The US opioid crisis has started to affect more than just humans.

Research from Seattle indicates that the local population is consuming so much oxycodone that it is now seeping into the local water supply.

Scientists at the Washington Department of Fish and Wildlife found traces of oxycodone in shellfish near Bremerton and in Seattle’s Elliott Bay. They made the discovery in a study involving mussels.

Scientists have also found antibiotics, antidepressants, chemotherapy drugs and heart medication in the systems of mussels.

RT reports: The shellfish are filter feeders who gain nourishment from their surroundings, while simultaneously absorbing whatever contaminants are also in the water – making them an ideal barometer for environmental scientists to test water pollution in a given area.

“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 CBS Seattle affiliate KIRO