Cocaine use in the Hub City rises significantly on the weekends, according to one graduate student at Texas Tech.

Juliet Kinyua, now a doctoral student at Texas Tech in the Institute of Environmental and Human Health, published her findings in the peer-reviewed Journal of Forensic Science while doing her master’s research project.

Kinyua tested sewage water headed for the Lubbock Wastewater Treatment Plant, and found that people in Lubbock used 900 grams of cocaine during an average weekday, but increase their usage by up to 1,200 grams on weekends.

Tech says that assuming 100 milligrams of cocaine makes a dose, that means usage can run from 9,000 and 12,000 doses.

The results were found using a process called sewage epidemiology. The system is more commonly used in Europe to find which neighborhoods use high amounts of illegal drugs, and what types of drugs are being used.

“We collected wastewater on Mondays and Fridays,” said Kinyua. “Mondays were representative of the weekends whereas Fridays were more representative of use during the week.”

A release from the university says that the study may be one of the first peer-reviewed research projects of its kind to publish illegal drug usage evidence found by screening water collected from a sewage treatment facility in the United States.