The Environmental Occurrence, Fate, and Ecotoxicity of Selective Serotonin Reuptake Inhibitors (SSRIs) in Aquatic Environments

EPA Grant Number: R829006
Title: The Environmental Occurrence, Fate, and Ecotoxicity of Selective Serotonin Reuptake Inhibitors (SSRIs) in Aquatic Environments
Investigators: Black, Marsha C. , Armbrust, Kevin L.
Institution: University of Georgia
EPA Project Officer: Page, Angela
Project Period: September 1, 2001 through August 31, 2004 (Extended to April 30, 2007)
Project Amount: $522,892
RFA: Drinking Water (2000) RFA Text |  Recipients Lists
Research Category: Drinking Water , Water Quality , Water


Selective Serotonin Reuptake Inhibitors (SSRIs) are among the most heavily prescribed drugs in the U.S. and have been shown to induce spawning in mussels at trace aqueous concentrations. The working hypothesis of this project is that due to their heavy usage, SSRIs are potentially present in wastewater treatment effluent released into water bodies and drinking water sources and that the persistence of them or their degradation products may cause adverse impacts on aquatic organisms, especially with respect to reproductive success.

The primary objectives of this investigation are to: (1) determine the environmental fate of Prozac (fluoxetine), Luvox (fluvoxamine), Paxil (paroxetine), Zoloft (sertraline) and Celexa (citalopram) in laboratory studies similar to those used for pesticide registration; (2) determine their occurrence in raw wastewater, treated effluent, and downstream receiving waters; (3) determine the acute and chronic toxicity of the five SSRIs and their major environmental metabolites to Ceriodaphnia dubia; and (4) determine the reproductive effects of chronic SSRI exposure to the mosquitofish, Gambusia holbrooki.


For each SSRI, laboratory environmental fate measurements will include the following: aqueous solubility; octanol-water partition coefficient (Kow); acid dissociation constant (pKa); soil adsorption coefficient (Koc); hydrolysis and aqueous direct photolysis rates at pH 5,7and 9; indirect photolysis rates including the hydroxyl radical rate constant; irradiated and dark aerobic-aquatic metabolism; and ready biodegradability. Major degradation products will be identified wherever possible. The occurrence of each SSRI and major metabolites/degradation products will be measured over one year in raw and treated wastewater, and receiving water at sub-ppb levels. Potential loads to waste treatment facilities will be assessed through surveys of numbers of prescriptions filled by local pharmacies. Acute toxicity and chronic exposure tests for survival and reproduction will be conducted with Ceriodaphnia following EPA protocols on each SSRI as well as on raw sewage water and treated effluent. Toxicity identification evaluation (TIE) methods will be used to determine if SSRIs are responsible for observed toxicity in any sample. Additionally, the mosquito fish, Gambusia, will be chronically exposed to SSRIs in outdoor microcosms to assess their impacts on the fish's spawning, potential and real fecundity, gonadal somatic index and brood clutch size.

Expected Results:

The ultimate benefit of this research will be to provide extensive environmental fate, ecotoxicological, and occurrence information on a class of chemicals for which little data is published in the literature but that have the potential to be present in water bodies, including drinking water sources receiving treated wastewater effluent. This information should allow environmental risk assessments to be conducted for these compounds and could be a model by which pharmaceutical manufacturers could begin to assess their products as they are commercialized. This work may also indicate that these compounds will degrade quickly in the environment and be of no cause for concern or it may indicate that most pharmaceuticals should be tested for environmental and ecological safety with the same rigor as pesticides.

Publications and Presentations:

Publications have been submitted on this project: View all 44 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 9 journal articles for this project

Supplemental Keywords:

pharmaceuticals, aquatic persistence, reproductive toxicity., RFA, Scientific Discipline, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Aquatic Ecosystems & Estuarine Research, Environmental Chemistry, Chemistry, Aquatic Ecosystem, Fate & Transport, Environmental Microbiology, Biochemistry, Ecology and Ecosystems, Drinking Water, fate and transport, ceriodaphnia dubia, pharmaceuticals, aquatic organisms, other - risk assessment, selective serotonin reuptake inhibitors (SSRIs), impact of pharmaceuticals, aquatic persistence, aquatic ecosystems, gambusia holbrooki

Progress and Final Reports:

  • 2002 Progress Report
  • 2003 Progress Report
  • 2004 Progress Report
  • 2005 Progress Report
  • 2006 Progress Report
  • Final Report