During a yearlong study, Florida International University (FIU) and the Bonefish & Tarpon Trust (BTT) found high levels of pharmaceuticals in Florida redfish blood and tissue. Over 50 percent of fish tested had the opioid tramadol and the antiarrhythmic medication flecainide in their systems. One in five was contaminated with antipsychotic drugs, and other fish were found with cardiovascular medications, pain relievers, and psychoactive medications. 

According to FIU News and a BTT press release, waterborne pharmaceutical contaminants are a statewide concern in Florida. The current research followed a 2018 study conducted on bonefish in the Florida Keys. The bonefish averaged seven kinds of drugs in their systems and one particular fish held 17. During that study, FIU also found pharmaceuticals in bonefish prey, like shrimp, crabs, and smaller fish. 

Map of Florida with pinned locations
Researchers sampled fish from nine key estuaries. BTT

As for the redfish study, volunteers, scientists, anglers, and guides sampled fish in nine estuaries—Pensacola, Apalachicola, Cedar Key, Tampa Bay, Charlotte Harbor, Everglades National Park, Northern Indian River Lagoon, St. Augustine, and Jacksonville—finding evidence of contamination in every one of them. Only seven of the 113 fish sampled didn’t have drugs in their systems. Just over 25 percent exceeded levels that are considered safe. 

“Given the impacts of many of these pharmaceuticals on other fish species and the types of pharmaceuticals found, we are concerned about the role pharmaceuticals play in the health of our fisheries,”  said Jennifer Rehage, FIU professor and lead researcher of the study. “We will continue this work to get more answers to these concerning questions.”

BTT President and CEO Jim McDuffie. said this study highlights the need for Florida to modernize its wastewater management systems. Pharmaceuticals get into the water through the improper disposal of drugs in septic and sewer systems. Currently, there are no regulations on disposing unused prescriptions. Once in the water contaminants from drugs can be released over time in low doses, negatively affecting all aspects of fish behavior. Contaminated fish experience changes in breeding, migrating, sociability, and feeding. 

Florida redfish swimming in grass.
Pharmaceutical contaminants affect fish behavior and can reduce their ability to successfully breed and survive. Pat Ford

“Human-based contaminants like these pose a significant threat to Florida’s recreational fishery, which has an annual economic impact of $13.9 billion and directly supports more than 120,000 jobs,” McDuffie said.

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Florida is working to update water treatment infrastructure by converting septic systems to sewers, but there are still opportunities to get pharmaceuticals out of the water. Some solutions could include retrofitting treatment plants with new technology, like ozone treatment, to remove pharmaceutical contaminants before they enter the water and requiring new treatment plants to have some kind of system in place to do the same.