Prozac Contamination in Water Threatens Ecosystem Survival

Recent research suggests that water contamination with the antidepressant Prozac (fluoxetine) may disrupt the body condition and behavior of guppies. (Alice Chaos)

POLLUTION of waterways with the antidepressant Prozac disrupts the bodies and behavior of fish in ways that could threaten their long-term survival, new research finds.

As global consumption of pharmaceuticals increases, residues from these drugs are entering rivers and streams via wastewater, raising concerns about their impact on ecosystems and wildlife.

Research published in the journal Animal Ecology found that low concentrations of fluoxetine, an antidepressant commonly known as Prozac, reduced the body condition and sperm vitality of male guppies over several generations.

Monash University’s Dr Upama Aich, who was the study’s lead author, said thousands of chemicals “are dumped into our waterways every day.” The researchers chose to study fluoxetine because it is “quite common.”

Aich said the changes observed in guppies due to low concentrations of the drug should be taken as a warning about their ability “to live, survive and thrive in a polluted environment.”

Researchers caught 3,600 wild guppies and randomly placed them in tanks equipped with gravel and aquatic plants.

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Over five years, they fed tanks with varying doses of fluoxetine — zero, low (31.5 nanograms per liter) and high (316 ng/L), matching levels found in the natural environment. The researchers then studied its effects on the behavior, body and reproductive characteristics of the male fish over several generations.

Aich said low exposure decreased the overall body condition of male fish, “which is very important, not only for mating, but also for fighting with other males, and their overall survival.” Low-dose exposure also decreased sperm velocity but increased the length of the gonopodium, a fin-like organ used to fertilize females.

He also said exposure to the drug reduced activity variation and risk-taking behavior, which could affect the guppies’ ability to respond to changes in the wild.

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Dr Minna Saaristo, principal scientist for ecological risks and emerging contaminants at Environment Protection Authority Victoria, said the drugs were designed to work at low doses, which could explain why there were more profound effects at lower concentrations.

Saaristo led an EPA study that found 18 common pharmaceuticals in four rivers and streams in Victoria, including upstream and downstream of wastewater treatment plants. The sampling detected common antidepressants, blood pressure medications, heart and epilepsy drugs, caffeine and antibiotics. “It’s a complex mix that we have to deal with,” Saaristo said.

The EPA also tested for the presence of drugs in commonly caught fish. The highest concentrations were found in antidepressants, including venlafaxine (150 micrograms per kilogram) in red perch and sertraline (100 μg/kg) in eel. Saaristo said there was no significant risk to human health but regulators were monitoring the situation.

He said people should not flush medicines down the toilet. Instead, they should return unwanted and expired medicines to the pharmacy.

“It will be a great help to the fish that swim in our waterways.” (The Guardian/Z-3)