[Pharmwaste] Study: Prozac In Rivers, Streams Endangering Freshwater Mussels

[DeBiasi,Deborah]

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Study: Prozac In Rivers, Streams Endangering Freshwater Mussels


A new laboratory study suggests that exposure to Prozac can disrupt the
reproductive cycle of freshwater mussels, potentially increasing their
risk of extinction.

The study, one of the first to examine the ecotoxicological effects of
Prozac (fluoxetine) on native freshwater mussels, found that the drug
caused females to prematurely release their larvae, essentially dooming
them. The findings were presented on Sept. 11 at the 232nd national
meeting of the American Chemical Society.

"The results from this study were quite alarming," said co-investigator
Rebecca Heltsley, a National Research Council Post-Doctoral Fellow at
the National Institute of Standards and Technology, Hollings Marine
Laboratory in Charleston, S.C. "When larvae are released too early, they
are not viable, which only contributes to the problems faced by
struggling populations of native freshwater mussels."

About 70 percent of the nearly 300 species of freshwater mussels native
to North America are extinct, endangered or declining, according to
Heltsley. In the past 100 years, no other widespread North American
animal group has experienced such notable collapse, she added.

In some cases, native mussels have been crowded out by invasive species
such as the zebra mussel, Heltsley said. In others, native mussels have
been devastated by increased sediment loads in rivers, habitat
alteration and loss, or killed off by pollutants.

"The presence of Prozac and similar drugs in U.S. rivers and streams has
likely compounded the problem," Heltsley said. "It's a big concern
because freshwater mussels are such an imperiled group."

Prozac, one of the nation's most prescribed anti-depressant medications,
helps relieve depression by increasing the brain's supply of a
neurotransmitter called serotonin. But like many prescription drugs,
some remnants of Prozac ultimately are mixed into wastewater that
reaches rivers and streams, Heltsley said. Recently, University of
Georgia researchers who found traces of Prozac in fish and frogs
concluded the drug slowed the development of these animals.

In their study, Heltsley, along with lead investigator Gregory Cope of
North Carolina State University and other colleagues, placed female
freshwater mussels carrying larvae into tanks containing laboratory
water with varying concentrations of fluoxetine, the active ingredient
in Prozac. The Prozac concentrations, which ranged from 0.3 to 3,000
micrograms per liter, mimicked those previously found in surface waters
of lakes and streams. They also exposed a similar set of mussels
directly to serotonin. Within 48 hours, the mussels in both groups had
released their larvae prematurely.

"Protecting freshwater mussels and other aquatic life that are
susceptible to the unintended consequences of exposure to
pharmaceuticals in our rivers and streams will take a concentrated
effort," Heltsley said. "These efforts could include the development of
more efficient wastewater treatment facilities that can filter out these
products before they reach our waterways."

Freshwater mussels have a key role in the ecology of rivers and streams,
Heltsley emphasized. They filter large volumes of water for food each
day, thereby helping filter contaminants and excessive nutrients from
water and serving as an early warning of water quality problems. They
also are an important source of food for muskrats, otters, fish and
other animals.

Heltsley and her colleagues are evaluating surface water and sediment
samples from a natural water system and will compare the results of this
work with the results of their laboratory based study.

Rebecca Heltsley: http://www.hml.noaa.gov/general/directory.html (scroll
down for contact information)




Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
Mail:          P.O. Box 10009, Richmond, VA  23240-0009 
Location:  629 E. Main Street, Richmond, VA  23219
PH:         804-698-4028
FAX:      804-698-4032