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.
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