May 25 (UPI) -- The growing use of opioids is showing up in an unexpected place -- the waters of the Puget Sound, specifically the marine life that lives there, scientists say.
Researchers at the Washington Department of Fish and Wildlife said that for the first time, mussels living in parts of the Puget Sound are testing positive for oxycodone, a prescription drug used to alleviate pain in humans.
Trace amounts of the opioid were detected in mussels near Bremerton's shipyard and Elliot Bay.
But diners don't have to worry about contaminated mussels ending up on their plates. Researchers took clean mussels from Penn Cove on Whidby Island and placed them in cages in Puget Sound, where they took in trace contaminants from their new home after two or three months.
The transplanted locations aren't near any commercial shellfish beds.
The opioids ended up in the sound through human sewage which is processed by wastewater management systems that can't filter out drugs. And it's not just opioids that end up in water, drugs like antidepressants and chemotherapy are detected in the mussels, too.
"What we eat and what we excrete goes into the Puget Sound," Jennifer Lanksbury, a biologist at the Washington Department of Fish and Wildlife, told KIRO-TV. "It's telling me there's a lot of people taking oxycodone in the Puget Sound area."
Researchers said the mussels aren't harmed by the opioids because they don't metabolize them, but other fish can.
"Those are definitely chemicals that are out there in the nearshore waters and they may be having an impact on the fish and shellfish that live there," Lanksbury said.