Mussels from the Seattle and Bremerton harbor areas of the Puget Sound have traces of oxycodone in them, according to a new study by the Washington Department of Fish and Wildlife. They also contain minute amounts of melphalan, a chemotherapy drug and possible carcinogen.

“It’s telling me there’s a lot of people taking oxycodone in the Puget Sound area,” Jennifer Lanksbury, a biologists at the Department of Fish and Wildlife, told KIRO7. “The contamination is likely coming from wastewater treatment plants.”

King County Wastewater Management told KIRO7 that although their system has the potential to detect and filter out most contaminants from the water, it cannot catch everything.

As concerning as this may seem, scientists say that people should not fear consuming shellfish that is local to the Seattle area. According to the Puget Sound Institute, the traces of detected opioids were significantly smaller than a typical human dose of the drug and none of the tested mussels are located near commercial shellfish beds.

Although, for now, at least, there is little chance that an oxycodone-infused mussel will end up on your plate, this new discovery underscores the increasing severity of the opioid epidemic nationwide and its potential effects on the environment.