Alarming Amounts of Pharmaceuticals Found in Florida Redfish

A study conducted by Florida International University's (FIU) Coastal Fisheries Research Lab, funded by the Bonefish & Tarpon Trust (BTT), found that redfish sampled from nine estuaries throughout Florida are contaminated with pharmaceuticals. The study detected 17 unique pharmaceuticals in the redfish, with cardiovascular medications, opioid pain relievers, and psychoactive medications being the most commonly detected.

“The results underscore the urgent need to modernize Florida’s wastewater treatment systems,” said BTT President and CEO Jim McDuffie in a press release. “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.”

Scientists and volunteer guides and anglers sampled redfish in nine of Florida’s most important estuaries: Pensacola, Apalachicola, Cedar Key, Tampa Bay, Charlotte Harbor, Florida Bay, Northern Indian River Lagoon, St. Augustine, and Jacksonville.

A study from 2022 found similar results in South Florida’s bonefish, crabs, shrimp, and other flats prey-fish species.

“These studies of bonefish and redfish are the first to document the concerning presence of pharmaceuticals in species that are important to Florida's recreational fisheries,” said Dr. Jennifer Rehage, FIU professor and the study’s lead researcher. "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. We will continue this work to get more answers to these concerning questions.”

Although the study raises concerns, there is hope as research from Europe shows that most pharmaceuticals can be removed from the wastewater treatment process by applying ozone treatment to wastewater. Therefore, significant investment in Florida's water infrastructure is required to address pharmaceuticals and other contaminants of emerging concern.

Some specific findings:

• Researchers sampled 113 Florida redfish for 94 commonly prescribed pharmaceuticals.
• Redfish blood plasma samples were collected at nine Florida estuaries: Pensacola, Apalachicola, Cedar Key, Tampa Bay, Charlotte Harbor, Florida Bay, Indian River Lagoon, St. Augustine, and Jacksonville.
• On average, researchers detected 2.1 pharmaceuticals per redfish; only seven redfish had zero pharmaceuticals.
• Across all samples, a total of 17 unique pharmaceuticals were detected, comprising eight pharmaceutical classes.
• Across estuaries, the number of pharmaceutical detections was highest in Apalachicola and Tampa Bay, intermediate in Charlotte Harbor, Cedar Key, Pensacola, St Augustine, and Jacksonville, and lowest in Florida Bay and Indian River Lagoon. The averages are as follows: Apalachicola = 3.3, Tampa Bay = 3.0, St. Augustine = 2.5, Cedar Key = 2.2, Jacksonville = 2.1, Charlotte Harbor = 1.8, Pensacola = 1.8, Florida Bay = 0.9, Indian River Lagoon = 0.9.
• A total of 12 pharmaceuticals accounted for over 97% of detections. Harmful effects on fish have been documented for 7 of these 12 pharmaceuticals. These include, tramadol, caffeine, donezepil, dicolfenac, diphenhydramine, sertraline, and ranitidine while the effects of the remaining 5 pharmaceuticals (felodipine, flecainide, flutamide, flupentixol, and clotrimazole) remain unassessed.
• The antiarrhythmic agent flecainide led detections, with 60 detections (53.1% of all redfish), while the synthetic opioid analgesic tramadol had 59 detections (52% of all redfish. Three other pharmaceuticals were commonly detected: caffeine (43.3% of samples), the psychoactive flupentixol (21.2% of samples), and the psychoactive donepezil (9.7% of samples).
• Exposure to pharmaceuticals by redfish may occur by inhalation (via water/sediment) or through prey.

See the full published results of the study here.