Scientists who track pollution have discovered traces of antibiotics and the pain reliever oxycodone in some Puget Sound mussels.

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 in 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.

Mussels in Puget Sound have tested positive for opioids and antibiotics. (Shutterstock)

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

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

She says mussels at a restaurant or store are healthy to eat because they come from clean locations.