Scientists who track pollution have discovered traces of antibiotics and the pain reliever oxycodone in some of Seattle's Puget Sound mussels, indicated "a lot of people" are using the drugs in the area.

KIRO-TV reported this week that the Washington Department of Fish and Wildlife obtained clean mussels from Penn Cove on Whidbey Island and put them different areas to test for water contamination.

Scientists worked with the Puget Sound Institute to analyze the data and discovered three out of 18 locations came back positive for trace amounts of oxycodone.

State Fish and Wildlife biologist Jennifer Lanksbury says the contamination likely comes through wastewater treatment plants.

"What we eat and what we excrete goes into the Puget Sound," Lanksbury told KIRO-TV.

"It's telling me there's a lot of people taking oxycodone in the Puget Sound area."

In 2016, Washington State's King County which includes Seattle and the Puget Sound saw a record 332 opioid-related overdoses.

She says the chemicals may be having an impact on fish and shellfish in the areas.

"People should be wary," Lanksbury said, but added that mussels at a restaurant or store are healthy to eat because they come from clean locations.

However the results of the research show that the U.S. opioid crisis is in fact affecting other organisms in the ecosystem.

"Hopefully our data show what's out there and can get the process started for cleaning up our waters," she said.