Reproductive Effects of the Pharmaceutical Fluoxetine on Native Freshwater Mussels

Rebecca M. Heltsley1, W. Cope2, R. Bringolf2, C. Eads3, J. Kucklick1, W. MacCrehan4, Damian Shea2

1National Institute of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Rd., Charleston, SC, USA.  2Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC, USA.  3College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.  4National Institute of Standards and Technology, 100 Bureau Drive, Stop 8392, Gaithersburg, MD, USA.

Recently, widespread occurrence of fluoxetine and other pharmaceuticals and personal care products (PPCPs) has been reported in surface waters of the United States and elsewhere. However, impacts of these environmental PPCPs on aquatic organisms are largely unknown. Fluoxetine is the active ingredient in the prescription anti-depressant drug ProzacTM, which acts as a selective serotonin reuptake inhibitor (SSRI) to increase serotonin levels at nerve synapses. Serotonin has previously been used to induce premature spawning in some bivalves. To determine the potential of fluoxetine to disrupt native freshwater mussel reproduction, gravid (carrying developing larva) adult female eastern elliptio (Elliptio complanata) mussels were exposed to fluoxetine at target concentrations of 0, 0.03, 0.3, 3.0, 30, 300, and 3000 g/L for 96 h in static-renewal tests. Serotonin was used as a positive control and methiothepin, an inhibitor of serotonin pathways, as a confirmatory agent of pathway effects. Time to reproductive glochidia (larval life stage of the freshwater mussel) release, glochidia maturity and viability, and the number of glochidia released (fecundity) were measured. Fluoxetine exposure concentrations were analyzed by liquid chromatography/mass spectroscopy (LC-MS and LC-MS-MS) to confirm exposure concentrations. Time to glochidial release was variable among the fluoxetine treatment groups, but was generally inversely related to exposure concentration. No glochidia were released by mussels in the control group in < 72 h; however, some mussels in each fluoxetine treatment, including low, environmentally relevant concentrations, released glochidia in < 24 hours. The average number of glochidia released was variable, but was generally positively correlated with fluoxetine exposure concentration. Released glochidia were predominantly immature, indicating that fluoxetine induced spawning in gravid mussels which could be potentially devastating to localized mussel populations.  

Contact Information:                                     Mentor: William MacCrehan

Rebecca M. Heltsley                                                    NIST-CSTL 839.02

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Category: Chemistry