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Pharmaceutical Contaminants Discovered in Florida Redfish  

Photo: Pat Ford

A year-long study by Florida International University (FIU) and Bonefish & Tarpon Trust (BTT) has discovered pharmaceutical contaminants in the blood and other tissues of redfish in Florida waters. This research follows a similar study of bonefish in the Florida Keys, which revealed high levels of pharmaceutical contamination. This new study shows that these waterborne contaminants are a concern statewide.

“The results underscore the urgent need to modernize Florida’s wastewater treatment systems,” said BTT President and CEO Jim McDuffie. “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 (IRL), St. Augustine, and Jacksonville.

Similar to the results of the previous bonefish study, pharmaceuticals were found in all of the estuaries sampled, with an average number of 2.1 drugs per fish and a maximum of five. Only seven out of the 113 sampled fish had zero drugs in their system. On average, 25.7 percent of the fish exceeded a level of pharmaceuticals considered safe, which equates to one-third of the therapeutic levels in humans.

“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.”

Cardiovascular medications, opioid pain relievers, and psychoactive medications were most commonly detected (from highest to lowest detections). The antiarrhythmic medication flecainide and the opioid pain reliever tramadol were detected in over 50 percent of the redfish. The antipsychotic medication flupentixol was detected above safe levels in one in five of the redfish samples. These are very concerning levels of exposure for redfish.

Approximately five billion prescriptions are filled each year in the US, yet there are no environmental regulations for the production nor disposal of pharmaceuticals worldwide. Pharmaceutical contaminants originate most often from human wastewater and are not sufficiently removed by conventional water treatment. They remain active at low doses, can be released constantly, and exposure can affect all aspects of fish behavior, with negative consequences for their reproduction and survival. Pharmaceutical contaminants have been shown to affect all aspects of the life of fish, including their feeding, activity, sociability, and migratory behavior.

“Florida is a leader in addressing water quality issues and wastewater infrastructure, including converting septic systems to sewage treatment,” said Kellie Ralston, BTT’s Vice President for Conservation and Public Policy. “The results of this study indicate that there are additional opportunities for improvement by retrofitting existing wastewater treatment plants with innovative technologies, like ozone treatment, to remove pharmaceuticals and requiring such technology on new wastewater facilities.”

Click Here to view a summary of Redfish Pharmaceutical Contaminants Study’s findings. 

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