I am not pleased opioids are found in mussels near urban areas. However, it might be well to keep this in perspective. Quote from the article: "The institute reported that the amount of oxycodone found in the tainted mussels was thousands of times lower than a therapeutic dose for humans. And the highly addictive drug was only ingested by mussels in three of 18 test sites, described as highly urbanized and not near any commercial shellfish beds."
With advances in analytical methods for detection of targeted molecules, it is now possible to detect almost any common drug in use by humans ... almost anywhere. This is a good thing, because it allows us to begin to establish cause and effect relationships, such as whether mussels are affected by oxycodone in the levels found. If so, we should take reasonable steps to prevent oxycodone from reaching marine environments.
Further, there are so many well recognized, fully documented environmental poisons contaminating selected water sources across the nation, whose presence is NOT being addressed, for technical as well as political reasons, that we should deal with the acute problems at hand before being diverted by what likely is a minor problem ... or not a problem at all.
Flint, Michigan, is by no means the only large US city with significant heavy metal contamination of its water supply. And we KNOW exactly what the effects of this contamination are on growing children.
Off the soap box.