Tox Tuesday: How were Seattle’s mussels contaminated with opioids?

September 18, 2018

Earlier this year, mussels fished from Puget Sound — the beautiful ocean inlet in the northeast corner of the U.S. state of Washington — tested positive for opioids.

No, the shellfish weren’t doing drugs. Rather, unprecedented levels of opioid prescriptions and opioid abuse have caused even the environment to be affected.

Opioid usage, both legitimate and illegal, is at unprecedented levels. According to the U.S. Centers for Disease Control and Prevention, almost 58 opioid prescriptions were written for every 100 people. We humans impact nature wherever we go, including in this way. It’s not unusual for common pharmaceuticals to be found in Puget Sound, but researchers told NPR this is the first time they’ve detected traces in local shellfish.

Oxycodone, a powerful painkiller, was specifically the opioid detected in the tainted mussels. NPR reports that the amount found was “thousands of times” lower than the dosage you’d expect from humans, and that contamination was only detected in areas away from any commercial shellfish beds. Just three of 18 locations that were examined yielded tainted mussels.

How is this happening? Researchers at the Washington Department of Fish and Wildlife said that discharge from wastewater treatment plants entered Puget Sound, and from there opioid residues were taken in by mussels.

Many shellfish are filter feeders, meaning they eat by filtering little bits of food, including plankton and tiny plants, from the water around them. In doing so, they pick up many toxins. It’s one of the main food safety concerns with shellfish — when filtering algae, they can be contaminated by dangerous toxins that lead to serious illnesses when humans consume them.

Mussels don’t metabolize opioids, so there are no worries of Seattle-area mussels getting high. Fish are known to be affected by the drugs though, so researchers intend to continue to monitor the biological effects on sea life in Washington’s waters.

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Category: Food Safety