Fish and marine life off South Florida’s coast are ingesting high amounts of pharmaceuticals flushed down the drain or excreted in wastewater, because outdated treatment facilities are unable to detect and filter out the contaminants.
Results from a study by researchers at Florida International University’s Coastal Fisheries Research Lab have identified 58 different pharmaceuticals in 93 bonefish, sampled along a 200-mile stretch of South Florida’s coastline over a three-year period. The researchers discovered 16 different drugs in one fish.
Although the study has not been published yet, Dr. Jennifer Rehage (lead researcher and associate professor at Florida International University’s Institute of Water and Environment) said that she and her coauthors plan to submit it to a peer reviewed journal.
She said that they decided to share their research findings before publication, because the Congress passed a bipartisan infrastructure bill in 2021. It offered an opportunity for investors to focus on key areas like the problems with water treatment and regulations that allow pharmaceutical contamination.
Congress approved President Joe Biden’s $1.2 trillion infrastructure bill in November 2021. Over five years, it provides more than $500 million in federal funding to improve roads, bridges and energy systems. The states will receive the majority of these investments, and they will decide which sectors will benefit.
Dr. Duane De Freeze, a marine biologist and executive director of Indian River Lagoon National Estuary Program, called the study an original contribution to existing research because it looked at the presence of contaminants in bonefish, an “incredibly important recreational sport fish with very high economic value.”
“When you look at the research over the last couple of decades,” he said, “whether it’s on Atlantic bottlenose dolphin, manatees and other species in Florida, what it’s building is a really strong case that we have toxicants and other emerging contaminants of concern that are getting through our wastewater systems.”
He stated that previous Florida studies had shown that wildlife can be exposed to some endocrine disruptors and human antibiotics.
“So, it is not surprising that we would see some of these chemicals in the tissue or the organs of marine organisms,” he said.
Unregulated Contaminants
In Florida, Rehage said, one-third of households have septic tanks and two-thirds have sewer lines, and “conventional wastewater treatment in Florida and other parts of the United States does not remove pharmaceuticals.”
“It’s in our drinking water. We also have it in our fish that we consume,” Rehage said, adding, “The risk is very small because concentrations are very small. But no one knows what it means for us to be exposed over our lifetimes to so many pharmaceuticals.”
Rehage stated that there are not regulations governing the disposal or production of pharmaceuticals. “So, they’re not considered a contaminant.”
Alexandra Kuchta, a spokesperson for the Florida Department of Environmental Protection, said that the department worked jointly with state health, agriculture and wildlife conservation officials “to determine if environmental chemicals are present in fish from Florida waters.”
Kuchta called pharmaceutical contaminants “an emerging issue,” and said that the environmental protection department ”looks forward to working with stakeholders as new science becomes available.”
To screen the fish, blood tests were performed and tissue analysis was done. The prescription drugs found included antidepressants and heart medications, pain relievers, blood pressure medications, blood pressure medication, heart medications, and antibiotics. These same contaminants were also found within crab, shrimp, and other small sea creatures that the bonefish eat, as well in water and sediment.
The study began in 2018 and was conducted by a team of Florida International University scientists in partnership with Sweden’s Umeå University and the University of Agricultural Sciences. The average number of pharmaceuticals found in South Florida waters was seven per fish. The contaminants were also found in fish taken from both urban and remote areas.
43 bonefish from waters close to the Caribbean, Bahamas, Puerto Rico and Mexico were also tested for contaminants.

Researchers found the highest concentration of contaminants in one fish from Biscayne Bay. The fish was found to contain eight different antidepressants at levels that were as high as 300 times those prescribed for humans. The study also found concentrations of Parkinson’s drugs, antifungal drugs, stomach medications and opiates in the fish.
“The levels in bonefish blood and tissue were high enough to have biological effects,” the researchers wrote, in a summary of their findings. A Miami-based nonprofit, the Bonefish & Tarpon Trust, funded the research. The study is the latest in a growing body of research over the last three decades that has documented the presence of pharmaceuticals, steroid hormones, and personal care products in Florida’s coastal waters.
Aaron Adam, director of science and conservation at the bonefish trust, called the study’s methodology rigorous and said the findings support the conclusions of previous research.
Sources of Contamination
A previous study published in February 2021 found that contaminants could reach coastal waters and wetlands from runoff or groundwater flow in heavily populated areas.
South Florida is home to a variety of protected ecosystems. These include wetlands and coral reefs located close to major metropolitan areas.
“Global pharmaceutical production is skyrocketing, compared to other things we care about such as human population growth, or CO2 emissions,” Rehage said. She explained that most of the contaminants come from prescription drugs people consume and excrete. Effluent travels through a sewer line to the ocean or any other body of water.
These waterborne chemicals pose a significant threat to the flats fishery, an important component of Florida’s recreational saltwater fishery, which generates more than $9 billion annually and supports nearly 90,000 jobs, Adam said.
He stated that the majority of chemical contamination is likely to be caused by people who take prescription medications. “Only a portion of the drugs that people take are absorbed by the body. We excrete the rest that gets sent to the wastewater treatment system,” Adam said, adding that to his knowledge, there were no regulations governing the disposal of pharmaceuticals in wastewater.
He said there was also a concern that pharmaceuticals — as well as nutrients in runoff from stormwater, agricultural lands or treatment plants — were entering the aquifer, the main source of drinking water for much of the state.
Through various sources of wastewater discharge, chemicals can reach groundwater and coastal waterways. The water can contain harmful algal blooms called Red Tide or toxic algae blooms. The blooms are caused when there is a high concentration of Karenia Brevis, a microscopic organism that looks like a plant and which eats the nutrients.
A recent report by the state’s task force on harmful algae blooms estimated “total losses of nearly $1 billion in revenue and an additional loss of $178 million in tax revenue in 23 Gulf coast counties” as a result of a prolonged Red Tide that lasted from 2017 to 2019.
The same wastewater source that releases nutrients can also cause contamination of fish.
“We need immediate improvement in infrastructure that we and others are pushing for, not only to remove more nutrients, but also removing these pharmaceutical contaminants,” Adam said.
The Problem is being Targeted
In his first days in office, Gov. Ron DeSantis said he would prioritize Florida’s environment and water quality improvement by funding programs and enabling legislation. His tenure has seen the passage and establishment of the 2020 Clean Waterways Act as well as a program for wastewater grants.
Christina Pushaw, the governor’s spokesperson, said the governor’s environment-related budget recommendations for next fiscal year includes $195 million for targeted water quality improvements.
“Most of this funding will support critical infrastructure and projects to provide advanced wastewater treatment and to upgrade wastewater facilities, Pushaw said. “These investments are crucial to achieve impactful nutrient reduction goals in key water bodies across the state.”
But advocates say that the state’s measures so far have stopped short of requiring private housing developers to invest in better treatment facilities or implementing better regulatory safeguards.
The presence of pharmaceuticals and other chemicals in Florida’s coastal waters compounds the adverse impact on the ecosystem of the excess nutrients that feed the harmful algal blooms. The Environmental Protection Agency says that there is strong evidence that fish and other marine mammals are negatively affected by exposure to a range of synthetic chemicals called endocrine disruptors.
Endocrine disruptors can have an impact on humans and wildlife — including reproduction, development and immune systems, according to the National Institute of Environmental Health Sciences. Endocrine disruption can be caused by a wide range of substances, including pesticides and pharmaceuticals.
Studies have shown that hormone-containing or mimicking pharmaceuticals like birth control pills can cause male fish to develop ovaries.
According to the bonefish contamination research, anti-anxiety drugs such as Valium can cause fish become more active, less social, and take more risks. This makes them more likely to be eaten or prey. According to Florida International researchers, the overall effect is lower survival rates for fish.
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Researchers believe that the effects of pharmaceuticals in water on fish could be permanent because brain chemistry changes occur after exposure. “This is similar to how opioids, like Oxy, affect humans who get addicted to them,” they wrote in their report of the research. According to the researchers, if pharmaceuticals make fish more skittish than usual, they will continue to be so, even if the pharmaceuticals have been removed.
The Centers for Disease Control and Prevention found that 45.8% of Americans had been prescribed drugs in the past 30 days. Central nervous system stimulants were the most prescribed drugs for children aged 12-19 years. Antidepressants were the most prescribed drugs for 20-59-year-olds.
Despite the fact that so many Americans have for decades consumed pharmaceuticals or flushed the drugs down the drain, there are no regulatory controls in place to check their discharge into the environment or to monitor the risk they may pose to ecosystems and human populations.
The Center for Biological Diversity, a Florida-based organization, petitioned the EPA in January 2010 to establish water quality criteria for endocrine disrupting chemical under the Clean Water Act.
The center claimed that the science proved that endocrine disrupting chemical persist in water bodies across the nation, mostly through runoff or treated wastewater discharges. The chemicals, the biological diversity center said, affect “the biological, chemical, and physical integrity of our water, and are having profound effects on the flora and fauna that rely on them.”
The EPA rejected the petition’s September 2011 response.
Jaclyn Lopez, Florida director of the biological diversity center, said the pharmaceuticals are getting into the water “because we are directly discharging our treated wastewater into our surface waters, where we then expect to have fishable, swimmable waters, and in some cases, drinkable waters.” She said that until the EPA establishes water quality criteria for endocrine disrupting chemicals, those activities will remain unregulated.
Calling it an unfortunate situation, Glenn Compton, chairperson of the environmental nonprofit Manasota-88, said the problem of pharmaceutical contamination has been known for about 30 years but that “little to nothing has been done to address the monitoring of pharmaceuticals in our wastewater supply. And that certainly needs to change.”
“I don’t see things getting better in the near future,” Compton said. “We need changes at the state level, with policymakers that truly understand the importance of the water quality in the state of Florida and the necessary things that need to be done.
Source: Inside Climate News