Remnants of pharmaceutical and recreational drugs found in New York City rivers

In the US, nearly 100 million people are currently recommended medications like metoprolol and atenolol to help reduce their blood pressure. As an unintended consequence, some of those drugs are ending up in US waterways. New research confirms that increased levels of pharmaceuticals, recreational drugs, and their byproducts can be found in the Hudson and East Rivers in New York City after heavy rainfall events, and might be found elsewhere too (Environ. Toxicol. Chem. 2024, DOI: 10.1002/etc.5891).

Typically drugs aren’t completely metabolized by the human body, and a measurable portion of them can be excreted in urine. That urine usually travels directly to wastewater treatment facilities, which vary in their effectiveness at removing drug contaminants. However, Marta Concheiro-Guisán, a forensic toxicologist at the John Jay College of Criminal Justice and one of the paper’s authors, says that New York City and many other major US cities use an “obsolete” combined wastewater and rain sewer overflow system, which during heavy rainfall can send that drug-filled waste “directly to the rivers.” Modern sewer systems, which have separate pipes to carry wastewater and stormwater, aren’t subject to overflows from rain.

Blood pressure medications were the pharmaceuticals detected at the highest concentration, but other medications, like the antidepressant fluoxetine and the antibiotic sulfamethoxazole, were also detected. Recreational drugs, including cocaine, methamphetamine, methadone, and fentanyl, and their byproducts, were detected too. These drugs were found at levels between 0.5 ng/L and roughly 100 ng/L. Scientists call contaminants at those concentrations micropollutants, though the US has no policy defining them as such.

It’s not currently clear how these drug micropollutants might affect people and the environment. Lloyd Wilson, an environmental toxicologist at the University at Albany, says that more information is needed to determine the potential consequences. “I believe, in general, the levels [of drugs] found are not a human health concern,” he says, adding the caveat that “contaminant monitoring is going to be needed forever” to track the effects.