The upcoming study is aimed at helping determine whether the opening of pot shops increase a community's marijuana use, whether data from the wastewater correlate to what people answer in surveys about their marijuana use, and whether weekday or weekend marijuana use has increased.
"We're trying to get a sense of the type of user," Burgard said. "If there's more use on the weekends, maybe that's more recreational. But if Sunday to Thursday use goes up as much, that might be a public health concern, with habitual users using a lot more."
The data could also show how much of the illicit black market for marijuana the state's legal stores are capturing, by comparing the wastewater data with the state's close tracking of marijuana sales. If sales figures continue to rise, but the wastewater levels show that overall pot use is flat, that would indicate that people are getting their marijuana at legal stores instead of on the black market.
But if sales figures rise and the sewer evidence of pot use also rises, that could indicate that people are still buying on the black market — and that legalization has increased overall use in the state without displacing much of the black market.
= new reply since forum marked as read