Wastewater helped us track COVID-19 strains. Some say it can do the same for drug use

To listen to this broadcast, click here: http://www.npr.org/templates/transcript/transcript.php?storyId=1240533982 HOST: AYESHA RASCOE AYESHA RASCOE: During the pandemic, cities across the country discovered an unexpected ally right beneath our feet - sewers. [...]