The method could help law enforcement identify new drug hot spots and monitor whether anti-drug measures are working, researchers said.
Kurunthachalam Kannan and Bikram Subedi from Wadsworth Center, New York State Department of Health, noted that to date, most methods to estimate drug use in the US are based on surveys, crime statistics and drug seizures by law enforcement.
But much illegal drug use happens off the radar. To better approximate usage, scientists have been turning to wastewater.
In Europe, a number of studies have been done to see how well wastewater treatment plants are removing illicit drugs from sludge before treated water is released into the environment.
But until now, no study in the US had looked at this, likely leading to underestimates of abuse, researchers said.
Kannan and Subedi wanted to form a more complete picture of drug use, so they studied levels of illicit drugs at two wastewater treatment plants in Albany, New York.
They found that the wastewater treatment plants didn't remove all illicit drugs before releasing water back into the environment - and eventually into drinking water.
The researchers suggest, tracking drugs in wastewater could help policymakers and law enforcement understand patterns of abuse and better fight it.
The study was published in the ACS journal Environmental Science & Technology.
