Fish in Biscayne Bay unwittingly on cocktails of prescription drugs, researchers say

The average bonefish had 7 different drugs in system, study finds

MIAMI-DADE COUNTY, Fla. – A pair of studies revealed startling information about the prolific presence of pharmaceuticals in water.

Cocktails of drugs have been found in our fish, the same fish that could wind up on your plate.

Nearly 70 percent of Americans take at least one prescription drug.

But for the average bonefish in Biscayne Bay, that number is seven.

“Psychoactive drugs like antidepressants, anti-anxiety medications, we’re talking about heart medications like beta blockers, even medications that are prescribed to manage prostate issues,” said Nick Castillo, a PhD candidate and researcher at FIU Fisheries. “We take a lot of these drugs and our body doesn’t use all of it, and the end of the pipe is always here, Biscayne Bay.”

Castillo is on the team that spent three years studying bonefish and pharmaceuticals.

“We tested 136 bonefish throughout the Caribbean and 93 from Florida,” he said. “Every single fish had at least one, or an average of seven. And it was all the way up to even one fish in Biscayne Bay had 17 different drugs in it.”

The study was sponsored by the Bonefish and Tarpon Trust in 2019 after fishermen noticed some concerning behavior among the fish.

“It was, for lack of a better word, paranoia, skittishness, twitchiness, it was very fearful,” said Bonefish and Tarpon scientist Dr. Ross Boucek.

The organization was founded in 1997, a time when populations were dangerously low.

“We were really concerned about their population in the late 90s, and to the 2010s,” said Castillo. “We saw a dramatic decline in their population.”

Such a loss could be costly to the environment and the economy.

“We’ve done economic studies and the conglomerate of bonefish permit and tarp in Florida Keys and Biscayne Bay generate just under a half a billion dollars a year in economic impact,” said Boucek.

Earlier this month, Local 10 News’ Louis Aguirre joined their team on Biscayne Bay for some bonefishing.

It didn’t take long to reel in some fish so that minimally invasive blood samples could be taken before releasing the fish back into the water.

“I would expect (the blood test results) to affirm what we’ve already found, which is that we’re going to find multiple drugs in these fish,” said Castillo.

In April, FIU concluded a follow-up study, but this time the focus was on redfish on the west coast of Florida.

“They did have fewer pharmaceuticals,” Castillo said. “On average, it was about two to three was the average number of red fish.”

But even with lower numbers, the results still concern researchers.

“They’re taking drugs that they don’t have a prescription for, they have no choice, but they’re being exposed,” said Castillo. “And unfortunately, it changes really important behaviors for survival.”

But what about the fish we eat and the impact this may have on humans? Castillo said you would need to have about 48,000 redfish filets to feel the effects of these pharmaceuticals directly.

“These are really low doses, but it’s a constant exposure,” he said. “So from fish, but your drinking water your produce, there’s so many different routes that were being exposed. And the question is, what happens over your entire lifetime?”

In order to mitigate the the proliferation of pharmaceuticals in our water, Miami-Dade Wastewater Treatment uses a biological unit process known as “activated sludge,” which is proven to break down some drugs, but not all.

“Tylenol is very well removed, but we do find it, which is telling us that there is either untreated water that’s entering our bay or septic systems that are leaching out into the bay,” said Castillo. “We can’t go out and clean and filter and remove it once it’s here. It’s really making sure it’s not introduced with wastewater treatment.”

It is a big problem. The county has over 120,000 septic tanks, many of them failing or at risk of failing due to sea level rise.

Last year, Miami-Dade County broke ground on Connect 2 Protect, a multiyear program to hook up homes and businesses still on septic to sewer lines.

In February, the south Miami-Dade Wastewater Treatment Plant got its first upgrade in 30 years, expanding the plant’s capacity by 16%, allowing it to treat more than 131 million gallons of wastewater per year.

“To me, this is a beauty because it reflects that we are really making sure that we keep water out of the bay where it could harm our wildlife and fresh water,” Miami-Dade Mayor Daniella Levine Cava said at the time.

While the lab results from Aguirre’s fishing trip won’t be known for a few months, there were one big positive takeaway.

“We were excited to see small ones, tiny ones,” Castillo said. “That’s telling us that these fish that have disappeared in the last 20 years now we’re getting an influx every single year of small fish. So that’s telling us something’s happening that’s great.”

Added Boucek: “It shows how resilient our fisheries can be in our ecosystems can be. When I say resilient, it’s also worrisome how far can we push the ecosystem before they collapse. But in the short term, we have fish again. And that’s optimism.”

Bonefish and Tarpon Trust has used the data from both studies to support the need for an innovative wastewater technology grant program. That legislation was funded this year at $2.5 million.

It’s also important to never ever flush your medications.

There are sites all across South Florida where people can safely dispose of old or unused prescriptions. To find a drop-off location near you, click here.

About the Authors:

Louis Aguirre is an Emmy-award winning journalist who anchors weekday newscasts and serves as WPLG Local 10’s Environmental Advocate.