Nantucket Wastewater Shows Cocaine Levels Increasing, But Why?

Cocaine levels in Nantucket waterways have jumped, but the reasons behind the surge remain elusive.

After testing 50% above the national average in September 2025, the island's readings have doubled in October and November, reaching 100% above national levels.

This surge comes as police have carried out several significant cocaine targeting campaigns over the past several months, including the largest bust in the department's history, which secured nearly six pounds of cocaine, according to a Boston.com report.

In an interview with the Nantucket Current, Police Chief Jody Kasper said that the busts were due to the department cracking down on illicit drug distribution overall, not just cocaine.

“We're not having a lot of people come into the booking room, and when we search them, finding cocaine in their pockets, or we're not pulling over a lot of people and finding cocaine present,” Kasper said to Boston.com. “It's not something that is in our day-to-day work that our officers and detectives are seeing out there.”  

According to Nantucket officials, cocaine and its primary metabolite, benzoylecgonine or BZE, typically appear together in wastewater data because the body converts much of the consumed cocaine into BZE before being excreted from the body.

When cocaine levels can rise without a corresponding BZE increase, the data indicate that some portion of the cocaine entering the sewer system did not come from human consumption but may have originated from cocaine being disposed of instead.  

According to Boston.com, town officials said that because Nantucket's cocaine levels are above national and regional averages, while the BZE is at or below the average, the most probable causes behind the surge could be whole-scale dumping, small-scale disposals, or complementary use with alcohol, which changes metabolism and can suppress the usual BZE signal.