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Fluoxetine is a widely used pharmaceutical used to treat depression. The likely environmental sources are from introduction via wastewater effluents, from human excretion. Fluoxetine has been detected in wastewater effluent, surface waters and sediment in Minnesota, and is more commonly found associated with wastewater treatment plants.

Environmental implications of fluoxetine

  • May elicit chronic effects to aquatic life at concentrations detected in surface waters in Minnesota. Because fluoxetine has the potential to bioconcentrate, secondary poisoning to wildlife eating aquatic organisms should be considered.
  • Has the potential to accumulate in sediment. It has been detected in sediment, but no toxicity testing has been done to evaluate effects to sediment-dwelling organisms.
  • Not volatile or persistent in air, so long-range atmospheric transport of this contaminant is not a concern.

Toxic mode of action

Fluoxetine works by inhibiting serotonin reuptake. In some aquatic organisms, serotonin is associated with changes in reproductive processes, and fluoxetine has been shown to affect these processes.

Relevant media for monitoring

Water, sediment, biota

Are there seasonal considerations for monitoring?

No. Fluoxetine is a widely used pharmaceutical, and is likely to be found in wastewater consistently year-round.

Important degradates

Fluoxetine is metabolized in the body to norfluoxetine. This metabolite also inhibits serotonin reuptake, but is less toxic. Norfluoxetine has not been detected in Minnesota.


Because this contaminant is persistent, bioaccumulative and toxic, continued monitoring of fluoxetine is a priority. Monitoring should focus on systems with effluent input, as this is where the concentrations are likely highest.

Fluoxetine may partition out of water and into sediment or biota, due to its physical-chemical properties, so monitoring of sediment and biota would be beneficial.

CAS RN: 54910-89-3

Alternate name(s): Prozac

Primary use(s): Pharmaceutical

Priority: High