If you're planning a trip to London, maybe you shouldn't order the shrimp.
Shrimp in five rivers in England have tested positive for cocaine.
A group of British scientists drug-tested freshwater shrimp from 15 sites across five rivers in Suffolk County, a rural area northeast of London. The results, published in Environment International, showed that all the shrimp contained trace amounts of cocaine, as well as the drug ketamine (an anesthetic sometimes used as a party drug) and a banned pesticide called fenuron.
Researchers said the drugs likely made their way into rivers and fresh water after human consumption; cocaine can pass from urine into our wastewater. Then — especially if raw human sewage is left unfiltered and untreated — the drug can flow from our sewage systems into surrounding aquatic ecosystems.
This isn't just a problem overseas, either.
A 2017 study Canada, found that shellfish living in close proximity to places where sewage gets discharged into the environment contained traces of drugs such as triclosan (the antibacterial agent in hand soap) and ibuprofen.
And last year, scientists also found traces of oxycodone, antidepressants, chemotherapy drugs, and heart medications in the muscle tissue of mussels in Seattle's Puget Sound. This suggests the mussels are feeding on contaminated human sewage, the researchers said.