHAPIRO, HOST:
Some public health officials are monitoring wastewater to track illicit drugs like methamphetamine and fentanyl, just as they did to follow COVID. The hope is that the data can help prevent overdoses, as Lesley McClurg of member station KQED reports.
LESLEY MCCLURG, BYLINE: Recently, a man came into an LGBTQ community center in Marin County, just north of San Francisco. He said he had smoked a bad batch of meth.
CHRISTOPHER BROWN: And I said, you know, what do you mean? He said, well, I used it, and I could tell something was different about it. It didn't feel the same.
MCCLURG: That's Christopher Brown. He runs the harm reduction program at the center. The man looking for help lifted up his shirt to reveal big, scabby sores on his torso.
BROWN: You know, and I was like, oh, God, you know? And I said, hey, you should go to the clinic. It was probably xylazine in your stuff that made it feel different.
MCCLURG: Xylazine is an animal tranquilizer. Brown knew the drugs might be tainted because he had just received a public health advisory alerting the community that xylazine was detected in the wastewater. Dealers use the drug to extend euphoric effects, but it can cause nasty chronic wounds. When a drug like xylazine is detected in sewers, officials can alert doctors, substance use counselors and treatment programs.
BROWN: So we can tackle it a bit upstream from sort of the disaster scenarios, which, of course, is always desirable.
MCCLURG: Meaning you can get the word out before people start dying. Testing sewer water can illustrate exactly what is hot and where, offering a much more accurate picture of the drug crisis than simply counting overdoses. Haylea Hannah is an epidemiologist for Marin County.
HAYLEA HANNAH: We know now that kind of our clinical data sources just show us the tip of the iceberg because if somebody has an overdose and doesn't call 911 or doesn't present to the emergency department, we might not necessarily ever hear about it.
MCCLURG: She says roughly 100 communities across the country are testing sewers. After someone consumes a drug, their body will metabolize it, and scientists can measure the metabolites - traces of the substance - that are flushed down the toilet or wash down the drain. Rolf Halden is an epidemiologist at Arizona State University who tracks wastewater in Tempe.
ROLF HALDEN: It seems, like, impossible, to find a needle in the haystack, but it can be done with new instrumentation that is available to find very small quantities of molecules of interest in this soup that is going down the drain and ultimately into the sewers.
MCCLURG: He says data collected during the pandemic illustrated that the drugs of choice changed. The same supply chain disruptions that plagued the consumer market hit drug dealers. For example, people in western Kentucky started taking more opioid pain meds and snorting less cocaine.
HALDEN: We never know who exactly took a drug, but we can determine the consumption rates of different substances in a community.
MCCLURG: That information can help officials craft prevention strategies to the neighborhoods that need it most. For example, if fentanyl spikes, then officials could boost Narcan distribution. Narcan can quickly restore breathing during an opioid overdose. And then, in theory, over time, counties like Marin hope to show whether a health policy is working to lower drug use or not. For NPR News, I'm Lesley McClurg in Marin County. Transcript provided by NPR, Copyright NPR.