[Pharmwaste] Drugs we flush may end up in shark's bloodstreams
Laurie.Tenace at dep.state.fl.us
Wed Jun 20 16:54:00 EDT 2007
Here's some shark research being done in Florida. I don't have a URL.
Sarasota Herald-Tribune, Jun 2, 2007
>From estrogen to Prozac, drugs we flush may end up in shark's bloodstreams
By KATE SPINNER
Surely some people wouldn't mind if bull sharks got an attitude adjustment,
but the aggressive predators might be getting one already.
Scientists recently found traces of prescription antidepressants,
cholesterol-lowering drugs and synthetic estrogens in the blood of young bull
sharks prowling the Caloosahatchee River.
Now, researchers want more blood.
Soaked from rain and armed with needles, scientists with Mote Marine
Laboratory fished for bull sharks Friday as part of a new study that aims to
find out what drugs the sharks encounter most and whether the doses are large
enough to alter how they behave and reproduce.
If enough research shows that drugs are causing problems for fish, steps can
be taken to prevent these new contaminants from getting into waterways.
Scientists believe such drugs in fish are not likely to pose a threat to
people who eat them.
"We don't really have a good sense of how much is in the environment and we
have certainly very little information on what the impacts are," said Jim
Gelsleichter, who is leading the study. He works for Mote Marine's Center for
Shark Research in Sarasota.
Another report last year showed that tiny amounts of Prozac -- a popular
antidepressant -- delayed reproduction in freshwater mussels, but the shark
study is the first to look at the effects of a wide range of pharmaceuticals
on a more advanced sea creature.
If the drugs interfere with the bull sharks' ability to reproduce, it could
eventually devastate the species, which already faces numerous threats from
humans and has been in a steep population decline since the 1970s.
This summer, Gelsleichter plans to draw blood from at least 20 bull sharks
and tag 50 to 100.
His study combines advanced science with the grueling work of long-line
Shivering in the rain, Gelsleichter stood on the rear of the boat while crew
members baited hooks with hunks of mullet. Like an assembly line worker, he
clamped each dangling hook on an anchored long-line.
After an hour and 160 set hooks, the boat turned back and the crew began
pulling up bait. Two hours later, the only thing they had caught were a
couple of catfish.
Then, as the crew pulled up the second-to-last hook, staff scientist
Stephanie Leggett exclaimed, "Shark." It was a year-old female.
The crew inserted a tag underneath the shark's skin, and Gelsleichter used a
syringe to draw a blood sample.
Next week, Gelsleichter will head back to the Caloosahatchee to repeat the
same work, rain or shine.
Bull sharks spend a full year swimming in brackish rivers before they grow
mature enough to venture into deep seas. Their tolerance for fresh water,
which brings them close to humans more frequently than other sharks, and
their territorial behavior has earned them a reputation as one of the world's
most dangerous sharks.
The bull shark's tendency to brave the fringes of human civilization exposes
them to some of the nasty things people flush down toilets.
Some people flush expired or unwanted pills. More importantly, human bodies
are great at getting rid of chemicals. That is why the common drug screen,
which involves a urine test, is so effective.
So the drugs wind up swirling around in sewer water and septic systems. And
while septic systems and sewer plants are good at removing bacteria, they are
not designed to remove the drugs.
The Caloosahatchee is a prime site for research on pharmaceutical pollution
because it receives treated wastewater from several sewer plants and passes
by numerous septic-system dependent communities such as Lehigh Acres.
The drugs identified in the Caloosahatchee include the cholesterol-reducer
Lipitor, various antidepressants such as Prozac and Zoloft, synthetic
estrogens used in birth-control pills, and anti-inflammatory drugs such as
According to Verispan, a pharmaceutical marketing research company, the
fourth-most-prescribed drug in Florida is Lipitor.
A drug like Lipitor could damage a shark's ability to store fat and interfere
Gelsleichter said the drugs are not likely to kill any species outright, but
they have the potential to push an already stressed species, such as the
endangered sawfish, over the edge. Sawfish are related to sharks, and several
live in the Caloosahatchee.
Scientists know virtually nothing about how most pharmaceuticals interact
with creatures of the wild, but a body of research is forming on synthetic
Male flounder in United Kingdom rivers and bass in Maryland's Potomac River
have been growing female parts for years. Scientific evidence shows that the
common thread behind those abnormalities are synthetic estrogens, mainly from
"We've called it the poster child of the pharmaceutical pollution problem,"
Ironically, wastewater treatment plants are at least 96 percent effective at
removing estrogens because they do not dissolve well in water. "There's just
so many users," Gelsleichter said.
In contrast, drugs such as Prozac, Lipitor and Celexa dissolve fast in water
and are easily introduced into the environment.
Sharks are perfect specimens for expanding research to other drugs because
they are large enough to tap for blood without harming them.
To get a sense of the effect of drugs on sharks over time, scientists are
tagging them with discs that absorb chemicals from the environment. By
calculating the amount of chemicals in both the discs and the blood,
scientists will be able to estimate how well the sharks absorb the chemicals
they encounter into their bodies.
The research is important because so little is known about pharmaceuticals in
the environment, said Lisa Beever, director of the Charlotte Harbor National
Estuary Program, an agency helping to fund the study.
"It's a public health concern because we swim in those waters, but it's also
an environmental concern," Beever said.
She pointed out that it is possible to control the amount of drugs in the
And that is a large part of the reason Gelsleichter decided to do the study.
Old pollutants, such as DDT, will remain in the environment forever. New
pollutants can be kept out through better technology, he said.
"I wanted to move to something that was manageable to some extent," he said.
DRUGS IN THE WATER?
How do Prozac and Lipitor wind up in rivers?
When we take medicine, only a small amount gets absorbed into our bodies. The
rest we flush. Septic systems and sewage treatment plants do not do a good
job filtering out pharmaceuticals.
What can these drugs do to me and the environment?
Mote Marine and the University of Florida are studying how drugs in the
Caloosahatchee River affect sharks. Trace amounts of drugs have been shown to
harm reproduction in smaller fish and shellfish. The effect on humans is
unknown but scientists say the leftover drugs are not likely to pose a
Why are bull sharks being studied?
Because bull sharks spend the first year of their lives in brackish rivers,
they get exposed to human pollutants. They also are large enough for
scientists to draw blood without killing them.
How can I help?
Fishermen can help by keeping an eye out for tagged bull sharks. If you see a
tag, remove it completely from the shark, wrap it in aluminum foil or a clean
plastic bag, put it in the freezer and call Mote's Center for Shark Research
at (941) 388-4441, Ext. 576.
Laurie J. Tenace
Florida Department of Environmental Protection
2600 Blair Stone Road, MS 4555
Tallahassee, Florida 32399-2400
PH: (850) 245-8759
FAX: (850) 245-8811
Laurie.Tenace at dep.state.fl.us
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